5842c5098f
I personally used filters within my IDE, but since others are now joining the project, it was brought to my attention that some better organization would be nice.
103 lines
2.7 KiB
C++
103 lines
2.7 KiB
C++
/* ScummVM - Graphic Adventure Engine
|
|
*
|
|
* ScummVM is the legal property of its developers, whose names
|
|
* are too numerous to list here. Please refer to the COPYRIGHT
|
|
* file distributed with this source distribution.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*
|
|
*/
|
|
|
|
#include "common/scummsys.h"
|
|
|
|
#include "zvision/lzss_read_stream.h"
|
|
|
|
|
|
namespace ZVision {
|
|
|
|
LzssReadStream::LzssReadStream(Common::SeekableReadStream *source)
|
|
: _source(source),
|
|
// It's convention to set the starting cursor position to blockSize - 16
|
|
_windowCursor(0x0FEE),
|
|
_eosFlag(false) {
|
|
// Clear the window to null
|
|
memset(_window, 0, BLOCK_SIZE);
|
|
}
|
|
|
|
uint32 LzssReadStream::decompressBytes(byte *destination, uint32 numberOfBytes) {
|
|
uint32 destinationCursor = 0;
|
|
|
|
while (destinationCursor < numberOfBytes) {
|
|
byte flagbyte = _source->readByte();
|
|
if (_source->eos())
|
|
break;
|
|
uint mask = 1;
|
|
|
|
for (int i = 0; i < 8; ++i) {
|
|
if ((flagbyte & mask) == mask) {
|
|
byte data = _source->readByte();
|
|
if (_source->eos()) {
|
|
return destinationCursor;
|
|
}
|
|
|
|
_window[_windowCursor] = data;
|
|
destination[destinationCursor++] = data;
|
|
|
|
// Increment and wrap the window cursor
|
|
_windowCursor = (_windowCursor + 1) & 0xFFF;
|
|
} else {
|
|
byte low = _source->readByte();
|
|
if (_source->eos()) {
|
|
return destinationCursor;
|
|
}
|
|
|
|
byte high = _source->readByte();
|
|
if (_source->eos()) {
|
|
return destinationCursor;
|
|
}
|
|
|
|
uint16 length = (high & 0xF) + 2;
|
|
uint16 offset = low | ((high & 0xF0)<<4);
|
|
|
|
for(int j = 0; j <= length; ++j) {
|
|
byte temp = _window[(offset + j) & 0xFFF];
|
|
_window[_windowCursor] = temp;
|
|
destination[destinationCursor++] = temp;
|
|
_windowCursor = (_windowCursor + 1) & 0xFFF;
|
|
}
|
|
}
|
|
|
|
mask = mask << 1;
|
|
}
|
|
}
|
|
|
|
return destinationCursor;
|
|
}
|
|
|
|
bool LzssReadStream::eos() const {
|
|
return _eosFlag;
|
|
}
|
|
|
|
uint32 LzssReadStream::read(void *dataPtr, uint32 dataSize) {
|
|
uint32 bytesRead = decompressBytes(static_cast<byte *>(dataPtr), dataSize);
|
|
if (bytesRead < dataSize) {
|
|
// Flag that we're at EOS
|
|
_eosFlag = true;
|
|
}
|
|
|
|
return dataSize;
|
|
}
|
|
|
|
} // End of namespace ZVision
|