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Switch-Toolbox/Switch_Toolbox_Library/Compression/LZ77_WII.cs
2020-04-10 15:32:49 -04:00

211 lines
7.8 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Runtime.InteropServices;
using Toolbox.Library.IO;
namespace Toolbox.Library
{
public class LZ77_WII
{
private readonly static int N = 4096;
private readonly static ushort[] textBuffer = new ushort[N + 17];
private readonly static int F = 18;
private static readonly int threshold = 2;
//Ported from
//https://github.com/mistydemeo/quickbms/blob/5752a6a2a38e16211952553fcffa59570855ac42/included/nintendo.c#L58
// various code from DSDecmp: http://code.google.com/p/dsdecmp/
// original code of unlz77wii_raw10 from "Hector Martin <marcan@marcansoft.com>" http://wiibrew.org/wiki/Wii.py
// ported to C by Luigi Auriemma
public static byte[] Decompress11(byte[] input, int decomp_size)
{
int i, j, disp = 0, len = 0, cdest;
byte b1, bt, b2, b3, flags;
int threshold = 1;
bool flag = false;
int inputOffset = 0;
int curr_size = 0;
byte[] outdata = new byte[decomp_size];
while (curr_size < decomp_size)
{
if (inputOffset >= input.Length) break;
flags = input[inputOffset++];
for (i = 0; i < 8 && curr_size < decomp_size; i++)
{
flag = (flags & (0x80 >> i)) > 0;
if (flag)
{
if (inputOffset > input.Length) break;
b1 = input[inputOffset++];
switch ((int)(b1 >> 4))
{
//#region case 0
case 0:
{
// ab cd ef
// =>
// len = abc + 0x11 = bc + 0x11
// disp = def
len = b1 << 4;
if (inputOffset >= input.Length) break;
bt = input[inputOffset++];
len |= bt >> 4;
len += 0x11;
disp = (bt & 0x0F) << 8;
if (inputOffset > input.Length) break;
b2 = input[inputOffset++];
disp |= b2;
break;
}
//#endregion
//#region case 1
case 1:
{
// ab cd ef gh
// =>
// len = bcde + 0x111
// disp = fgh
// 10 04 92 3F => disp = 0x23F, len = 0x149 + 0x11 = 0x15A
if (inputOffset + 3 > input.Length) break;
bt = input[inputOffset++];
b2 = input[inputOffset++];
b3 = input[inputOffset++];
len = (b1 & 0xF) << 12; // len = b000
len |= bt << 4; // len = bcd0
len |= (b2 >> 4); // len = bcde
len += 0x111; // len = bcde + 0x111
disp = (b2 & 0x0F) << 8; // disp = f
disp |= b3; // disp = fgh
break;
}
//#endregion
//#region other
default:
{
// ab cd
// =>
// len = a + threshold = a + 1
// disp = bcd
len = (b1 >> 4) + threshold;
disp = (b1 & 0x0F) << 8;
if (inputOffset >= input.Length) break;
b2 = input[inputOffset++];
disp |= b2;
break;
}
//#endregion
}
if (disp > curr_size)
return null;
cdest = curr_size;
for (j = 0; j < len && curr_size < decomp_size; j++)
outdata[curr_size++] = outdata[cdest - disp - 1 + j];
if (curr_size > decomp_size)
{
break;
}
}
else
{
if (inputOffset >= input.Length) break;
outdata[curr_size++] = input[inputOffset++];
if (curr_size > decomp_size)
{
break;
}
}
}
}
return outdata;
}
public static byte[] Decompress(byte[] input, bool useMagic = true)
{
if (input == null) throw new ArgumentNullException(nameof(input));
using (var reader = new FileReader(new MemoryStream(input), true))
{
reader.SetByteOrder(true);
reader.ReadSignature(4, "LZ77");
reader.Position = 0;
int i, j, k, r, c, z;
uint flags, decompressedSize, currentSize = 0;
byte[] temp = new byte[8];
reader.Read(temp, 0, 8);
if (temp[4] != 0x10)
{ reader.Dispose(); throw new Exception("Unsupported Compression Type!"); }
decompressedSize = (BitConverter.ToUInt32(temp, 4)) >> 8;
for (i = 0; i < N - F; i++) textBuffer[i] = 0xdf;
r = N - F; flags = 7; z = 7;
MemoryStream outFile = new MemoryStream();
while (outFile.Length < decompressedSize)
{
flags <<= 1;
z++;
if (z == 8)
{
if ((c = reader.ReadByte()) == -1) break;
flags = (uint)c;
z = 0;
}
if ((flags & 0x80) == 0)
{
if ((c = reader.ReadByte()) == reader.Length - 1) break;
if (currentSize < decompressedSize) outFile.WriteByte((byte)c);
textBuffer[r++] = (byte)c;
r &= (N - 1);
currentSize++;
}
else
{
if ((i = reader.ReadByte()) == -1) break;
if ((j = reader.ReadByte()) == -1) break;
j = j | ((i << 8) & 0xf00);
i = ((i >> 4) & 0x0f) + threshold;
for (k = 0; k <= i; k++)
{
c = textBuffer[(r - j - 1) & (N - 1)];
if (currentSize < decompressedSize) outFile.WriteByte((byte)c); textBuffer[r++] = (byte)c; r &= (N - 1); currentSize++;
}
}
}
return outFile.ToArray();
}
return input;
}
}
}