Fast? Hex Parser

$ mkdir build
$ cd build
$ cmake ..
$ make
$ make test
$ ./perf/fqhex-perf-test-generic
 0:01.000790524	152.78 M op/s	to_bytes	char    	32	generic
 0:01.001119847	269.90 M op/s	to_bytes	char    	16	generic
 0:01.000606484	541.17 M op/s	to_bytes	char    	8	generic
...
$ ./perf/fqhex-perf-test-ssse3
$ ./perf/fqhex-perf-test-avx2

Features

• Converts hexadecimal strings to byte arrays.
• Converts byte arrays to hexadecimal strings.
• Performs error detection for hexadecimal strings.
• Supports x86 SSSE3 and AVX2.
• Supports multiple string types (char, wchar_t, char8_t, char16_t, char32_t).
• Supports multiple byte types (uint8_t, std::byte).

Results

Linux x86_64 (WSL2) gcc-14.2.1

Method	Type	Size	Generic code	SSSE3 code	AVX2 code
to_bytes	char	32	152.78 M op/s	288.41 M op/s	559.99 M op/s
to_bytes	char	16	269.90 M op/s	575.16 M op/s	599.47 M op/s
to_bytes	char	8	541.17 M op/s	534.44 M op/s	561.72 M op/s
to_bytes	char	4	903.34 M op/s	953.44 M op/s	960.23 M op/s
to_string	char	32	157.61 M op/s	812.16 M op/s	912.00 M op/s
to_string	char	16	273.84 M op/s	1.27 G op/s	1.35 G op/s
to_string	char	8	496.36 M op/s	504.67 M op/s	506.16 M op/s
to_string	char	4	806.37 M op/s	827.95 M op/s	833.72 M op/s
to_bytes	char16_t	32	119.46 M op/s	174.31 M op/s	296.53 M op/s
to_bytes	char16_t	16	229.89 M op/s	348.88 M op/s	354.35 M op/s
to_bytes	char16_t	8	419.43 M op/s	401.87 M op/s	430.86 M op/s
to_bytes	char16_t	4	827.13 M op/s	856.45 M op/s	926.53 M op/s
to_string	char16_t	32	165.46 M op/s	605.32 M op/s	736.10 M op/s
to_string	char16_t	16	362.85 M op/s	1.10 G op/s	1.10 G op/s
to_string	char16_t	8	613.98 M op/s	612.71 M op/s	614.69 M op/s
to_string	char16_t	4	1.68 G op/s	1.70 G op/s	1.71 G op/s
to_bytes	char32_t	32	114.73 M op/s	142.35 M op/s	254.93 M op/s
to_bytes	char32_t	16	232.22 M op/s	288.28 M op/s	296.54 M op/s
to_bytes	char32_t	8	409.29 M op/s	430.50 M op/s	430.14 M op/s
to_bytes	char32_t	4	790.89 M op/s	804.85 M op/s	815.09 M op/s
to_string	char32_t	32	166.87 M op/s	358.42 M op/s	401.39 M op/s
to_string	char32_t	16	364.78 M op/s	709.05 M op/s	709.01 M op/s
to_string	char32_t	8	612.78 M op/s	615.90 M op/s	615.63 M op/s
to_string	char32_t	4	1.68 G op/s	1.65 G op/s	1.72 G op/s

Example

#include <cstdint>
#include <iostream>
#include <string>
#include <fqhex.hpp>

void example()
{
    std::string s = "7c86ef21711c5d5e3a8408b5b305b49c";

    // parse
    std::array<uint8_t, 16> a;
    try {
        fqhex::hex_avx2<char, uint8_t>::to_bytes(s, a);
    }
    catch (std::invalid_argument& e) {
        std::cerr << e.what() << std::endl; // parse error
    }

    // to string
    std::wstring ws = fqhex::hex_avx2<wchar_t, uint8_t>::to_string(a);

    // to char array (non null terminated)
    std::array<char32_t, 32> u32;
    fqhex::hex_avx2<char32_t, uint8_t>::to_string(a, u32);
}