thirdparty/scummvm
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SHERLOCK: Merged decompression code into Resources class

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This commit is contained in:
Paul Gilbert 2015-05-16 08:56:50 -04:00
parent 8c7f5bf92f
commit 052e04c005
7 changed files with 77 additions and 132 deletions
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66
engines/sherlock/resources.cpp
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@ -21,14 +21,14 @@
*/
#include "sherlock/resources.h"
#include "sherlock/decompress.h"
#include "sherlock/screen.h"
#include "sherlock/sherlock.h"
#include "common/debug.h"
#include "common/memstream.h"
namespace Sherlock {
Cache::Cache() {
Cache::Cache(SherlockEngine *vm): _vm(vm) {
}
/**
@ -76,7 +76,7 @@ void Cache::load(const Common::String &name, Common::SeekableReadStream &stream)
// Check whether the file is compressed
if (signature == MKTAG('L', 'Z', 'V', 26)) {
// It's compressed, so decompress the file and store it's data in the cache entry
Common::SeekableReadStream *decompressed = decompressLZ(stream);
Common::SeekableReadStream *decompressed = _vm->_res->decompressLZ(stream);
cacheEntry.resize(decompressed->size());
decompressed->read(&cacheEntry[0], decompressed->size());
@ -99,7 +99,7 @@ Common::SeekableReadStream *Cache::get(const Common::String &filename) const {
/*----------------------------------------------------------------*/
Resources::Resources() {
Resources::Resources(SherlockEngine *vm): _vm(vm), _cache(vm) {
_resourceIndex = -1;
addToCache("vgs.lib");
@ -404,4 +404,62 @@ void ImageFile::decompressFrame(ImageFrame &frame, const byte *src) {
}
}
/**
* Decompress an LZW compressed resource
*/
Common::SeekableReadStream *Resources::decompressLZ(Common::SeekableReadStream &source) {
if (_vm->getGameID() == GType_SerratedScalpel) {
uint32 id = source.readUint32BE();
assert(id == MKTAG('L', 'Z', 'V', 0x1A));
}
uint32 size = source.readUint32LE();
return decompressLZ(source, size);
}
/**
* Decompresses an LZW block of data with a specified output size
*/
Common::SeekableReadStream *Resources::decompressLZ(Common::SeekableReadStream &source, uint32 outSize) {
byte lzWindow[4096];
uint16 lzWindowPos;
uint16 cmd;
byte *outBuffer = (byte *)malloc(outSize);
byte *outBufferEnd = outBuffer + outSize;
Common::MemoryReadStream *outS = new Common::MemoryReadStream(outBuffer, outSize, DisposeAfterUse::YES);
memset(lzWindow, 0xFF, 0xFEE);
lzWindowPos = 0xFEE;
cmd = 0;
do {
cmd >>= 1;
if (!(cmd & 0x100))
cmd = source.readByte() | 0xFF00;
if (cmd & 1) {
byte literal = source.readByte();
*outBuffer++ = literal;
lzWindow[lzWindowPos] = literal;
lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
} else {
int copyPos, copyLen;
copyPos = source.readByte();
copyLen = source.readByte();
copyPos = copyPos | ((copyLen & 0xF0) << 4);
copyLen = (copyLen & 0x0F) + 3;
while (copyLen--) {
byte literal = lzWindow[copyPos];
copyPos = (copyPos + 1) & 0x0FFF;
*outBuffer++ = literal;
lzWindow[lzWindowPos] = literal;
lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
}
}
} while (outBuffer < outBufferEnd);
return outS;
}
} // End of namespace Sherlock