PKHeX/PKHeX.Core/Saves/SAV3GCMemoryCard.cs
2022-06-30 07:17:47 -07:00

367 lines
13 KiB
C#

using System;
using System.Collections.Generic;
using System.Text;
using static System.Buffers.Binary.BinaryPrimitives;
namespace PKHeX.Core;
/* GameCube memory card format data, checksum and code to extract files based on Dolphin code, adapted from C++ to C#
* https://github.com/dolphin-emu/dolphin/
*/
/// <summary>
/// Flags for indicating what data is present in the Memory Card
/// </summary>
public enum GCMemoryCardState
{
Invalid,
NoPkmSaveGame,
SaveGameCOLO,
SaveGameXD,
SaveGameRSBOX,
MultipleSaveGame,
DuplicateCOLO,
DuplicateXD,
DuplicateRSBOX,
}
/// <summary>
/// GameCube save container which may or may not contain Generation 3 <see cref="SaveFile"/> objects.
/// </summary>
public sealed class SAV3GCMemoryCard
{
private const int BLOCK_SIZE = 0x2000;
private const int MBIT_TO_BLOCKS = 0x10;
private const int DENTRY_STRLEN = 0x20;
private const int DENTRY_SIZE = 0x40;
private const int NumEntries_Directory = BLOCK_SIZE / DENTRY_SIZE;
private static readonly HashSet<int> ValidMemoryCardSizes = new()
{
0x0080000, // 512KB 59 Blocks Memory Card
0x0100000, // 1MB
0x0200000, // 2MB
0x0400000, // 4MB 251 Blocks Memory Card
0x0800000, // 8MB
0x1000000, // 16MB 1019 Blocks Default Dolphin Memory Card
0x2000000, // 64MB
0x4000000, // 128MB
};
public static bool IsMemoryCardSize(long Size) => ValidMemoryCardSizes.Contains((int)Size);
public static bool IsMemoryCardSize(ReadOnlySpan<byte> Data)
{
if (!IsMemoryCardSize(Data.Length))
return false; // bad size
if (ReadUInt64BigEndian(Data) == ulong.MaxValue)
return false; // uninitialized
return true;
}
// Control blocks
private const int Header_Block = 0;
private const int Directory_Block = 1;
private const int DirectoryBackup_Block = 2;
private const int BlockAlloc_Block = 3;
private const int BlockAllocBackup_Block = 4;
private const int Header = BLOCK_SIZE * Header_Block;
private const int Directory = BLOCK_SIZE * Directory_Block;
private const int DirectoryBAK = BLOCK_SIZE * DirectoryBackup_Block;
private const int BlockAlloc = BLOCK_SIZE * BlockAlloc_Block;
private const int BlockAllocBAK = BLOCK_SIZE * BlockAllocBackup_Block;
public SAV3GCMemoryCard(byte[] data) => Data = data;
// Checksums
private (ushort Checksum, ushort Inverse) GetChecksum(int block, int offset, int length)
{
ushort csum = 0;
ushort inv_csum = 0;
var ofs = (block * BLOCK_SIZE) + offset;
var span = Data.AsSpan(ofs, length);
for (int i = 0; i < span.Length; i += 2)
{
var value = ReadUInt16BigEndian(span[i..]);
csum += value;
inv_csum += (ushort)~value;
}
if (csum == 0xffff)
csum = 0;
if (inv_csum == 0xffff)
inv_csum = 0;
return (csum, inv_csum);
}
private MemoryCardChecksumStatus VerifyChecksums()
{
MemoryCardChecksumStatus results = 0;
var (chk, inv) = GetChecksum(Header_Block, 0, 0x1FC);
if (Header_Checksum != chk || Header_Checksum_Inv != inv)
results |= MemoryCardChecksumStatus.HeaderBad;
(chk, inv) = GetChecksum(Directory_Block, 0, 0x1FFC);
if (Directory_Checksum != chk || Directory_Checksum_Inv != inv)
results |= MemoryCardChecksumStatus.DirectoryBad;
(chk, inv) = GetChecksum(DirectoryBackup_Block, 0, 0x1FFC);
if (DirectoryBAK_Checksum != chk || DirectoryBAK_Checksum_Inv != inv)
results |= MemoryCardChecksumStatus.DirectoryBackupBad;
(chk, inv) = GetChecksum(BlockAlloc_Block, 4, 0x1FFC);
if (BlockAlloc_Checksum != chk || BlockAlloc_Checksum_Inv != inv)
results |= MemoryCardChecksumStatus.BlockAllocBad;
(chk, inv) = GetChecksum(BlockAllocBackup_Block, 4, 0x1FFC);
if ((BlockAllocBAK_Checksum != chk) || BlockAllocBAK_Checksum_Inv != inv)
results |= MemoryCardChecksumStatus.BlockAllocBackupBad;
return results;
}
// Structure
private int Header_Size => ReadUInt16BigEndian(Data.AsSpan(Header + 0x0022));
private ushort Header_Checksum => ReadUInt16BigEndian(Data.AsSpan(Header + 0x01fc));
private ushort Header_Checksum_Inv => ReadUInt16BigEndian(Data.AsSpan(Header + 0x01fe));
// Encoding (Windows-1252 or Shift JIS)
private int Header_Encoding => ReadUInt16BigEndian(Data.AsSpan(Header + 0x0024));
private bool Header_Japanese => Header_Encoding == 1;
private Encoding EncodingType => Header_Japanese ? Encoding.GetEncoding(1252) : Encoding.GetEncoding(932);
private int Directory_UpdateCounter => ReadUInt16BigEndian(Data.AsSpan(Directory + 0x1ffa));
private int Directory_Checksum => ReadUInt16BigEndian(Data.AsSpan(Directory + 0x1ffc));
private int Directory_Checksum_Inv => ReadUInt16BigEndian(Data.AsSpan(Directory + 0x1ffe));
private int DirectoryBAK_UpdateCounter => ReadUInt16BigEndian(Data.AsSpan(DirectoryBAK + 0x1ffa));
private int DirectoryBAK_Checksum => ReadUInt16BigEndian(Data.AsSpan(DirectoryBAK + 0x1ffc));
private int DirectoryBAK_Checksum_Inv => ReadUInt16BigEndian(Data.AsSpan(DirectoryBAK + 0x1ffe));
private int BlockAlloc_Checksum => ReadUInt16BigEndian(Data.AsSpan(BlockAlloc + 0x0000));
private int BlockAlloc_Checksum_Inv => ReadUInt16BigEndian(Data.AsSpan(BlockAlloc + 0x0002));
private int BlockAllocBAK_Checksum => ReadUInt16BigEndian(Data.AsSpan(BlockAllocBAK + 0x0000));
private int BlockAllocBAK_Checksum_Inv => ReadUInt16BigEndian(Data.AsSpan(BlockAllocBAK + 0x0002));
private int DirectoryBlock_Used;
private int EntryCOLO = -1;
private int EntryXD = -1;
private int EntryRSBOX = -1;
private int EntrySelected = -1;
public bool HasCOLO => EntryCOLO >= 0;
public bool HasXD => EntryXD >= 0;
public bool HasRSBOX => EntryRSBOX >= 0;
public int SaveGameCount { get; private set; }
[Flags]
public enum MemoryCardChecksumStatus
{
None = 0,
HeaderBad = 1 << 0,
DirectoryBad = 1 << 1,
DirectoryBackupBad = 1 << 2,
BlockAllocBad,
BlockAllocBackupBad,
}
private bool IsCorruptedMemoryCard()
{
var csums = VerifyChecksums();
if ((csums & MemoryCardChecksumStatus.HeaderBad) != 0)
return true;
if ((csums & MemoryCardChecksumStatus.DirectoryBad) != 0)
{
if ((csums & MemoryCardChecksumStatus.DirectoryBackupBad) != 0) // backup is also wrong
return true; // Directory checksum and directory backup checksum failed
// backup is correct, restore
RestoreBackup();
csums = VerifyChecksums(); // update checksums
}
if ((csums & MemoryCardChecksumStatus.BlockAllocBad) != 0)
{
if ((csums & MemoryCardChecksumStatus.BlockAllocBackupBad) != 0) // backup is also wrong
return true;
// backup is correct, restore
RestoreBackup();
}
return false;
}
private void RestoreBackup()
{
Array.Copy(Data, DirectoryBackup_Block*BLOCK_SIZE, Data, Directory_Block*BLOCK_SIZE, BLOCK_SIZE);
Array.Copy(Data, BlockAllocBackup_Block*BLOCK_SIZE, Data, BlockAlloc_Block*BLOCK_SIZE, BLOCK_SIZE);
}
public GCMemoryCardState GetMemoryCardState()
{
if (!IsMemoryCardSize(Data))
return GCMemoryCardState.Invalid; // Invalid size
// Size in megabits, not megabytes
int m_sizeMb = Data.Length / BLOCK_SIZE / MBIT_TO_BLOCKS;
if (m_sizeMb != Header_Size) // Memory card file size does not match the header size
return GCMemoryCardState.Invalid;
if (IsCorruptedMemoryCard())
return GCMemoryCardState.Invalid;
// Use the most recent directory block
DirectoryBlock_Used = DirectoryBAK_UpdateCounter > Directory_UpdateCounter
? DirectoryBackup_Block
: Directory_Block;
// Search for pokemon savegames in the directory
for (int i = 0; i < NumEntries_Directory; i++)
{
int offset = (DirectoryBlock_Used * BLOCK_SIZE) + (i * DENTRY_SIZE);
if (ReadUInt32BigEndian(Data.AsSpan(offset)) == uint.MaxValue) // empty entry
continue;
int FirstBlock = ReadUInt16BigEndian(Data.AsSpan(offset + 0x36));
if (FirstBlock < 5)
continue;
int BlockCount = ReadUInt16BigEndian(Data.AsSpan(offset + 0x38));
var dataEnd = (FirstBlock + BlockCount) * BLOCK_SIZE;
// Memory card directory contains info for deleted files with boundaries beyond memory card size, ignore
if (dataEnd > Data.Length)
continue;
SaveGameCount = 0;
var header = Data.AsSpan(offset, 4);
var ver = SaveHandlerGCI.GetGameCode(header);
if (ver == GameVersion.COLO)
{
if (HasCOLO) // another entry already exists
return GCMemoryCardState.DuplicateCOLO;
EntryCOLO = i;
SaveGameCount++;
}
if (ver == GameVersion.XD)
{
if (HasXD) // another entry already exists
return GCMemoryCardState.DuplicateXD;
EntryXD = i;
SaveGameCount++;
}
if (ver == GameVersion.RSBOX)
{
if (HasRSBOX) // another entry already exists
return GCMemoryCardState.DuplicateRSBOX;
EntryRSBOX = i;
SaveGameCount++;
}
}
if (SaveGameCount == 0)
return GCMemoryCardState.NoPkmSaveGame;
if (SaveGameCount > 1)
return GCMemoryCardState.MultipleSaveGame;
if (HasCOLO)
{
EntrySelected = EntryCOLO;
return GCMemoryCardState.SaveGameCOLO;
}
if (HasXD)
{
EntrySelected = EntryXD;
return GCMemoryCardState.SaveGameXD;
}
EntrySelected = EntryRSBOX;
return GCMemoryCardState.SaveGameRSBOX;
}
public GameVersion SelectedGameVersion
{
get
{
if (EntrySelected < 0)
return GameVersion.Any;
if (EntrySelected == EntryCOLO)
return GameVersion.COLO;
if (EntrySelected == EntryXD)
return GameVersion.XD;
if (EntrySelected == EntryRSBOX)
return GameVersion.RSBOX;
return GameVersion.Any; //Default for no game selected
}
}
public void SelectSaveGame(GameVersion Game)
{
switch (Game)
{
case GameVersion.COLO: if (HasCOLO) EntrySelected = EntryCOLO; break;
case GameVersion.XD: if (HasXD) EntrySelected = EntryXD; break;
case GameVersion.RSBOX: if (HasRSBOX) EntrySelected = EntryRSBOX; break;
}
}
public string GCISaveName => GCISaveGameName();
public readonly byte[] Data;
private string GCISaveGameName()
{
int offset = (DirectoryBlock_Used * BLOCK_SIZE) + (EntrySelected * DENTRY_SIZE);
string GameCode = EncodingType.GetString(Data, offset, 4);
string Makercode = EncodingType.GetString(Data, offset + 0x04, 2);
string FileName = EncodingType.GetString(Data, offset + 0x08, DENTRY_STRLEN);
return $"{Makercode}-{GameCode}-{Util.TrimFromZero(FileName)}.gci";
}
public byte[] ReadSaveGameData()
{
var entry = EntrySelected;
if (entry < 0)
return Array.Empty<byte>(); // No entry selected
return ReadSaveGameData(entry);
}
private byte[] ReadSaveGameData(int entry)
{
int offset = (DirectoryBlock_Used * BLOCK_SIZE) + (entry * DENTRY_SIZE);
var span = Data.AsSpan(offset);
int blockFirst = ReadUInt16BigEndian(span[0x36..]);
int blockCount = ReadUInt16BigEndian(span[0x38..]);
return Data.AsSpan(blockFirst * BLOCK_SIZE, blockCount * BLOCK_SIZE).ToArray();
}
public void WriteSaveGameData(ReadOnlySpan<byte> data)
{
var entry = EntrySelected;
if (entry < 0) // Can't write anywhere
return;
WriteSaveGameData(data, entry);
}
private void WriteSaveGameData(ReadOnlySpan<byte> data, int entry)
{
int offset = (DirectoryBlock_Used * BLOCK_SIZE) + (entry * DENTRY_SIZE);
var span = Data.AsSpan(offset);
int blockFirst = ReadUInt16BigEndian(span[0x36..]);
int blockCount = ReadUInt16BigEndian(span[0x38..]);
if (data.Length != blockCount * BLOCK_SIZE) // Invalid File Size
return;
var dest = Data.AsSpan(blockFirst * BLOCK_SIZE);
data[..(blockCount * BLOCK_SIZE)].CopyTo(dest);
}
}