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(BinOpener): refined LZW decompression.

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This commit is contained in:
morkt 2015-12-20 09:27:30 +04:00
parent d2e7882e6d
commit b592a7dd52
1 changed files with 52 additions and 81 deletions
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133
ArcFormats/Favorite/ArcFVP.cs
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@ -50,7 +50,7 @@ namespace GameRes.Formats.FVP
if (!file.View.AsciiEqual (4, "PK01"))
return null;
int count = file.View.ReadInt32 (8);
if (count <= 0 || count > 0xfffff)
if (!IsSaneCount (count))
return null;
long index_offset = 0x0c;
uint index_size = (uint)(0x28 * count);
@ -73,117 +73,88 @@ namespace GameRes.Formats.FVP
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var entry_offset = entry.Offset;
var input = new ArcView.Frame (arc.File, entry_offset, entry.Size);
try
if (!(entry.Size > 8 && arc.File.View.AsciiEqual (entry.Offset, "acp\0")))
return base.OpenEntry (arc, entry);
int unpacked_size = Binary.BigEndian (arc.File.View.ReadInt32 (entry.Offset+4));
using (var input = arc.File.CreateStream (entry.Offset+8, entry.Size-8))
using (var decoder = new LzwDecoder (input, unpacked_size))
{
if (entry.Size > 8 && input.AsciiEqual (entry_offset, "acp\0"))
{
using (var decoder = new LzwDecoder (input))
{
decoder.Unpack();
return new MemoryStream (decoder.Output, false);
}
}
return new ArcView.ArcStream (input, entry_offset, entry.Size);
}
catch
{
input.Dispose();
throw;
decoder.Unpack();
return new MemoryStream (decoder.Output);
}
}
}
internal sealed class LzwDecoder : IDisposable
{
private Stream m_input;
private byte[] m_output;
private MsbBitStream m_input;
private byte[] m_output;
public byte[] Output { get { return m_output; } }
uint m_dst_size;
public LzwDecoder (ArcView.Frame input)
public LzwDecoder (Stream input, int unpacked_size)
{
m_dst_size = Binary.BigEndian (input.ReadUInt32 (input.Offset+4));
m_input = new ArcView.ArcStream (input, input.Offset+8, input.Reserved-8);
m_output = new byte[m_dst_size];
m_input = new MsbBitStream (input, true);
m_output = new byte[unpacked_size];
}
public void Unpack ()
{
int dst = 0;
int bits = 0;
var buf = new int[0x8c00];
uint dst_left = m_dst_size;
uint L0 = 0x800000;
uint edx = 0x102;
for (;;)
var lzw_dict = new int[0x8900];
int token_width = 9;
int dict_pos = 0;
while (dst < m_output.Length)
{
uint eax = L0;
bool hi = false;
while (!hi)
{
bits <<= 1;
if (0 == (bits&0xff))
{
bits = m_input.ReadByte();
if (-1 == bits)
throw new EndOfStreamException ("Invalid compressed stream");
bits = (bits << 1) | 1;
}
int next_bit = (bits >> 8) & 1;
hi = 0 != (eax & 0x80000000);
eax = (eax << 1) | (uint)next_bit;
}
if (0x100 == (eax & 0xff00) && 2 >= (eax & 0xff))
{
if (2 == (eax & 0xff))
{
L0 = 0x800000;
edx = 0x102;
continue;
}
if (0 == (eax & 0xff))
break;
L0 >>= 1;
if (0 != (L0 & 0xff00))
throw new EndOfStreamException ("Invalid compressed stream");
continue;
}
++edx;
if (edx >= 0x8c00)
int token = m_input.GetBits (token_width);
if (-1 == token)
throw new EndOfStreamException ("Invalid compressed stream");
buf[edx] = dst;
if (0 == (eax & 0xff00))
else if (0x100 == token) // end of input
break;
else if (0x101 == token) // increase token width
{
if (0 == dst_left--)
throw new EndOfStreamException ("Invalid compressed stream");
m_output[dst++] = (byte)(eax & 0xff);
++token_width;
if (token_width > 24)
throw new InvalidFormatException ("Invalid comressed stream");
}
else if (0x102 == token) // reset dictionary
{
token_width = 9;
dict_pos = 0;
}
else
{
if (eax >= edx)
throw new EndOfStreamException ("Invalid compressed stream");
int src = buf[eax];
int count = buf[eax+1] - src + 1;
if (dst_left < count)
throw new EndOfStreamException ("Invalid compressed stream");
dst_left -= (uint)count;
Binary.CopyOverlapped (m_output, src, dst, count);
dst += count;
if (dict_pos >= lzw_dict.Length)
throw new InvalidFormatException ("Invalid comressed stream");
lzw_dict[dict_pos++] = dst;
if (token < 0x100)
{
m_output[dst++] = (byte)token;
}
else
{
token -= 0x103;
if (token >= dict_pos)
throw new InvalidFormatException ("Invalid comressed stream");
int src = lzw_dict[token];
int count = Math.Min (m_output.Length-dst, lzw_dict[token+1] - src + 1);
if (count < 0)
throw new InvalidFormatException ("Invalid comressed stream");
Binary.CopyOverlapped (m_output, src, dst, count);
dst += count;
}
}
}
}
#region IDisposable Members
bool _disposed = false;
public void Dispose ()
{
if (null != m_input)
if (!_disposed)
{
m_input.Dispose();
m_input = null;
_disposed = true;
}
GC.SuppressFinalize (this);
}