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(DscDecoder): derive from MsbBitStream class.

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This commit is contained in:
morkt 2015-08-27 03:12:42 +04:00
parent 29b0658460
commit d67b4b05fa
1 changed files with 59 additions and 90 deletions
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149
ArcFormats/Ethornell/ArcBGI.cs
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@ -2,7 +2,7 @@
//! \date Tue Sep 09 09:29:12 2014
//! \brief BGI/Ethornell engine archive implementation.
//
// Copyright (C) 2014 by morkt
// 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
@ -111,36 +111,76 @@ namespace GameRes.Formats.BGI
}
return new ArcView.ArcStream (input);
}
catch
catch (Exception X)
{
input.Dispose();
throw;
System.Diagnostics.Trace.WriteLine (X.Message, "BgiOpener");
return arc.File.CreateStream (entry.Offset, entry.Size);
}
}
}
internal sealed class DscDecoder : IDisposable
internal class BgiDecoderBase : MsbBitStream
{
private Stream m_input;
private byte[] m_output;
protected uint m_key;
protected uint m_magic;
private uint m_key;
private uint m_dst_size;
private uint m_dec_count;
private uint m_magic;
protected BgiDecoderBase (Stream input, bool leave_open = false) : base (input, leave_open)
{
}
protected byte UpdateKey ()
{
uint v0 = 20021 * (m_key & 0xffff);
uint v1 = m_magic | (m_key >> 16);
v1 = v1 * 20021 + m_key * 346;
v1 = (v1 + (v0 >> 16)) & 0xffff;
m_key = (v1 << 16) + (v0 & 0xffff) + 1;
return (byte)v1;
}
}
internal sealed class DscDecoder : BgiDecoderBase
{
byte[] m_output;
uint m_dst_size;
uint m_dec_count;
public byte[] Output { get { return m_output; } }
public DscDecoder (ArcView.Frame input)
: base (new ArcView.ArcStream (input, input.Offset+0x20, input.Reserved-0x20))
{
m_magic = (uint)input.ReadUInt16 (input.Offset) << 16;
m_key = input.ReadUInt32 (input.Offset+0x10);
m_dst_size = input.ReadUInt32 (input.Offset+0x14);
m_dec_count = input.ReadUInt32 (input.Offset+0x18);
m_input = new ArcView.ArcStream (input, input.Offset+0x20, input.Reserved-0x20);
m_output = new byte[m_dst_size];
}
public void Unpack ()
{
HuffmanCode[] hcodes = new HuffmanCode[512];
HuffmanNode[] hnodes = new HuffmanNode[1023];
int leaf_node_count = 0;
for (ushort i = 0; i < 512; i++)
{
int src = Input.ReadByte();
if (-1 == src)
throw new EndOfStreamException ("Incomplete compressed stream");
byte depth = (byte)(src - UpdateKey());
if (0 != depth)
{
hcodes[leaf_node_count].Depth = depth;
hcodes[leaf_node_count].Code = i;
leaf_node_count++;
}
}
Array.Sort (hcodes, 0, leaf_node_count);
CreateHuffmanTree (hnodes, hcodes, leaf_node_count);
HuffmanDecompress (hnodes, m_dec_count);
}
struct HuffmanCode : IComparable<HuffmanCode>
{
public ushort Code;
@ -163,31 +203,7 @@ namespace GameRes.Formats.BGI
public uint RightChildIndex;
}
public void Unpack ()
{
HuffmanCode[] hcodes = new HuffmanCode[512];
HuffmanNode[] hnodes = new HuffmanNode[1023];
int leaf_node_count = 0;
for (ushort i = 0; i < 512; i++)
{
int src = m_input.ReadByte();
if (-1 == src)
throw new EndOfStreamException ("Incomplete compressed stream");
byte depth = (byte)(src - UpdateKey());
if (0 != depth)
{
hcodes[leaf_node_count].Depth = depth;
hcodes[leaf_node_count].Code = i;
leaf_node_count++;
}
}
Array.Sort (hcodes, 0, leaf_node_count);
CreateHuffmanTree (hnodes, hcodes, leaf_node_count);
HuffmanDecompress (hnodes, m_dec_count);
}
void CreateHuffmanTree (HuffmanNode[] hnodes, HuffmanCode[] hcode, int node_count)
static void CreateHuffmanTree (HuffmanNode[] hnodes, HuffmanCode[] hcode, int node_count)
{
uint[,] nodes_index = new uint[2,512];
uint next_node_index = 1;
@ -221,34 +237,6 @@ namespace GameRes.Formats.BGI
}
}
int m_bits = 0;
bool GetNextBit ()
{
bool carry = 0 != (m_bits & 0x80);
m_bits <<= 1;
if (0 == (m_bits & 0xff))
{
m_bits = m_input.ReadByte();
if (-1 == m_bits)
throw new EndOfStreamException ("Invalid compressed stream");
carry = 0 != (m_bits & 0x80);
m_bits = (m_bits << 1) | 1;
}
return carry;
}
bool GetBits (int count, out int bits)
{
bits = 0;
for (int i = 0; i < count; ++i)
{
bits <<= 1;
bits |= GetNextBit() ? 1 : 0;
}
return true;
}
uint HuffmanDecompress (HuffmanNode[] hnodes, uint dec_count)
{
uint dst_ptr = 0;
@ -258,7 +246,10 @@ namespace GameRes.Formats.BGI
uint node_index = 0;
do
{
if (!GetNextBit())
int bit = GetNextBit();
if (-1 == bit)
throw new EndOfStreamException();
if (0 == bit)
node_index = hnodes[node_index].LeftChildIndex;
else
node_index = hnodes[node_index].RightChildIndex;
@ -268,8 +259,8 @@ namespace GameRes.Formats.BGI
uint code = hnodes[node_index].Code;
if (code >= 256)
{
int win_pos;
if (!GetBits (12, out win_pos))
int win_pos = GetBits (12);
if (-1 == win_pos)
break;
uint copy_bytes = (code & 0xff) + 2;
@ -284,27 +275,5 @@ namespace GameRes.Formats.BGI
}
return dst_ptr;
}
byte UpdateKey ()
{
uint v0 = 20021 * (m_key & 0xffff);
uint v1 = m_magic | (m_key >> 16);
v1 = v1 * 20021 + m_key * 346;
v1 = (v1 + (v0 >> 16)) & 0xffff;
m_key = (v1 << 16) + (v0 & 0xffff) + 1;
return (byte)v1;
}
#region IDisposable Members
public void Dispose ()
{
if (null != m_input)
{
m_input.Dispose();
m_input = null;
}
GC.SuppressFinalize (this);
}
#endregion
}
}