/* 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. * */ // Disable symbol overrides so that we can use zlib.h #define FORBIDDEN_SYMBOL_ALLOW_ALL #include "common/zlib.h" #include "common/util.h" #include "common/stream.h" #if defined(USE_ZLIB) #ifdef __SYMBIAN32__ #include #else #include #endif #if ZLIB_VERNUM < 0x1204 #error Version 1.2.0.4 or newer of zlib is required for this code #endif #endif namespace Common { #if defined(USE_ZLIB) bool uncompress(byte *dst, unsigned long *dstLen, const byte *src, unsigned long srcLen) { return Z_OK == ::uncompress(dst, dstLen, src, srcLen); } /** * A simple wrapper class which can be used to wrap around an arbitrary * other SeekableReadStream and will then provide on-the-fly decompression support. * Assumes the compressed data to be in gzip format. */ class GZipReadStream : public Common::SeekableReadStream { protected: enum { BUFSIZE = 16384 // 1 << MAX_WBITS }; byte _buf[BUFSIZE]; Common::SeekableReadStream *_wrapped; z_stream _stream; int _zlibErr; uint32 _pos; uint32 _origSize; bool _eos; public: GZipReadStream(Common::SeekableReadStream *w) : _wrapped(w) { assert(w != 0); _stream.zalloc = Z_NULL; _stream.zfree = Z_NULL; _stream.opaque = Z_NULL; _stream.avail_in = 0; _stream.next_in = Z_NULL; // Verify file header is correct w->seek(0, SEEK_SET); uint16 header = w->readUint16BE(); assert(header == 0x1F8B || ((header & 0x0F00) == 0x0800 && header % 31 == 0)); if (header == 0x1F8B) { // Retrieve the original file size w->seek(-4, SEEK_END); _origSize = w->readUint32LE(); } else { // Original size not available in zlib format _origSize = 0; } _pos = 0; w->seek(0, SEEK_SET); _eos = false; // Adding 32 to windowBits indicates to zlib that it is supposed to // automatically detect whether gzip or zlib headers are used for // the compressed file. This feature was added in zlib 1.2.0.4, // released 10 August 2003. // Note: This is *crucial* for savegame compatibility, do *not* remove! _zlibErr = inflateInit2(&_stream, MAX_WBITS + 32); if (_zlibErr != Z_OK) return; // Setup input buffer _stream.next_in = _buf; _stream.avail_in = 0; } ~GZipReadStream() { inflateEnd(&_stream); delete _wrapped; } bool err() const { return (_zlibErr != Z_OK) && (_zlibErr != Z_STREAM_END); } void clearErr() { // only reset _eos; I/O errors are not recoverable _eos = false; } uint32 read(void *dataPtr, uint32 dataSize) { _stream.next_out = (byte *)dataPtr; _stream.avail_out = dataSize; // Keep going while we get no error while (_zlibErr == Z_OK && _stream.avail_out) { if (_stream.avail_in == 0 && !_wrapped->eos()) { // If we are out of input data: Read more data, if available. _stream.next_in = _buf; _stream.avail_in = _wrapped->read(_buf, BUFSIZE); } _zlibErr = inflate(&_stream, Z_NO_FLUSH); } // Update the position counter _pos += dataSize - _stream.avail_out; if (_zlibErr == Z_STREAM_END && _stream.avail_out > 0) _eos = true; return dataSize - _stream.avail_out; } bool eos() const { return _eos; } int32 pos() const { return _pos; } int32 size() const { return _origSize; } bool seek(int32 offset, int whence = SEEK_SET) { int32 newPos = 0; assert(whence != SEEK_END); // SEEK_END not supported switch (whence) { case SEEK_SET: newPos = offset; break; case SEEK_CUR: newPos = _pos + offset; } assert(newPos >= 0); if ((uint32)newPos < _pos) { // To search backward, we have to restart the whole decompression // from the start of the file. A rather wasteful operation, best // to avoid it. :/ #if DEBUG warning("Backward seeking in GZipReadStream detected"); #endif _pos = 0; _wrapped->seek(0, SEEK_SET); _zlibErr = inflateReset(&_stream); if (_zlibErr != Z_OK) return false; // FIXME: STREAM REWRITE _stream.next_in = _buf; _stream.avail_in = 0; } offset = newPos - _pos; // Skip the given amount of data (very inefficient if one tries to skip // huge amounts of data, but usually client code will only skip a few // bytes, so this should be fine. byte tmpBuf[1024]; while (!err() && offset > 0) { offset -= read(tmpBuf, MIN((int32)sizeof(tmpBuf), offset)); } _eos = false; return true; // FIXME: STREAM REWRITE } }; /** * A simple wrapper class which can be used to wrap around an arbitrary * other WriteStream and will then provide on-the-fly compression support. * The compressed data is written in the gzip format. */ class GZipWriteStream : public Common::WriteStream { protected: enum { BUFSIZE = 16384 // 1 << MAX_WBITS }; byte _buf[BUFSIZE]; Common::WriteStream *_wrapped; z_stream _stream; int _zlibErr; void processData(int flushType) { // This function is called by both write() and finalize(). while (_zlibErr == Z_OK && (_stream.avail_in || flushType == Z_FINISH)) { if (_stream.avail_out == 0) { if (_wrapped->write(_buf, BUFSIZE) != BUFSIZE) { _zlibErr = Z_ERRNO; break; } _stream.next_out = _buf; _stream.avail_out = BUFSIZE; } _zlibErr = deflate(&_stream, flushType); } } public: GZipWriteStream(Common::WriteStream *w) : _wrapped(w) { assert(w != 0); _stream.zalloc = Z_NULL; _stream.zfree = Z_NULL; _stream.opaque = Z_NULL; // Adding 16 to windowBits indicates to zlib that it is supposed to // write gzip headers. This feature was added in zlib 1.2.0.4, // released 10 August 2003. // Note: This is *crucial* for savegame compatibility, do *not* remove! _zlibErr = deflateInit2(&_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, MAX_WBITS + 16, 8, Z_DEFAULT_STRATEGY); assert(_zlibErr == Z_OK); _stream.next_out = _buf; _stream.avail_out = BUFSIZE; _stream.avail_in = 0; _stream.next_in = 0; } ~GZipWriteStream() { finalize(); deflateEnd(&_stream); delete _wrapped; } bool err() const { // CHECKME: does Z_STREAM_END make sense here? return (_zlibErr != Z_OK && _zlibErr != Z_STREAM_END) || _wrapped->err(); } void clearErr() { // Note: we don't reset the _zlibErr here, as it is not // clear in general how _wrapped->clearErr(); } void finalize() { if (_zlibErr != Z_OK) return; // Process whatever remaining data there is. processData(Z_FINISH); // Since processData only writes out blocks of size BUFSIZE, // we may have to flush some stragglers. uint remainder = BUFSIZE - _stream.avail_out; if (remainder > 0) { if (_wrapped->write(_buf, remainder) != remainder) { _zlibErr = Z_ERRNO; } } // Finalize the wrapped savefile, too _wrapped->finalize(); } uint32 write(const void *dataPtr, uint32 dataSize) { if (err()) return 0; // Hook in the new data ... // Note: We need to make a const_cast here, as zlib is not aware // of the const keyword. _stream.next_in = const_cast((const byte *)dataPtr); _stream.avail_in = dataSize; // ... and flush it to disk processData(Z_NO_FLUSH); return dataSize - _stream.avail_in; } }; #endif // USE_ZLIB Common::SeekableReadStream *wrapCompressedReadStream(Common::SeekableReadStream *toBeWrapped) { #if defined(USE_ZLIB) if (toBeWrapped) { uint16 header = toBeWrapped->readUint16BE(); bool isCompressed = (header == 0x1F8B || ((header & 0x0F00) == 0x0800 && header % 31 == 0)); toBeWrapped->seek(-2, SEEK_CUR); if (isCompressed) return new GZipReadStream(toBeWrapped); } #endif return toBeWrapped; } Common::WriteStream *wrapCompressedWriteStream(Common::WriteStream *toBeWrapped) { #if defined(USE_ZLIB) if (toBeWrapped) return new GZipWriteStream(toBeWrapped); #endif return toBeWrapped; } } // End of namespace Common