byte[] 转 string

char.cs

/// <summary>
/// 十六进制映射表
/// </summary>
private static readonly Char[] _lookup = new Char[]
{
    '0', '1', '2', '3',
    '4', '5', '6', '7',
    '8', '9', 'A', 'B',
    'C', 'D', 'E', 'F'
};

/// <summary>
/// 将byte数组转换成十六进制字符串
/// </summary>
/// <param name="arr"></param>
/// <returns></returns>
public static String ToHex(Byte[] arr)
{
    Char[] chars = new Char[arr.Length * 2];
    for (int i = 0; i < arr.Length; i++)
    {
        Byte c = arr[i];
        chars[i * 2] = _lookup[(c >> 4) & 0x0F];
        chars[i * 2 + 1] = _lookup[c & 0x0F];
    }
    return new String(chars, 0, chars.Length);
}

unsafe.cs

private static readonly sbyte[] _lookup = new sbyte[] { 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46 };
public static unsafe string ToHex(this byte[] arr)
{
    int len = arr.Length;
    int i = 0;

    sbyte* chars = stackalloc sbyte[len * 2];
    fixed (byte* pSrc = arr)
    {
        byte* pIn = pSrc;
        sbyte* pOut = chars;
        while (i++ < len)
        {
            *pOut++ = _lookup[*pIn >> 4];
            *pOut++ = _lookup[*pIn++ & 0xF];
        }
    }
    return new String(chars, 0, len * 2);
}