Compiler Explorer

Source code

using System;
using System.Runtime.CompilerServices;

public class C {
    private const byte IsWhiteSpaceFlag = 0x80;

public bool IsWhiteSpace(char c) =>
        IsLatin1(c) && (Latin1CharInfo[c] & 0x80) != 0;

//[MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static bool IsLatin1(char c) => c < Latin1CharInfo.Length;

private static ReadOnlySpan<byte> Latin1CharInfo => new byte[]
    {
    //  0     1     2     3     4     5     6     7     8     9     A     B     C     D     E     F
        0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x8E, 0x8E, 0x8E, 0x8E, 0x8E, 0x0E, 0x0E, // U+0000..U+000F
        0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, // U+0001..U+001F
        0x8B, 0x18, 0x18, 0x18, 0x1A, 0x18, 0x18, 0x18, 0x14, 0x15, 0x18, 0x19, 0x18, 0x13, 0x18, 0x18, // U+0002..U+002F
        0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x18, 0x18, 0x19, 0x19, 0x19, 0x18, // U+0003..U+003F
        0x18, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, // U+0004..U+004F
        0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x14, 0x18, 0x15, 0x1B, 0x12, // U+0005..U+005F
        0x1B, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, // U+0006..U+006F
        0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x14, 0x19, 0x15, 0x19, 0x0E, // U+0007..U+007F
        0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x8E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, // U+0008..U+008F
        0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, 0x0E, // U+0009..U+009F
        0x8B, 0x18, 0x1A, 0x1A, 0x1A, 0x1A, 0x1C, 0x18, 0x1B, 0x1C, 0x04, 0x16, 0x19, 0x0F, 0x1C, 0x1B, // U+000A..U+00AF
        0x1C, 0x19, 0x0A, 0x0A, 0x1B, 0x21, 0x18, 0x18, 0x1B, 0x0A, 0x04, 0x17, 0x0A, 0x0A, 0x0A, 0x18, // U+000B..U+00BF
        0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, // U+000C..U+00CF
        0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x19, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x21, // U+000D..U+00DF
        0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, // U+000E..U+00EF
        0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x19, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, // U+000F..U+00FF
    };
}