perfaware/part3: Complete 61 Page faults (aggregate faults in each test)

build.bat

@@ -1,6 +1,6 @@
 @echo off
 
-REM Setup ==========================================================================================
+REM Setup //////////////////////////////////////////////////////////////////////////////////////////
 set script_dir_backslash=%~dp0
 set script_dir=%script_dir_backslash:~0,-1%
 set build_dir=%script_dir%\Build
@@ -12,15 +12,19 @@ if not exist %part1_build_dir% mkdir %part1_build_dir%
 set part2_dir=%script_dir%\part2
 set part2_build_dir=%build_dir%\part2
 if not exist %part2_build_dir% mkdir %part2_build_dir%
-goto :part2
 
-REM Part 1 =========================================================================================
-REM Build ==========================================================================================
+set part3_dir=%script_dir%\part3
+set part3_build_dir=%build_dir%\part3
+if not exist %part3_build_dir% mkdir %part3_build_dir%
+goto :part3
+
+REM Part 1 /////////////////////////////////////////////////////////////////////////////////////////
+REM Build //////////////////////////////////////////////////////////////////////////////////////////
 pushd %part1_build_dir%
 cl %part1_dir%\sim8086.c /W4 /WX /Z7 /nologo || exit /b 1
 popd
 
-REM Tests ==========================================================================================
+REM Tests //////////////////////////////////////////////////////////////////////////////////////////
 set listing_0037=listing_0037_single_register_mov
 set part1_build_dir_listing_0037=%part1_build_dir%\%listing_0037%
 
@@ -30,7 +34,7 @@ copy /Y %part1_dir%\%listing_0037% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0037%_disassembled.asm
 fc /B %part1_build_dir_listing_0037% %part1_build_dir_listing_0037%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0038=listing_0038_many_register_mov
 set part1_build_dir_listing_0038=%part1_build_dir%\%listing_0038%
 
@@ -40,7 +44,7 @@ copy /Y %part1_dir%\%listing_0038% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0038%_disassembled.asm
 fc /B %part1_build_dir_listing_0038% %part1_build_dir_listing_0038%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0039=listing_0039_more_movs
 set part1_build_dir_listing_0039=%part1_build_dir%\%listing_0039%
 
@@ -50,7 +54,7 @@ copy /Y %part1_dir%\%listing_0039% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0039%_disassembled.asm
 fc /B %part1_build_dir_listing_0039% %part1_build_dir_listing_0039%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0040=listing_0040_challenge_movs
 set part1_build_dir_listing_0040=%part1_build_dir%\%listing_0040%
 
@@ -60,7 +64,7 @@ copy /Y %part1_dir%\%listing_0040% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0040%_disassembled.asm
 fc /B %part1_build_dir_listing_0040% %part1_build_dir_listing_0040%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0041=listing_0041_add_sub_cmp_jnz
 set part1_build_dir_listing_0041=%part1_build_dir%\%listing_0041%
 
@@ -70,7 +74,7 @@ copy /Y %part1_dir%\%listing_0041% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0041%_disassembled.asm
 fc /B %part1_build_dir_listing_0041% %part1_build_dir_listing_0041%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0042=listing_0042_completionist_decode
 set part1_build_dir_listing_0042=%part1_build_dir%\%listing_0042%
 
@@ -80,7 +84,7 @@ copy /Y %part1_dir%\%listing_0042% %part1_build_dir% 1>NUL
 nasm %part1_build_dir_listing_0042%_disassembled.asm
 fc /B %part1_build_dir_listing_0042% %part1_build_dir_listing_0042%_disassembled || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0043=listing_0043_immediate_movs
 set part1_build_dir_listing_0043=%part1_build_dir%\%listing_0043%
 
@@ -95,7 +99,7 @@ nasm %part1_build_dir_listing_0043%_disassembled.asm
 fc /B %part1_build_dir_listing_0043%     %part1_build_dir_listing_0043%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0043%.txt %part1_build_dir_listing_0043%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0044=listing_0044_register_movs
 set part1_build_dir_listing_0044=%part1_build_dir%\%listing_0044%
 
@@ -110,7 +114,7 @@ nasm %part1_build_dir_listing_0044%_disassembled.asm
 fc /B %part1_build_dir_listing_0044%     %part1_build_dir_listing_0044%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0044%.txt %part1_build_dir_listing_0044%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0045=listing_0045_challenge_register_movs
 set part1_build_dir_listing_0045=%part1_build_dir%\%listing_0045%
 
@@ -125,7 +129,7 @@ nasm %part1_build_dir_listing_0045%_disassembled.asm
 fc /B %part1_build_dir_listing_0045%     %part1_build_dir_listing_0045%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0045%.txt %part1_build_dir_listing_0045%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0046=listing_0046_add_sub_cmp
 set part1_build_dir_listing_0046=%part1_build_dir%\%listing_0046%
 
@@ -140,7 +144,7 @@ nasm %part1_build_dir_listing_0046%_disassembled.asm
 fc /B %part1_build_dir_listing_0046%     %part1_build_dir_listing_0046%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0046%.txt %part1_build_dir_listing_0046%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0047=listing_0047_challenge_flags
 set part1_build_dir_listing_0047=%part1_build_dir%\%listing_0047%
 
@@ -155,7 +159,7 @@ nasm %part1_build_dir_listing_0047%_disassembled.asm
 fc /B %part1_build_dir_listing_0047%     %part1_build_dir_listing_0047%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0047%.txt %part1_build_dir_listing_0047%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0048=listing_0048_ip_register
 set part1_build_dir_listing_0048=%part1_build_dir%\%listing_0048%
 
@@ -170,7 +174,7 @@ nasm %part1_build_dir_listing_0048%_disassembled.asm
 fc /B %part1_build_dir_listing_0048%     %part1_build_dir_listing_0048%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0048%.txt %part1_build_dir_listing_0048%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0049=listing_0049_conditional_jumps
 set part1_build_dir_listing_0049=%part1_build_dir%\%listing_0049%
 
@@ -185,7 +189,7 @@ nasm %part1_build_dir_listing_0049%_disassembled.asm
 fc /B %part1_build_dir_listing_0049%     %part1_build_dir_listing_0049%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0049%.txt %part1_build_dir_listing_0049%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0050=listing_0050_challenge_jumps
 set part1_build_dir_listing_0050=%part1_build_dir%\%listing_0050%
 
@@ -200,7 +204,7 @@ nasm %part1_build_dir_listing_0050%_disassembled.asm
 fc /B %part1_build_dir_listing_0050%     %part1_build_dir_listing_0050%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0050%.txt %part1_build_dir_listing_0050%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0051=listing_0051_memory_mov
 set part1_build_dir_listing_0051=%part1_build_dir%\%listing_0051%
 
@@ -215,7 +219,7 @@ nasm %part1_build_dir_listing_0051%_disassembled.asm
 fc /B %part1_build_dir_listing_0051%     %part1_build_dir_listing_0051%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0051%.txt %part1_build_dir_listing_0051%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0052=listing_0052_memory_add_loop
 set part1_build_dir_listing_0052=%part1_build_dir%\%listing_0052%
 
@@ -230,7 +234,7 @@ nasm %part1_build_dir_listing_0052%_disassembled.asm
 fc /B %part1_build_dir_listing_0052%     %part1_build_dir_listing_0052%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0052%.txt %part1_build_dir_listing_0052%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0053=listing_0053_add_loop_challenge
 set part1_build_dir_listing_0053=%part1_build_dir%\%listing_0053%
 
@@ -245,7 +249,7 @@ nasm %part1_build_dir_listing_0053%_disassembled.asm
 fc /B %part1_build_dir_listing_0053%     %part1_build_dir_listing_0053%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0053%.txt %part1_build_dir_listing_0053%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0054=listing_0054_draw_rectangle
 set part1_build_dir_listing_0054=%part1_build_dir%\%listing_0054%
 
@@ -262,7 +266,7 @@ nasm %part1_build_dir_listing_0054%_disassembled.asm
 fc /B %part1_build_dir_listing_0054%     %part1_build_dir_listing_0054%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0054%.txt %part1_build_dir_listing_0054%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0055=listing_0055_challenge_rectangle
 set part1_build_dir_listing_0055=%part1_build_dir%\%listing_0055%
 
@@ -279,7 +283,7 @@ nasm %part1_build_dir_listing_0055%_disassembled.asm
 fc /B %part1_build_dir_listing_0055%     %part1_build_dir_listing_0055%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0055%.txt %part1_build_dir_listing_0055%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0056=listing_0056_estimating_cycles
 set part1_build_dir_listing_0056=%part1_build_dir%\%listing_0056%
 
@@ -297,7 +301,7 @@ nasm %part1_build_dir_listing_0056%_disassembled.asm
 fc /B %part1_build_dir_listing_0056%     %part1_build_dir_listing_0056%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0056%.txt %part1_build_dir_listing_0056%_disassembled.txt || exit /b 1
 
-REM ================================================================================================
+REM ////////////////////////////////////////////////////////////////////////////////////////////////
 set listing_0057=listing_0057_challenge_cycles
 set part1_build_dir_listing_0057=%part1_build_dir%\%listing_0057%
 
@@ -315,8 +319,8 @@ nasm %part1_build_dir_listing_0057%_disassembled.asm
 fc /B %part1_build_dir_listing_0057%     %part1_build_dir_listing_0057%_disassembled     || exit /b 1
 fc /N %part1_build_dir_listing_0057%.txt %part1_build_dir_listing_0057%_disassembled.txt || exit /b 1
 
-REM Part 2 =========================================================================================
-REM Build ==========================================================================================
+REM Part 2 /////////////////////////////////////////////////////////////////////////////////////////
+REM Build //////////////////////////////////////////////////////////////////////////////////////////
 :part2
 pushd %part2_build_dir%
 cl %part2_dir%\haversine_generator.c /W4 /WX /Z7 /nologo     /Fe:haversine_generator_debug || exit /b 1
@@ -335,3 +339,12 @@ cl %part2_dir%\listing_0071_os_timer_main.cpp /W4 /WX /Z7 /O2 /nologo /Fe:listin
 cl %part2_dir%\listing_0072_cpu_timer_main.cpp /W4 /WX /Z7 /O2 /nologo /Fe:listing_0072_cpu_timer_main_release || exit /b 1
 cl %part2_dir%\listing_0073_cpu_timer_guessfreq_main.cpp /W4 /WX /Z7 /O2 /nologo /Fe:listing_0073_cpu_timer_guessfreq_release || exit /b 1
 popd
+
+REM Part 3 /////////////////////////////////////////////////////////////////////////////////////////
+REM Build //////////////////////////////////////////////////////////////////////////////////////////
+:part3
+pushd %part3_build_dir%
+cl %part3_dir%\repetition_tester.c /W4 /WX /Z7 /nologo     /Fe:repetition_tester_debug   || exit /b 1
+cl %part3_dir%\repetition_tester.c /W4 /WX /Z7 /nologo /O2 /Fe:repetition_tester_release || exit /b 1
+popd
+

part1/sim8086.c

@@ -382,8 +382,7 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
     size_t op_code_size           = 0;
     op_code_bytes[op_code_size++] = S86_BufferIteratorNextByte(buffer_it);
 
-    // NOTE: Match the assembly bytes to the desired instruction
-    // =====================================================================
+    // NOTE: Match the assembly bytes to the desired instruction ///////////////////////////////////
     S86_OpDecodeType    op_decode_type = S86_OpDecodeType_Count;
     S86_OpDecode const *op_decode      = NULL;
     for (size_t op_index = 0;
@@ -392,13 +391,11 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
     {
         S86_OpDecode const *item = decode_table + op_index;
 
-        // NOTE: Check first instruction byte
-        // =================================================================
+        // NOTE: Check first instruction byte //////////////////////////////////////////////////////
         if ((op_code_bytes[0] & item->op_mask0) != item->op_bits0)
             continue;
 
-        // NOTE Check multi-byte instruction
-        // =================================================================
+        // NOTE Check multi-byte instruction ///////////////////////////////////////////////////////
         // If the matched instruction has a bit mask for the 2nd byte, this
         // is a multi-byte instruction. Check if the 2nd byte checks out.
         bool op_match = true;
@@ -418,8 +415,7 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
         }
     }
 
-    // NOTE: Disassemble bytes to assembly mnemonics
-    // =================================================================
+    // NOTE: Disassemble bytes to assembly mnemonics ///////////////////////////////////////////////
     S86_ASSERT(op_code_size > 0 && op_code_size <= S86_ARRAY_UCOUNT(op_code_bytes));
     S86_ASSERT(op_decode_type != S86_OpDecodeType_Count && "Unknown instruction");
 
@@ -677,8 +673,7 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
         case S86_OpDecodeType_ORImmediateToAccum:    /*FALLTHRU*/
         case S86_OpDecodeType_XORImmediateToAccum:   /*FALLTHRU*/
         case S86_OpDecodeType_MOVImmediateToReg: {
-            // NOTE: Parse opcode control bits
-            // =============================================================
+            // NOTE: Parse opcode control bits /////////////////////////////////////////////////////
             S86_ASSERT(op_code_size == 1);
             uint8_t w   = 0;
             if (op_decode_type == S86_OpDecodeType_ADDImmediateToAccum ||
@@ -695,16 +690,14 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
                 w = (op_code_bytes[0] & 0b0000'1000) >> 3;
             }
 
-            // NOTE: Parse data payload
-            // =============================================================
+            // NOTE: Parse data payload ////////////////////////////////////////////////////////////
             uint16_t data = S86_BufferIteratorNextByte(buffer_it);
             if (w) { // 16 bit data
                 uint8_t data_hi = S86_BufferIteratorNextByte(buffer_it);
                 data |= (uint16_t)(data_hi) << 8;
             }
 
-            // NOTE: Disassemble
-            // =============================================================
+            // NOTE: Disassemble ///////////////////////////////////////////////////////////////////
             result.effective_addr = S86_EffectiveAddress_Dest;
             result.src            = S86_MnemonicOp_Immediate;
             result.wide           = w;
@@ -893,8 +886,7 @@ char const CLI_ARG_DUMP[]                = "--dump";
 
 int main(int argc, char **argv)
 {
-    // NOTE: Argument handling
-    // =========================================================================
+    // NOTE: Argument handling /////////////////////////////////////////////////////////////////////
     if (argc < 2) {
         PRINT_USAGE;
         return -1;
@@ -965,8 +957,7 @@ int main(int argc, char **argv)
         return -1;
     }
 
-    // NOTE: Sim8086
-    // =========================================================================
+    // NOTE: Sim8086 ///////////////////////////////////////////////////////////////////////////////
     S86_OpDecode const DECODE_TABLE[] = {
         [S86_OpDecodeType_MOVRegOrMemToOrFromReg]       = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
                                                            .op_bits0 = 0b1000'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
@@ -1257,8 +1248,7 @@ int main(int argc, char **argv)
                                                            .op_bits0 = 0b0010'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SEGMENT},
     };
 
-    // NOTE: Decode assembly
-    // =========================================================================
+    // NOTE: Decode assembly ///////////////////////////////////////////////////////////////////////
     if (exec_mode) {
         if (log_cycle_counts != CycleCount_None) { // NOTE: Print disclaimer + header
             S86_PrintLn(S86_STR8("**************"));
@@ -1337,7 +1327,7 @@ int main(int argc, char **argv)
             continue;
         }
 
-        // NOTE: Simulate instruction ==============================================================
+        // NOTE: Simulate instruction //////////////////////////////////////////////////////////////
         bool cycle_count_8088             = log_cycle_counts == CycleCount_8088;
         uint32_t base_clocks              = 0;
         uint32_t effective_address_clocks = 0;
@@ -1800,7 +1790,7 @@ int main(int argc, char **argv)
 
         clocks_counter += base_clocks + effective_address_clocks + transfer_penalty_clocks;
 
-        // NOTE: Printing ==========================================================================
+        // NOTE: Printing //////////////////////////////////////////////////////////////////////////
         S86_PrintFmt(" ; ");
 
         // NOTE: Clocks

part1/sim8086.h

@@ -1,5 +1,4 @@
-// NOTE: Sim8086
-// ============================================================================
+// NOTE: Sim8086 ///////////////////////////////////////////////////////////////////////////////////
 typedef enum S86_OpDecodeType {
     S86_OpDecodeType_MOVRegOrMemToOrFromReg,
     S86_OpDecodeType_MOVImmediateToRegOrMem,

part2/haversine_generator.c

@@ -13,8 +13,7 @@
 #define PRINT_USAGE HAV_PrintLnFmt("Usage: %s [uniform/cluster] [random seed] [number of coordinate pairs to generate]", argv[0])
 int main(int argc, char **argv)
 {
-    // NOTE: Unit Tests
-    // =========================================================================
+    // NOTE: Unit Tests ////////////////////////////////////////////////////////////////////////////
     {
         {
             HAV_Str8ToU64Result result = HAV_Str8_ToU64(HAV_STR8("00"));
@@ -44,8 +43,7 @@ int main(int argc, char **argv)
         }
     }
 
-    // NOTE: Arg Parsing
-    // =========================================================================
+    // NOTE: Arg Parsing ///////////////////////////////////////////////////////////////////////////
     if (argc != 4) {
         PRINT_USAGE;
         return -1;
@@ -95,8 +93,7 @@ int main(int argc, char **argv)
         return -1;
     }
 
-    // NOTE: Generator
-    // =========================================================================
+    // NOTE: Generator /////////////////////////////////////////////////////////////////////////////
     uint64_t point_count = number_of_coordinate_pairs_to_generate_u64_result.value;
     uint64_t random_seed = random_seed_u64_result.value;
     uint64_t rng_state   = random_seed;

part2/haversine_stdlib.c

@@ -1,5 +1,4 @@
-// NOTE: Implementation
-// ============================================================================
+// NOTE: Implementation ////////////////////////////////////////////////////////////////////////////
 bool HAV_Str8_Equals(HAV_Str8 lhs, HAV_Str8 rhs)
 {
     bool result = lhs.size == rhs.size && memcmp(lhs.data, rhs.data, lhs.size) == 0;
@@ -181,14 +180,12 @@ HAV_Buffer HAV_FileRead(char const *file_path)
 {
     HAV_Buffer result = {0};
 
-    // NOTE: Determine file size
-    // =========================================================================
+    // NOTE: Determine file size ///////////////////////////////////////////////////////////////////
     WIN32_FILE_ATTRIBUTE_DATA file_attrib_data = {0};
     if (GetFileAttributesEx(file_path, GetFileExInfoStandard, &file_attrib_data) == 0)
         return result;
 
-    // NOTE: Open file
-    // =========================================================================
+    // NOTE: Open file /////////////////////////////////////////////////////////////////////////////
     HANDLE file_handle = CreateFile(
       /*LPCSTR                lpFileName*/ file_path,
       /*DWORD                 dwDesiredAccess*/ GENERIC_READ,
@@ -202,8 +199,7 @@ HAV_Buffer HAV_FileRead(char const *file_path)
     if (file_handle == INVALID_HANDLE_VALUE)
         return result;
 
-    // NOTE: Allocate buffer
-    // =========================================================================
+    // NOTE: Allocate buffer ///////////////////////////////////////////////////////////////////////
     uint64_t file_size = (uint64_t)file_attrib_data.nFileSizeHigh << 32 | (uint64_t)file_attrib_data.nFileSizeLow << 0;
     HAV_ASSERT(file_size < (DWORD)-1);
     char *buffer = VirtualAlloc(
@@ -216,8 +212,7 @@ HAV_Buffer HAV_FileRead(char const *file_path)
     if (!buffer)
         goto end;
 
-    // NOTE: Read file to buffer
-    // =========================================================================
+    // NOTE: Read file to buffer ///////////////////////////////////////////////////////////////////
     DWORD bytes_read = 0;
     HAV_ProfilerZone prof_file_read_zone = HAV_Profiler_BeginZoneBandwidth("File Read", file_size);
     BOOL read_file_result = ReadFile(
@@ -229,8 +224,7 @@ HAV_Buffer HAV_FileRead(char const *file_path)
     );
     HAV_Profiler_EndZone(prof_file_read_zone);
 
-    // NOTE: Handle read result
-    // =========================================================================
+    // NOTE: Handle read result ////////////////////////////////////////////////////////////////////
     if (read_file_result == 0) {
         VirtualFree(buffer, 0, MEM_RELEASE);
     } else {
@@ -253,8 +247,7 @@ bool HAV_FileWrite(char const *file_path, void const *buffer, size_t buffer_size
 {
     bool result = false;
 
-    // NOTE: Open file
-    // =========================================================================
+    // NOTE: Open file /////////////////////////////////////////////////////////////////////////////
     HANDLE file_handle = CreateFile(
       /*LPCSTR                lpFileName*/ file_path,
       /*DWORD                 dwDesiredAccess*/ GENERIC_WRITE,
@@ -268,8 +261,7 @@ bool HAV_FileWrite(char const *file_path, void const *buffer, size_t buffer_size
     if (file_handle == INVALID_HANDLE_VALUE)
         return result;
 
-    // NOTE: Write file to disk
-    // =========================================================================
+    // NOTE: Write file to disk ////////////////////////////////////////////////////////////////////
     DWORD bytes_written = 0;
     BOOL write_file_result = WriteFile(
       /*HANDLE       hFile*/ file_handle,

part2/haversine_stdlib.h

@@ -1,7 +1,6 @@
 #include <stdint.h>
 
-// NOTE: Macros
-// ============================================================================
+// NOTE: Macros ////////////////////////////////////////////////////////////////////////////////////
 #define HAV_STRINGIFY2(token) #token
 #define HAV_STRINGIFY(token) HAV_STRINGIFY2(token)
 
@@ -24,8 +23,7 @@ typedef float f32;
 typedef double f64;
 typedef uint64_t u64;
 
-// NOTE: Globals
-// ============================================================================
+// NOTE: Globals ///////////////////////////////////////////////////////////////////////////////////
 typedef struct HAV_Globals {
     HANDLE stdout_handle;
     bool   write_to_console;
@@ -33,8 +31,7 @@ typedef struct HAV_Globals {
 
 HAV_Globals pap_globals;
 
-// NOTE: Strings
-// ============================================================================
+// NOTE: Strings ///////////////////////////////////////////////////////////////////////////////////
 typedef struct HAV_Str8 {
     char *data;
     size_t size;
@@ -60,8 +57,7 @@ HAV_Str8BinarySplitResult HAV_Str8_BinarySplit(HAV_Str8 buffer, HAV_Str8 find);
 bool                      HAV_CharIsWhiteSpace(char ch);
 bool                      HAV_CharIsDigit(char ch);
 
-// NOTE: Profiler
-// ============================================================================
+// NOTE: Profiler //////////////////////////////////////////////////////////////////////////////////
 typedef struct HAV_ProfilerAnchor {
     HAV_Str8 label;
     u64      elapsed_tsc_exclusive; // Does not include children
@@ -91,12 +87,11 @@ static HAV_Profiler g_profiler;
 #define HAV_Profiler_BeginZone(label) HAV_Profiler_BeginZone_(HAV_STR8(label), __COUNTER__ + 1, 0)
 #define HAV_Profiler_BeginZoneBandwidth(label, byte_count) HAV_Profiler_BeginZone_(HAV_STR8(label), __COUNTER__ + 1, byte_count)
 
-static void HAV_Profiler_Dump();
+static void             HAV_Profiler_Dump      ();
 static HAV_ProfilerZone HAV_Profiler_BeginZone_(HAV_Str8 label, uint32_t index, u64 byte_count);
-static void HAV_Profiler_EndZone(HAV_ProfilerZone zone);
+static void             HAV_Profiler_EndZone   (HAV_ProfilerZone zone);
 
-// NOTE: PCG32
-// ============================================================================
+// NOTE: PCG32 /////////////////////////////////////////////////////////////////////////////////////
 // NOTE: PCG RNG from Demetri Spanos: https://github.com/demetri/scribbles
 // pcg32_pie, based on the minimal C version from O'Neill at pcg-random.org;
 // I've made a few (subjective) UX improvements for beginner use
@@ -119,8 +114,7 @@ static void HAV_Profiler_EndZone(HAV_ProfilerZone zone);
 uint32_t HAV_PCG32_Pie   (uint64_t *state);
 f64      HAV_PCG32_PieF64(uint64_t *state, f64 min, f64 max);
 
-// NOTE: Buffer
-// ============================================================================
+// NOTE: Buffer ////////////////////////////////////////////////////////////////////////////////////
 typedef struct HAV_Buffer {
     char *data;
     size_t size;
@@ -136,14 +130,12 @@ HAV_BufferIterator HAV_BufferIteratorInit        (HAV_Buffer buffer);
 bool               HAV_BufferIteratorHasMoreBytes(HAV_BufferIterator it);
 uint8_t            HAV_BufferIteratorNextByte    (HAV_BufferIterator *it);
 
-// NOTE: File
-// ============================================================================
+// NOTE: File //////////////////////////////////////////////////////////////////////////////////////
 HAV_Buffer HAV_FileRead (char const *file_path);
 void       HAV_FileFree (HAV_Buffer buffer);
 bool       HAV_FileWrite(char const *file_path, void const *buffer, size_t buffer_size);
 
-// NOTE: Print
-// ============================================================================
+// NOTE: Print /////////////////////////////////////////////////////////////////////////////////////
 void HAV_PrintHandle(void *handle, HAV_Str8 string);
 void HAV_PrintLn    (HAV_Str8 string);
 void HAV_PrintLnFmt (char const *fmt, ...);

part2/listing_0089_allfuncs_lookup_json_parser.cpp

@@ -0,0 +1,537 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 89
+   ======================================================================== */
+
+enum json_token_type
+{
+    Token_end_of_stream,
+    Token_error,
+    
+    Token_open_brace,
+    Token_open_bracket,
+    Token_close_brace,
+    Token_close_bracket,
+    Token_comma,
+    Token_colon,
+    Token_string_literal,
+    Token_number,
+    Token_true,
+    Token_false,
+    Token_null,
+    
+    Token_count,
+};
+
+struct json_token
+{
+    json_token_type Type;
+    buffer Value;
+};
+
+struct json_element
+{
+    buffer Label;
+    buffer Value;
+    json_element *FirstSubElement;
+    
+    json_element *NextSibling;
+};
+
+struct json_parser
+{
+    buffer Source;
+    u64 At;
+    b32 HadError;
+};
+
+static b32 IsJSONDigit(buffer Source, u64 At)
+{
+    TimeFunction;
+    
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val >= '0') && (Val <= '9'));
+    }
+    
+    return Result;
+}
+
+static b32 IsJSONWhitespace(buffer Source, u64 At)
+{
+    TimeFunction;
+    
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val == ' ') || (Val == '\t') || (Val == '\n') || (Val == '\r'));
+    }
+    
+    return Result;
+}
+
+static b32 IsParsing(json_parser *Parser)
+{
+    TimeFunction;
+    
+    b32 Result = !Parser->HadError && IsInBounds(Parser->Source, Parser->At);
+    return Result;
+}
+
+static void Error(json_parser *Parser, json_token Token, char const *Message)
+{
+    TimeFunction;
+    
+    Parser->HadError = true;
+    fprintf(stderr, "ERROR: \"%.*s\" - %s\n", (u32)Token.Value.Count, (char *)Token.Value.Data, Message);
+}
+
+static void ParseKeyword(buffer Source, u64 *At, buffer KeywordRemaining, json_token_type Type, json_token *Result)
+{
+    TimeFunction;
+    
+    if((Source.Count - *At) >= KeywordRemaining.Count)
+    {
+        buffer Check = Source;
+        Check.Data += *At;
+        Check.Count = KeywordRemaining.Count;
+        if(AreEqual(Check, KeywordRemaining))
+        {
+            Result->Type = Type;
+            Result->Value.Count += KeywordRemaining.Count;
+            *At += KeywordRemaining.Count;
+        }
+    }
+}
+
+static json_token GetJSONToken(json_parser *Parser)
+{
+    TimeFunction;
+    
+    json_token Result = {};
+    
+    buffer Source = Parser->Source;
+    u64 At = Parser->At;
+    
+    while(IsJSONWhitespace(Source, At))
+    {
+        ++At;
+    }
+    
+    if(IsInBounds(Source, At))
+    {
+        Result.Type = Token_error;
+        Result.Value.Count = 1;
+        Result.Value.Data = Source.Data + At;
+        u8 Val = Source.Data[At++];
+        switch(Val)
+        {
+            case '{': {Result.Type = Token_open_brace;} break;
+            case '[': {Result.Type = Token_open_bracket;} break;
+            case '}': {Result.Type = Token_close_brace;} break;
+            case ']': {Result.Type = Token_close_bracket;} break;
+            case ',': {Result.Type = Token_comma;} break;
+            case ':': {Result.Type = Token_colon;} break;
+
+            case 'f':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("alse"), Token_false, &Result);
+            } break;
+            
+            case 'n':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("ull"), Token_null, &Result);
+            } break;
+            
+            case 't':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("rue"), Token_true, &Result);
+            } break;
+            
+            case '"':
+            {
+                Result.Type = Token_string_literal;
+                
+                u64 StringStart = At;
+                
+                while(IsInBounds(Source, At) && (Source.Data[At] != '"'))
+                {
+                    if(IsInBounds(Source, (At + 1)) &&
+                       (Source.Data[At] == '\\') &&
+                       (Source.Data[At + 1] == '"'))
+                    {
+                        // NOTE(casey): Skip escaped quotation marks
+                        ++At;
+                    }
+                    
+                    ++At;
+                }
+                
+                Result.Value.Data = Source.Data + StringStart;
+                Result.Value.Count = At - StringStart;
+                if(IsInBounds(Source, At))
+                {
+                    ++At;
+                }
+            } break;
+
+            case '-':
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                u64 Start = At - 1;
+                Result.Type = Token_number;
+
+                // NOTE(casey): Move past a leading negative sign if one exists
+                if((Val == '-') && IsInBounds(Source, At))
+                {
+                    Val = Source.Data[At++];
+                }
+                
+                // NOTE(casey): If the leading digit wasn't 0, parse any digits before the decimal point
+                if(Val != '0')
+                {
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If there is a decimal point, parse any digits after the decimal point
+                if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+                {
+                    ++At;
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If it's in scientific notation, parse any digits after the "e"
+                if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+                {
+                    ++At;
+                    
+                    if(IsInBounds(Source, At) && ((Source.Data[At] == '+') || (Source.Data[At] == '-')))
+                    {
+                        ++At;
+                    }
+                    
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                Result.Value.Count = At - Start;
+            } break;
+            
+            default:
+            {
+            } break;
+        }
+    }
+    
+    Parser->At = At;
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels);
+static json_element *ParseJSONElement(json_parser *Parser, buffer Label, json_token Value)
+{
+    TimeFunction;
+    
+    b32 Valid = true;
+    
+    json_element *SubElement = 0;
+    if(Value.Type == Token_open_bracket)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_bracket, false);
+    }
+    else if(Value.Type == Token_open_brace)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_brace, true);
+    }
+    else if((Value.Type == Token_string_literal) ||
+            (Value.Type == Token_true) ||
+            (Value.Type == Token_false) ||
+            (Value.Type == Token_null) ||
+            (Value.Type == Token_number))
+    {
+        // NOTE(casey): Nothing to do here, since there is no additional data
+    }
+    else
+    {
+        Valid = false;
+    }
+    
+    json_element *Result = 0;
+    
+    if(Valid)
+    {
+        Result = (json_element *)malloc(sizeof(json_element));
+        Result->Label = Label;
+        Result->Value = Value.Value;
+        Result->FirstSubElement = SubElement;
+        Result->NextSibling = 0;
+    }
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels)
+{
+    TimeFunction;
+    
+    json_element *FirstElement = {};
+    json_element *LastElement = {};
+    
+    while(IsParsing(Parser))
+    {
+        buffer Label = {};
+        json_token Value = GetJSONToken(Parser);
+        if(HasLabels)
+        {
+            if(Value.Type == Token_string_literal)
+            {
+                Label = Value.Value;
+                
+                json_token Colon = GetJSONToken(Parser);
+                if(Colon.Type == Token_colon)
+                {
+                    Value = GetJSONToken(Parser);
+                }
+                else
+                {
+                    Error(Parser, Colon, "Expected colon after field name");
+                }
+            }
+            else if(Value.Type != EndType)
+            {
+                Error(Parser, Value, "Unexpected token in JSON");
+            }
+        }
+        
+        json_element *Element = ParseJSONElement(Parser, Label, Value);
+        if(Element)
+        {
+            LastElement = (LastElement ? LastElement->NextSibling : FirstElement) = Element;
+        }
+        else if(Value.Type == EndType)
+        {
+            break;
+        }
+        else
+        {
+            Error(Parser, Value, "Unexpected token in JSON");
+        }
+        
+        json_token Comma = GetJSONToken(Parser);
+        if(Comma.Type == EndType)
+        {
+            break;
+        }
+        else if(Comma.Type != Token_comma)
+        {
+            Error(Parser, Comma, "Unexpected token in JSON");
+        }
+    }
+    
+    return FirstElement;
+}
+
+static json_element *ParseJSON(buffer InputJSON)
+{
+    TimeFunction;
+    
+    json_parser Parser = {};
+    Parser.Source = InputJSON;
+    
+    json_element *Result = ParseJSONElement(&Parser, {}, GetJSONToken(&Parser));
+    return Result;
+}
+
+static void FreeJSON(json_element *Element)
+{
+    TimeFunction;
+    
+    while(Element)
+    {
+        json_element *FreeElement = Element;
+        Element = Element->NextSibling;
+    
+        FreeJSON(FreeElement->FirstSubElement);
+        free(FreeElement);
+    }
+}
+
+static json_element *LookupElement(json_element *Object, buffer ElementName)
+{
+    TimeFunction;
+    
+    json_element *Result = 0;
+    
+    if(Object)
+    {
+        for(json_element *Search = Object->FirstSubElement; Search; Search = Search->NextSibling)
+        {
+            if(AreEqual(Search->Label, ElementName))
+            {
+                Result = Search;
+                break;
+            }
+        }
+    }
+    
+    return Result;
+}
+
+static f64 ConvertJSONSign(buffer Source, u64 *AtResult)
+{
+    TimeFunction;
+    
+    u64 At = *AtResult;
+
+    f64 Result = 1.0;
+    if(IsInBounds(Source, At) && (Source.Data[At] == '-'))
+    {
+        Result = -1.0;
+        ++At;
+    }
+    
+    *AtResult = At;
+
+    return Result;
+}
+
+static f64 ConvertJSONNumber(buffer Source, u64 *AtResult)
+{
+    TimeFunction;
+    
+    u64 At = *AtResult;
+    
+    f64 Result = 0.0;
+    while(IsInBounds(Source, At))
+    {
+        u8 Char = Source.Data[At] - (u8)'0';
+        if(Char < 10)
+        {
+            Result = 10.0*Result + (f64)Char;
+            ++At;
+        }
+        else
+        {
+            break;
+        }
+    }
+    
+    *AtResult = At;
+    
+    return Result;
+}
+
+static f64 ConvertElementToF64(json_element *Object, buffer ElementName)
+{
+    TimeFunction;
+    
+    f64 Result = 0.0;
+    
+    json_element *Element = LookupElement(Object, ElementName);
+    if(Element)
+    {
+        buffer Source = Element->Value;
+        u64 At = 0;
+        
+        f64 Sign = ConvertJSONSign(Source, &At);
+        f64 Number = ConvertJSONNumber(Source, &At);
+        
+        if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+        {
+            ++At;
+            f64 C = 1.0 / 10.0;
+            while(IsInBounds(Source, At))
+            {
+                u8 Char = Source.Data[At] - (u8)'0';
+                if(Char < 10)
+                {
+                    Number = Number + C*(f64)Char;
+                    C *= 1.0 / 10.0;
+                    ++At;
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+        
+        if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+        {
+            ++At;
+            if(IsInBounds(Source, At) && (Source.Data[At] == '+'))
+            {
+                ++At;
+            }
+
+            f64 ExponentSign = ConvertJSONSign(Source, &At);
+            f64 Exponent = ExponentSign*ConvertJSONNumber(Source, &At);
+            Number *= pow(10.0, Exponent);
+        }
+        
+        Result = Sign*Number;
+    }
+    
+    return Result;
+}
+
+static u64 ParseHaversinePairs(buffer InputJSON, u64 MaxPairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    u64 PairCount = 0;
+    
+    json_element *JSON = ParseJSON(InputJSON);
+    
+    json_element *PairsArray = LookupElement(JSON, CONSTANT_STRING("pairs"));
+    if(PairsArray)
+    {
+        for(json_element *Element = PairsArray->FirstSubElement;
+            Element && (PairCount < MaxPairCount);
+            Element = Element->NextSibling)
+        {
+            haversine_pair *Pair = Pairs + PairCount++;
+            
+            Pair->X0 = ConvertElementToF64(Element, CONSTANT_STRING("x0"));
+            Pair->Y0 = ConvertElementToF64(Element, CONSTANT_STRING("y0"));
+            Pair->X1 = ConvertElementToF64(Element, CONSTANT_STRING("x1"));
+            Pair->Y1 = ConvertElementToF64(Element, CONSTANT_STRING("y1"));
+        }
+    }
+   
+    FreeJSON(JSON);
+    
+    return PairCount;
+}

part2/listing_0090_allfuncs_counted_haversine_main.cpp

@@ -0,0 +1,184 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 90
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#include "listing_0087_simplified_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0089_allfuncs_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+static_assert(__COUNTER__ < ArrayCount(profiler::Anchors), "Number of profile points exceeds size of profiler::Anchors array");

part2/listing_0091_switchable_profiler.cpp

@@ -0,0 +1,142 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 91
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+#ifndef PROFILER
+#define PROFILER 0
+#endif
+
+#if PROFILER
+
+struct profile_anchor
+{
+    u64 TSCElapsedExclusive; // NOTE(casey): Does NOT include children
+    u64 TSCElapsedInclusive; // NOTE(casey): DOES include children
+    u64 HitCount;
+    char const *Label;
+};
+static profile_anchor GlobalProfilerAnchors[4096];
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        OldTSCElapsedInclusive = Anchor->TSCElapsedInclusive;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = ReadCPUTimer();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = ReadCPUTimer() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+    
+        profile_anchor *Parent = GlobalProfilerAnchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        
+        Parent->TSCElapsedExclusive -= Elapsed;
+        Anchor->TSCElapsedExclusive += Elapsed;
+        Anchor->TSCElapsedInclusive = OldTSCElapsedInclusive + Elapsed;
+        ++Anchor->HitCount;
+        
+        /* NOTE(casey): This write happens every time solely because there is no
+           straightforward way in C++ to have the same ease-of-use. In a better programming
+           language, it would be simple to have the anchor points gathered and labeled at compile
+           time, and this repetative write would be eliminated. */
+        Anchor->Label = Label;
+    }
+    
+    char const *Label;
+    u64 OldTSCElapsedInclusive;
+    u64 StartTSC;
+    u32 ParentIndex;
+    u32 AnchorIndex;
+};
+
+#define NameConcat2(A, B) A##B
+#define NameConcat(A, B) NameConcat2(A, B)
+#define TimeBlock(Name) profile_block NameConcat(Block, __LINE__)(Name, __COUNTER__ + 1);
+#define ProfilerEndOfCompilationUnit static_assert(__COUNTER__ < ArrayCount(GlobalProfilerAnchors), "Number of profile points exceeds size of profiler::Anchors array")
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, profile_anchor *Anchor)
+{
+    f64 Percent = 100.0 * ((f64)Anchor->TSCElapsedExclusive / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%", Anchor->Label, Anchor->HitCount, Anchor->TSCElapsedExclusive, Percent);
+    if(Anchor->TSCElapsedInclusive != Anchor->TSCElapsedExclusive)
+    {
+        f64 PercentWithChildren = 100.0 * ((f64)Anchor->TSCElapsedInclusive / (f64)TotalTSCElapsed);
+        printf(", %.2f%% w/children", PercentWithChildren);
+    }
+    printf(")\n");
+}
+
+static void PrintAnchorData(u64 TotalCPUElapsed)
+{
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfilerAnchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        if(Anchor->TSCElapsedInclusive)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}
+
+#else
+
+#define TimeBlock(...)
+#define PrintAnchorData(...)
+#define ProfilerEndOfCompilationUnit
+
+#endif
+
+struct profiler
+{
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+
+#define TimeFunction TimeBlock(__func__)
+
+static void BeginProfile(void)
+{
+    GlobalProfiler.StartTSC = ReadCPUTimer();
+}
+
+static void EndAndPrintProfile()
+{
+    GlobalProfiler.EndTSC = ReadCPUTimer();
+    u64 CPUFreq = EstimateCPUTimerFreq();
+    
+    u64 TotalCPUElapsed = GlobalProfiler.EndTSC - GlobalProfiler.StartTSC;
+    
+    if(CPUFreq)
+    {
+        printf("\nTotal time: %0.4fms (CPU freq %llu)\n", 1000.0 * (f64)TotalCPUElapsed / (f64)CPUFreq, CPUFreq);
+    }
+    
+    PrintAnchorData(TotalCPUElapsed);
+}

part2/listing_0092_profiler_on_haversine_main.cpp

@@ -0,0 +1,185 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 92
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#include "listing_0091_switchable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0089_allfuncs_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part2/listing_0093_profiler_off_haversine_main.cpp

@@ -0,0 +1,184 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 93
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#include "listing_0091_switchable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0089_allfuncs_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part2/listing_0094_profiled_lookup_json_parser.cpp

@@ -0,0 +1,516 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 94
+   ======================================================================== */
+
+enum json_token_type
+{
+    Token_end_of_stream,
+    Token_error,
+    
+    Token_open_brace,
+    Token_open_bracket,
+    Token_close_brace,
+    Token_close_bracket,
+    Token_comma,
+    Token_colon,
+    Token_string_literal,
+    Token_number,
+    Token_true,
+    Token_false,
+    Token_null,
+    
+    Token_count,
+};
+
+struct json_token
+{
+    json_token_type Type;
+    buffer Value;
+};
+
+struct json_element
+{
+    buffer Label;
+    buffer Value;
+    json_element *FirstSubElement;
+    
+    json_element *NextSibling;
+};
+
+struct json_parser
+{
+    buffer Source;
+    u64 At;
+    b32 HadError;
+};
+
+static b32 IsJSONDigit(buffer Source, u64 At)
+{
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val >= '0') && (Val <= '9'));
+    }
+    
+    return Result;
+}
+
+static b32 IsJSONWhitespace(buffer Source, u64 At)
+{
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val == ' ') || (Val == '\t') || (Val == '\n') || (Val == '\r'));
+    }
+    
+    return Result;
+}
+
+static b32 IsParsing(json_parser *Parser)
+{
+    b32 Result = !Parser->HadError && IsInBounds(Parser->Source, Parser->At);
+    return Result;
+}
+
+static void Error(json_parser *Parser, json_token Token, char const *Message)
+{
+    Parser->HadError = true;
+    fprintf(stderr, "ERROR: \"%.*s\" - %s\n", (u32)Token.Value.Count, (char *)Token.Value.Data, Message);
+}
+
+static void ParseKeyword(buffer Source, u64 *At, buffer KeywordRemaining, json_token_type Type, json_token *Result)
+{
+    if((Source.Count - *At) >= KeywordRemaining.Count)
+    {
+        buffer Check = Source;
+        Check.Data += *At;
+        Check.Count = KeywordRemaining.Count;
+        if(AreEqual(Check, KeywordRemaining))
+        {
+            Result->Type = Type;
+            Result->Value.Count += KeywordRemaining.Count;
+            *At += KeywordRemaining.Count;
+        }
+    }
+}
+
+static json_token GetJSONToken(json_parser *Parser)
+{
+    json_token Result = {};
+    
+    buffer Source = Parser->Source;
+    u64 At = Parser->At;
+    
+    while(IsJSONWhitespace(Source, At))
+    {
+        ++At;
+    }
+    
+    if(IsInBounds(Source, At))
+    {
+        Result.Type = Token_error;
+        Result.Value.Count = 1;
+        Result.Value.Data = Source.Data + At;
+        u8 Val = Source.Data[At++];
+        switch(Val)
+        {
+            case '{': {Result.Type = Token_open_brace;} break;
+            case '[': {Result.Type = Token_open_bracket;} break;
+            case '}': {Result.Type = Token_close_brace;} break;
+            case ']': {Result.Type = Token_close_bracket;} break;
+            case ',': {Result.Type = Token_comma;} break;
+            case ':': {Result.Type = Token_colon;} break;
+
+            case 'f':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("alse"), Token_false, &Result);
+            } break;
+            
+            case 'n':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("ull"), Token_null, &Result);
+            } break;
+            
+            case 't':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("rue"), Token_true, &Result);
+            } break;
+            
+            case '"':
+            {
+                Result.Type = Token_string_literal;
+                
+                u64 StringStart = At;
+                
+                while(IsInBounds(Source, At) && (Source.Data[At] != '"'))
+                {
+                    if(IsInBounds(Source, (At + 1)) &&
+                       (Source.Data[At] == '\\') &&
+                       (Source.Data[At + 1] == '"'))
+                    {
+                        // NOTE(casey): Skip escaped quotation marks
+                        ++At;
+                    }
+                    
+                    ++At;
+                }
+                
+                Result.Value.Data = Source.Data + StringStart;
+                Result.Value.Count = At - StringStart;
+                if(IsInBounds(Source, At))
+                {
+                    ++At;
+                }
+            } break;
+
+            case '-':
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                u64 Start = At - 1;
+                Result.Type = Token_number;
+
+                // NOTE(casey): Move past a leading negative sign if one exists
+                if((Val == '-') && IsInBounds(Source, At))
+                {
+                    Val = Source.Data[At++];
+                }
+                
+                // NOTE(casey): If the leading digit wasn't 0, parse any digits before the decimal point
+                if(Val != '0')
+                {
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If there is a decimal point, parse any digits after the decimal point
+                if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+                {
+                    ++At;
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If it's in scientific notation, parse any digits after the "e"
+                if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+                {
+                    ++At;
+                    
+                    if(IsInBounds(Source, At) && ((Source.Data[At] == '+') || (Source.Data[At] == '-')))
+                    {
+                        ++At;
+                    }
+                    
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                Result.Value.Count = At - Start;
+            } break;
+            
+            default:
+            {
+            } break;
+        }
+    }
+    
+    Parser->At = At;
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels);
+static json_element *ParseJSONElement(json_parser *Parser, buffer Label, json_token Value)
+{
+    b32 Valid = true;
+    
+    json_element *SubElement = 0;
+    if(Value.Type == Token_open_bracket)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_bracket, false);
+    }
+    else if(Value.Type == Token_open_brace)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_brace, true);
+    }
+    else if((Value.Type == Token_string_literal) ||
+            (Value.Type == Token_true) ||
+            (Value.Type == Token_false) ||
+            (Value.Type == Token_null) ||
+            (Value.Type == Token_number))
+    {
+        // NOTE(casey): Nothing to do here, since there is no additional data
+    }
+    else
+    {
+        Valid = false;
+    }
+    
+    json_element *Result = 0;
+    
+    if(Valid)
+    {
+        Result = (json_element *)malloc(sizeof(json_element));
+        Result->Label = Label;
+        Result->Value = Value.Value;
+        Result->FirstSubElement = SubElement;
+        Result->NextSibling = 0;
+    }
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels)
+{
+    json_element *FirstElement = {};
+    json_element *LastElement = {};
+    
+    while(IsParsing(Parser))
+    {
+        buffer Label = {};
+        json_token Value = GetJSONToken(Parser);
+        if(HasLabels)
+        {
+            if(Value.Type == Token_string_literal)
+            {
+                Label = Value.Value;
+                
+                json_token Colon = GetJSONToken(Parser);
+                if(Colon.Type == Token_colon)
+                {
+                    Value = GetJSONToken(Parser);
+                }
+                else
+                {
+                    Error(Parser, Colon, "Expected colon after field name");
+                }
+            }
+            else if(Value.Type != EndType)
+            {
+                Error(Parser, Value, "Unexpected token in JSON");
+            }
+        }
+        
+        json_element *Element = ParseJSONElement(Parser, Label, Value);
+        if(Element)
+        {
+            LastElement = (LastElement ? LastElement->NextSibling : FirstElement) = Element;
+        }
+        else if(Value.Type == EndType)
+        {
+            break;
+        }
+        else
+        {
+            Error(Parser, Value, "Unexpected token in JSON");
+        }
+        
+        json_token Comma = GetJSONToken(Parser);
+        if(Comma.Type == EndType)
+        {
+            break;
+        }
+        else if(Comma.Type != Token_comma)
+        {
+            Error(Parser, Comma, "Unexpected token in JSON");
+        }
+    }
+    
+    return FirstElement;
+}
+
+static json_element *ParseJSON(buffer InputJSON)
+{
+    TimeFunction;
+    
+    json_parser Parser = {};
+    Parser.Source = InputJSON;
+    
+    json_element *Result = ParseJSONElement(&Parser, {}, GetJSONToken(&Parser));
+    return Result;
+}
+
+static void FreeJSON(json_element *Element)
+{
+    while(Element)
+    {
+        json_element *FreeElement = Element;
+        Element = Element->NextSibling;
+    
+        FreeJSON(FreeElement->FirstSubElement);
+        free(FreeElement);
+    }
+}
+
+static json_element *LookupElement(json_element *Object, buffer ElementName)
+{
+    json_element *Result = 0;
+    
+    if(Object)
+    {
+        for(json_element *Search = Object->FirstSubElement; Search; Search = Search->NextSibling)
+        {
+            if(AreEqual(Search->Label, ElementName))
+            {
+                Result = Search;
+                break;
+            }
+        }
+    }
+    
+    return Result;
+}
+
+static f64 ConvertJSONSign(buffer Source, u64 *AtResult)
+{
+    u64 At = *AtResult;
+
+    f64 Result = 1.0;
+    if(IsInBounds(Source, At) && (Source.Data[At] == '-'))
+    {
+        Result = -1.0;
+        ++At;
+    }
+    
+    *AtResult = At;
+
+    return Result;
+}
+
+static f64 ConvertJSONNumber(buffer Source, u64 *AtResult)
+{
+    u64 At = *AtResult;
+    
+    f64 Result = 0.0;
+    while(IsInBounds(Source, At))
+    {
+        u8 Char = Source.Data[At] - (u8)'0';
+        if(Char < 10)
+        {
+            Result = 10.0*Result + (f64)Char;
+            ++At;
+        }
+        else
+        {
+            break;
+        }
+    }
+    
+    *AtResult = At;
+    
+    return Result;
+}
+
+static f64 ConvertElementToF64(json_element *Object, buffer ElementName)
+{
+    f64 Result = 0.0;
+    
+    json_element *Element = LookupElement(Object, ElementName);
+    if(Element)
+    {
+        buffer Source = Element->Value;
+        u64 At = 0;
+        
+        f64 Sign = ConvertJSONSign(Source, &At);
+        f64 Number = ConvertJSONNumber(Source, &At);
+        
+        if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+        {
+            ++At;
+            f64 C = 1.0 / 10.0;
+            while(IsInBounds(Source, At))
+            {
+                u8 Char = Source.Data[At] - (u8)'0';
+                if(Char < 10)
+                {
+                    Number = Number + C*(f64)Char;
+                    C *= 1.0 / 10.0;
+                    ++At;
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+        
+        if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+        {
+            ++At;
+            if(IsInBounds(Source, At) && (Source.Data[At] == '+'))
+            {
+                ++At;
+            }
+
+            f64 ExponentSign = ConvertJSONSign(Source, &At);
+            f64 Exponent = ExponentSign*ConvertJSONNumber(Source, &At);
+            Number *= pow(10.0, Exponent);
+        }
+        
+        Result = Sign*Number;
+    }
+    
+    return Result;
+}
+
+static u64 ParseHaversinePairs(buffer InputJSON, u64 MaxPairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    u64 PairCount = 0;
+    
+    json_element *JSON = ParseJSON(InputJSON);
+    
+    json_element *PairsArray = LookupElement(JSON, CONSTANT_STRING("pairs"));
+    if(PairsArray)
+    {
+        TimeBlock("Lookup and Convert");
+        
+        for(json_element *Element = PairsArray->FirstSubElement;
+            Element && (PairCount < MaxPairCount);
+            Element = Element->NextSibling)
+        {
+            haversine_pair *Pair = Pairs + PairCount++;
+            
+            Pair->X0 = ConvertElementToF64(Element, CONSTANT_STRING("x0"));
+            Pair->Y0 = ConvertElementToF64(Element, CONSTANT_STRING("y0"));
+            Pair->X1 = ConvertElementToF64(Element, CONSTANT_STRING("x1"));
+            Pair->Y1 = ConvertElementToF64(Element, CONSTANT_STRING("y1"));
+        }
+    }
+   
+    {
+        TimeBlock("FreeJSON");
+        FreeJSON(JSON);
+    }
+    
+    return PairCount;
+}

part2/listing_0095_profiled_haversine_main.cpp

@@ -0,0 +1,185 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 95
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#include "listing_0091_switchable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0094_profiled_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part2/listing_0096_selectable_profiler.cpp

@@ -0,0 +1,176 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 96
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+#ifndef PROFILER
+#define PROFILER 0
+#endif
+
+#ifndef READ_BLOCK_TIMER
+#define READ_BLOCK_TIMER ReadCPUTimer
+#endif
+
+#if PROFILER
+
+struct profile_anchor
+{
+    u64 TSCElapsedExclusive; // NOTE(casey): Does NOT include children
+    u64 TSCElapsedInclusive; // NOTE(casey): DOES include children
+    u64 HitCount;
+    char const *Label;
+};
+static profile_anchor GlobalProfilerAnchors[4096];
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        OldTSCElapsedInclusive = Anchor->TSCElapsedInclusive;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = READ_BLOCK_TIMER();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = READ_BLOCK_TIMER() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+    
+        profile_anchor *Parent = GlobalProfilerAnchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        
+        Parent->TSCElapsedExclusive -= Elapsed;
+        Anchor->TSCElapsedExclusive += Elapsed;
+        Anchor->TSCElapsedInclusive = OldTSCElapsedInclusive + Elapsed;
+        ++Anchor->HitCount;
+        
+        /* NOTE(casey): This write happens every time solely because there is no
+           straightforward way in C++ to have the same ease-of-use. In a better programming
+           language, it would be simple to have the anchor points gathered and labeled at compile
+           time, and this repetative write would be eliminated. */
+        Anchor->Label = Label;
+    }
+    
+    char const *Label;
+    u64 OldTSCElapsedInclusive;
+    u64 StartTSC;
+    u32 ParentIndex;
+    u32 AnchorIndex;
+};
+
+#define NameConcat2(A, B) A##B
+#define NameConcat(A, B) NameConcat2(A, B)
+#define TimeBlock(Name) profile_block NameConcat(Block, __LINE__)(Name, __COUNTER__ + 1);
+#define ProfilerEndOfCompilationUnit static_assert(__COUNTER__ < ArrayCount(GlobalProfilerAnchors), "Number of profile points exceeds size of profiler::Anchors array")
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, profile_anchor *Anchor)
+{
+    f64 Percent = 100.0 * ((f64)Anchor->TSCElapsedExclusive / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%", Anchor->Label, Anchor->HitCount, Anchor->TSCElapsedExclusive, Percent);
+    if(Anchor->TSCElapsedInclusive != Anchor->TSCElapsedExclusive)
+    {
+        f64 PercentWithChildren = 100.0 * ((f64)Anchor->TSCElapsedInclusive / (f64)TotalTSCElapsed);
+        printf(", %.2f%% w/children", PercentWithChildren);
+    }
+    printf(")\n");
+}
+
+static void PrintAnchorData(u64 TotalCPUElapsed)
+{
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfilerAnchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        if(Anchor->TSCElapsedInclusive)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}
+
+#else
+
+#define TimeBlock(...)
+#define PrintAnchorData(...)
+#define ProfilerEndOfCompilationUnit
+
+#endif
+
+struct profiler
+{
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+
+#define TimeFunction TimeBlock(__func__)
+
+static u64 EstimateBlockTimerFreq(void)
+{
+    (void)&EstimateCPUTimerFreq; // NOTE(casey): This has to be voided here to prevent compilers from warning us that it is not used
+    
+	u64 MillisecondsToWait = 100;
+	u64 OSFreq = GetOSTimerFreq();
+
+	u64 BlockStart = READ_BLOCK_TIMER();
+	u64 OSStart = ReadOSTimer();
+	u64 OSEnd = 0;
+	u64 OSElapsed = 0;
+	u64 OSWaitTime = OSFreq * MillisecondsToWait / 1000;
+	while(OSElapsed < OSWaitTime)
+	{
+		OSEnd = ReadOSTimer();
+		OSElapsed = OSEnd - OSStart;
+	}
+	
+	u64 BlockEnd = READ_BLOCK_TIMER();
+	u64 BlockElapsed = BlockEnd - BlockStart;
+	
+	u64 BlockFreq = 0;
+	if(OSElapsed)
+	{
+		BlockFreq = OSFreq * BlockElapsed / OSElapsed;
+	}
+	
+	return BlockFreq;
+}
+
+static void BeginProfile(void)
+{
+    GlobalProfiler.StartTSC = READ_BLOCK_TIMER();
+}
+
+static void EndAndPrintProfile()
+{
+    GlobalProfiler.EndTSC = READ_BLOCK_TIMER();
+    u64 TimerFreq = EstimateBlockTimerFreq();
+    
+    u64 TotalTSCElapsed = GlobalProfiler.EndTSC - GlobalProfiler.StartTSC;
+    
+    if(TimerFreq)
+    {
+        printf("\nTotal time: %0.4fms (timer freq %llu)\n", 1000.0 * (f64)TotalTSCElapsed / (f64)TimerFreq, TimerFreq);
+    }
+    
+    PrintAnchorData(TotalTSCElapsed);
+}

part2/listing_0097_tsc_select_main.cpp

@@ -0,0 +1,185 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 97
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#include "listing_0096_selectable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0083_recursive_timed_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part2/listing_0098_qpc_select_main.cpp

@@ -0,0 +1,186 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 98
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#define READ_BLOCK_TIMER ReadOSTimer
+#include "listing_0096_selectable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0083_recursive_timed_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part2/listing_0099_qpc_minimal_blocks_main.cpp

@@ -0,0 +1,186 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 99
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#define READ_BLOCK_TIMER ReadOSTimer
+#include "listing_0091_switchable_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0094_profiled_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part3/base.c

@@ -0,0 +1,353 @@
+// NOTE: Implementation ////////////////////////////////////////////////////////////////////////////
+bool Str8_Equals(Str8 lhs, Str8 rhs)
+{
+    bool result = lhs.size == rhs.size && memcmp(lhs.data, rhs.data, lhs.size) == 0;
+    return result;
+}
+
+Str8ToU64Result Str8_ToU64(Str8 string)
+{
+    Str8ToU64Result result = {0};
+
+    size_t ch_index = 0;
+    while (ch_index < string.size && CharIsWhiteSpace(string.data[ch_index]))
+        ch_index++;
+
+    for (; ch_index < string.size; ch_index++) {
+        char ch = string.data[ch_index];
+        if (ch >= '0' && ch <= '9') {
+            result.value = (result.value * 10) + (ch - '0');
+        } else {
+            return result;
+        }
+    }
+
+    result.success = true;
+    return result;
+}
+
+Str8BinarySplitResult Str8_BinarySplit(Str8 buffer, Str8 find)
+{
+    Str8BinarySplitResult result = {0};
+    result.lhs                       = buffer;
+    for (size_t index = 0; (index + find.size) <= buffer.size; index++) {
+        Str8 check = {buffer.data + index, find.size};
+        if (Str8_Equals(find, check)) {
+            result.lhs.size = index;
+            result.rhs.data = check.data + find.size;
+            result.rhs.size = buffer.size - (index + find.size);
+            break;
+        }
+    }
+    return result;
+}
+
+bool CharIsWhiteSpace(char ch)
+{
+    bool result = ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t';
+    return result;
+}
+
+bool CharIsDigit(char ch)
+{
+    bool result = ch >= '0' && ch <= '9';
+    return result;
+}
+
+void Profiler_Dump()
+{
+    u64 total_elapsed_tsc = g_profiler.end_tsc - g_profiler.begin_tsc;
+    u64 cpu_frequency = EstimateCPUTimerFreq();
+    if (cpu_frequency)
+        printf("\nTotal time: %0.4fms (CPU freq %llu)\n", 1000.0 * (f64)total_elapsed_tsc / (f64)cpu_frequency, cpu_frequency);
+
+    for (uint32_t index = 1; index < ARRAY_UCOUNT(g_profiler.anchors); index++) {
+        ProfilerAnchor const *anchor = g_profiler.anchors + index;
+        if (!anchor->elapsed_tsc_inclusive)
+            break;
+
+        f64 percent = total_elapsed_tsc ? (f64)anchor->elapsed_tsc_exclusive / (f64)total_elapsed_tsc * 100.0 : 100.0;
+        printf("   %.*s[%zu]: %llu (%.2f%%", STR8_FMT(anchor->label), anchor->hits, anchor->elapsed_tsc_exclusive, percent);
+        if (anchor->elapsed_tsc_inclusive != anchor->elapsed_tsc_exclusive) {
+            f64 percent_w_children = total_elapsed_tsc ? ((f64)anchor->elapsed_tsc_inclusive / (f64)total_elapsed_tsc * 100.0) : 100.0;
+            printf(", %.2f%% w/children", percent_w_children);
+        }
+        printf(")");
+
+        if (anchor->byte_count) {
+            f64 megabytes_processed = anchor->byte_count / (1024.f * 1024.f);
+            f64 elapsed_s           = anchor->elapsed_tsc_inclusive / CAST(f64)cpu_frequency;
+            f64 bytes_per_s         = anchor->byte_count / elapsed_s;
+            f64 gigabytes_bandwidth = bytes_per_s / (1024.f * 1024.f * 1024.f);
+            printf("  %.3fmb at %.2fgb/s", megabytes_processed, gigabytes_bandwidth);
+        }
+        printf("\n");
+    }
+}
+
+ProfilerZone Profiler_BeginZone_(Str8 label, uint32_t index, u64 byte_count)
+{
+    ProfilerZone result      = {0};
+    #if defined(PROFILER)
+    result.index                 = index;
+    result.label                 = label;
+    result.tsc                   = ReadCPUTimer();
+    result.elapsed_tsc_inclusive = g_profiler.anchors[index].elapsed_tsc_inclusive;
+    result.byte_count            = byte_count;
+    result.parent_index          = g_profiler.parent_index;
+    g_profiler.parent_index      = index;
+    #else
+    (void)label; (void)index; (void)byte_count;
+    #endif
+    return result;
+}
+
+void Profiler_EndZone(ProfilerZone zone)
+{
+    #if defined(PROFILER)
+    u64 elapsed_tsc             = ReadCPUTimer() - zone.tsc;
+    ProfilerAnchor* anchor  = g_profiler.anchors + zone.index;
+    ProfilerAnchor* parent  = g_profiler.anchors + zone.parent_index;
+
+    anchor->elapsed_tsc_exclusive += elapsed_tsc;
+    anchor->elapsed_tsc_inclusive  = zone.elapsed_tsc_inclusive + elapsed_tsc;
+    anchor->label                  = zone.label;
+    anchor->byte_count            += zone.byte_count;
+    anchor->hits++;
+    parent->elapsed_tsc_exclusive -= elapsed_tsc;
+    g_profiler.parent_index        = zone.parent_index;
+    #else
+    (void)zone;
+    #endif
+}
+
+#pragma warning(push)
+#pragma warning(disable: 4146) // warning C4146: unary minus operator applied to unsigned type, result still unsigned
+uint32_t PCG32_Pie (uint64_t *state)
+{
+    uint64_t old = *state ^ 0xc90fdaa2adf85459ULL;
+    *state = *state * 6364136223846793005ULL + 0xc90fdaa2adf85459ULL;
+    uint32_t xorshifted = (uint32_t)(((old >> 18u) ^ old) >> 27u);
+    uint32_t rot = old >> 59u;
+    return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
+}
+#pragma warning(pop)
+
+f64 PCG32_PieF64(uint64_t *state, f64 min, f64 max)
+{
+    uint32_t u32_value = PCG32_Pie(state);
+    f64 t01            = CAST(f64)u32_value / CAST(f64)CAST(uint32_t)-1;
+    f64 result         = min + (max - min) * t01;
+    return result;
+}
+
+bool BufferIsValid(Buffer buffer)
+{
+    bool result = buffer.data && buffer.size;
+    return result;
+}
+
+BufferIterator BufferIteratorInit(Buffer buffer)
+{
+    BufferIterator result = {0};
+    result.buffer             = buffer;
+    return result;
+}
+
+bool BufferIteratorHasMoreBytes(BufferIterator it)
+{
+    bool result = BufferIsValid(it.buffer) && it.index < it.buffer.size;
+    return result;
+}
+
+uint8_t BufferIteratorPeekByte(BufferIterator *it)
+{
+    ASSERT(it);
+    ASSERT(BufferIsValid(it->buffer));
+    ASSERT(it->index < it->buffer.size);
+    uint8_t result = it->buffer.data[it->index];
+    return result;
+}
+
+uint8_t BufferIteratorNextByte(BufferIterator *it)
+{
+    uint8_t result = BufferIteratorPeekByte(it);
+    it->index++;
+    return result;
+}
+
+Buffer FileRead(char const *file_path)
+{
+    Buffer result = {0};
+
+    // NOTE: Determine file size ///////////////////////////////////////////////////////////////////
+    WIN32_FILE_ATTRIBUTE_DATA file_attrib_data = {0};
+    if (GetFileAttributesEx(file_path, GetFileExInfoStandard, &file_attrib_data) == 0)
+        return result;
+
+    // NOTE: Open file /////////////////////////////////////////////////////////////////////////////
+    HANDLE file_handle = CreateFile(
+      /*LPCSTR                lpFileName*/ file_path,
+      /*DWORD                 dwDesiredAccess*/ GENERIC_READ,
+      /*DWORD                 dwShareMode*/ 0,
+      /*LPSECURITY_ATTRIBUTES lpSecurityAttributes*/ NULL,
+      /*DWORD                 dwCreationDisposition*/ OPEN_EXISTING,
+      /*DWORD                 dwFlagsAndAttributes*/ 0,
+      /*HANDLE                hTemplateFile*/ NULL
+    );
+
+    if (file_handle == INVALID_HANDLE_VALUE)
+        return result;
+
+    // NOTE: Allocate buffer ///////////////////////////////////////////////////////////////////////
+    uint64_t file_size = (uint64_t)file_attrib_data.nFileSizeHigh << 32 | (uint64_t)file_attrib_data.nFileSizeLow << 0;
+    ASSERT(file_size < (DWORD)-1);
+    char *buffer = VirtualAlloc(
+      /*LPVOID lpAddress*/ NULL,
+      /*SIZE_T dwSize*/ file_size,
+      /*DWORD  flAllocationType*/ MEM_COMMIT | MEM_RESERVE,
+      /*DWORD  flProtect*/ PAGE_READWRITE
+    );
+
+    if (!buffer)
+        goto end;
+
+    // NOTE: Read file to buffer ///////////////////////////////////////////////////////////////////
+    DWORD bytes_read = 0;
+    ProfilerZone prof_file_read_zone = Profiler_BeginZoneBandwidth("File Read", file_size);
+    BOOL read_file_result = ReadFile(
+      /*HANDLE       hFile*/ file_handle,
+      /*LPVOID       lpBuffer*/ buffer,
+      /*DWORD        nNumberOfBytesToRead*/ CAST(DWORD)file_size,
+      /*LPDWORD      lpNumberOfBytesRead*/ &bytes_read,
+      /*LPOVERLAPPED lpOverlapped*/ NULL
+    );
+    Profiler_EndZone(prof_file_read_zone);
+
+    // NOTE: Handle read result ////////////////////////////////////////////////////////////////////
+    if (read_file_result == 0) {
+        VirtualFree(buffer, 0, MEM_RELEASE);
+    } else {
+        result.data = buffer;
+        result.size = file_size;
+    }
+
+end:
+    CloseHandle(file_handle);
+    return result;
+};
+
+void FileFree(Buffer buffer)
+{
+    if (BufferIsValid(buffer))
+        VirtualFree(buffer.data, 0, MEM_RELEASE);
+}
+
+bool FileWrite(char const *file_path, void const *buffer, size_t buffer_size)
+{
+    bool result = false;
+
+    // NOTE: Open file /////////////////////////////////////////////////////////////////////////////
+    HANDLE file_handle = CreateFile(
+      /*LPCSTR                lpFileName*/ file_path,
+      /*DWORD                 dwDesiredAccess*/ GENERIC_WRITE,
+      /*DWORD                 dwShareMode*/ 0,
+      /*LPSECURITY_ATTRIBUTES lpSecurityAttributes*/ NULL,
+      /*DWORD                 dwCreationDisposition*/ CREATE_ALWAYS,
+      /*DWORD                 dwFlagsAndAttributes*/ 0,
+      /*HANDLE                hTemplateFile*/ NULL
+    );
+
+    if (file_handle == INVALID_HANDLE_VALUE)
+        return result;
+
+    // NOTE: Write file to disk ////////////////////////////////////////////////////////////////////
+    DWORD bytes_written = 0;
+    BOOL write_file_result = WriteFile(
+      /*HANDLE       hFile*/ file_handle,
+      /*LPVOID       lpBuffer*/ buffer,
+      /*DWORD        nNumberOfBytesToWrite*/ CAST(DWORD)buffer_size,
+      /*LPDWORD      lpNumberOfBytesWrite*/ &bytes_written,
+      /*LPOVERLAPPED lpOverlapped*/ NULL
+    );
+
+    ASSERT(bytes_written == buffer_size);
+    result = write_file_result && bytes_written == buffer_size;
+    CloseHandle(file_handle);
+    return result;
+};
+
+void PrintHandle(void *handle, Str8 string)
+{
+    DWORD bytes_written = 0;
+    WriteFile(handle, string.data, CAST(DWORD)string.size, &bytes_written, NULL);
+    (void)bytes_written;
+}
+
+void Print(Str8 string)
+{
+    if (pap_globals.stdout_handle == NULL) {
+        pap_globals.stdout_handle = GetStdHandle(STD_OUTPUT_HANDLE);
+        DWORD mode = 0;
+        BOOL get_console_mode_result = GetConsoleMode(
+          /*HANDLE  hConsoleHandle*/ pap_globals.stdout_handle,
+          /*LPDWORD lpMode*/ &mode
+        );
+        pap_globals.write_to_console = get_console_mode_result != 0;
+    }
+
+
+    ASSERT(string.size < CAST(DWORD)-1);
+    if (pap_globals.write_to_console) {
+        DWORD chars_written = 0;
+        WriteConsoleA(pap_globals.stdout_handle, string.data, (DWORD)string.size, &chars_written, NULL);
+    } else {
+        PrintHandle(pap_globals.stdout_handle, string);
+    }
+}
+
+void PrintFmt(char const *fmt, ...)
+{
+    va_list args, args_copy;
+    va_start(args, fmt);
+
+    va_copy(args_copy, args);
+    int string_size = vsnprintf(NULL, 0, fmt, args_copy);
+    va_end(args_copy);
+
+    char buffer[8192];
+    ASSERT(string_size >= 0 && string_size < ARRAY_UCOUNT(buffer));
+    if (string_size) {
+        vsnprintf(buffer, sizeof(buffer), fmt, args);
+        Str8 string = {.data = buffer, .size = string_size};
+        Print(string);
+    }
+
+    va_end(args);
+}
+
+void PrintLn(Str8 string)
+{
+    Print(string);
+    Print(STR8("\n"));
+}
+
+void PrintLnFmt(char const *fmt, ...)
+{
+    va_list args, args_copy;
+    va_start(args, fmt);
+
+    va_copy(args_copy, args);
+    int string_size = vsnprintf(NULL, 0, fmt, args_copy);
+    va_end(args_copy);
+
+    char buffer[8192];
+    ASSERT(string_size >= 0 && string_size < ARRAY_UCOUNT(buffer));
+    if (string_size) {
+        vsnprintf(buffer, sizeof(buffer), fmt, args);
+        Str8 string = {.data = buffer, .size = string_size};
+        PrintLn(string);
+    }
+
+    va_end(args);
+}

part3/base.h

@@ -0,0 +1,145 @@
+#include <stdint.h>
+
+// NOTE: Macros ////////////////////////////////////////////////////////////////////////////////////
+#define STRINGIFY2(token) #token
+#define STRINGIFY(token) STRINGIFY2(token)
+
+#if defined(NDEBUG)
+    #define ASSERT(expr)
+#else
+    #define ASSERT(expr)                                                                         \
+        if (!(expr)) {                                                                               \
+            PrintLnFmt("Assertion triggered [file=\"" __FILE__ ":" STRINGIFY(__LINE__) "\", expr=\"" #expr "\"]");                                                                     \
+            __debugbreak();                                                                          \
+        }
+#endif
+
+#define ARRAY_UCOUNT(array) sizeof((array)) / sizeof((array)[0])
+#define CAST(Type) (Type)
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+typedef float    f32;
+typedef double   f64;
+typedef bool     b32;
+typedef uint8_t  u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+// NOTE: Globals ///////////////////////////////////////////////////////////////////////////////////
+typedef struct Globals {
+    HANDLE stdout_handle;
+    bool   write_to_console;
+} Globals;
+
+Globals pap_globals;
+
+// NOTE: Strings ///////////////////////////////////////////////////////////////////////////////////
+typedef struct Str8 {
+    char *data;
+    size_t size;
+} Str8;
+
+typedef struct Str8ToU64Result {
+    bool     success;
+    uint64_t value;
+} Str8ToU64Result;
+
+typedef struct Str8BinarySplitResult {
+    Str8 lhs;
+    Str8 rhs;
+} Str8BinarySplitResult;
+
+#define STR8(string) (Str8){.data = (char *)(string), .size = ARRAY_UCOUNT(string) - 1 }
+#define STR8_FMT(string) (int)((string).size), (string).data
+
+bool                  Str8_Equals(Str8 lhs, Str8 rhs);
+Str8ToU64Result       Str8_ToU64(Str8 string);
+Str8BinarySplitResult Str8_BinarySplit(Str8 buffer, Str8 find);
+
+bool                  CharIsWhiteSpace(char ch);
+bool                  CharIsDigit(char ch);
+
+// NOTE: Profiler //////////////////////////////////////////////////////////////////////////////////
+typedef struct ProfilerAnchor {
+    Str8 label;
+    u64      elapsed_tsc_exclusive; // Does not include children
+    u64      elapsed_tsc_inclusive; // Includes children
+    u64      byte_count;
+    u64      hits;
+} ProfilerAnchor;
+
+typedef struct Profiler {
+    ProfilerAnchor anchors[4096];
+    u64            begin_tsc;
+    u64            end_tsc;
+    u64            parent_index;
+} Profiler;
+
+typedef struct ProfilerZone {
+    u64      parent_index;
+    uint32_t index;
+    Str8     label;
+    u64      elapsed_tsc_inclusive;
+    u64      tsc;
+    u64      byte_count;
+} ProfilerZone;
+
+static Profiler g_profiler;
+
+#define Profiler_BeginZone(label) Profiler_BeginZone_(STR8(label), __COUNTER__ + 1, 0)
+#define Profiler_BeginZoneBandwidth(label, byte_count) Profiler_BeginZone_(STR8(label), __COUNTER__ + 1, byte_count)
+
+static void         Profiler_Dump      ();
+static ProfilerZone Profiler_BeginZone_(Str8 label, uint32_t index, u64 byte_count);
+static void         Profiler_EndZone   (ProfilerZone zone);
+
+// NOTE: PCG32 /////////////////////////////////////////////////////////////////////////////////////
+// NOTE: PCG RNG from Demetri Spanos: https://github.com/demetri/scribbles
+// pcg32_pie, based on the minimal C version from O'Neill at pcg-random.org;
+// I've made a few (subjective) UX improvements for beginner use
+//
+// I'm not allowing the user to pick the stream/increment constant at all,
+// since there is almost never a reason for doing this in common applications.
+// This means that the prng state is reduced to a single uint64_t which also
+// means we can avoid having a state struct at all. The (fixed) stream constant
+// uses the leading hex digits of pi and e multipled by 2^30 (c90fdaa2 and
+// adf85459).
+//
+// I have also added an XOR with the same digits on the output path prior
+// to xorshift mixing.  This prevents the "surprising" result that the 
+// first "random 32-bit number" from a (very common) 0 seed is 0.
+//
+// use:
+//   uint64_t state = 12345; // whatever you like can go here
+//   uint32_t some_random_32_bits = pcg32_pie(&state);
+//   uint32_t more_random_32_bits = pcg32_pie(&state);
+uint32_t PCG32_Pie   (uint64_t *state);
+f64      PCG32_PieF64(uint64_t *state, f64 min, f64 max);
+
+// NOTE: Buffer ////////////////////////////////////////////////////////////////////////////////////
+typedef struct Buffer {
+    char *data;
+    size_t size;
+} Buffer;
+
+typedef struct BufferIterator {
+    Buffer buffer;
+    size_t     index;
+} BufferIterator;
+
+bool           BufferIsValid             (Buffer buffer);
+BufferIterator BufferIteratorInit        (Buffer buffer);
+bool           BufferIteratorHasMoreBytes(BufferIterator it);
+uint8_t        BufferIteratorNextByte    (BufferIterator *it);
+
+// NOTE: File //////////////////////////////////////////////////////////////////////////////////////
+Buffer FileRead (char const *file_path);
+void   FileFree (Buffer buffer);
+bool   FileWrite(char const *file_path, void const *buffer, size_t buffer_size);
+
+// NOTE: Print /////////////////////////////////////////////////////////////////////////////////////
+void PrintHandle(void *handle, Str8 string);
+void PrintLn    (Str8 string);
+void PrintLnFmt (char const *fmt, ...);

part3/listing_0065_haversine_formula.cpp

@@ -0,0 +1,53 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 65
+   ======================================================================== */
+
+static f64 Square(f64 A)
+{
+    f64 Result = (A*A);
+    return Result;
+}
+
+static f64 RadiansFromDegrees(f64 Degrees)
+{
+    f64 Result = 0.01745329251994329577 * Degrees;
+    return Result;
+}
+
+// NOTE(casey): EarthRadius is generally expected to be 6372.8
+static f64 ReferenceHaversine(f64 X0, f64 Y0, f64 X1, f64 Y1, f64 EarthRadius)
+{
+    /* NOTE(casey): This is not meant to be a "good" way to calculate the Haversine distance.
+       Instead, it attempts to follow, as closely as possible, the formula used in the real-world
+       question on which these homework exercises are loosely based.
+    */
+    
+    f64 lat1 = Y0;
+    f64 lat2 = Y1;
+    f64 lon1 = X0;
+    f64 lon2 = X1;
+    
+    f64 dLat = RadiansFromDegrees(lat2 - lat1);
+    f64 dLon = RadiansFromDegrees(lon2 - lon1);
+    lat1 = RadiansFromDegrees(lat1);
+    lat2 = RadiansFromDegrees(lat2);
+    
+    f64 a = Square(sin(dLat/2.0)) + cos(lat1)*cos(lat2)*Square(sin(dLon/2));
+    f64 c = 2.0*asin(sqrt(a));
+    
+    f64 Result = EarthRadius * c;
+    
+    return Result;
+}

part3/listing_0068_buffer.cpp

@@ -0,0 +1,72 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 68
+   ======================================================================== */
+
+struct buffer
+{
+    size_t Count;
+    u8 *Data;
+};
+
+#define CONSTANT_STRING(String) {sizeof(String) - 1, (u8 *)(String)}
+
+static b32 IsInBounds(buffer Source, u64 At)
+{
+    b32 Result = (At < Source.Count);
+    return Result;
+}
+
+static b32 AreEqual(buffer A, buffer B)
+{
+    if(A.Count != B.Count)
+    {
+        return false;
+    }
+    
+    for(u64 Index = 0; Index < A.Count; ++Index)
+    {
+        if(A.Data[Index] != B.Data[Index])
+        {
+            return false;
+        }
+    }
+    
+    return true;
+}
+
+static buffer AllocateBuffer(size_t Count)
+{
+    buffer Result = {};
+    Result.Data = (u8 *)malloc(Count);
+    if(Result.Data)
+    {
+        Result.Count = Count;
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to allocate %llu bytes.\n", Count);
+    }
+    
+    return Result;
+}
+
+static void FreeBuffer(buffer *Buffer)
+{
+    if(Buffer->Data)
+    {
+        free(Buffer->Data);
+    }
+    *Buffer = {};
+}

part3/listing_0074_platform_metrics.cpp

@@ -0,0 +1,98 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 74
+   ======================================================================== */
+
+#if _WIN32
+
+#include <intrin.h>
+#include <windows.h>
+
+static u64 GetOSTimerFreq(void)
+{
+	LARGE_INTEGER Freq;
+	QueryPerformanceFrequency(&Freq);
+	return Freq.QuadPart;
+}
+
+static u64 ReadOSTimer(void)
+{
+	LARGE_INTEGER Value;
+	QueryPerformanceCounter(&Value);
+	return Value.QuadPart;
+}
+
+#else
+
+#include <x86intrin.h>
+#include <sys/time.h>
+
+static u64 GetOSTimerFreq(void)
+{
+	return 1000000;
+}
+
+static u64 ReadOSTimer(void)
+{
+	// NOTE(casey): The "struct" keyword is not necessary here when compiling in C++,
+	// but just in case anyone is using this file from C, I include it.
+	struct timeval Value;
+	gettimeofday(&Value, 0);
+	
+	u64 Result = GetOSTimerFreq()*(u64)Value.tv_sec + (u64)Value.tv_usec;
+	return Result;
+}
+
+#endif
+
+/* NOTE(casey): This does not need to be "inline", it could just be "static"
+   because compilers will inline it anyway. But compilers will warn about 
+   static functions that aren't used. So "inline" is just the simplest way 
+   to tell them to stop complaining about that. */
+inline u64 ReadCPUTimer(void)
+{
+	// NOTE(casey): If you were on ARM, you would need to replace __rdtsc
+	// with one of their performance counter read instructions, depending
+	// on which ones are available on your platform.
+	
+	return __rdtsc();
+}
+
+static u64 EstimateCPUTimerFreq(void)
+{
+	u64 MillisecondsToWait = 100;
+	u64 OSFreq = GetOSTimerFreq();
+
+	u64 CPUStart = ReadCPUTimer();
+	u64 OSStart = ReadOSTimer();
+	u64 OSEnd = 0;
+	u64 OSElapsed = 0;
+	u64 OSWaitTime = OSFreq * MillisecondsToWait / 1000;
+	while(OSElapsed < OSWaitTime)
+	{
+		OSEnd = ReadOSTimer();
+		OSElapsed = OSEnd - OSStart;
+	}
+	
+	u64 CPUEnd = ReadCPUTimer();
+	u64 CPUElapsed = CPUEnd - CPUStart;
+	
+	u64 CPUFreq = 0;
+	if(OSElapsed)
+	{
+		CPUFreq = OSFreq * CPUElapsed / OSElapsed;
+	}
+	
+	return CPUFreq;
+}

part3/listing_0094_profiled_lookup_json_parser.cpp

@@ -0,0 +1,516 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 94
+   ======================================================================== */
+
+enum json_token_type
+{
+    Token_end_of_stream,
+    Token_error,
+    
+    Token_open_brace,
+    Token_open_bracket,
+    Token_close_brace,
+    Token_close_bracket,
+    Token_comma,
+    Token_colon,
+    Token_string_literal,
+    Token_number,
+    Token_true,
+    Token_false,
+    Token_null,
+    
+    Token_count,
+};
+
+struct json_token
+{
+    json_token_type Type;
+    buffer Value;
+};
+
+struct json_element
+{
+    buffer Label;
+    buffer Value;
+    json_element *FirstSubElement;
+    
+    json_element *NextSibling;
+};
+
+struct json_parser
+{
+    buffer Source;
+    u64 At;
+    b32 HadError;
+};
+
+static b32 IsJSONDigit(buffer Source, u64 At)
+{
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val >= '0') && (Val <= '9'));
+    }
+    
+    return Result;
+}
+
+static b32 IsJSONWhitespace(buffer Source, u64 At)
+{
+    b32 Result = false;
+    if(IsInBounds(Source, At))
+    {
+        u8 Val = Source.Data[At];
+        Result = ((Val == ' ') || (Val == '\t') || (Val == '\n') || (Val == '\r'));
+    }
+    
+    return Result;
+}
+
+static b32 IsParsing(json_parser *Parser)
+{
+    b32 Result = !Parser->HadError && IsInBounds(Parser->Source, Parser->At);
+    return Result;
+}
+
+static void Error(json_parser *Parser, json_token Token, char const *Message)
+{
+    Parser->HadError = true;
+    fprintf(stderr, "ERROR: \"%.*s\" - %s\n", (u32)Token.Value.Count, (char *)Token.Value.Data, Message);
+}
+
+static void ParseKeyword(buffer Source, u64 *At, buffer KeywordRemaining, json_token_type Type, json_token *Result)
+{
+    if((Source.Count - *At) >= KeywordRemaining.Count)
+    {
+        buffer Check = Source;
+        Check.Data += *At;
+        Check.Count = KeywordRemaining.Count;
+        if(AreEqual(Check, KeywordRemaining))
+        {
+            Result->Type = Type;
+            Result->Value.Count += KeywordRemaining.Count;
+            *At += KeywordRemaining.Count;
+        }
+    }
+}
+
+static json_token GetJSONToken(json_parser *Parser)
+{
+    json_token Result = {};
+    
+    buffer Source = Parser->Source;
+    u64 At = Parser->At;
+    
+    while(IsJSONWhitespace(Source, At))
+    {
+        ++At;
+    }
+    
+    if(IsInBounds(Source, At))
+    {
+        Result.Type = Token_error;
+        Result.Value.Count = 1;
+        Result.Value.Data = Source.Data + At;
+        u8 Val = Source.Data[At++];
+        switch(Val)
+        {
+            case '{': {Result.Type = Token_open_brace;} break;
+            case '[': {Result.Type = Token_open_bracket;} break;
+            case '}': {Result.Type = Token_close_brace;} break;
+            case ']': {Result.Type = Token_close_bracket;} break;
+            case ',': {Result.Type = Token_comma;} break;
+            case ':': {Result.Type = Token_colon;} break;
+
+            case 'f':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("alse"), Token_false, &Result);
+            } break;
+            
+            case 'n':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("ull"), Token_null, &Result);
+            } break;
+            
+            case 't':
+            {
+                ParseKeyword(Source, &At, CONSTANT_STRING("rue"), Token_true, &Result);
+            } break;
+            
+            case '"':
+            {
+                Result.Type = Token_string_literal;
+                
+                u64 StringStart = At;
+                
+                while(IsInBounds(Source, At) && (Source.Data[At] != '"'))
+                {
+                    if(IsInBounds(Source, (At + 1)) &&
+                       (Source.Data[At] == '\\') &&
+                       (Source.Data[At + 1] == '"'))
+                    {
+                        // NOTE(casey): Skip escaped quotation marks
+                        ++At;
+                    }
+                    
+                    ++At;
+                }
+                
+                Result.Value.Data = Source.Data + StringStart;
+                Result.Value.Count = At - StringStart;
+                if(IsInBounds(Source, At))
+                {
+                    ++At;
+                }
+            } break;
+
+            case '-':
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                u64 Start = At - 1;
+                Result.Type = Token_number;
+
+                // NOTE(casey): Move past a leading negative sign if one exists
+                if((Val == '-') && IsInBounds(Source, At))
+                {
+                    Val = Source.Data[At++];
+                }
+                
+                // NOTE(casey): If the leading digit wasn't 0, parse any digits before the decimal point
+                if(Val != '0')
+                {
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If there is a decimal point, parse any digits after the decimal point
+                if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+                {
+                    ++At;
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                // NOTE(casey): If it's in scientific notation, parse any digits after the "e"
+                if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+                {
+                    ++At;
+                    
+                    if(IsInBounds(Source, At) && ((Source.Data[At] == '+') || (Source.Data[At] == '-')))
+                    {
+                        ++At;
+                    }
+                    
+                    while(IsJSONDigit(Source, At))
+                    {
+                        ++At;
+                    }
+                }
+                
+                Result.Value.Count = At - Start;
+            } break;
+            
+            default:
+            {
+            } break;
+        }
+    }
+    
+    Parser->At = At;
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels);
+static json_element *ParseJSONElement(json_parser *Parser, buffer Label, json_token Value)
+{
+    b32 Valid = true;
+    
+    json_element *SubElement = 0;
+    if(Value.Type == Token_open_bracket)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_bracket, false);
+    }
+    else if(Value.Type == Token_open_brace)
+    {
+        SubElement = ParseJSONList(Parser, Token_close_brace, true);
+    }
+    else if((Value.Type == Token_string_literal) ||
+            (Value.Type == Token_true) ||
+            (Value.Type == Token_false) ||
+            (Value.Type == Token_null) ||
+            (Value.Type == Token_number))
+    {
+        // NOTE(casey): Nothing to do here, since there is no additional data
+    }
+    else
+    {
+        Valid = false;
+    }
+    
+    json_element *Result = 0;
+    
+    if(Valid)
+    {
+        Result = (json_element *)malloc(sizeof(json_element));
+        Result->Label = Label;
+        Result->Value = Value.Value;
+        Result->FirstSubElement = SubElement;
+        Result->NextSibling = 0;
+    }
+    
+    return Result;
+}
+
+static json_element *ParseJSONList(json_parser *Parser, json_token_type EndType, b32 HasLabels)
+{
+    json_element *FirstElement = {};
+    json_element *LastElement = {};
+    
+    while(IsParsing(Parser))
+    {
+        buffer Label = {};
+        json_token Value = GetJSONToken(Parser);
+        if(HasLabels)
+        {
+            if(Value.Type == Token_string_literal)
+            {
+                Label = Value.Value;
+                
+                json_token Colon = GetJSONToken(Parser);
+                if(Colon.Type == Token_colon)
+                {
+                    Value = GetJSONToken(Parser);
+                }
+                else
+                {
+                    Error(Parser, Colon, "Expected colon after field name");
+                }
+            }
+            else if(Value.Type != EndType)
+            {
+                Error(Parser, Value, "Unexpected token in JSON");
+            }
+        }
+        
+        json_element *Element = ParseJSONElement(Parser, Label, Value);
+        if(Element)
+        {
+            LastElement = (LastElement ? LastElement->NextSibling : FirstElement) = Element;
+        }
+        else if(Value.Type == EndType)
+        {
+            break;
+        }
+        else
+        {
+            Error(Parser, Value, "Unexpected token in JSON");
+        }
+        
+        json_token Comma = GetJSONToken(Parser);
+        if(Comma.Type == EndType)
+        {
+            break;
+        }
+        else if(Comma.Type != Token_comma)
+        {
+            Error(Parser, Comma, "Unexpected token in JSON");
+        }
+    }
+    
+    return FirstElement;
+}
+
+static json_element *ParseJSON(buffer InputJSON)
+{
+    TimeFunction;
+    
+    json_parser Parser = {};
+    Parser.Source = InputJSON;
+    
+    json_element *Result = ParseJSONElement(&Parser, {}, GetJSONToken(&Parser));
+    return Result;
+}
+
+static void FreeJSON(json_element *Element)
+{
+    while(Element)
+    {
+        json_element *FreeElement = Element;
+        Element = Element->NextSibling;
+    
+        FreeJSON(FreeElement->FirstSubElement);
+        free(FreeElement);
+    }
+}
+
+static json_element *LookupElement(json_element *Object, buffer ElementName)
+{
+    json_element *Result = 0;
+    
+    if(Object)
+    {
+        for(json_element *Search = Object->FirstSubElement; Search; Search = Search->NextSibling)
+        {
+            if(AreEqual(Search->Label, ElementName))
+            {
+                Result = Search;
+                break;
+            }
+        }
+    }
+    
+    return Result;
+}
+
+static f64 ConvertJSONSign(buffer Source, u64 *AtResult)
+{
+    u64 At = *AtResult;
+
+    f64 Result = 1.0;
+    if(IsInBounds(Source, At) && (Source.Data[At] == '-'))
+    {
+        Result = -1.0;
+        ++At;
+    }
+    
+    *AtResult = At;
+
+    return Result;
+}
+
+static f64 ConvertJSONNumber(buffer Source, u64 *AtResult)
+{
+    u64 At = *AtResult;
+    
+    f64 Result = 0.0;
+    while(IsInBounds(Source, At))
+    {
+        u8 Char = Source.Data[At] - (u8)'0';
+        if(Char < 10)
+        {
+            Result = 10.0*Result + (f64)Char;
+            ++At;
+        }
+        else
+        {
+            break;
+        }
+    }
+    
+    *AtResult = At;
+    
+    return Result;
+}
+
+static f64 ConvertElementToF64(json_element *Object, buffer ElementName)
+{
+    f64 Result = 0.0;
+    
+    json_element *Element = LookupElement(Object, ElementName);
+    if(Element)
+    {
+        buffer Source = Element->Value;
+        u64 At = 0;
+        
+        f64 Sign = ConvertJSONSign(Source, &At);
+        f64 Number = ConvertJSONNumber(Source, &At);
+        
+        if(IsInBounds(Source, At) && (Source.Data[At] == '.'))
+        {
+            ++At;
+            f64 C = 1.0 / 10.0;
+            while(IsInBounds(Source, At))
+            {
+                u8 Char = Source.Data[At] - (u8)'0';
+                if(Char < 10)
+                {
+                    Number = Number + C*(f64)Char;
+                    C *= 1.0 / 10.0;
+                    ++At;
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+        
+        if(IsInBounds(Source, At) && ((Source.Data[At] == 'e') || (Source.Data[At] == 'E')))
+        {
+            ++At;
+            if(IsInBounds(Source, At) && (Source.Data[At] == '+'))
+            {
+                ++At;
+            }
+
+            f64 ExponentSign = ConvertJSONSign(Source, &At);
+            f64 Exponent = ExponentSign*ConvertJSONNumber(Source, &At);
+            Number *= pow(10.0, Exponent);
+        }
+        
+        Result = Sign*Number;
+    }
+    
+    return Result;
+}
+
+static u64 ParseHaversinePairs(buffer InputJSON, u64 MaxPairCount, haversine_pair *Pairs)
+{
+    TimeFunction;
+    
+    u64 PairCount = 0;
+    
+    json_element *JSON = ParseJSON(InputJSON);
+    
+    json_element *PairsArray = LookupElement(JSON, CONSTANT_STRING("pairs"));
+    if(PairsArray)
+    {
+        TimeBlock("Lookup and Convert");
+        
+        for(json_element *Element = PairsArray->FirstSubElement;
+            Element && (PairCount < MaxPairCount);
+            Element = Element->NextSibling)
+        {
+            haversine_pair *Pair = Pairs + PairCount++;
+            
+            Pair->X0 = ConvertElementToF64(Element, CONSTANT_STRING("x0"));
+            Pair->Y0 = ConvertElementToF64(Element, CONSTANT_STRING("y0"));
+            Pair->X1 = ConvertElementToF64(Element, CONSTANT_STRING("x1"));
+            Pair->Y1 = ConvertElementToF64(Element, CONSTANT_STRING("y1"));
+        }
+    }
+   
+    {
+        TimeBlock("FreeJSON");
+        FreeJSON(JSON);
+    }
+    
+    return PairCount;
+}

part3/listing_0100_bandwidth_profiler.cpp

@@ -0,0 +1,194 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 100
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+#ifndef PROFILER
+#define PROFILER 0
+#endif
+
+#ifndef READ_BLOCK_TIMER
+#define READ_BLOCK_TIMER ReadCPUTimer
+#endif
+
+#if PROFILER
+
+struct profile_anchor
+{
+    u64 TSCElapsedExclusive; // NOTE(casey): Does NOT include children
+    u64 TSCElapsedInclusive; // NOTE(casey): DOES include children
+    u64 HitCount;
+    u64 ProcessedByteCount;
+    char const *Label;
+};
+static profile_anchor GlobalProfilerAnchors[4096];
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_, u64 ByteCount)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        OldTSCElapsedInclusive = Anchor->TSCElapsedInclusive;
+        Anchor->ProcessedByteCount += ByteCount;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = READ_BLOCK_TIMER();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = READ_BLOCK_TIMER() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+    
+        profile_anchor *Parent = GlobalProfilerAnchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        
+        Parent->TSCElapsedExclusive -= Elapsed;
+        Anchor->TSCElapsedExclusive += Elapsed;
+        Anchor->TSCElapsedInclusive = OldTSCElapsedInclusive + Elapsed;
+        ++Anchor->HitCount;
+        
+        /* NOTE(casey): This write happens every time solely because there is no
+           straightforward way in C++ to have the same ease-of-use. In a better programming
+           language, it would be simple to have the anchor points gathered and labeled at compile
+           time, and this repetative write would be eliminated. */
+        Anchor->Label = Label;
+    }
+    
+    char const *Label;
+    u64 OldTSCElapsedInclusive;
+    u64 StartTSC;
+    u32 ParentIndex;
+    u32 AnchorIndex;
+};
+
+#define NameConcat2(A, B) A##B
+#define NameConcat(A, B) NameConcat2(A, B)
+#define TimeBandwidth(Name, ByteCount) profile_block NameConcat(Block, __LINE__)(Name, __COUNTER__ + 1, ByteCount)
+#define ProfilerEndOfCompilationUnit static_assert(__COUNTER__ < ArrayCount(GlobalProfilerAnchors), "Number of profile points exceeds size of profiler::Anchors array")
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, u64 TimerFreq, profile_anchor *Anchor)
+{
+    f64 Percent = 100.0 * ((f64)Anchor->TSCElapsedExclusive / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%", Anchor->Label, Anchor->HitCount, Anchor->TSCElapsedExclusive, Percent);
+    if(Anchor->TSCElapsedInclusive != Anchor->TSCElapsedExclusive)
+    {
+        f64 PercentWithChildren = 100.0 * ((f64)Anchor->TSCElapsedInclusive / (f64)TotalTSCElapsed);
+        printf(", %.2f%% w/children", PercentWithChildren);
+    }
+    printf(")");
+    
+    if(Anchor->ProcessedByteCount)
+    {
+        f64 Megabyte = 1024.0f*1024.0f;
+        f64 Gigabyte = Megabyte*1024.0f;
+        
+        f64 Seconds = (f64)Anchor->TSCElapsedInclusive / (f64)TimerFreq;
+        f64 BytesPerSecond = (f64)Anchor->ProcessedByteCount / Seconds;
+        f64 Megabytes = (f64)Anchor->ProcessedByteCount / (f64)Megabyte;
+        f64 GigabytesPerSecond = BytesPerSecond / Gigabyte;
+        
+        printf("  %.3fmb at %.2fgb/s", Megabytes, GigabytesPerSecond);
+    }
+    
+    printf("\n");
+}
+
+static void PrintAnchorData(u64 TotalCPUElapsed, u64 TimerFreq)
+{
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfilerAnchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfilerAnchors + AnchorIndex;
+        if(Anchor->TSCElapsedInclusive)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, TimerFreq, Anchor);
+        }
+    }
+}
+
+#else
+
+#define TimeBandwidth(...)
+#define PrintAnchorData(...)
+#define ProfilerEndOfCompilationUnit
+
+#endif
+
+struct profiler
+{
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+
+#define TimeBlock(Name) TimeBandwidth(Name, 0)
+#define TimeFunction TimeBlock(__func__)
+
+static u64 EstimateBlockTimerFreq(void)
+{
+    (void)&EstimateCPUTimerFreq; // NOTE(casey): This has to be voided here to prevent compilers from warning us that it is not used
+    
+	u64 MillisecondsToWait = 100;
+	u64 OSFreq = GetOSTimerFreq();
+
+	u64 BlockStart = READ_BLOCK_TIMER();
+	u64 OSStart = ReadOSTimer();
+	u64 OSEnd = 0;
+	u64 OSElapsed = 0;
+	u64 OSWaitTime = OSFreq * MillisecondsToWait / 1000;
+	while(OSElapsed < OSWaitTime)
+	{
+		OSEnd = ReadOSTimer();
+		OSElapsed = OSEnd - OSStart;
+	}
+	
+	u64 BlockEnd = READ_BLOCK_TIMER();
+	u64 BlockElapsed = BlockEnd - BlockStart;
+	
+	u64 BlockFreq = 0;
+	if(OSElapsed)
+	{
+		BlockFreq = OSFreq * BlockElapsed / OSElapsed;
+	}
+	
+	return BlockFreq;
+}
+
+static void BeginProfile(void)
+{
+    GlobalProfiler.StartTSC = READ_BLOCK_TIMER();
+}
+
+static void EndAndPrintProfile()
+{
+    GlobalProfiler.EndTSC = READ_BLOCK_TIMER();
+    u64 TimerFreq = EstimateBlockTimerFreq();
+    
+    u64 TotalTSCElapsed = GlobalProfiler.EndTSC - GlobalProfiler.StartTSC;
+    
+    if(TimerFreq)
+    {
+        printf("\nTotal time: %0.4fms (timer freq %llu)\n", 1000.0 * (f64)TotalTSCElapsed / (f64)TimerFreq, TimerFreq);
+    }
+    
+    PrintAnchorData(TotalTSCElapsed, TimerFreq);
+}

part3/listing_0101_read_bandwidth_main.cpp

@@ -0,0 +1,186 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 101
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+struct haversine_pair
+{
+    f64 X0, Y0;
+    f64 X1, Y1;
+};
+
+#define PROFILER 1
+#include "listing_0100_bandwidth_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0094_profiled_lookup_json_parser.cpp"
+
+static buffer ReadEntireFile(char *FileName)
+{
+    TimeFunction;
+    
+    buffer Result = {};
+        
+    FILE *File = fopen(FileName, "rb");
+    if(File)
+    {
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        Result = AllocateBuffer(Stat.st_size);
+        if(Result.Data)
+        {
+            TimeBandwidth("fread", Result.Count);
+            if(fread(Result.Data, Result.Count, 1, File) != 1)
+            {
+                fprintf(stderr, "ERROR: Unable to read \"%s\".\n", FileName);
+                FreeBuffer(&Result);
+            }
+        }
+        
+        fclose(File);
+    }
+    else
+    {
+        fprintf(stderr, "ERROR: Unable to open \"%s\".\n", FileName);
+    }
+    
+    return Result;
+}
+
+static f64 SumHaversineDistances(u64 PairCount, haversine_pair *Pairs)
+{
+    TimeBandwidth(__func__, PairCount*sizeof(haversine_pair));
+    
+    f64 Sum = 0;
+    
+    f64 SumCoef = 1 / (f64)PairCount;
+    for(u64 PairIndex = 0; PairIndex < PairCount; ++PairIndex)
+    {
+        haversine_pair Pair = Pairs[PairIndex];
+        f64 EarthRadius = 6372.8;
+        f64 Dist = ReferenceHaversine(Pair.X0, Pair.Y0, Pair.X1, Pair.Y1, EarthRadius);
+        Sum += SumCoef*Dist;
+    }
+    
+    return Sum;
+}
+
+int main(int ArgCount, char **Args)
+{
+    BeginProfile();
+	
+    int Result = 1;
+    
+    if((ArgCount == 2) || (ArgCount == 3))
+    {
+        buffer InputJSON = ReadEntireFile(Args[1]);
+        
+        u32 MinimumJSONPairEncoding = 6*4;
+        u64 MaxPairCount = InputJSON.Count / MinimumJSONPairEncoding;
+        if(MaxPairCount)
+        {
+            buffer ParsedValues = AllocateBuffer(MaxPairCount * sizeof(haversine_pair));
+            if(ParsedValues.Count)
+            {
+                haversine_pair *Pairs = (haversine_pair *)ParsedValues.Data;
+				
+                u64 PairCount = ParseHaversinePairs(InputJSON, MaxPairCount, Pairs);
+                f64 Sum = SumHaversineDistances(PairCount, Pairs);
+                
+				Result = 0;
+
+                fprintf(stdout, "Input size: %llu\n", InputJSON.Count);
+                fprintf(stdout, "Pair count: %llu\n", PairCount);
+                fprintf(stdout, "Haversine sum: %.16f\n", Sum);
+                
+                if(ArgCount == 3)
+                {
+                    buffer AnswersF64 = ReadEntireFile(Args[2]);
+                    if(AnswersF64.Count >= sizeof(f64))
+                    {
+                        f64 *AnswerValues = (f64 *)AnswersF64.Data;
+                        
+                        fprintf(stdout, "\nValidation:\n");
+                        
+                        u64 RefAnswerCount = (AnswersF64.Count - sizeof(f64)) / sizeof(f64);
+                        if(PairCount != RefAnswerCount)
+                        {
+                            fprintf(stdout, "FAILED - pair count doesn't match %llu.\n", RefAnswerCount);
+                        }
+                        
+                        f64 RefSum = AnswerValues[RefAnswerCount];
+                        fprintf(stdout, "Reference sum: %.16f\n", RefSum);
+                        fprintf(stdout, "Difference: %.16f\n", Sum - RefSum);
+                        
+                        fprintf(stdout, "\n");
+                    }
+                }
+            }
+            
+            FreeBuffer(&ParsedValues);
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Malformed input JSON\n");
+        }
+
+        FreeBuffer(&InputJSON);
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [haversine_input.json]\n", Args[0]);
+        fprintf(stderr, "       %s [haversine_input.json] [answers.f64]\n", Args[0]);
+    }
+
+    if(Result == 0)
+	{
+        EndAndPrintProfile();
+	}
+		
+    return Result;
+}
+
+ProfilerEndOfCompilationUnit;

part3/listing_0102_read_overhead_test.cpp

@@ -0,0 +1,151 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 102
+   ======================================================================== */
+
+#include <windows.h>
+#include <fcntl.h>
+#include <io.h>
+
+struct read_parameters
+{
+    buffer Dest;
+    char const *FileName;
+};
+
+typedef void read_overhead_test_func(repetition_tester *Tester, read_parameters *Params);
+
+static void ReadViaFRead(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        FILE *File = fopen(Params->FileName, "rb");
+        if(File)
+        {
+            buffer DestBuffer = Params->Dest;
+            
+            BeginTime(Tester);
+            size_t Result = fread(DestBuffer.Data, DestBuffer.Count, 1, File);
+            EndTime(Tester);
+            
+            if(Result == 1)
+            {
+                CountBytes(Tester, DestBuffer.Count);
+            }
+            else
+            {
+                Error(Tester, "fread failed");
+            }
+            
+            fclose(File);
+        }
+        else
+        {
+            Error(Tester, "fopen failed");
+        }
+    }
+}
+
+static void ReadViaRead(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        int File = _open(Params->FileName, _O_BINARY|_O_RDONLY);
+        if(File != -1)
+        {
+            buffer DestBuffer = Params->Dest;
+        
+            u8 *Dest = DestBuffer.Data;
+            u64 SizeRemaining = DestBuffer.Count;
+            while(SizeRemaining)
+            {
+                u32 ReadSize = INT_MAX;
+                if((u64)ReadSize > SizeRemaining)
+                {
+                    ReadSize = (u32)SizeRemaining;
+                }
+
+                BeginTime(Tester);
+                int Result = _read(File, Dest, ReadSize);
+                EndTime(Tester);
+
+                if(Result == (int)ReadSize)
+                {
+                    CountBytes(Tester, ReadSize);
+                }
+                else
+                {
+                    Error(Tester, "_read failed");
+                    break;
+                }
+                
+                SizeRemaining -= ReadSize;
+                Dest += ReadSize;
+            }
+            
+            _close(File);
+        }
+        else
+        {
+            Error(Tester, "_open failed");
+        }
+    }
+}
+
+static void ReadViaReadFile(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        HANDLE File = CreateFileA(Params->FileName, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, 0,
+                                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
+        if(File != INVALID_HANDLE_VALUE)
+        {
+            buffer DestBuffer = Params->Dest;
+            
+            u64 SizeRemaining = Params->Dest.Count;
+            u8 *Dest = (u8 *)DestBuffer.Data;
+            while(SizeRemaining)
+            {
+                u32 ReadSize = (u32)-1;
+                if((u64)ReadSize > SizeRemaining)
+                {
+                    ReadSize = (u32)SizeRemaining;
+                }
+                
+                DWORD BytesRead = 0;
+                BeginTime(Tester);
+                BOOL Result = ReadFile(File, Dest, ReadSize, &BytesRead, 0);
+                EndTime(Tester);
+                
+                if(Result && (BytesRead == ReadSize))
+                {
+                    CountBytes(Tester, ReadSize);
+                }
+                else
+                {
+                    Error(Tester, "ReadFile failed");
+                }
+                
+                SizeRemaining -= ReadSize;
+                Dest += ReadSize;
+            }
+            
+            CloseHandle(File);
+        }
+        else
+        {
+            Error(Tester, "CreateFileA failed");
+        }
+    }
+}

part3/listing_0103_repetition_tester.cpp

@@ -0,0 +1,211 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 103
+   ======================================================================== */
+
+enum test_mode : u32
+{
+    TestMode_Uninitialized,
+    TestMode_Testing,
+    TestMode_Completed,
+    TestMode_Error,
+};
+
+struct repetition_test_results
+{
+    u64 TestCount;
+    u64 TotalTime;
+    u64 MaxTime;
+    u64 MinTime;
+};
+
+struct repetition_tester
+{
+    u64 TargetProcessedByteCount;
+    u64 CPUTimerFreq;
+    u64 TryForTime;
+    u64 TestsStartedAt;
+    
+    test_mode Mode;
+    b32 PrintNewMinimums;
+    u32 OpenBlockCount;
+    u32 CloseBlockCount;
+    u64 TimeAccumulatedOnThisTest;
+    u64 BytesAccumulatedOnThisTest;
+
+    repetition_test_results Results;
+};
+
+static f64 SecondsFromCPUTime(f64 CPUTime, u64 CPUTimerFreq)
+{
+    f64 Result = 0.0;
+    if(CPUTimerFreq)
+    {
+        Result = (CPUTime / (f64)CPUTimerFreq);
+    }
+    
+    return Result;
+}
+ 
+static void PrintTime(char const *Label, f64 CPUTime, u64 CPUTimerFreq, u64 ByteCount)
+{
+    printf("%s: %.0f", Label, CPUTime);
+    if(CPUTimerFreq)
+    {
+        f64 Seconds = SecondsFromCPUTime(CPUTime, CPUTimerFreq);
+        printf(" (%fms)", 1000.0f*Seconds);
+    
+        if(ByteCount)
+        {
+            f64 Gigabyte = (1024.0f * 1024.0f * 1024.0f);
+            f64 BestBandwidth = ByteCount / (Gigabyte * Seconds);
+            printf(" %fgb/s", BestBandwidth);
+        }
+    }
+}
+
+static void PrintTime(char const *Label, u64 CPUTime, u64 CPUTimerFreq, u64 ByteCount)
+{
+    PrintTime(Label, (f64)CPUTime, CPUTimerFreq, ByteCount);
+}
+
+static void PrintResults(repetition_test_results Results, u64 CPUTimerFreq, u64 ByteCount)
+{
+    PrintTime("Min", (f64)Results.MinTime, CPUTimerFreq, ByteCount);
+    printf("\n");
+    
+    PrintTime("Max", (f64)Results.MaxTime, CPUTimerFreq, ByteCount);
+    printf("\n");
+    
+    if(Results.TestCount)
+    {
+        PrintTime("Avg", (f64)Results.TotalTime / (f64)Results.TestCount, CPUTimerFreq, ByteCount);
+        printf("\n");
+    }
+}
+
+static void Error(repetition_tester *Tester, char const *Message)
+{
+    Tester->Mode = TestMode_Error;
+    fprintf(stderr, "ERROR: %s\n", Message);
+}
+
+static void NewTestWave(repetition_tester *Tester, u64 TargetProcessedByteCount, u64 CPUTimerFreq, u32 SecondsToTry = 10)
+{
+    if(Tester->Mode == TestMode_Uninitialized)
+    {
+        Tester->Mode = TestMode_Testing;
+        Tester->TargetProcessedByteCount = TargetProcessedByteCount;
+        Tester->CPUTimerFreq = CPUTimerFreq;
+        Tester->PrintNewMinimums = true;
+        Tester->Results.MinTime = (u64)-1;
+    }
+    else if(Tester->Mode == TestMode_Completed)
+    {
+        Tester->Mode = TestMode_Testing;
+        
+        if(Tester->TargetProcessedByteCount != TargetProcessedByteCount)
+        {
+            Error(Tester, "TargetProcessedByteCount changed");
+        }
+        
+        if(Tester->CPUTimerFreq != CPUTimerFreq)
+        {
+            Error(Tester, "CPU frequency changed");
+        }
+    }
+
+    Tester->TryForTime = SecondsToTry*CPUTimerFreq;
+    Tester->TestsStartedAt = ReadCPUTimer();
+}
+
+static void BeginTime(repetition_tester *Tester)
+{
+    ++Tester->OpenBlockCount;
+    Tester->TimeAccumulatedOnThisTest -= ReadCPUTimer();
+}
+
+static void EndTime(repetition_tester *Tester)
+{
+    ++Tester->CloseBlockCount;
+    Tester->TimeAccumulatedOnThisTest += ReadCPUTimer();
+}
+
+static void CountBytes(repetition_tester *Tester, u64 ByteCount)
+{
+    Tester->BytesAccumulatedOnThisTest += ByteCount;
+}
+
+static b32 IsTesting(repetition_tester *Tester)
+{
+    if(Tester->Mode == TestMode_Testing)
+    {
+        u64 CurrentTime = ReadCPUTimer();
+        
+        if(Tester->OpenBlockCount) // NOTE(casey): We don't count tests that had no timing blocks - we assume they took some other path
+        {
+            if(Tester->OpenBlockCount != Tester->CloseBlockCount)
+            {
+                Error(Tester, "Unbalanced BeginTime/EndTime");
+            }
+            
+            if(Tester->BytesAccumulatedOnThisTest != Tester->TargetProcessedByteCount)
+            {
+                Error(Tester, "Processed byte count mismatch");
+            }
+    
+            if(Tester->Mode == TestMode_Testing)
+            {
+                repetition_test_results *Results = &Tester->Results;
+                u64 ElapsedTime = Tester->TimeAccumulatedOnThisTest;
+                Results->TestCount += 1;
+                Results->TotalTime += ElapsedTime;
+                if(Results->MaxTime < ElapsedTime)
+                {
+                    Results->MaxTime = ElapsedTime;
+                }
+                
+                if(Results->MinTime > ElapsedTime)
+                {
+                    Results->MinTime = ElapsedTime;
+                    
+                    // NOTE(casey): Whenever we get a new minimum time, we reset the clock to the full trial time
+                    Tester->TestsStartedAt = CurrentTime;
+                    
+                    if(Tester->PrintNewMinimums)
+                    {
+                        PrintTime("Min", Results->MinTime, Tester->CPUTimerFreq, Tester->BytesAccumulatedOnThisTest);
+                        printf("               \r");
+                    }
+                }
+                
+                Tester->OpenBlockCount = 0;
+                Tester->CloseBlockCount = 0;
+                Tester->TimeAccumulatedOnThisTest = 0;
+                Tester->BytesAccumulatedOnThisTest = 0;
+            }
+        }
+        
+        if((CurrentTime - Tester->TestsStartedAt) > Tester->TryForTime)
+        {
+            Tester->Mode = TestMode_Completed;
+            
+            printf("                                                          \r");
+            PrintResults(Tester->Results, Tester->CPUTimerFreq, Tester->TargetProcessedByteCount);
+        }
+    }
+    
+    b32 Result = (Tester->Mode == TestMode_Testing);
+    return Result;
+}

part3/listing_0104_read_overhead_main.cpp

@@ -0,0 +1,116 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 104
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0068_buffer.cpp"
+#include "listing_0074_platform_metrics.cpp"
+#include "listing_0103_repetition_tester.cpp"
+#include "listing_0102_read_overhead_test.cpp"
+
+struct test_function
+{
+    char const *Name;
+    read_overhead_test_func *Func;
+};
+test_function TestFunctions[] =
+{
+    {"fread", ReadViaFRead},
+    {"_read", ReadViaRead},
+    {"ReadFile", ReadViaReadFile},
+};
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&IsInBounds;
+    (void)&AreEqual;
+    
+    u64 CPUTimerFreq = EstimateCPUTimerFreq();
+    
+    if(ArgCount == 2)
+    {
+        char *FileName = Args[1];
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        read_parameters Params = {};
+        Params.Dest = AllocateBuffer(Stat.st_size);
+        Params.FileName = FileName;
+    
+        if(Params.Dest.Count > 0)
+        {
+            repetition_tester Testers[ArrayCount(TestFunctions)] = {};
+            
+            for(;;)
+            {
+                for(u32 FuncIndex = 0; FuncIndex < ArrayCount(TestFunctions); ++FuncIndex)
+                {
+                    repetition_tester *Tester = Testers + FuncIndex;
+                    test_function TestFunc = TestFunctions[FuncIndex];
+                    
+                    printf("\n--- %s ---\n", TestFunc.Name);
+                    NewTestWave(Tester, Params.Dest.Count, CPUTimerFreq);
+                    TestFunc.Func(Tester, &Params);
+                }
+            }
+            
+            // NOTE(casey): We would normally call this here, but we can't because the compiler will complain about "unreachable code".
+            // So instead we just reference the pointer to prevent the compiler complaining about unused function :(
+            (void)&FreeBuffer;
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Test data size must be non-zero\n");
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [existing filename]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/listing_0105_read_overhead_reordered_main.cpp

@@ -0,0 +1,116 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 105
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0068_buffer.cpp"
+#include "listing_0074_platform_metrics.cpp"
+#include "listing_0103_repetition_tester.cpp"
+#include "listing_0102_read_overhead_test.cpp"
+
+struct test_function
+{
+    char const *Name;
+    read_overhead_test_func *Func;
+};
+test_function TestFunctions[] =
+{
+    {"ReadFile", ReadViaReadFile},
+    {"_read", ReadViaRead},
+    {"fread", ReadViaFRead},
+};
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&IsInBounds;
+    (void)&AreEqual;
+    
+    u64 CPUTimerFreq = EstimateCPUTimerFreq();
+    
+    if(ArgCount == 2)
+    {
+        char *FileName = Args[1];
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        read_parameters Params = {};
+        Params.Dest = AllocateBuffer(Stat.st_size);
+        Params.FileName = FileName;
+    
+        if(Params.Dest.Count > 0)
+        {
+            repetition_tester Testers[ArrayCount(TestFunctions)] = {};
+            
+            for(;;)
+            {
+                for(u32 FuncIndex = 0; FuncIndex < ArrayCount(TestFunctions); ++FuncIndex)
+                {
+                    repetition_tester *Tester = Testers + FuncIndex;
+                    test_function TestFunc = TestFunctions[FuncIndex];
+                    
+                    printf("\n--- %s ---\n", TestFunc.Name);
+                    NewTestWave(Tester, Params.Dest.Count, CPUTimerFreq);
+                    TestFunc.Func(Tester, &Params);
+                }
+            }
+            
+            // NOTE(casey): We would normally call this here, but we can't because the compiler will complain about "unreachable code".
+            // So instead we just reference the pointer to prevent the compiler complaining about unused function :(
+            (void)&FreeBuffer;
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Test data size must be non-zero\n");
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [existing filename]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/listing_0106_mallocread_overhead_test.cpp

@@ -0,0 +1,219 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 106
+   ======================================================================== */
+
+#include <windows.h>
+#include <fcntl.h>
+#include <io.h>
+
+enum allocation_type
+{
+    AllocType_none,
+    AllocType_malloc,
+    
+    AllocType_Count,
+};
+
+struct read_parameters
+{
+    allocation_type AllocType;
+    buffer Dest;
+    char const *FileName;
+};
+
+typedef void read_overhead_test_func(repetition_tester *Tester, read_parameters *Params);
+
+static char const *DescribeAllocationType(allocation_type AllocType)
+{
+    char const *Result;
+    switch(AllocType)
+    {
+        case AllocType_none: {Result = "";} break;
+        case AllocType_malloc: {Result = "malloc";} break;
+        default : {Result = "UNKNOWN";} break;
+    }
+    
+    return Result;
+}
+
+static void HandleAllocation(read_parameters *Params, buffer *Buffer)
+{
+    switch(Params->AllocType)
+    {
+        case AllocType_none:
+        {
+        } break;
+        
+        case AllocType_malloc:
+        {
+            *Buffer = AllocateBuffer(Params->Dest.Count);
+        } break;
+        
+        default:
+        {
+            fprintf(stderr, "ERROR: Unrecognized allocation type");
+        } break;
+    }
+}
+
+static void HandleDeallocation(read_parameters *Params, buffer *Buffer)
+{
+    switch(Params->AllocType)
+    {
+        case AllocType_none:
+        {
+        } break;
+        
+        case AllocType_malloc:
+        {
+            FreeBuffer(Buffer);
+        } break;
+        
+        default:
+        {
+            fprintf(stderr, "ERROR: Unrecognized allocation type");
+        } break;
+    }
+}
+
+static void ReadViaFRead(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        FILE *File = fopen(Params->FileName, "rb");
+        if(File)
+        {
+            buffer DestBuffer = Params->Dest;
+            HandleAllocation(Params, &DestBuffer);
+            
+            BeginTime(Tester);
+            size_t Result = fread(DestBuffer.Data, DestBuffer.Count, 1, File);
+            EndTime(Tester);
+            
+            if(Result == 1)
+            {
+                CountBytes(Tester, DestBuffer.Count);
+            }
+            else
+            {
+                Error(Tester, "fread failed");
+            }
+            
+            HandleDeallocation(Params, &DestBuffer);
+            fclose(File);
+        }
+        else
+        {
+            Error(Tester, "fopen failed");
+        }
+    }
+}
+
+static void ReadViaRead(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        int File = _open(Params->FileName, _O_BINARY|_O_RDONLY);
+        if(File != -1)
+        {
+            buffer DestBuffer = Params->Dest;
+            HandleAllocation(Params, &DestBuffer);
+        
+            u8 *Dest = DestBuffer.Data;
+            u64 SizeRemaining = DestBuffer.Count;
+            while(SizeRemaining)
+            {
+                u32 ReadSize = INT_MAX;
+                if((u64)ReadSize > SizeRemaining)
+                {
+                    ReadSize = (u32)SizeRemaining;
+                }
+
+                BeginTime(Tester);
+                int Result = _read(File, Dest, ReadSize);
+                EndTime(Tester);
+
+                if(Result == (int)ReadSize)
+                {
+                    CountBytes(Tester, ReadSize);
+                }
+                else
+                {
+                    Error(Tester, "_read failed");
+                    break;
+                }
+                
+                SizeRemaining -= ReadSize;
+                Dest += ReadSize;
+            }
+            
+            HandleDeallocation(Params, &DestBuffer);
+            _close(File);
+        }
+        else
+        {
+            Error(Tester, "_open failed");
+        }
+    }
+}
+
+static void ReadViaReadFile(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        HANDLE File = CreateFileA(Params->FileName, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, 0,
+                                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
+        if(File != INVALID_HANDLE_VALUE)
+        {
+            buffer DestBuffer = Params->Dest;
+            HandleAllocation(Params, &DestBuffer);
+            
+            u64 SizeRemaining = Params->Dest.Count;
+            u8 *Dest = (u8 *)DestBuffer.Data;
+            while(SizeRemaining)
+            {
+                u32 ReadSize = (u32)-1;
+                if((u64)ReadSize > SizeRemaining)
+                {
+                    ReadSize = (u32)SizeRemaining;
+                }
+                
+                DWORD BytesRead = 0;
+                BeginTime(Tester);
+                BOOL Result = ReadFile(File, Dest, ReadSize, &BytesRead, 0);
+                EndTime(Tester);
+                
+                if(Result && (BytesRead == ReadSize))
+                {
+                    CountBytes(Tester, ReadSize);
+                }
+                else
+                {
+                    Error(Tester, "ReadFile failed");
+                }
+                
+                SizeRemaining -= ReadSize;
+                Dest += ReadSize;
+            }
+            
+            HandleDeallocation(Params, &DestBuffer);
+            CloseHandle(File);
+        }
+        else
+        {
+            Error(Tester, "CreateFileA failed");
+        }
+    }
+}

part3/listing_0107_mallocread_overhead_main.cpp

@@ -0,0 +1,124 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 107
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0068_buffer.cpp"
+#include "listing_0074_platform_metrics.cpp"
+#include "listing_0103_repetition_tester.cpp"
+#include "listing_0106_mallocread_overhead_test.cpp"
+
+struct test_function
+{
+    char const *Name;
+    read_overhead_test_func *Func;
+};
+test_function TestFunctions[] =
+{
+    {"fread", ReadViaFRead},
+    {"_read", ReadViaRead},
+    {"ReadFile", ReadViaReadFile},
+};
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&IsInBounds;
+    (void)&AreEqual;
+    
+    u64 CPUTimerFreq = EstimateCPUTimerFreq();
+    
+    if(ArgCount == 2)
+    {
+        char *FileName = Args[1];
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        read_parameters Params = {};
+        Params.Dest = AllocateBuffer(Stat.st_size);
+        Params.FileName = FileName;
+    
+        if(Params.Dest.Count > 0)
+        {
+            repetition_tester Testers[ArrayCount(TestFunctions)][AllocType_Count] = {};
+            
+            for(;;)
+            {
+                for(u32 FuncIndex = 0; FuncIndex < ArrayCount(TestFunctions); ++FuncIndex)
+                {
+                    for(u32 AllocType = 0; AllocType < AllocType_Count; ++AllocType)
+                    {
+                        Params.AllocType = (allocation_type)AllocType;
+                        
+                        repetition_tester *Tester = &Testers[FuncIndex][AllocType];
+                        test_function TestFunc = TestFunctions[FuncIndex];
+                        
+                        printf("\n--- %s%s%s ---\n",
+                               DescribeAllocationType(Params.AllocType),
+                               Params.AllocType ? " + " : "",
+                               TestFunc.Name);
+                        NewTestWave(Tester, Params.Dest.Count, CPUTimerFreq);
+                        TestFunc.Func(Tester, &Params);
+                    }
+                }
+            }
+            
+            // NOTE(casey): We would normally call this here, but we can't because the compiler will complain about "unreachable code".
+            // So instead we just reference the pointer to prevent the compiler complaining about unused function :(
+            (void)&FreeBuffer;
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Test data size must be non-zero\n");
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [existing filename]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/listing_0108_platform_metrics.cpp

@@ -0,0 +1,145 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 108
+   ======================================================================== */
+
+#if _WIN32
+
+#include <intrin.h>
+#include <windows.h>
+#include <psapi.h>
+
+typedef struct os_metrics
+{
+    b32 Initialized;
+    HANDLE ProcessHandle;
+} os_metrics;
+static os_metrics GlobalMetrics;
+
+static u64 GetOSTimerFreq(void)
+{
+	LARGE_INTEGER Freq;
+	QueryPerformanceFrequency(&Freq);
+	return Freq.QuadPart;
+}
+
+static u64 ReadOSTimer(void)
+{
+	LARGE_INTEGER Value;
+	QueryPerformanceCounter(&Value);
+	return Value.QuadPart;
+}
+
+static u64 ReadOSPageFaultCount(void)
+{
+    PROCESS_MEMORY_COUNTERS_EX MemoryCounters = {};
+    MemoryCounters.cb = sizeof(MemoryCounters);
+    GetProcessMemoryInfo(GlobalMetrics.ProcessHandle, (PROCESS_MEMORY_COUNTERS *)&MemoryCounters, sizeof(MemoryCounters));
+    
+    u64 Result = MemoryCounters.PageFaultCount;
+    return Result;
+}
+
+static void InitializeOSMetrics(void)
+{
+    if(!GlobalMetrics.Initialized)
+    {
+        GlobalMetrics.Initialized = true;
+        GlobalMetrics.ProcessHandle = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, GetCurrentProcessId());
+    }
+}
+
+#else
+
+#include <x86intrin.h>
+#include <sys/time.h>
+
+static u64 GetOSTimerFreq(void)
+{
+	return 1000000;
+}
+
+static u64 ReadOSTimer(void)
+{
+	// NOTE(casey): The "struct" keyword is not necessary here when compiling in C++,
+	// but just in case anyone is using this file from C, I include it.
+	struct timeval Value;
+	gettimeofday(&Value, 0);
+	
+	u64 Result = GetOSTimerFreq()*(u64)Value.tv_sec + (u64)Value.tv_usec;
+	return Result;
+}
+
+static u64 ReadOSPageFaultCount(void)
+{
+    // NOTE(casey): The course materials are not tested on MacOS/Linux.
+    // This code was contributed to the public github. It may or may not work
+    // for your system.
+    
+    struct rusage Usage = {};
+    getrusage(RUSAGE_SELF, &Usage);
+    
+    // ru_minflt  the number of page faults serviced without any I/O activity.
+    // ru_majflt  the number of page faults serviced that required I/O activity.
+    u64 Result = Usage.ru_minflt + Usage.ru_majflt;
+    
+    return Result;
+}
+
+static void InitializeOSMetrics(void)
+{
+}
+
+#endif
+
+/* NOTE(casey): This does not need to be "inline", it could just be "static"
+   because compilers will inline it anyway. But compilers will warn about
+   static functions that aren't used. So "inline" is just the simplest way
+   to tell them to stop complaining about that. */
+inline u64 ReadCPUTimer(void)
+{
+	// NOTE(casey): If you were on ARM, you would need to replace __rdtsc
+	// with one of their performance counter read instructions, depending
+	// on which ones are available on your platform.
+	
+	return __rdtsc();
+}
+
+static u64 EstimateCPUTimerFreq(void)
+{
+	u64 MillisecondsToWait = 100;
+	u64 OSFreq = GetOSTimerFreq();
+
+	u64 CPUStart = ReadCPUTimer();
+	u64 OSStart = ReadOSTimer();
+	u64 OSEnd = 0;
+	u64 OSElapsed = 0;
+	u64 OSWaitTime = OSFreq * MillisecondsToWait / 1000;
+	while(OSElapsed < OSWaitTime)
+	{
+		OSEnd = ReadOSTimer();
+		OSElapsed = OSEnd - OSStart;
+	}
+	
+	u64 CPUEnd = ReadCPUTimer();
+	u64 CPUElapsed = CPUEnd - CPUStart;
+	
+	u64 CPUFreq = 0;
+	if(OSElapsed)
+	{
+		CPUFreq = OSFreq * CPUElapsed / OSElapsed;
+	}
+	
+	return CPUFreq;
+}

part3/listing_0109_pagefault_repetition_tester.cpp

@@ -0,0 +1,240 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 109
+   ======================================================================== */
+
+enum test_mode : u32
+{
+    TestMode_Uninitialized,
+    TestMode_Testing,
+    TestMode_Completed,
+    TestMode_Error,
+};
+
+enum repetition_value_type
+{
+    RepValue_TestCount,
+    
+    RepValue_CPUTimer,
+    RepValue_MemPageFaults,
+    RepValue_ByteCount,
+    
+    RepValue_Count,
+};
+
+struct repetition_value
+{
+    u64 E[RepValue_Count];
+};
+
+struct repetition_test_results
+{
+    repetition_value Total;
+    repetition_value Min;
+    repetition_value Max;
+};
+
+struct repetition_tester
+{
+    u64 TargetProcessedByteCount;
+    u64 CPUTimerFreq;
+    u64 TryForTime;
+    u64 TestsStartedAt;
+    
+    test_mode Mode;
+    b32 PrintNewMinimums;
+    u32 OpenBlockCount;
+    u32 CloseBlockCount;
+    
+    repetition_value AccumulatedOnThisTest;
+    repetition_test_results Results;
+};
+
+static f64 SecondsFromCPUTime(f64 CPUTime, u64 CPUTimerFreq)
+{
+    f64 Result = 0.0;
+    if(CPUTimerFreq)
+    {
+        Result = (CPUTime / (f64)CPUTimerFreq);
+    }
+    
+    return Result;
+}
+ 
+static void PrintValue(char const *Label, repetition_value Value, u64 CPUTimerFreq)
+{
+    u64 TestCount = Value.E[RepValue_TestCount];
+    f64 Divisor = TestCount ? (f64)TestCount : 1;
+    
+    f64 E[RepValue_Count];
+    for(u32 EIndex = 0; EIndex < ArrayCount(E); ++EIndex)
+    {
+        E[EIndex] = (f64)Value.E[EIndex] / Divisor;
+    }
+    
+    printf("%s: %.0f", Label, E[RepValue_CPUTimer]);
+    if(CPUTimerFreq)
+    {
+        f64 Seconds = SecondsFromCPUTime(E[RepValue_CPUTimer], CPUTimerFreq);
+        printf(" (%fms)", 1000.0f*Seconds);
+    
+        if(E[RepValue_ByteCount] > 0)
+        {
+            f64 Gigabyte = (1024.0f * 1024.0f * 1024.0f);
+            f64 Bandwidth = E[RepValue_ByteCount] / (Gigabyte * Seconds);
+            printf(" %fgb/s", Bandwidth);
+        }
+    }
+
+    if(E[RepValue_MemPageFaults] > 0)
+    {
+        printf(" PF: %0.4f (%0.4fk/fault)", E[RepValue_MemPageFaults], E[RepValue_ByteCount] / (E[RepValue_MemPageFaults] * 1024.0));
+    }
+}
+
+static void PrintResults(repetition_test_results Results, u64 CPUTimerFreq)
+{
+    PrintValue("Min", Results.Min, CPUTimerFreq);
+    printf("\n");
+    PrintValue("Max", Results.Max, CPUTimerFreq);
+    printf("\n");
+    PrintValue("Avg", Results.Total, CPUTimerFreq);
+    printf("\n");
+}
+
+static void Error(repetition_tester *Tester, char const *Message)
+{
+    Tester->Mode = TestMode_Error;
+    fprintf(stderr, "ERROR: %s\n", Message);
+}
+
+static void NewTestWave(repetition_tester *Tester, u64 TargetProcessedByteCount, u64 CPUTimerFreq, u32 SecondsToTry = 10)
+{
+    if(Tester->Mode == TestMode_Uninitialized)
+    {
+        Tester->Mode = TestMode_Testing;
+        Tester->TargetProcessedByteCount = TargetProcessedByteCount;
+        Tester->CPUTimerFreq = CPUTimerFreq;
+        Tester->PrintNewMinimums = true;
+        Tester->Results.Min.E[RepValue_CPUTimer] = (u64)-1;
+    }
+    else if(Tester->Mode == TestMode_Completed)
+    {
+        Tester->Mode = TestMode_Testing;
+        
+        if(Tester->TargetProcessedByteCount != TargetProcessedByteCount)
+        {
+            Error(Tester, "TargetProcessedByteCount changed");
+        }
+        
+        if(Tester->CPUTimerFreq != CPUTimerFreq)
+        {
+            Error(Tester, "CPU frequency changed");
+        }
+    }
+
+    Tester->TryForTime = SecondsToTry*CPUTimerFreq;
+    Tester->TestsStartedAt = ReadCPUTimer();
+}
+
+static void BeginTime(repetition_tester *Tester)
+{
+    ++Tester->OpenBlockCount;
+    
+    repetition_value *Accum = &Tester->AccumulatedOnThisTest;
+    Accum->E[RepValue_MemPageFaults] -= ReadOSPageFaultCount();
+    Accum->E[RepValue_CPUTimer] -= ReadCPUTimer();
+}
+
+static void EndTime(repetition_tester *Tester)
+{
+    repetition_value *Accum = &Tester->AccumulatedOnThisTest;
+    Accum->E[RepValue_CPUTimer] += ReadCPUTimer();
+    Accum->E[RepValue_MemPageFaults] += ReadOSPageFaultCount();
+
+    ++Tester->CloseBlockCount;
+}
+
+static void CountBytes(repetition_tester *Tester, u64 ByteCount)
+{
+    repetition_value *Accum = &Tester->AccumulatedOnThisTest;
+    Accum->E[RepValue_ByteCount] += ByteCount;
+}
+
+static b32 IsTesting(repetition_tester *Tester)
+{
+    if(Tester->Mode == TestMode_Testing)
+    {
+        repetition_value Accum = Tester->AccumulatedOnThisTest;
+        u64 CurrentTime = ReadCPUTimer();
+        
+        if(Tester->OpenBlockCount) // NOTE(casey): We don't count tests that had no timing blocks - we assume they took some other path
+        {
+            if(Tester->OpenBlockCount != Tester->CloseBlockCount)
+            {
+                Error(Tester, "Unbalanced BeginTime/EndTime");
+            }
+            
+            if(Accum.E[RepValue_ByteCount] != Tester->TargetProcessedByteCount)
+            {
+                Error(Tester, "Processed byte count mismatch");
+            }
+    
+            if(Tester->Mode == TestMode_Testing)
+            {
+                repetition_test_results *Results = &Tester->Results;
+                
+                Accum.E[RepValue_TestCount] = 1;
+                for(u32 EIndex = 0; EIndex < ArrayCount(Accum.E); ++EIndex)
+                {
+                    Results->Total.E[EIndex] += Accum.E[EIndex];
+                }
+                
+                if(Results->Max.E[RepValue_CPUTimer] < Accum.E[RepValue_CPUTimer])
+                {
+                    Results->Max = Accum;
+                }
+                
+                if(Results->Min.E[RepValue_CPUTimer] > Accum.E[RepValue_CPUTimer])
+                {
+                    Results->Min = Accum;
+                    
+                    // NOTE(casey): Whenever we get a new minimum time, we reset the clock to the full trial time
+                    Tester->TestsStartedAt = CurrentTime;
+                    
+                    if(Tester->PrintNewMinimums)
+                    {
+                        PrintValue("Min", Results->Min, Tester->CPUTimerFreq);
+                        printf("                                   \r");
+                    }
+                }
+                
+                Tester->OpenBlockCount = 0;
+                Tester->CloseBlockCount = 0;
+                Tester->AccumulatedOnThisTest = {};
+            }
+        }
+        
+        if((CurrentTime - Tester->TestsStartedAt) > Tester->TryForTime)
+        {
+            Tester->Mode = TestMode_Completed;
+            
+            printf("                                                          \r");
+            PrintResults(Tester->Results, Tester->CPUTimerFreq);
+        }
+    }
+    
+    b32 Result = (Tester->Mode == TestMode_Testing);
+    return Result;
+}

part3/listing_0110_pagefault_overhead_test.cpp

@@ -0,0 +1,35 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 110
+   ======================================================================== */
+
+static void WriteToAllBytes(repetition_tester *Tester, read_parameters *Params)
+{
+    while(IsTesting(Tester))
+    {
+        buffer DestBuffer = Params->Dest;
+        HandleAllocation(Params, &DestBuffer);
+        
+        BeginTime(Tester);
+        for(u64 Index = 0; Index < DestBuffer.Count; ++Index)
+        {
+            DestBuffer.Data[Index] = (u8)Index;
+        }
+        EndTime(Tester);
+        
+        CountBytes(Tester, DestBuffer.Count);
+        
+        HandleDeallocation(Params, &DestBuffer);
+    }
+}

part3/listing_0111_pagefault_overhead_main.cpp

@@ -0,0 +1,127 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 111
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/stat.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0068_buffer.cpp"
+#include "listing_0108_platform_metrics.cpp"
+#include "listing_0109_pagefault_repetition_tester.cpp"
+#include "listing_0106_mallocread_overhead_test.cpp"
+#include "listing_0110_pagefault_overhead_test.cpp"
+
+struct test_function
+{
+    char const *Name;
+    read_overhead_test_func *Func;
+};
+test_function TestFunctions[] =
+{
+    {"WriteToAllBytes", WriteToAllBytes},
+    {"fread", ReadViaFRead},
+    {"_read", ReadViaRead},
+    {"ReadFile", ReadViaReadFile},
+};
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&IsInBounds;
+    (void)&AreEqual;
+
+    InitializeOSMetrics();
+    u64 CPUTimerFreq = EstimateCPUTimerFreq();
+    
+    if(ArgCount == 2)
+    {
+        char *FileName = Args[1];
+#if _WIN32
+        struct __stat64 Stat;
+        _stat64(FileName, &Stat);
+#else
+        struct stat Stat;
+        stat(FileName, &Stat);
+#endif
+        
+        read_parameters Params = {};
+        Params.Dest = AllocateBuffer(Stat.st_size);
+        Params.FileName = FileName;
+    
+        if(Params.Dest.Count > 0)
+        {
+            repetition_tester Testers[ArrayCount(TestFunctions)][AllocType_Count] = {};
+            
+            for(;;)
+            {
+                for(u32 FuncIndex = 0; FuncIndex < ArrayCount(TestFunctions); ++FuncIndex)
+                {
+                    for(u32 AllocType = 0; AllocType < AllocType_Count; ++AllocType)
+                    {
+                        Params.AllocType = (allocation_type)AllocType;
+                        
+                        repetition_tester *Tester = &Testers[FuncIndex][AllocType];
+                        test_function TestFunc = TestFunctions[FuncIndex];
+                        
+                        printf("\n--- %s%s%s ---\n",
+                               DescribeAllocationType(Params.AllocType),
+                               Params.AllocType ? " + " : "",
+                               TestFunc.Name);
+                        NewTestWave(Tester, Params.Dest.Count, CPUTimerFreq);
+                        TestFunc.Func(Tester, &Params);
+                    }
+                }
+            }
+            
+            // NOTE(casey): We would normally call this here, but we can't because the compiler will complain about "unreachable code".
+            // So instead we just reference the pointer to prevent the compiler complaining about unused function :(
+            (void)&FreeBuffer;
+        }
+        else
+        {
+            fprintf(stderr, "ERROR: Test data size must be non-zero\n");
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [existing filename]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/listing_0112_os_fault_counter_main.cpp

@@ -0,0 +1,89 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 112
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdint.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0108_platform_metrics.cpp"
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&EstimateCPUTimerFreq;
+    
+    InitializeOSMetrics();
+    
+    if(ArgCount == 2)
+    {
+        u64 PageSize = 4096; // NOTE(casey): This may not be the OS page size! It is merely our testing page size.
+        u64 PageCount = atol(Args[1]);
+        u64 TotalSize = PageSize*PageCount;
+        
+        printf("Page Count, Touch Count, Fault Count, Extra Faults\n");
+        
+        for(u64 TouchCount = 0; TouchCount <= PageCount; ++TouchCount)
+        {
+            u64 TouchSize = PageSize*TouchCount;
+            u8 *Data = (u8 *)VirtualAlloc(0, TotalSize, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
+            if(Data)
+            {
+                u64 StartFaultCount = ReadOSPageFaultCount();
+                for(u64 Index = 0; Index < TouchSize; ++Index)
+                {
+                    Data[Index] = (u8)Index;
+                }
+                u64 EndFaultCount = ReadOSPageFaultCount();
+                
+                u64 FaultCount = EndFaultCount - StartFaultCount;
+                
+                printf("%llu, %llu, %llu, %lld\n", PageCount, TouchCount, FaultCount, (FaultCount - TouchCount));
+                
+                VirtualFree(Data, 0, MEM_RELEASE);
+            }
+            else
+            {
+                fprintf(stderr, "ERROR: Unable to allocate memory\n");
+            }
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [# of 4k pages to allocate]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/listing_0113_os_fault_counter_backward_main.cpp

@@ -0,0 +1,89 @@
+/* ========================================================================
+
+   (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
+   
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any damages
+   arising from the use of this software.
+   
+   Please see https://computerenhance.com for more information
+   
+   ======================================================================== */
+
+/* ========================================================================
+   LISTING 113
+   ======================================================================== */
+
+/* NOTE(casey): _CRT_SECURE_NO_WARNINGS is here because otherwise we cannot
+   call fopen(). If we replace fopen() with fopen_s() to avoid the warning,
+   then the code doesn't compile on Linux anymore, since fopen_s() does not
+   exist there.
+   
+   What exactly the CRT maintainers were thinking when they made this choice,
+   I have no idea. */
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdio.h>
+#include <stdint.h>
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int32_t b32;
+
+typedef float f32;
+typedef double f64;
+
+#define ArrayCount(Array) (sizeof(Array)/sizeof((Array)[0]))
+
+#include "listing_0108_platform_metrics.cpp"
+
+int main(int ArgCount, char **Args)
+{
+    // NOTE(casey): Since we do not use these functions in this particular build, we reference their pointers
+    // here to prevent the compiler from complaining about "unused functions".
+    (void)&EstimateCPUTimerFreq;
+    
+    InitializeOSMetrics();
+    
+    if(ArgCount == 2)
+    {
+        u64 PageSize = 4096; // NOTE(casey): This may not be the OS page size! It is merely our testing page size.
+        u64 PageCount = atol(Args[1]);
+        u64 TotalSize = PageSize*PageCount;
+        
+        printf("Page Count, Touch Count, Fault Count, Extra Faults\n");
+        
+        for(u64 TouchCount = 0; TouchCount <= PageCount; ++TouchCount)
+        {
+            u64 TouchSize = PageSize*TouchCount;
+            u8 *Data = (u8 *)VirtualAlloc(0, TotalSize, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
+            if(Data)
+            {
+                u64 StartFaultCount = ReadOSPageFaultCount();
+                for(u64 Index = 0; Index < TouchSize; ++Index)
+                {
+                    Data[TotalSize - 1 - Index] = (u8)Index;
+                }
+                u64 EndFaultCount = ReadOSPageFaultCount();
+                
+                u64 FaultCount = EndFaultCount - StartFaultCount;
+                
+                printf("%llu, %llu, %llu, %lld\n", PageCount, TouchCount, FaultCount, (FaultCount - TouchCount));
+                
+                VirtualFree(Data, 0, MEM_RELEASE);
+            }
+            else
+            {
+                fprintf(stderr, "ERROR: Unable to allocate memory\n");
+            }
+        }
+    }
+    else
+    {
+        fprintf(stderr, "Usage: %s [# of 4k pages to allocate]\n", Args[0]);
+    }
+		
+    return 0;
+}

part3/repetition_tester.c

@@ -0,0 +1,385 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdbool.h>
+#include <stdio.h>
+#include <Windows.h>
+#include <fcntl.h>
+#include <io.h>
+#include <sys/stat.h>
+
+#include "base.h"
+#include "listing_0108_platform_metrics.cpp"
+#include "base.c"
+#include "repetition_tester.h"
+
+// NOTE: Allocate //////////////////////////////////////////////////////////////////////////////////
+Str8 AllocTypeStr8(AllocType type)
+{
+    Str8 result = {};
+    switch (type) {
+        case AllocType_None:         result = STR8("Pre-Allocated"); break;
+        case AllocType_VirtualAlloc: result = STR8("VirtualAlloc"); break;
+        case AllocType_Malloc:       result = STR8("Malloc"); break;
+        case AllocType_Count: break;
+    }
+    return result;
+}
+
+void TestAlloc(ReadArgs *args, Buffer *buffer)
+{
+    switch (args->alloc_type) {
+        case AllocType_None: break;
+        case AllocType_VirtualAlloc: {
+            buffer->data = VirtualAlloc(/*LPVOID lpAddress*/        NULL,
+                                        /*SIZE_T dwSize*/           buffer->size,
+                                        /*DWORD  flAllocationType*/ MEM_COMMIT | MEM_RESERVE,
+                                        /*DWORD  flProtect*/        PAGE_READWRITE);
+        } break;
+
+        case AllocType_Malloc: {
+            buffer->data = malloc(buffer->size);
+        } break;
+
+        case AllocType_Count: break;
+    }
+}
+
+void TestDealloc(ReadArgs *args, Buffer *buffer)
+{
+    switch (args->alloc_type) {
+        case AllocType_None:         break;
+        case AllocType_Malloc:       free(buffer->data); break;
+        case AllocType_VirtualAlloc: VirtualFree(buffer->data, 0, MEM_RELEASE); break;
+        case AllocType_Count:        break;
+    }
+}
+
+// NOTE: RepTester /////////////////////////////////////////////////////////////////////////////////
+void RepTester_Error(RepTester *tester, Str8 msg)
+{
+    tester->mode = RepTesterMode_Error;
+    fprintf(stderr, "ERROR: %.*s\n", STR8_FMT(msg));
+}
+
+void RepTester_BeginTime(RepTester *tester)
+{
+    tester->open_block_count++;
+    tester->accumulated_on_this_test.e[RepTesterValueType_CPUTimer] -= ReadCPUTimer();
+    tester->accumulated_on_this_test.e[RepTesterValueType_MemPageFaults] -= ReadOSPageFaultCount();
+}
+
+void RepTester_EndTime(RepTester *tester)
+{
+    tester->close_block_count++;
+    tester->accumulated_on_this_test.e[RepTesterValueType_CPUTimer] += ReadCPUTimer();
+    tester->accumulated_on_this_test.e[RepTesterValueType_MemPageFaults] += ReadOSPageFaultCount();
+}
+
+void RepTester_CountBytes(RepTester *tester, size_t bytes_read)
+{
+    tester->accumulated_on_this_test.e[RepTesterValueType_ByteCount] += bytes_read;
+}
+
+static void PrintTime(Str8 label, f64 cpu_time, u64 cpu_timer_freq, u64 byte_count)
+{
+    printf("%.*s: %.0f", STR8_FMT(label), cpu_time);
+    if (cpu_timer_freq) {
+        f64 seconds = cpu_time / CAST(f64)cpu_timer_freq;
+        printf(" (%fms)", 1000.0f * seconds);
+
+        if (byte_count) {
+            f64 gigabyte      = (1024.0f * 1024.0f * 1024.0f);
+            f64 best_bandwidth = byte_count / (gigabyte * seconds);
+            printf(" %fgb/s", best_bandwidth);
+        }
+    }
+}
+
+static void RepTester_PrintValue(Str8 label, RepTesterValue value, u64 cpu_timer_freq)
+{
+    u64 test_count = value.e[RepTesterValueType_TestCount];
+    f64 divisor    = test_count ? (f64)test_count : 1;
+
+    f64 avg_values[ARRAY_UCOUNT(value.e)];
+    for (u64 index = 0; index < ARRAY_UCOUNT(value.e); index++)
+        avg_values[index] = value.e[index] / divisor;
+
+    printf("%.*s: %.0f", STR8_FMT(label), avg_values[RepTesterValueType_CPUTimer]);
+    if (cpu_timer_freq) {
+        f64 seconds = avg_values[RepTesterValueType_CPUTimer] / cpu_timer_freq;
+        printf(" (%fms)", 1000.0f*seconds);
+
+        if (avg_values[RepTesterValueType_ByteCount] > 0) {
+            f64 gigabyte  = (1024.0f * 1024.0f * 1024.0f);
+            f64 bandwidth = avg_values[RepTesterValueType_ByteCount] / (gigabyte * seconds);
+            printf(" %fgb/s", bandwidth);
+        }
+    }
+
+    if(avg_values[RepTesterValueType_MemPageFaults] > 0) {
+        printf(" PF: %0.4f (%0.4fk/fault)",
+               avg_values[RepTesterValueType_MemPageFaults],
+               avg_values[RepTesterValueType_ByteCount] / (avg_values[RepTesterValueType_MemPageFaults] * 1024.0));
+    }
+}
+
+static void RepTester_PrintResult(RepTesterResults results, u64 cpu_timer_freq)
+{
+    RepTester_PrintValue(STR8("Min"), results.min, cpu_timer_freq);
+    printf("\n");
+    RepTester_PrintValue(STR8("Max"), results.max, cpu_timer_freq);
+    printf("\n");
+    RepTester_PrintValue(STR8("Avg"), results.total, cpu_timer_freq);
+    printf("\n");
+}
+
+bool RepTester_IsTesting(RepTester *tester)
+{
+    if (tester->mode == RepTesterMode_Testing) {
+        u64 current_time = ReadCPUTimer();
+        if (tester->open_block_count) {
+            if (tester->open_block_count != tester->close_block_count)
+                RepTester_Error(tester, STR8("Unbalanced begin/end time"));
+
+            RepTesterValue accum = tester->accumulated_on_this_test;
+            if (accum.e[RepTesterValueType_ByteCount] != tester->desired_bytes_read)
+                RepTester_Error(tester, STR8("Processed byte count mismatch"));
+
+            if (tester->mode == RepTesterMode_Testing) {
+                RepTesterResults *results = &tester->results;
+                accum.e[RepTesterValueType_TestCount] = 1;
+
+                for (u64 index = 0; index < ARRAY_UCOUNT(accum.e); index++) {
+                    results->total.e[index] += accum.e[index];
+                }
+
+                if (results->max.e[RepTesterValueType_CPUTimer] < accum.e[RepTesterValueType_CPUTimer]) {
+                    results->max = accum;
+                }
+
+                if (results->min.e[RepTesterValueType_CPUTimer] > accum.e[RepTesterValueType_CPUTimer]) {
+                    results->min = accum;
+
+                    // NOTE: Reset the trial time when new min time is achieved
+                    tester->start_time = current_time;
+                    RepTester_PrintValue(STR8("Min"), results->min, tester->cpu_timer_freq);
+                    printf("                                                  \r");
+                }
+
+                tester->open_block_count         = 0;
+                tester->close_block_count        = 0;
+                tester->accumulated_on_this_test = (RepTesterValue){};
+            }
+        }
+
+        if ((current_time - tester->start_time) > tester->run_duration) {
+            tester->mode = RepTesterMode_Complete;
+
+            printf("                                                          \r");
+            RepTester_PrintResult(tester->results, tester->cpu_timer_freq);
+        }
+    }
+
+    bool result = tester->mode == RepTesterMode_Testing;
+    return result;
+}
+
+// NOTE: Read testing functions ////////////////////////////////////////////////////////////////////
+static void ReadWithFRead(RepTester *tester, ReadArgs *args)
+{
+    while (RepTester_IsTesting(tester)) {
+        FILE *file = fopen(args->file_name.data, "rb");
+        if (file) {
+            Buffer buffer = args->dest;
+            TestAlloc(args, &buffer);
+
+            RepTester_BeginTime(tester);
+            size_t result = fread(buffer.data, buffer.size, 1, file);
+            RepTester_EndTime(tester);
+
+            if (result == 1) {
+                RepTester_CountBytes(tester, buffer.size);
+            } else {
+                RepTester_Error(tester, STR8("fopen failed"));
+            }
+            TestDealloc(args, &buffer);
+            fclose(file);
+        } else {
+            RepTester_Error(tester, STR8("fopen failed"));
+        }
+    }
+}
+
+static void ReadWithRead(RepTester *tester, ReadArgs *args)
+{
+    while (RepTester_IsTesting(tester)) {
+        int file = _open(args->file_name.data, _O_BINARY | _O_RDONLY);
+        if (file != -1) {
+            Buffer buffer = args->dest;
+            TestAlloc(args, &buffer);
+
+            char *dest            = buffer.data;
+            u64   space_remaining = buffer.size;
+            while (space_remaining) {
+                u32 read_size = INT_MAX;
+                if ((u64)read_size > space_remaining)
+                    read_size = (u32)space_remaining;
+
+                RepTester_BeginTime(tester);
+                int result = _read(file, dest, read_size);
+                RepTester_EndTime(tester);
+
+                if (result == (int)read_size) {
+                    RepTester_CountBytes(tester, read_size);
+                } else {
+                    RepTester_Error(tester, STR8("_read failed"));
+                    break;
+                }
+
+                space_remaining -= read_size;
+                dest += read_size;
+            }
+
+            TestDealloc(args, &buffer);
+            _close(file);
+        } else {
+            RepTester_Error(tester, STR8("_open failed"));
+        }
+    }
+}
+
+static void ReadWithReadFile(RepTester *tester, ReadArgs *args)
+{
+    while (RepTester_IsTesting(tester)) {
+        HANDLE file = CreateFileA(args->file_name.data,
+                                  GENERIC_READ,
+                                  FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                  0,
+                                  OPEN_EXISTING,
+                                  FILE_ATTRIBUTE_NORMAL,
+                                  0);
+
+        if (file != INVALID_HANDLE_VALUE) {
+            Buffer buffer = args->dest;
+            TestAlloc(args, &buffer);
+
+            char *dest            = buffer.data;
+            u64   space_remaining = buffer.size;
+            while (space_remaining) {
+                u32 read_size = UINT32_MAX;
+                if ((u64)read_size > space_remaining)
+                    read_size = (u32)space_remaining;
+
+                DWORD bytes_read = 0;
+                RepTester_BeginTime(tester);
+                BOOL result = ReadFile(file, dest, read_size, &bytes_read, 0);
+                RepTester_EndTime(tester);
+
+                if (result && (bytes_read == read_size))
+                    RepTester_CountBytes(tester, read_size);
+                else
+                    RepTester_Error(tester, STR8("ReadFile failed"));
+
+                space_remaining -= read_size;
+                dest += read_size;
+            }
+
+            TestDealloc(args, &buffer);
+            CloseHandle(file);
+        } else {
+            RepTester_Error(tester, STR8("CreateFileA failed"));
+        }
+    }
+}
+
+static void WriteToAllBytes(RepTester *tester, ReadArgs *args)
+{
+    while (RepTester_IsTesting(tester)) {
+        Buffer buffer = args->dest;
+        TestAlloc(args, &buffer);
+        RepTester_BeginTime(tester);
+        for (u64 index = 0; index < buffer.size; index++)
+            buffer.data[index] = (u8)index;
+        RepTester_EndTime(tester);
+        RepTester_CountBytes(tester, buffer.size);
+        TestDealloc(args, &buffer);
+    }
+}
+
+typedef void TestFuncPtr(RepTester *tester, ReadArgs *args);
+typedef struct TestFunction {
+    Str8         name;
+    TestFuncPtr *func;
+} TestFunction;
+
+int main(int argc, char const **argv)
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s [existing filename]\n", argv[0]);
+        return -1;
+    }
+
+    Str8 file_name = {.data = CAST(char *) argv[1], .size = strlen(argv[1])};
+    struct __stat64 stat;
+    _stat64(file_name.data, &stat);
+
+    ReadArgs args  = {};
+    args.dest.data = VirtualAlloc(NULL, stat.st_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
+    args.dest.size = stat.st_size;
+    args.file_name = file_name;
+
+    if (stat.st_size <= 0) {
+        fprintf(stderr, "ERROR: Test data size must be non-zero\n");
+        return -1;
+    }
+
+    if (!args.dest.data) {
+        fprintf(stderr, "ERROR: Failed to allocate %zu bytes\n", stat.st_size);
+        return -1;
+    }
+
+    InitializeOSMetrics();
+
+    TestFunction test_functions[] = {
+        {STR8("WriteToAllBytes"), WriteToAllBytes},
+        {STR8("fread"),           ReadWithFRead},
+        {STR8("_read"),           ReadWithRead},
+        {STR8("ReadFile"),        ReadWithReadFile},
+    };
+
+    RepTester testers[ARRAY_UCOUNT(test_functions)][AllocType_Count] = {};
+    u64       cpu_timer_freq                                         = EstimateCPUTimerFreq();
+    for (u64 index = 0; index != UINT64_MAX; index++) {
+        for (u64 func_index = 0; func_index < ARRAY_UCOUNT(testers); func_index++) {
+            for (u64 alloc_index = 0; alloc_index < AllocType_Count; alloc_index++) {
+                RepTester   *tester    = &testers[func_index][alloc_index];
+                TestFunction test_func = test_functions[func_index];
+
+                printf("\n--- %.*s + %.*s ---\n",
+                       STR8_FMT(AllocTypeStr8((AllocType)alloc_index)),
+                       STR8_FMT(test_func.name));
+
+                if (tester->mode == RepTesterMode_Nil) {
+                    tester->mode                                       = RepTesterMode_Testing;
+                    tester->desired_bytes_read                         = args.dest.size;
+                    tester->cpu_timer_freq                             = cpu_timer_freq;
+                    tester->results.min.e[RepTesterValueType_CPUTimer] = (u64)-1;
+                } else if (tester->mode == RepTesterMode_Complete) {
+                    tester->mode = RepTesterMode_Testing;
+
+                    if (tester->desired_bytes_read != args.dest.size)
+                        RepTester_Error(tester, STR8("desired_bytes_read changed"));
+                    if (tester->cpu_timer_freq != cpu_timer_freq)
+                        RepTester_Error(tester, STR8("cpu frequency changed"));
+                }
+
+                tester->run_duration = /*seconds_to_try*/ 10 * cpu_timer_freq;
+                tester->start_time   = ReadCPUTimer();
+                args.alloc_type      = alloc_index;
+
+                test_func.func(tester, &args);
+            }
+        }
+    }
+
+    return 0;
+}

part3/repetition_tester.h

@@ -0,0 +1,52 @@
+typedef enum RepTesterMode {
+    RepTesterMode_Nil,
+    RepTesterMode_Testing,
+    RepTesterMode_Error,
+    RepTesterMode_Complete,
+} RepTesterMode;
+
+typedef enum RepTesterValueType {
+    RepTesterValueType_TestCount,
+    RepTesterValueType_CPUTimer,
+    RepTesterValueType_MemPageFaults,
+    RepTesterValueType_ByteCount,
+    RepTesterValueType_Count,
+} RepTesterValueType;
+
+typedef struct RepTesterValue {
+    u64 e[RepTesterValueType_Count];
+} RepTesterValue;
+
+typedef struct RepTesterResults {
+    RepTesterValue total;
+    RepTesterValue max;
+    RepTesterValue min;
+} RepTesterResults;
+
+typedef struct RepTester {
+    RepTesterMode    mode;
+    u32              open_block_count;
+    u32              close_block_count;
+    u64              cpu_timer_freq;
+
+    RepTesterResults results;
+    RepTesterValue   accumulated_on_this_test;
+
+    size_t           desired_bytes_read;
+
+    u64              start_time;
+    u64              run_duration;
+} RepTester;
+
+typedef enum AllocType {
+    AllocType_None,
+    AllocType_VirtualAlloc,
+    AllocType_Malloc,
+    AllocType_Count,
+} AllocType;
+
+typedef struct ReadArgs {
+    Buffer    dest;
+    Str8      file_name;
+    AllocType alloc_type;
+} ReadArgs;