PercentEncodingHelper.cs

Go to the documentation of this file.

using System.Buffers;
using System.Text;
 
namespace System;
 
internal static class PercentEncodingHelper
{
    public unsafe static int UnescapePercentEncodedUTF8Sequence(char* input, int length, ref System.Text.ValueStringBuilder dest, bool isQuery, bool iriParsing)
    {
        uint num = 0u;
        int num2 = 0;
        int num3 = 0;
        int num4 = 0;
        int bytesConsumed = 0;
        while (true)
        {
            int num5 = num3 + num2 * 3;
            while (true)
            {
                if ((uint)(length - num5) > 2u && input[num5] == '%')
                {
                    uint num6 = input[num5 + 1];
                    if ((uint)((num6 - 65) & -33) <= 5)
                    {
                        num6 = (num6 | 0x20) - 97 + 10;
                    }
                    else
                    {
                        if (num6 - 56 > 1)
                        {
                            goto IL_0135;
                        }
                        num6 -= 48;
                    }
                    uint num7 = (uint)(input[num5 + 2] - 48);
                    if (num7 > 9)
                    {
                        if ((uint)((num7 - 17) & -33) > 5)
                        {
                            goto IL_0135;
                        }
                        num7 = ((num7 + 48) | 0x20) - 97 + 10;
                    }
                    num6 = (num6 << 4) | num7;
                    num = ((!BitConverter.IsLittleEndian) ? ((num << 8) | num6) : ((num >> 8) | (num6 << 24)));
                    if (++num2 == 4)
                    {
                        break;
                    }
                    num5 += 3;
                    continue;
                }
                goto IL_0135;
                IL_0135:
                if (num2 > 1)
                {
                    num = ((bytesConsumed != 1) ? ((!BitConverter.IsLittleEndian) ? (num << 32 - (num2 << 3)) : (num >> 32 - (num2 << 3))) : ((!BitConverter.IsLittleEndian) ? (num << 8) : (num >> 8)));
                    break;
                }
                if ((num2 | num4) == 0)
                {
                    return num3;
                }
                num2 *= 3;
                dest.Append(input + num3 - num4, num4 + num2);
                return num3 + num2;
            }
            uint num8 = num;
            if (Rune.DecodeFromUtf8(new ReadOnlySpan<byte>(&num8, num2), out var result, out bytesConsumed) == OperationStatus.Done && (!iriParsing || IriHelper.CheckIriUnicodeRange((uint)result.Value, isQuery)))
            {
                if (num4 != 0)
                {
                    dest.Append(input + num3 - num4, num4);
                    num4 = 0;
                }
                dest.Append(result);
            }
            else
            {
                num4 += bytesConsumed * 3;
            }
            num2 -= bytesConsumed;
            num3 += bytesConsumed * 3;
        }
    }
}