perfaware/part2: Add bandwidth tracking

build.bat

@@ -322,9 +322,15 @@ pushd %part2_build_dir%
 cl %part2_dir%\haversine_generator.c /W4 /WX /Z7 /nologo     /Fe:haversine_generator_debug || exit /b 1
 cl %part2_dir%\haversine_generator.c /W4 /WX /Z7 /nologo /O2 /Fe:haversine_generator_release || exit /b 1
 
+cl %part2_dir%\haversine_generator.c /DHAV_PROFILER /W4 /WX /Z7 /nologo     /Fe:haversine_generator_profiled_debug || exit /b 1
+cl %part2_dir%\haversine_generator.c /DHAV_PROFILER /W4 /WX /Z7 /nologo /O2 /Fe:haversine_generator_profiled_release || exit /b 1
+
 cl %part2_dir%\haversine.c /W4 /WX /Z7 /nologo     /Fe:haversine_debug || exit /b 1
 cl %part2_dir%\haversine.c /W4 /WX /Z7 /nologo /O2 /Fe:haversine_release || exit /b 1
 
+cl %part2_dir%\haversine.c /DHAV_PROFILER /W4 /WX /Z7 /nologo     /Fe:haversine_profiled_debug || exit /b 1
+cl %part2_dir%\haversine.c /DHAV_PROFILER /W4 /WX /Z7 /nologo /O2 /Fe:haversine_profiled_release || exit /b 1
+
 cl %part2_dir%\listing_0071_os_timer_main.cpp /W4 /WX /Z7 /O2 /nologo /Fe:listing_0071_os_timer_main_release || exit /b 1
 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

part2/haversine.c

@@ -3,83 +3,12 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <Windows.h>
-#include "haversine_stdlib.h"
-#include "haversine_stdlib.c"
 #include <math.h>
 
+#include "haversine_stdlib.h"
 #include "listing_0065_haversine_formula.cpp"
 #include "listing_0074_platform_metrics.cpp"
-
+#include "haversine_stdlib.c"
-typedef struct ProfilerRecord {
-    HAV_Str8 label;
-    u64      elapsed_tsc;
-    u64      elapsed_tsc_child;
-    u64      hits;
-} ProfilerRecord;
-
-typedef struct ProfilerAnchor {
-    u64      parent_index;
-    uint32_t index;
-    HAV_Str8 label;
-    u64      tsc;
-} ProfilerAnchor;
-
-typedef struct Profiler {
-    ProfilerRecord records[4096];
-    u64            begin_tsc;
-    u64            end_tsc;
-    u64            parent_index;
-} Profiler;
-
-static Profiler g_profiler;
-
-#define Profiler_BeginAnchor(label) Profiler_BeginAnchor_(HAV_STR8(label), __COUNTER__ + 1)
-static ProfilerAnchor Profiler_BeginAnchor_(HAV_Str8 label, uint32_t index)
-{
-    ProfilerAnchor result   = {0};
-    result.index            = index;
-    result.label            = label;
-    result.tsc              = ReadCPUTimer();
-    result.parent_index     = g_profiler.parent_index;
-    g_profiler.parent_index = index;
-    return result;
-}
-
-static void Profiler_EndAnchor(ProfilerAnchor anchor)
-{
-    u64 elapsed_tsc         = ReadCPUTimer() - anchor.tsc;
-    ProfilerRecord* record  = g_profiler.records + anchor.index;
-    record->elapsed_tsc    += elapsed_tsc;
-    record->label           = anchor.label;
-    record->hits++;
-
-    ProfilerRecord* parent     = g_profiler.records + anchor.parent_index;
-    parent->elapsed_tsc_child += elapsed_tsc;
-    g_profiler.parent_index    = anchor.parent_index;
-}
-
-static 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 < HAV_ARRAY_UCOUNT(g_profiler.records); index++) {
-        ProfilerRecord const *record = g_profiler.records + index;
-        if (!record->elapsed_tsc)
-            break;
-
-        u64 record_exclusive_tsc = record->elapsed_tsc - record->elapsed_tsc_child;
-        f64 percent = total_elapsed_tsc ? (f64)record_exclusive_tsc / (f64)total_elapsed_tsc * 100.0 : 100.0;
-        printf("   %.*s[%zu]: %llu (%.2f%%", HAV_STR8_FMT(record->label), record->hits, record_exclusive_tsc, percent);
-        if (record->elapsed_tsc_child) {
-            f64 percent_w_children = total_elapsed_tsc ? ((f64)record->elapsed_tsc / (f64)total_elapsed_tsc * 100.0) : 100.0;
-            printf(", %.2f%% w/children", percent_w_children);
-        }
-        printf(")\n");
-    }
-}
 
 typedef struct Str8FindResult {
     bool     found;
@@ -163,20 +92,17 @@ int main(int argc, char **argv)
     if (argc == 3)
         arg_answers = (HAV_Str8){.data = argv[2], .size = strlen(argv[2])};
 
-    ProfilerAnchor prof_file_read_anchor = Profiler_BeginAnchor("File Read");
     HAV_Buffer json_buffer = HAV_FileRead(arg_json.data);
-    Profiler_EndAnchor(prof_file_read_anchor);
-
     if (!HAV_BufferIsValid(json_buffer))
         return 0;
 
-    ProfilerAnchor prof_parse_and_sum_anchor = Profiler_BeginAnchor("Parse&Hav Sum");
+    HAV_ProfilerZone prof_parse_and_sum_zone = HAV_Profiler_BeginZone("Parse&Hav Sum");
     f64 haversine_sum = 0;
     size_t pair_count = 0;
     HAV_Str8 json_it  = (HAV_Str8){.data = json_buffer.data, .size = json_buffer.size};
     for (;; pair_count++) {
-        ProfilerAnchor prof_json_parse_anchor = Profiler_BeginAnchor("Parse");
         f64 x0 = 0.f, y0 = 0.f, x1 = 0.f, y1 = 0.f;
+        HAV_ProfilerZone prof_json_parse_zone = HAV_Profiler_BeginZoneBandwidth("Parse", json_it.size);
         HAV_Str8BinarySplitResult x0_key = HAV_Str8_BinarySplit(json_it, HAV_STR8("x0"));
         if (x0_key.rhs.size) {
             Str8FindResult            x0_find_value = FindFirstCharThatLooksLikeANumber(x0_key.rhs);
@@ -209,16 +135,16 @@ int main(int argc, char **argv)
                        HAV_STR8_FMT(y1_value.lhs), y1);
         #endif
 
-        Profiler_EndAnchor(prof_json_parse_anchor);
+        HAV_Profiler_EndZone(prof_json_parse_zone);
         if (!x0_key.rhs.size)
             break;
 
-        ProfilerAnchor prof_haversine_sum_anchor = Profiler_BeginAnchor("Hav Sum");
+        HAV_ProfilerZone prof_haversine_sum_zone = HAV_Profiler_BeginZoneBandwidth("Hav Sum", sizeof(x0) + sizeof(y0) + sizeof(x1) + sizeof(y1));
         f64 haversine_dist = ReferenceHaversine(x0, y0, x1, y1, /*EarthRadius*/ 6372.8);
         haversine_sum     += haversine_dist;
-        Profiler_EndAnchor(prof_haversine_sum_anchor);
+        HAV_Profiler_EndZone(prof_haversine_sum_zone);
     }
-    Profiler_EndAnchor(prof_parse_and_sum_anchor);
+    HAV_Profiler_EndZone(prof_parse_and_sum_zone);
 
     haversine_sum /= pair_count;
     size_t input_size = json_buffer.size;
@@ -242,6 +168,6 @@ int main(int argc, char **argv)
     }
 
     g_profiler.end_tsc = ReadCPUTimer();
-    Profiler_Dump();
+    HAV_Profiler_Dump();
     return 0;
 }

part2/haversine_generator.c

@@ -3,10 +3,12 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <Windows.h>
-#include "haversine_stdlib.h"
-#include "haversine_stdlib.c"
 #include <math.h>
+
+#include "haversine_stdlib.h"
+#include "listing_0074_platform_metrics.cpp"
 #include "listing_0065_haversine_formula.cpp"
+#include "haversine_stdlib.c"
 
 #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)

part2/haversine_stdlib.c

@@ -55,6 +55,73 @@ bool HAV_CharIsDigit(char ch)
     return result;
 }
 
+void HAV_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 < HAV_ARRAY_UCOUNT(g_profiler.anchors); index++) {
+        HAV_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%%", HAV_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 / HAV_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");
+    }
+}
+
+HAV_ProfilerZone HAV_Profiler_BeginZone_(HAV_Str8 label, uint32_t index, u64 byte_count)
+{
+    HAV_ProfilerZone result      = {0};
+    #if defined(HAV_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 HAV_Profiler_EndZone(HAV_ProfilerZone zone)
+{
+    #if defined(HAV_PROFILER)
+    u64 elapsed_tsc             = ReadCPUTimer() - zone.tsc;
+    HAV_ProfilerAnchor* anchor  = g_profiler.anchors + zone.index;
+    HAV_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 HAV_PCG32_Pie (uint64_t *state)
@@ -152,6 +219,7 @@ HAV_Buffer HAV_FileRead(char const *file_path)
     // 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(
       /*HANDLE       hFile*/ file_handle,
       /*LPVOID       lpBuffer*/ buffer,
@@ -159,6 +227,7 @@ HAV_Buffer HAV_FileRead(char const *file_path)
       /*LPDWORD      lpNumberOfBytesRead*/ &bytes_read,
       /*LPOVERLAPPED lpOverlapped*/ NULL
     );
+    HAV_Profiler_EndZone(prof_file_read_zone);
 
     // NOTE: Handle read result
     // =========================================================================

part2/haversine_stdlib.h

@@ -60,6 +60,41 @@ HAV_Str8BinarySplitResult HAV_Str8_BinarySplit(HAV_Str8 buffer, HAV_Str8 find);
 bool                      HAV_CharIsWhiteSpace(char ch);
 bool                      HAV_CharIsDigit(char ch);
 
+// NOTE: Profiler
+// ============================================================================
+typedef struct HAV_ProfilerAnchor {
+    HAV_Str8 label;
+    u64      elapsed_tsc_exclusive; // Does not include children
+    u64      elapsed_tsc_inclusive; // Includes children
+    u64      byte_count;
+    u64      hits;
+} HAV_ProfilerAnchor;
+
+typedef struct HAV_Profiler {
+    HAV_ProfilerAnchor anchors[4096];
+    u64                begin_tsc;
+    u64                end_tsc;
+    u64                parent_index;
+} HAV_Profiler;
+
+typedef struct HAV_ProfilerZone {
+    u64      parent_index;
+    uint32_t index;
+    HAV_Str8 label;
+    u64      elapsed_tsc_inclusive;
+    u64      tsc;
+    u64      byte_count;
+} HAV_ProfilerZone;
+
+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 HAV_ProfilerZone HAV_Profiler_BeginZone_(HAV_Str8 label, uint32_t index, u64 byte_count);
+static void HAV_Profiler_EndZone(HAV_ProfilerZone zone);
+
 // NOTE: PCG32
 // ============================================================================
 // NOTE: PCG RNG from Demetri Spanos: https://github.com/demetri/scribbles

part2/listing_0076_simple_profiler.cpp

@@ -0,0 +1,101 @@
+/* ========================================================================
+
+   (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 76
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+struct profile_anchor
+{
+    u64 TSCElapsed;
+    u64 HitCount;
+    char const *Label;
+};
+
+struct profiler
+{
+    profile_anchor Anchors[4096];
+    
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+        StartTSC = ReadCPUTimer();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = ReadCPUTimer() - StartTSC;
+        
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        Anchor->TSCElapsed += 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 StartTSC;
+    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 TimeFunction TimeBlock(__func__)
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, profile_anchor *Anchor)
+{
+    u64 Elapsed = Anchor->TSCElapsed;
+    f64 Percent = 100.0 * ((f64)Elapsed / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%)\n", Anchor->Label, Anchor->HitCount, Elapsed, Percent);
+}
+
+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);
+    }
+    
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfiler.Anchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        if(Anchor->TSCElapsed)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}

part2/listing_0077_profiled_lookup_json_parser.cpp

@@ -0,0 +1,509 @@
+/* ========================================================================
+
+   (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 77
+   ======================================================================== */
+
+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)
+{
+    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)
+    {
+        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_0078_profiled_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 78
+   ======================================================================== */
+
+/* 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_0076_simple_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0077_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);
+            }
+        }
+    }
+    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_0079_timedblock_lookup_json_parser.cpp

@@ -0,0 +1,510 @@
+/* ========================================================================
+
+   (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 79
+   ======================================================================== */
+
+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)
+{
+    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"));
+        }
+    }
+    
+    FreeJSON(JSON);
+    
+    return PairCount;
+}

part2/listing_0080_double_counted_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 80
+   ======================================================================== */
+
+/* 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_0076_simple_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0079_timedblock_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);
+            }
+        }
+    }
+    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_0081_nesting_profiler.cpp

@@ -0,0 +1,118 @@
+/* ========================================================================
+
+   (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 81
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+struct profile_anchor
+{
+    u64 TSCElapsed;
+    u64 TSCElapsedChildren;
+    u64 HitCount;
+    char const *Label;
+};
+
+struct profiler
+{
+    profile_anchor Anchors[4096];
+    
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = ReadCPUTimer();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = ReadCPUTimer() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+        
+        profile_anchor *Parent = GlobalProfiler.Anchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        
+        Parent->TSCElapsedChildren += Elapsed;
+        Anchor->TSCElapsed += 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 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 TimeFunction TimeBlock(__func__)
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, profile_anchor *Anchor)
+{
+    u64 Elapsed = Anchor->TSCElapsed - Anchor->TSCElapsedChildren;
+    f64 Percent = 100.0 * ((f64)Elapsed / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%", Anchor->Label, Anchor->HitCount, Elapsed, Percent);
+    if(Anchor->TSCElapsedChildren)
+    {
+        f64 PercentWithChildren = 100.0 * ((f64)Anchor->TSCElapsed / (f64)TotalTSCElapsed);
+        printf(", %.2f%% w/children", PercentWithChildren);
+    }
+    printf(")\n");
+}
+
+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);
+    }
+    
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfiler.Anchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        if(Anchor->TSCElapsed)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}

part2/listing_0082_nesting_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 82
+   ======================================================================== */
+
+/* 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_0081_nesting_profiler.cpp"
+#include "listing_0065_haversine_formula.cpp"
+#include "listing_0068_buffer.cpp"
+#include "listing_0079_timedblock_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);
+            }
+        }
+    }
+    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_0083_recursive_timed_lookup_json_parser.cpp

@@ -0,0 +1,512 @@
+/* ========================================================================
+
+   (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 83
+   ======================================================================== */
+
+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)
+{
+    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)
+{
+    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)
+{
+    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"));
+        }
+    }
+    
+    FreeJSON(JSON);
+    
+    return PairCount;
+}

part2/listing_0084_recursive_timed_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 84
+   ======================================================================== */
+
+/* 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_0081_nesting_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);
+            }
+        }
+    }
+    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_0085_recursive_profiler.cpp

@@ -0,0 +1,125 @@
+/* ========================================================================
+
+   (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 85
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+struct profile_anchor
+{
+    u64 TSCElapsed;
+    u64 TSCElapsedChildren;
+    u64 TSCElapsedAtRoot;
+    u64 HitCount;
+    char const *Label;
+};
+
+struct profiler
+{
+    profile_anchor Anchors[4096];
+    
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+        
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        OldTSCElapsedAtRoot = Anchor->TSCElapsedAtRoot;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = ReadCPUTimer();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = ReadCPUTimer() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+    
+        profile_anchor *Parent = GlobalProfiler.Anchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        
+        Parent->TSCElapsedChildren += Elapsed;
+        Anchor->TSCElapsedAtRoot = OldTSCElapsedAtRoot + Elapsed;
+        Anchor->TSCElapsed += 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 OldTSCElapsedAtRoot;
+    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 TimeFunction TimeBlock(__func__)
+
+static void PrintTimeElapsed(u64 TotalTSCElapsed, profile_anchor *Anchor)
+{
+    u64 TSCElapsedSelf = Anchor->TSCElapsed - Anchor->TSCElapsedChildren;
+    f64 Percent = 100.0 * ((f64)TSCElapsedSelf / (f64)TotalTSCElapsed);
+    printf("  %s[%llu]: %llu (%.2f%%", Anchor->Label, Anchor->HitCount, TSCElapsedSelf, Percent);
+    if(Anchor->TSCElapsedAtRoot != TSCElapsedSelf)
+    {
+        f64 PercentWithChildren = 100.0 * ((f64)Anchor->TSCElapsedAtRoot / (f64)TotalTSCElapsed);
+        printf(", %.2f%% w/children", PercentWithChildren);
+    }
+    printf(")\n");
+}
+
+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);
+    }
+    
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfiler.Anchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        if(Anchor->TSCElapsed)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}
+        

part2/listing_0086_recursive_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 86
+   ======================================================================== */
+
+/* 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_0085_recursive_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);
+            }
+        }
+    }
+    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_0087_simplified_profiler.cpp

@@ -0,0 +1,123 @@
+/* ========================================================================
+
+   (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 87
+   ======================================================================== */
+
+#include "listing_0074_platform_metrics.cpp"
+
+struct profile_anchor
+{
+    u64 TSCElapsedExclusive; // NOTE(casey): Does NOT include children
+    u64 TSCElapsedInclusive; // NOTE(casey): DOES include children
+    u64 HitCount;
+    char const *Label;
+};
+
+struct profiler
+{
+    profile_anchor Anchors[4096];
+    
+    u64 StartTSC;
+    u64 EndTSC;
+};
+static profiler GlobalProfiler;
+static u32 GlobalProfilerParent;
+
+struct profile_block
+{
+    profile_block(char const *Label_, u32 AnchorIndex_)
+    {
+        ParentIndex = GlobalProfilerParent;
+        
+        AnchorIndex = AnchorIndex_;
+        Label = Label_;
+
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        OldTSCElapsedInclusive = Anchor->TSCElapsedInclusive;
+        
+        GlobalProfilerParent = AnchorIndex;
+        StartTSC = ReadCPUTimer();
+    }
+    
+    ~profile_block(void)
+    {
+        u64 Elapsed = ReadCPUTimer() - StartTSC;
+        GlobalProfilerParent = ParentIndex;
+    
+        profile_anchor *Parent = GlobalProfiler.Anchors + ParentIndex;
+        profile_anchor *Anchor = GlobalProfiler.Anchors + 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 TimeFunction TimeBlock(__func__)
+
+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 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);
+    }
+    
+    for(u32 AnchorIndex = 0; AnchorIndex < ArrayCount(GlobalProfiler.Anchors); ++AnchorIndex)
+    {
+        profile_anchor *Anchor = GlobalProfiler.Anchors + AnchorIndex;
+        if(Anchor->TSCElapsedInclusive)
+        {
+            PrintTimeElapsed(TotalCPUElapsed, Anchor);
+        }
+    }
+}
+        

part2/listing_0088_simplified_haversine_main.cpp

@@ -0,0 +1,182 @@
+/* ========================================================================
+
+   (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 88
+   ======================================================================== */
+
+/* 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_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);
+            }
+        }
+    }
+    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");