PKHeX/PKHeX.Core/Saves/Blocks/BlockInfo3DS.cs
Kurt 47071b41f3
Refactoring: Span-based value writes and method signatures (#3361)
Existing `get`/`set` logic is flawed in that it doesn't work on Big Endian operating systems, and it allocates heap objects when it doesn't need to.

`System.Buffers.Binary.BinaryPrimitives` in the `System.Memory` NuGet package provides both Little Endian and Big Endian methods to read and write data; all the `get`/`set` operations have been reworked to use this new API. This removes the need for PKHeX's manual `BigEndian` class, as all functions are already covered by the BinaryPrimitives API.

The `StringConverter` has now been rewritten to accept a Span to read from & write to, no longer requiring a temporary StringBuilder.

Other Fixes included:
- The Super Training UI for Gen6 has been reworked according to the latest block structure additions.
- Cloning a Stadium2 Save File now works correctly (opening from the Folder browser list).
- Checksum & Sanity properties removed from parent PKM class, and is now implemented via interface.
2022-01-02 21:35:59 -08:00

68 lines
2.2 KiB
C#

using System;
using static System.Buffers.Binary.BinaryPrimitives;
namespace PKHeX.Core
{
/// <summary>
/// Gen6+ Block Info (inside BEEF chunk)
/// </summary>
public abstract class BlockInfo3DS : BlockInfo
{
private readonly int BlockInfoOffset;
// ==chunk def== @ BlockInfoOffset
// u64 timestamp1
// u64 timestamp2
// u8[4] BEEF magic
// n*{blockInfo}, where n varies per sav type
// ==block info def==
// u32 length
// u16 id
// u16 checksum
// when stored, each block size is rounded up to nearest 0x200, and the next chunk is immediately after
protected BlockInfo3DS(int bo, uint id, int ofs, int len)
{
BlockInfoOffset = bo;
ID = id;
Offset = ofs;
Length = len;
}
private int ChecksumOffset => BlockInfoOffset + 0x14 + ((int)ID * 8) + 6;
protected abstract ushort GetChecksum(Span<byte> data);
protected override bool ChecksumValid(Span<byte> data)
{
ushort chk = GetChecksum(data);
var old = ReadUInt16LittleEndian(data[ChecksumOffset..]);
return chk == old;
}
protected override void SetChecksum(Span<byte> data)
{
ushort chk = GetChecksum(data);
WriteUInt16LittleEndian(data[ChecksumOffset..], chk);
}
}
public sealed class BlockInfo6 : BlockInfo3DS
{
public BlockInfo6(int bo, uint id, int ofs, int len) : base(bo, id, ofs, len) { }
protected override ushort GetChecksum(Span<byte> data) => Checksums.CRC16_CCITT(data.Slice(Offset, Length));
}
public sealed class BlockInfo7 : BlockInfo3DS
{
public BlockInfo7(int bo, uint id, int ofs, int len) : base(bo, id, ofs, len) { }
protected override ushort GetChecksum(Span<byte> data) => Checksums.CRC16Invert(data.Slice(Offset, Length));
}
public sealed class BlockInfo7b : BlockInfo3DS
{
public BlockInfo7b(int bo, uint id, int ofs, int len) : base(bo, id, ofs, len) { }
protected override ushort GetChecksum(Span<byte> data) => Checksums.CRC16NoInvert(data.Slice(Offset, Length));
}
}