BizHawk/BizHawk.Client.Common/cheats/SnesGameGenieDecoder.cs

113 lines
2.7 KiB
C#

using System;
using System.Collections.Generic;
namespace BizHawk.Client.Common.cheats
{
public static class SnesGameGenieDecoder
{
// including transposition
// Code: D F 4 7 0 9 1 5 6 B C 8 A 2 3 E
// Hex: 0 1 2 3 4 5 6 7 8 9 A B C D E F
// This only applies to the SNES
private static readonly Dictionary<char, int> SNESGameGenieTable = new Dictionary<char, int>
{
['D'] = 0, // 0000
['F'] = 1, // 0001
['4'] = 2, // 0010
['7'] = 3, // 0011
['0'] = 4, // 0100
['9'] = 5, // 0101
['1'] = 6, // 0110
['5'] = 7, // 0111
['6'] = 8, // 1000
['B'] = 9, // 1001
['C'] = 10, // 1010
['8'] = 11, // 1011
['A'] = 12, // 1100
['2'] = 13, // 1101
['3'] = 14, // 1110
['E'] = 15 // 1111
};
public static IDecodeResult Decode(string code)
{
if (code == null)
{
throw new ArgumentNullException(nameof(code));
}
if (!code.Contains("-") && code.Length != 9)
{
return new InvalidCheatCode("Game genie codes must be 9 characters with a format of xxyy-yyyy");
}
// Code: D F 4 7 0 9 1 5 6 B C 8 A 2 3 E
// Hex: 0 1 2 3 4 5 6 7 8 9 A B C D E F
// XXYY-YYYY, where XX is the value, and YY-YYYY is the address.
// Char # | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
// Bit # |3|2|1|0|3|2|1|0|3|2|1|0|3|2|1|0|3|2|1|0|3|2|1|0|3|2|1|0|3|2|1|0|
// maps to| Value |i|j|k|l|q|r|s|t|o|p|a|b|c|d|u|v|w|x|e|f|g|h|m|n|
// order | Value |a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|
var result = new DecodeResult { Size = WatchSize.Byte };
int x;
// Value
if (code.Length > 0)
{
SNESGameGenieTable.TryGetValue(code[0], out x);
result.Value = x << 4;
}
if (code.Length > 1)
{
SNESGameGenieTable.TryGetValue(code[1], out x);
result.Value |= x;
}
// Address
if (code.Length > 2)
{
SNESGameGenieTable.TryGetValue(code[2], out x);
result.Address = x << 12;
}
if (code.Length > 3)
{
SNESGameGenieTable.TryGetValue(code[3], out x);
result.Address |= x << 4;
}
if (code.Length > 4)
{
SNESGameGenieTable.TryGetValue(code[4], out x);
result.Address |= (x & 0xC) << 6;
result.Address |= (x & 0x3) << 22;
}
if (code.Length > 5)
{
SNESGameGenieTable.TryGetValue(code[5], out x);
result.Address |= (x & 0xC) << 18;
result.Address |= (x & 0x3) << 2;
}
if (code.Length > 6)
{
SNESGameGenieTable.TryGetValue(code[6], out x);
result.Address |= (x & 0xC) >> 2;
result.Address |= (x & 0x3) << 18;
}
if (code.Length > 7)
{
SNESGameGenieTable.TryGetValue(code[7], out x);
result.Address |= (x & 0xC) << 14;
result.Address |= (x & 0x3) << 10;
}
return result;
}
}
}