GARbro-mirror/ArcFormats/LzssStream.cs

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//! \file LzssStream.cs
//! \date Sat Jul 25 03:48:03 2015
//! \brief LZSS compressed stream I/O
//
// LempelZivStorerSzymanski (LZSS) compression algorithm.
//
// C# implementation Copyright (C) 2014-2015 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.IO;
namespace GameRes.Compression
{
public enum LzssMode
{
Decompress,
Compress,
};
public class LzssSettings
{
public int FrameSize { get; set; }
public byte FrameFill { get; set; }
public int FrameInitPos { get; set; }
}
public sealed class LzssCoroutine : Decompressor
{
Stream m_input;
LzssSettings m_settings;
public LzssSettings Settings { get { return m_settings; } }
public override void Initialize (Stream input)
{
m_input = input;
m_settings = new LzssSettings {
FrameSize = 0x1000,
FrameFill = 0,
FrameInitPos = 0xFEE,
};
}
protected override IEnumerator<int> Unpack ()
{
byte[] frame = new byte[Settings.FrameSize];
if (Settings.FrameFill != 0)
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for (int i = 0; i < frame.Length; ++i)
frame[i] = Settings.FrameFill;
int frame_pos = Settings.FrameInitPos;
int frame_mask = Settings.FrameSize-1;
for (;;)
{
int ctl = m_input.ReadByte();
if (-1 == ctl)
yield break;
for (int bit = 1; bit != 0x100; bit <<= 1)
{
if (0 != (ctl & bit))
{
int b = m_input.ReadByte();
if (-1 == b)
yield break;
frame[frame_pos++ & frame_mask] = (byte)b;
m_buffer[m_pos++] = (byte)b;
if (0 == --m_length)
yield return m_pos;
}
else
{
int lo = m_input.ReadByte();
if (-1 == lo)
yield break;
int hi = m_input.ReadByte();
if (-1 == hi)
yield break;
int offset = (hi & 0xf0) << 4 | lo;
for (int count = 3 + (hi & 0xF); count != 0; --count)
{
byte v = frame[offset++ & frame_mask];
frame[frame_pos++ & frame_mask] = v;
m_buffer[m_pos++] = v;
if (0 == --m_length)
yield return m_pos;
}
}
}
}
}
}
public class LzssStream : PackedStream<LzssCoroutine>
{
public LzssStream (Stream input, LzssMode mode = LzssMode.Decompress, bool leave_open = false)
: base (input, leave_open)
{
if (mode != LzssMode.Decompress)
throw new NotImplementedException ("LzssStream compression not implemented");
}
public LzssSettings Config { get { return Reader.Settings; } }
}
public class LzssReader : IDisposable
{
BinaryReader m_input;
byte[] m_output;
int m_size;
public BinaryReader Input { get { return m_input; } }
public byte[] Data { get { return m_output; } }
public int FrameSize { get; set; }
public byte FrameFill { get; set; }
public int FrameInitPos { get; set; }
public LzssReader (Stream input, int input_length, int output_length)
{
m_input = new BinaryReader (input, System.Text.Encoding.ASCII, true);
m_output = new byte[output_length];
m_size = input_length;
FrameSize = 0x1000;
FrameFill = 0;
FrameInitPos = 0xfee;
}
public void Unpack ()
{
int dst = 0;
var frame = new byte[FrameSize];
if (FrameFill != 0)
for (int i = 0; i < frame.Length; ++i)
frame[i] = FrameFill;
int frame_pos = FrameInitPos;
int frame_mask = FrameSize-1;
int remaining = (int)m_size;
while (remaining > 0)
{
int ctl = m_input.ReadByte();
--remaining;
for (int bit = 1; remaining > 0 && bit != 0x100; bit <<= 1)
{
if (dst >= m_output.Length)
return;
if (0 != (ctl & bit))
{
byte b = m_input.ReadByte();
--remaining;
frame[frame_pos++] = b;
frame_pos &= frame_mask;
m_output[dst++] = b;
}
else
{
if (remaining < 2)
return;
int lo = m_input.ReadByte();
int hi = m_input.ReadByte();
remaining -= 2;
int offset = (hi & 0xf0) << 4 | lo;
for (int count = 3 + (hi & 0xF); count != 0; --count)
{
if (dst >= m_output.Length)
break;
byte v = frame[offset++];
offset &= frame_mask;
frame[frame_pos++] = v;
frame_pos &= frame_mask;
m_output[dst++] = v;
}
}
}
}
}
#region IDisposable Members
bool disposed = false;
public void Dispose ()
{
Dispose (true);
GC.SuppressFinalize (this);
}
protected virtual void Dispose (bool disposing)
{
if (!disposed)
{
if (disposing)
{
m_input.Dispose();
}
disposed = true;
}
}
#endregion
}
}