diff options
Diffstat (limited to 'Impostor-dev/src/Impostor.Api/Innersloth/GameCodeParser.cs')
| -rw-r--r-- | Impostor-dev/src/Impostor.Api/Innersloth/GameCodeParser.cs | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/Impostor-dev/src/Impostor.Api/Innersloth/GameCodeParser.cs b/Impostor-dev/src/Impostor.Api/Innersloth/GameCodeParser.cs new file mode 100644 index 0000000..9717cff --- /dev/null +++ b/Impostor-dev/src/Impostor.Api/Innersloth/GameCodeParser.cs @@ -0,0 +1,142 @@ +using System; +using System.Buffers.Binary; +using System.Linq; +using System.Security.Cryptography; +using System.Text; + +namespace Impostor.Api.Innersloth +{ + public static class GameCodeParser + { + private const string V2 = "QWXRTYLPESDFGHUJKZOCVBINMA"; + private static readonly int[] V2Map = { + 25, + 21, + 19, + 10, + 8, + 11, + 12, + 13, + 22, + 15, + 16, + 6, + 24, + 23, + 18, + 7, + 0, + 3, + 9, + 4, + 14, + 20, + 1, + 2, + 5, + 17 + }; + private static readonly RNGCryptoServiceProvider Random = new RNGCryptoServiceProvider(); + + public static string IntToGameName(int input) + { + // V2. + if (input < -1) + { + return IntToGameNameV2(input); + } + + // V1. + Span<byte> code = stackalloc byte[4]; + BinaryPrimitives.WriteInt32LittleEndian(code, input); +#if NETSTANDARD2_0 + return Encoding.UTF8.GetString(code.Slice(0, 4).ToArray()); +#else + return Encoding.UTF8.GetString(code.Slice(0, 4)); +#endif + } + + private static string IntToGameNameV2(int input) + { + var a = input & 0x3FF; + var b = (input >> 10) & 0xFFFFF; + + return new string(new [] + { + V2[a % 26], + V2[a / 26], + V2[b % 26], + V2[b / 26 % 26], + V2[b / (26 * 26) % 26], + V2[b / (26 * 26 * 26) % 26] + }); + } + + public static int GameNameToInt(string code) + { + var upper = code.ToUpperInvariant(); + if (upper.Any(x => !char.IsLetter(x))) + { + return -1; + } + + var len = code.Length; + if (len == 6) + { + return GameNameToIntV2(upper); + } + + if (len == 4) + { + return code[0] | ((code[1] | ((code[2] | (code[3] << 8)) << 8)) << 8); + } + + return -1; + } + + private static int GameNameToIntV2(string code) + { + var a = V2Map[code[0] - 65]; + var b = V2Map[code[1] - 65]; + var c = V2Map[code[2] - 65]; + var d = V2Map[code[3] - 65]; + var e = V2Map[code[4] - 65]; + var f = V2Map[code[5] - 65]; + + var one = (a + 26 * b) & 0x3FF; + var two = (c + 26 * (d + 26 * (e + 26 * f))); + + return (int) (one | ((two << 10) & 0x3FFFFC00) | 0x80000000); + } + + public static int GenerateCode(int len) + { + if (len != 4 && len != 6) + { + throw new ArgumentException("should be 4 or 6", nameof(len)); + } + + // Generate random bytes. +#if NETSTANDARD2_0 + var data = new byte[len]; +#else + Span<byte> data = stackalloc byte[len]; +#endif + Random.GetBytes(data); + + // Convert to their char representation. + Span<char> dataChar = stackalloc char[len]; + for (var i = 0; i < len; i++) + { + dataChar[i] = V2[V2Map[data[i] % 26]]; + } + +#if NETSTANDARD2_0 + return GameNameToInt(new string(dataChar.ToArray())); +#else + return GameNameToInt(new string(dataChar)); +#endif + } + } +}
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