Byte 배열을 Hex(16진수) 문자열로 변환하는 방법

[evan-choi]

.NET Core 5 + Benchmark 테스트 결과입니다.

Score: 1690.9 / 186.5 = 9.066487935656836

변환 코드

const string table = "0123456789ABCDEF";

return string.Create(Size * 2, _buffer, static(span, buffer) =>
{
    for (int i = 0; i < Size; i++)
    {
        span[0] = table[(buffer[i] & 0xF0) >> 4];
        span[1] = table[buffer[i] & 0x0F];
        span = span.Slice(2);
    }
});

전체 테스트 코드

using System;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;

[SimpleJob(RuntimeMoniker.NetCoreApp50)]
public class ByteHex16
{
    private const int Size = 8192 * 10000;

    private byte[] _buffer;

    [GlobalSetup]
    public void Setup()
    {
        _buffer = new byte[Size];
        new Random().NextBytes(_buffer);
    }

    [Benchmark]
    public string BitConverter()
    {
        return System.BitConverter.ToString(_buffer).Replace("-", "");
    }

    [Benchmark]
    public string Dimohy()
    {
        var bc = new char[Size * 2];

        for (var i = 0; i < _buffer.Length; i++)
        {
            var index = i << 1;
            (bc[index], bc[index + 1]) = ToHexa(_buffer[i]);
        }

        return new string(bc);

        static (char, char) ToHexa(byte d)
        {
            var a = (d & 0xF0) >> 4;
            var b = d & 0x0F;

            if (a < 10)
                a += '0';
            else
                a += 'A' - 10;

            if (b < 10)
                b += '0';
            else
                b += 'A' - 10;

            return ((char)a, (char)b);
        }
    }

    [Benchmark]
    public string EvanChoi()
    {
        const string table = "0123456789ABCDEF";

        return string.Create(Size * 2, _buffer, static(span, buffer) =>
        {
            for (int i = 0; i < Size; i++)
            {
                span[0] = table[(buffer[i] & 0xF0) >> 4];
                span[1] = table[buffer[i] & 0x0F];
                span = span.Slice(2);
            }
        });
    }
}