intc/README.md

intc

A MIT licensed C/C++ uint128/256 type library, originally adapted from calccrypto's uint128/256 library turned into a primarily C first library and opt out C++ features when compiling in C++ mode.

The overarching motivation of the library can be summed up as follows

• Single header, drop in - no build configuration required.
• Minimal dependencies (only depends on stdbool.h when compiling in C).
• Zero allocations (in other libs typically when converting to strings).
• Ability to rename the API via the pre-processor for tighter integration into C code bases
• C++ features are optional and can be opt out via the pre-processor, i.e. operator overloading and constructors.

Usage

Include intc.h and defined INTC_IMPLEMENTATION in one and only one file to enable the implementation in that translation unit.

#define INTC_IMPLEMENTATION
#include "intc.h"
#include <stdio.h>

int main(int, char**)
{
#if defined(__cplusplus)
    intc_u256 value = 32;
    value += 32;
    if (value == 64)
        value *= 1'000'000'000'000;
    intc_u256_string string = intc_u256_readable_int_str(value);
    printf("%.*s\n", string.size, string.str); // 64,000,000,000,000
#else
    intc_u256 value = INTC_U64_TO_U256(32);
    value = intc_u256_add_u64(value, 32);
    if (intc_u256_eq_u64(value, 64))
        value = intc_u256_mul(value, INTC_U64_TO_U256(1'000'000'000'000));
    intc_u256_string string = intc_u256_readable_int_str(value);
    printf("%.*s\n", string.size, string.str); // 64,000,000,000,000
#endif
    return 0;
}

Tests

Tests are adapted from calccrypto's test suite and can be built by running build_tests.bat for Windows and build_tests.sh for Unix. For Windows MSVC's cl compiler must be available on the path and GCC must be available on Unix.