public int Decompress(Stream inData, int inLen, Stream outData, int outLen)
{
BitBuffer bitbuf = new BitBuffer(inData);
long startpos = inData.Position;
long endpos = inData.Position + inLen;
byte[] window = m_state.window;
uint window_posn = m_state.window_posn;
uint window_size = m_state.window_size;
uint R0 = m_state.R0;
uint R1 = m_state.R1;
uint R2 = m_state.R2;
uint i, j;
int togo = outLen, this_run, main_element, match_length, match_offset, length_footer, extra, verbatim_bits;
int rundest, runsrc, copy_length, aligned_bits;
bitbuf.InitBitStream();
/* read header if necessary */
if(m_state.header_read == 0)
{
uint intel = bitbuf.ReadBits(1);
if(intel != 0)
{
// read the filesize
i = bitbuf.ReadBits(16); j = bitbuf.ReadBits(16);
m_state.intel_filesize = (int)((i << 16) | j);
}
m_state.header_read = 1;
}
/* main decoding loop */
while(togo > 0)
{
/* last block finished, new block expected */
if(m_state.block_remaining == 0)
{
// TODO may screw something up here
if(m_state.block_type == LzxConstants.BLOCKTYPE.UNCOMPRESSED) {
if((m_state.block_length & 1) == 1) inData.ReadByte(); /* realign bitstream to word */
bitbuf.InitBitStream();
}
m_state.block_type = (LzxConstants.BLOCKTYPE)bitbuf.ReadBits(3);;
i = bitbuf.ReadBits(16);
j = bitbuf.ReadBits(8);
m_state.block_remaining = m_state.block_length = (uint)((i << 8) | j);
switch(m_state.block_type)
{
case LzxConstants.BLOCKTYPE.ALIGNED:
for(i = 0, j = 0; i < 8; i++) { j = bitbuf.ReadBits(3); m_state.ALIGNED_len[i] = (byte)j; }
MakeDecodeTable(LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
m_state.ALIGNED_len, m_state.ALIGNED_table);
/* rest of aligned header is same as verbatim */
goto case LzxConstants.BLOCKTYPE.VERBATIM;
case LzxConstants.BLOCKTYPE.VERBATIM:
ReadLengths(m_state.MAINTREE_len, 0, 256, bitbuf);
ReadLengths(m_state.MAINTREE_len, 256, m_state.main_elements, bitbuf);
MakeDecodeTable(LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
m_state.MAINTREE_len, m_state.MAINTREE_table);
if(m_state.MAINTREE_len[0xE8] != 0) m_state.intel_started = 1;
ReadLengths(m_state.LENGTH_len, 0, LzxConstants.NUM_SECONDARY_LENGTHS, bitbuf);
MakeDecodeTable(LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
m_state.LENGTH_len, m_state.LENGTH_table);
break;
case LzxConstants.BLOCKTYPE.UNCOMPRESSED:
m_state.intel_started = 1; /* because we can't assume otherwise */
bitbuf.EnsureBits(16); /* get up to 16 pad bits into the buffer */
if(bitbuf.GetBitsLeft() > 16) inData.Seek(-2, SeekOrigin.Current); /* and align the bitstream! */
byte hi, mh, ml, lo;
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R0 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R1 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R2 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
break;
default:
return -1; // TODO throw proper exception
}
}
/* buffer exhaustion check */
if(inData.Position > (startpos + inLen))
{
/* it's possible to have a file where the next run is less than
* 16 bits in size. In this case, the READ_HUFFSYM() macro used
* in building the tables will exhaust the buffer, so we should
* allow for this, but not allow those accidentally read bits to
* be used (so we check that there are at least 16 bits
* remaining - in this boundary case they aren't really part of
* the compressed data)
*/
Console.WriteLine("WTF");
if(inData.Position > (startpos+inLen+2) || bitbuf.GetBitsLeft() < 16) return -1; //TODO throw proper exception
}
while((this_run = (int)m_state.block_remaining) > 0 && togo > 0)
{
if(this_run > togo) this_run = togo;
togo -= this_run;
m_state.block_remaining -= (uint)this_run;
/* apply 2^x-1 mask */
window_posn &= window_size - 1;
/* runs can't straddle the window wraparound */
if((window_posn + this_run) > window_size)
return -1; //TODO throw proper exception
switch(m_state.block_type)
{
case LzxConstants.BLOCKTYPE.VERBATIM:
while(this_run > 0)
{
main_element = (int)ReadHuffSym(m_state.MAINTREE_table, m_state.MAINTREE_len,
LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
bitbuf);
if(main_element < LzxConstants.NUM_CHARS)
{
/* literal: 0 to NUM_CHARS-1 */
window[window_posn++] = (byte)main_element;
this_run--;
}
else
{
/* match: NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LzxConstants.NUM_CHARS;
match_length = main_element & LzxConstants.NUM_PRIMARY_LENGTHS;
if(match_length == LzxConstants.NUM_PRIMARY_LENGTHS)
{
length_footer = (int)ReadHuffSym(m_state.LENGTH_table, m_state.LENGTH_len,
LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
bitbuf);
match_length += length_footer;
}
match_length += LzxConstants.MIN_MATCH;
match_offset = main_element >> 3;
if(match_offset > 2)
{
/* not repeated offset */
if(match_offset != 3)
{
extra = extra_bits[match_offset];
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset = (int)position_base[match_offset] - 2 + verbatim_bits;
}
else
{
match_offset = 1;
}
/* update repeated offset LRU queue */
R2 = R1; R1 = R0; R0 = (uint)match_offset;
}
else if(match_offset == 0)
{
match_offset = (int)R0;
}
else if(match_offset == 1)
{
match_offset = (int)R1;
R1 = R0; R0 = (uint)match_offset;
}
else /* match_offset == 2 */
{
match_offset = (int)R2;
R2 = R0; R0 = (uint)match_offset;
}
rundest = (int)window_posn;
this_run -= match_length;
/* copy any wrapped around source data */
if(window_posn >= match_offset)
{
/* no wrap */
runsrc = rundest - match_offset;
}
else
{
runsrc = rundest + ((int)window_size - match_offset);
copy_length = match_offset - (int)window_posn;
if(copy_length < match_length)
{
match_length -= copy_length;
window_posn += (uint)copy_length;
while(copy_length-- > 0) window[rundest++] = window[runsrc++];
runsrc = 0;
}
}
window_posn += (uint)match_length;
/* copy match data - no worries about destination wraps */
while(match_length-- > 0) window[rundest++] = window[runsrc++];
}
}
break;
case LzxConstants.BLOCKTYPE.ALIGNED:
while(this_run > 0)
{
main_element = (int)ReadHuffSym(m_state.MAINTREE_table, m_state.MAINTREE_len,
LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
bitbuf);
if(main_element < LzxConstants.NUM_CHARS)
{
/* literal 0 to NUM_CHARS-1 */
window[window_posn++] = (byte)main_element;
this_run--;
}
else
{
/* match: NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LzxConstants.NUM_CHARS;
match_length = main_element & LzxConstants.NUM_PRIMARY_LENGTHS;
if(match_length == LzxConstants.NUM_PRIMARY_LENGTHS)
{
length_footer = (int)ReadHuffSym(m_state.LENGTH_table, m_state.LENGTH_len,
LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
bitbuf);
match_length += length_footer;
}
match_length += LzxConstants.MIN_MATCH;
match_offset = main_element >> 3;
if(match_offset > 2)
{
/* not repeated offset */
extra = extra_bits[match_offset];
match_offset = (int)position_base[match_offset] - 2;
if(extra > 3)
{
/* verbatim and aligned bits */
extra -= 3;
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset += (verbatim_bits << 3);
aligned_bits = (int)ReadHuffSym(m_state.ALIGNED_table, m_state.ALIGNED_len,
LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
bitbuf);
match_offset += aligned_bits;
}
else if(extra == 3)
{
/* aligned bits only */
aligned_bits = (int)ReadHuffSym(m_state.ALIGNED_table, m_state.ALIGNED_len,
LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
bitbuf);
match_offset += aligned_bits;
}
else if (extra > 0) /* extra==1, extra==2 */
{
/* verbatim bits only */
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset += verbatim_bits;
}
else /* extra == 0 */
{
/* ??? */
match_offset = 1;
}
/* update repeated offset LRU queue */
R2 = R1; R1 = R0; R0 = (uint)match_offset;
}
else if( match_offset == 0)
{
match_offset = (int)R0;
}
else if(match_offset == 1)
{
match_offset = (int)R1;
R1 = R0; R0 = (uint)match_offset;
}
else /* match_offset == 2 */
{
match_offset = (int)R2;
R2 = R0; R0 = (uint)match_offset;
}
rundest = (int)window_posn;
this_run -= match_length;
/* copy any wrapped around source data */
if(window_posn >= match_offset)
{
/* no wrap */
runsrc = rundest - match_offset;
}
else
{
runsrc = rundest + ((int)window_size - match_offset);
copy_length = match_offset - (int)window_posn;
if(copy_length < match_length)
{
match_length -= copy_length;
window_posn += (uint)copy_length;
while(copy_length-- > 0) window[rundest++] = window[runsrc++];
runsrc = 0;
}
}
window_posn += (uint)match_length;
/* copy match data - no worries about destination wraps */
while(match_length-- > 0) window[rundest++] = window[runsrc++];
}
}
break;
case LzxConstants.BLOCKTYPE.UNCOMPRESSED:
if((inData.Position + this_run) > endpos) return -1; //TODO throw proper exception
byte[] temp_buffer = new byte[this_run];
inData.Read(temp_buffer, 0, this_run);
temp_buffer.CopyTo(window, window_posn);
window_posn += (uint)this_run;
break;
default:
return -1; //TODO throw proper exception
}
}
}
if(togo != 0) return -1; //TODO throw proper exception
int start_window_pos = (int)window_posn;
if(start_window_pos == 0) start_window_pos = (int)window_size;
start_window_pos -= outLen;
outData.Write(window, start_window_pos, outLen);
m_state.window_posn = window_posn;
m_state.R0 = R0;
m_state.R1 = R1;
m_state.R2 = R2;
// TODO finish intel E8 decoding
/* intel E8 decoding */
if((m_state.frames_read++ < 32768) && m_state.intel_filesize != 0)
{
if(outLen <= 6 || m_state.intel_started == 0)
{
m_state.intel_curpos += outLen;
}
else
{
int dataend = outLen - 10;
uint curpos = (uint)m_state.intel_curpos;
uint filesize = (uint)m_state.intel_filesize;
uint abs_off, rel_off;
m_state.intel_curpos = (int)curpos + outLen;
while(outData.Position < dataend)
{
if(outData.ReadByte() != 0xE8) { curpos++; continue; }
//abs_off =
}
}
return -1;
}
return 0;
}
public int Decompress(Stream inData, int inLen, Stream outData, int outLen)
{
BitBuffer bitbuf = new BitBuffer(inData);
long startpos = inData.Position;
long endpos = inData.Position + inLen;
byte[] window = m_state.window;
uint window_posn = m_state.window_posn;
uint window_size = m_state.window_size;
uint R0 = m_state.R0;
uint R1 = m_state.R1;
uint R2 = m_state.R2;
uint i, j;
int togo = outLen, this_run, main_element, match_length, match_offset, length_footer, extra, verbatim_bits;
int rundest, runsrc, copy_length, aligned_bits;
bitbuf.InitBitStream();
/* read header if necessary */
if (m_state.header_read == 0)
{
uint intel = bitbuf.ReadBits(1);
if (intel != 0)
{
// read the filesize
i = bitbuf.ReadBits(16); j = bitbuf.ReadBits(16);
m_state.intel_filesize = (int)((i << 16) | j);
}
m_state.header_read = 1;
}
/* main decoding loop */
while (togo > 0)
{
/* last block finished, new block expected */
if (m_state.block_remaining == 0)
{
// TODO may screw something up here
if (m_state.block_type == LzxConstants.BLOCKTYPE.UNCOMPRESSED)
{
if ((m_state.block_length & 1) == 1)
{
inData.ReadByte(); /* realign bitstream to word */
}
bitbuf.InitBitStream();
}
m_state.block_type = (LzxConstants.BLOCKTYPE)bitbuf.ReadBits(3);;
i = bitbuf.ReadBits(16);
j = bitbuf.ReadBits(8);
m_state.block_remaining = m_state.block_length = (uint)((i << 8) | j);
switch (m_state.block_type)
{
case LzxConstants.BLOCKTYPE.ALIGNED:
for (i = 0, j = 0; i < 8; i++)
{
j = bitbuf.ReadBits(3); m_state.ALIGNED_len[i] = (byte)j;
}
MakeDecodeTable(LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
m_state.ALIGNED_len, m_state.ALIGNED_table);
/* rest of aligned header is same as verbatim */
goto case LzxConstants.BLOCKTYPE.VERBATIM;
case LzxConstants.BLOCKTYPE.VERBATIM:
ReadLengths(m_state.MAINTREE_len, 0, 256, bitbuf);
ReadLengths(m_state.MAINTREE_len, 256, m_state.main_elements, bitbuf);
MakeDecodeTable(LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
m_state.MAINTREE_len, m_state.MAINTREE_table);
if (m_state.MAINTREE_len[0xE8] != 0)
{
m_state.intel_started = 1;
}
ReadLengths(m_state.LENGTH_len, 0, LzxConstants.NUM_SECONDARY_LENGTHS, bitbuf);
MakeDecodeTable(LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
m_state.LENGTH_len, m_state.LENGTH_table);
break;
case LzxConstants.BLOCKTYPE.UNCOMPRESSED:
m_state.intel_started = 1; /* because we can't assume otherwise */
bitbuf.EnsureBits(16); /* get up to 16 pad bits into the buffer */
if (bitbuf.GetBitsLeft() > 16)
{
inData.Seek(-2, SeekOrigin.Current); /* and align the bitstream! */
}
byte hi, mh, ml, lo;
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R0 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R1 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R2 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
break;
default:
return(-1); // TODO throw proper exception
}
}
/* buffer exhaustion check */
if (inData.Position > (startpos + inLen))
{
/* it's possible to have a file where the next run is less than
* 16 bits in size. In this case, the READ_HUFFSYM() macro used
* in building the tables will exhaust the buffer, so we should
* allow for this, but not allow those accidentally read bits to
* be used (so we check that there are at least 16 bits
* remaining - in this boundary case they aren't really part of
* the compressed data)
*/
//Debug.WriteLine("WTF");
if (inData.Position > (startpos + inLen + 2) || bitbuf.GetBitsLeft() < 16)
{
return(-1); //TODO throw proper exception
}
}
while ((this_run = (int)m_state.block_remaining) > 0 && togo > 0)
{
if (this_run > togo)
{
this_run = togo;
}
togo -= this_run;
m_state.block_remaining -= (uint)this_run;
/* apply 2^x-1 mask */
window_posn &= window_size - 1;
/* runs can't straddle the window wraparound */
if ((window_posn + this_run) > window_size)
{
return(-1); //TODO throw proper exception
}
switch (m_state.block_type)
{
case LzxConstants.BLOCKTYPE.VERBATIM:
while (this_run > 0)
{
main_element = (int)ReadHuffSym(m_state.MAINTREE_table, m_state.MAINTREE_len,
LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
bitbuf);
if (main_element < LzxConstants.NUM_CHARS)
{
/* literal: 0 to NUM_CHARS-1 */
window[window_posn++] = (byte)main_element;
this_run--;
}
else
{
/* match: NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LzxConstants.NUM_CHARS;
match_length = main_element & LzxConstants.NUM_PRIMARY_LENGTHS;
if (match_length == LzxConstants.NUM_PRIMARY_LENGTHS)
{
length_footer = (int)ReadHuffSym(m_state.LENGTH_table, m_state.LENGTH_len,
LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
bitbuf);
match_length += length_footer;
}
match_length += LzxConstants.MIN_MATCH;
match_offset = main_element >> 3;
if (match_offset > 2)
{
/* not repeated offset */
if (match_offset != 3)
{
extra = extra_bits[match_offset];
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset = (int)position_base[match_offset] - 2 + verbatim_bits;
}
else
{
match_offset = 1;
}
/* update repeated offset LRU queue */
R2 = R1; R1 = R0; R0 = (uint)match_offset;
}
else if (match_offset == 0)
{
match_offset = (int)R0;
}
else if (match_offset == 1)
{
match_offset = (int)R1;
R1 = R0; R0 = (uint)match_offset;
}
else /* match_offset == 2 */
{
match_offset = (int)R2;
R2 = R0; R0 = (uint)match_offset;
}
rundest = (int)window_posn;
this_run -= match_length;
/* copy any wrapped around source data */
if (window_posn >= match_offset)
{
/* no wrap */
runsrc = rundest - match_offset;
}
else
{
runsrc = rundest + ((int)window_size - match_offset);
copy_length = match_offset - (int)window_posn;
if (copy_length < match_length)
{
match_length -= copy_length;
window_posn += (uint)copy_length;
while (copy_length-- > 0)
{
window[rundest++] = window[runsrc++];
}
runsrc = 0;
}
}
window_posn += (uint)match_length;
/* copy match data - no worries about destination wraps */
while (match_length-- > 0)
{
window[rundest++] = window[runsrc++];
}
}
}
break;
case LzxConstants.BLOCKTYPE.ALIGNED:
while (this_run > 0)
{
main_element = (int)ReadHuffSym(m_state.MAINTREE_table, m_state.MAINTREE_len,
LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
bitbuf);
if (main_element < LzxConstants.NUM_CHARS)
{
/* literal 0 to NUM_CHARS-1 */
window[window_posn++] = (byte)main_element;
this_run--;
}
else
{
/* match: NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LzxConstants.NUM_CHARS;
match_length = main_element & LzxConstants.NUM_PRIMARY_LENGTHS;
if (match_length == LzxConstants.NUM_PRIMARY_LENGTHS)
{
length_footer = (int)ReadHuffSym(m_state.LENGTH_table, m_state.LENGTH_len,
LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
bitbuf);
match_length += length_footer;
}
match_length += LzxConstants.MIN_MATCH;
match_offset = main_element >> 3;
if (match_offset > 2)
{
/* not repeated offset */
extra = extra_bits[match_offset];
match_offset = (int)position_base[match_offset] - 2;
if (extra > 3)
{
/* verbatim and aligned bits */
extra -= 3;
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset += (verbatim_bits << 3);
aligned_bits = (int)ReadHuffSym(m_state.ALIGNED_table, m_state.ALIGNED_len,
LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
bitbuf);
match_offset += aligned_bits;
}
else if (extra == 3)
{
/* aligned bits only */
aligned_bits = (int)ReadHuffSym(m_state.ALIGNED_table, m_state.ALIGNED_len,
LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
bitbuf);
match_offset += aligned_bits;
}
else if (extra > 0) /* extra==1, extra==2 */
{
/* verbatim bits only */
verbatim_bits = (int)bitbuf.ReadBits((byte)extra);
match_offset += verbatim_bits;
}
else /* extra == 0 */
{
/* ??? */
match_offset = 1;
}
/* update repeated offset LRU queue */
R2 = R1; R1 = R0; R0 = (uint)match_offset;
}
else if (match_offset == 0)
{
match_offset = (int)R0;
}
else if (match_offset == 1)
{
match_offset = (int)R1;
R1 = R0; R0 = (uint)match_offset;
}
else /* match_offset == 2 */
{
match_offset = (int)R2;
R2 = R0; R0 = (uint)match_offset;
}
rundest = (int)window_posn;
this_run -= match_length;
/* copy any wrapped around source data */
if (window_posn >= match_offset)
{
/* no wrap */
runsrc = rundest - match_offset;
}
else
{
runsrc = rundest + ((int)window_size - match_offset);
copy_length = match_offset - (int)window_posn;
if (copy_length < match_length)
{
match_length -= copy_length;
window_posn += (uint)copy_length;
while (copy_length-- > 0)
{
window[rundest++] = window[runsrc++];
}
runsrc = 0;
}
}
window_posn += (uint)match_length;
/* copy match data - no worries about destination wraps */
while (match_length-- > 0)
{
window[rundest++] = window[runsrc++];
}
}
}
break;
case LzxConstants.BLOCKTYPE.UNCOMPRESSED:
if ((inData.Position + this_run) > endpos)
{
return(-1); //TODO throw proper exception
}
byte[] temp_buffer = new byte[this_run];
inData.Read(temp_buffer, 0, this_run);
temp_buffer.CopyTo(window, (int)window_posn);
window_posn += (uint)this_run;
break;
default:
return(-1); //TODO throw proper exception
}
}
}
if (togo != 0)
{
return(-1); //TODO throw proper exception
}
int start_window_pos = (int)window_posn;
if (start_window_pos == 0)
{
start_window_pos = (int)window_size;
}
start_window_pos -= outLen;
outData.Write(window, start_window_pos, outLen);
m_state.window_posn = window_posn;
m_state.R0 = R0;
m_state.R1 = R1;
m_state.R2 = R2;
// TODO finish intel E8 decoding
/* intel E8 decoding */
if ((m_state.frames_read++ < 32768) && m_state.intel_filesize != 0)
{
if (outLen <= 6 || m_state.intel_started == 0)
{
m_state.intel_curpos += outLen;
}
else
{
int dataend = outLen - 10;
uint curpos = (uint)m_state.intel_curpos;
uint filesize = (uint)m_state.intel_filesize;
//uint abs_off, rel_off;
m_state.intel_curpos = (int)curpos + outLen;
while (outData.Position < dataend)
{
if (outData.ReadByte() != 0xE8)
{
curpos++; continue;
}
//abs_off =
}
}
return(-1);
}
return(0);
}
public int Decompress(Stream inData, int inLen, Stream outData, int outLen)
{
BitBuffer bitbuf = new BitBuffer(inData);
long startpos = inData.Position;
long endpos = inData.Position + inLen;
byte[] window = m_state.window;
uint window_posn = m_state.window_posn;
uint window_size = m_state.window_size;
uint R0 = m_state.R0;
uint R1 = m_state.R1;
uint R2 = m_state.R2;
uint i, j;
int togo = outLen, this_run, main_element, match_length, match_offset, length_footer, extra, verbatim_bits;
int rundest, runsrc, copy_length, aligned_bits;
bitbuf.InitBitStream();
/* read header if necessary */
if (m_state.header_read == 0)
{
uint intel = bitbuf.ReadBits(1);
if (intel != 0)
{
// read the filesize
i = bitbuf.ReadBits(16); j = bitbuf.ReadBits(16);
m_state.intel_filesize = (int)((i << 16) | j);
}
m_state.header_read = 1;
}
/* main decoding loop */
while (togo > 0)
{
/* last block finished, new block expected */
if (m_state.block_remaining == 0)
{
// TODO may screw something up here
if (m_state.block_type == LzxConstants.BLOCKTYPE.UNCOMPRESSED)
{
if ((m_state.block_length & 1) == 1)
{
inData.ReadByte(); /* realign bitstream to word */
}
bitbuf.InitBitStream();
}
m_state.block_type = (LzxConstants.BLOCKTYPE)bitbuf.ReadBits(3);;
i = bitbuf.ReadBits(16);
j = bitbuf.ReadBits(8);
m_state.block_remaining = m_state.block_length = (uint)((i << 8) | j);
switch (m_state.block_type)
{
case LzxConstants.BLOCKTYPE.ALIGNED:
for (i = 0, j = 0; i < 8; i++)
{
j = bitbuf.ReadBits(3); m_state.ALIGNED_len[i] = (byte)j;
}
MakeDecodeTable(LzxConstants.ALIGNED_MAXSYMBOLS, LzxConstants.ALIGNED_TABLEBITS,
m_state.ALIGNED_len, m_state.ALIGNED_table);
/* rest of aligned header is same as verbatim */
goto case LzxConstants.BLOCKTYPE.VERBATIM;
case LzxConstants.BLOCKTYPE.VERBATIM:
ReadLengths(m_state.MAINTREE_len, 0, 256, bitbuf);
ReadLengths(m_state.MAINTREE_len, 256, m_state.main_elements, bitbuf);
MakeDecodeTable(LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
m_state.MAINTREE_len, m_state.MAINTREE_table);
if (m_state.MAINTREE_len[0xE8] != 0)
{
m_state.intel_started = 1;
}
ReadLengths(m_state.LENGTH_len, 0, LzxConstants.NUM_SECONDARY_LENGTHS, bitbuf);
MakeDecodeTable(LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
m_state.LENGTH_len, m_state.LENGTH_table);
break;
case LzxConstants.BLOCKTYPE.UNCOMPRESSED:
m_state.intel_started = 1; /* because we can't assume otherwise */
bitbuf.EnsureBits(16); /* get up to 16 pad bits into the buffer */
if (bitbuf.GetBitsLeft() > 16)
{
inData.Seek(-2, SeekOrigin.Current); /* and align the bitstream! */
}
byte hi, mh, ml, lo;
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R0 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R1 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
lo = (byte)inData.ReadByte(); ml = (byte)inData.ReadByte(); mh = (byte)inData.ReadByte(); hi = (byte)inData.ReadByte();
R2 = (uint)(lo | ml << 8 | mh << 16 | hi << 24);
break;
default:
return(-1); // TODO throw proper exception
}
}
/* buffer exhaustion check */
if (inData.Position > (startpos + inLen))
{
/* it's possible to have a file where the next run is less than
* 16 bits in size. In this case, the READ_HUFFSYM() macro used
* in building the tables will exhaust the buffer, so we should
* allow for this, but not allow those accidentally read bits to
* be used (so we check that there are at least 16 bits
* remaining - in this boundary case they aren't really part of
* the compressed data)
*/
//Debug.WriteLine("WTF");
if (inData.Position > (startpos + inLen + 2) || bitbuf.GetBitsLeft() < 16)
{
return(-1); //TODO throw proper exception
}
}
while ((this_run = (int)m_state.block_remaining) > 0 && togo > 0)
{
if (this_run > togo)
{
this_run = togo;
}
togo -= this_run;
m_state.block_remaining -= (uint)this_run;
/* apply 2^x-1 mask */
window_posn &= window_size - 1;
/* runs can't straddle the window wraparound */
if ((window_posn + this_run) > window_size)
{
return(-1); //TODO throw proper exception
}
switch (m_state.block_type)
{
case LzxConstants.BLOCKTYPE.VERBATIM:
while (this_run > 0)
{
main_element = (int)ReadHuffSym(m_state.MAINTREE_table, m_state.MAINTREE_len,
LzxConstants.MAINTREE_MAXSYMBOLS, LzxConstants.MAINTREE_TABLEBITS,
bitbuf);
if (main_element < LzxConstants.NUM_CHARS)
{
/* literal: 0 to NUM_CHARS-1 */
window[window_posn++] = (byte)main_element;
this_run--;
}
else
{
/* match: NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LzxConstants.NUM_CHARS;
match_length = main_element & LzxConstants.NUM_PRIMARY_LENGTHS;
if (match_length == LzxConstants.NUM_PRIMARY_LENGTHS)
{
length_footer = (int)ReadHuffSym(m_state.LENGTH_table, m_state.LENGTH_len,
LzxConstants.LENGTH_MAXSYMBOLS, LzxConstants.LENGTH_TABLEBITS,
bitbuf);
match_length += length_footer;
}
match_length += LzxConstants.MIN_MATCH;
match_offset = main_element >> 3;
if (match_offset > 2)
{
/* not repeated offset */
if (match_offset != 3)
{
extra = extra_bits ![match_offset];