mirror of
https://github.com/libretro/scummvm.git
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335 lines
8.4 KiB
C++
335 lines
8.4 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#include "common/zlib.h"
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#include "common/util.h"
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#if defined(USE_ZLIB)
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#ifdef __SYMBIAN32__
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#include <zlib\zlib.h>
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#else
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#include <zlib.h>
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#endif
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#if ZLIB_VERNUM < 0x1204
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#error Version 1.2.0.4 or newer of zlib is required for this code
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#endif
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#endif
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namespace Common {
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#if defined(USE_ZLIB)
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bool uncompress(byte *dst, unsigned long *dstLen, const byte *src, unsigned long srcLen) {
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return Z_OK == ::uncompress(dst, dstLen, src, srcLen);
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}
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/**
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* A simple wrapper class which can be used to wrap around an arbitrary
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* other SeekableReadStream and will then provide on-the-fly decompression support.
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* Assumes the compressed data to be in gzip format.
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*/
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class GZipReadStream : public Common::SeekableReadStream {
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protected:
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enum {
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BUFSIZE = 16384 // 1 << MAX_WBITS
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};
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byte _buf[BUFSIZE];
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Common::SeekableReadStream *_wrapped;
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z_stream _stream;
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int _zlibErr;
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uint32 _pos;
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uint32 _origSize;
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bool _eos;
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public:
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GZipReadStream(Common::SeekableReadStream *w) : _wrapped(w) {
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assert(w != 0);
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_stream.zalloc = Z_NULL;
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_stream.zfree = Z_NULL;
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_stream.opaque = Z_NULL;
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// Verify file header is correct
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w->seek(0, SEEK_SET);
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uint16 header = w->readUint16BE();
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assert(header == 0x1F8B ||
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((header & 0x0F00) == 0x0800 && header % 31 == 0));
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if (header == 0x1F8B) {
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// Retrieve the original file size
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w->seek(-4, SEEK_END);
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_origSize = w->readUint32LE();
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} else {
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// Original size not available in zlib format
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_origSize = 0;
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}
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_pos = 0;
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w->seek(0, SEEK_SET);
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_eos = false;
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// Adding 32 to windowBits indicates to zlib that it is supposed to
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// automatically detect whether gzip or zlib headers are used for
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// the compressed file. This feature was added in zlib 1.2.0.4,
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// released 10 August 2003.
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// Note: This is *crucial* for savegame compatibility, do *not* remove!
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_zlibErr = inflateInit2(&_stream, MAX_WBITS + 32);
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if (_zlibErr != Z_OK)
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return;
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// Setup input buffer
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_stream.next_in = _buf;
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_stream.avail_in = 0;
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}
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~GZipReadStream() {
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inflateEnd(&_stream);
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delete _wrapped;
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}
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bool err() const { return (_zlibErr != Z_OK) && (_zlibErr != Z_STREAM_END); }
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void clearErr() {
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// only reset _eos; I/O errors are not recoverable
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_eos = false;
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}
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uint32 read(void *dataPtr, uint32 dataSize) {
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_stream.next_out = (byte *)dataPtr;
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_stream.avail_out = dataSize;
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// Keep going while we get no error
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while (_zlibErr == Z_OK && _stream.avail_out) {
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if (_stream.avail_in == 0 && !_wrapped->eos()) {
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// If we are out of input data: Read more data, if available.
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_stream.next_in = _buf;
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_stream.avail_in = _wrapped->read(_buf, BUFSIZE);
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}
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_zlibErr = inflate(&_stream, Z_NO_FLUSH);
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}
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// Update the position counter
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_pos += dataSize - _stream.avail_out;
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if (_zlibErr == Z_STREAM_END && _stream.avail_out > 0)
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_eos = true;
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return dataSize - _stream.avail_out;
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}
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bool eos() const {
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return _eos;
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}
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int32 pos() const {
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return _pos;
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}
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int32 size() const {
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return _origSize;
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}
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bool seek(int32 offset, int whence = SEEK_SET) {
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int32 newPos = 0;
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assert(whence != SEEK_END); // SEEK_END not supported
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switch(whence) {
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case SEEK_SET:
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newPos = offset;
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break;
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case SEEK_CUR:
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newPos = _pos + offset;
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}
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assert(newPos >= 0);
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if ((uint32)newPos < _pos) {
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// To search backward, we have to restart the whole decompression
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// from the start of the file. A rather wasteful operation, best
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// to avoid it. :/
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#if DEBUG
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warning("Backward seeking in GZipReadStream detected");
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#endif
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_pos = 0;
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_wrapped->seek(0, SEEK_SET);
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_zlibErr = inflateReset(&_stream);
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if (_zlibErr != Z_OK)
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return false; // FIXME: STREAM REWRITE
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_stream.next_in = _buf;
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_stream.avail_in = 0;
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}
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offset = newPos - _pos;
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// Skip the given amount of data (very inefficient if one tries to skip
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// huge amounts of data, but usually client code will only skip a few
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// bytes, so this should be fine.
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byte tmpBuf[1024];
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while (!err() && offset > 0) {
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offset -= read(tmpBuf, MIN((int32)sizeof(tmpBuf), offset));
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}
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_eos = false;
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return true; // FIXME: STREAM REWRITE
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}
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};
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/**
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* A simple wrapper class which can be used to wrap around an arbitrary
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* other WriteStream and will then provide on-the-fly compression support.
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* The compressed data is written in the gzip format.
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*/
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class GZipWriteStream : public Common::WriteStream {
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protected:
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enum {
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BUFSIZE = 16384 // 1 << MAX_WBITS
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};
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byte _buf[BUFSIZE];
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Common::WriteStream *_wrapped;
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z_stream _stream;
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int _zlibErr;
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void processData(int flushType) {
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// This function is called by both write() and finalize().
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while (_zlibErr == Z_OK && (_stream.avail_in || flushType == Z_FINISH)) {
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if (_stream.avail_out == 0) {
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if (_wrapped->write(_buf, BUFSIZE) != BUFSIZE) {
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_zlibErr = Z_ERRNO;
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break;
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}
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_stream.next_out = _buf;
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_stream.avail_out = BUFSIZE;
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}
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_zlibErr = deflate(&_stream, flushType);
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}
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}
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public:
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GZipWriteStream(Common::WriteStream *w) : _wrapped(w) {
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assert(w != 0);
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_stream.zalloc = Z_NULL;
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_stream.zfree = Z_NULL;
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_stream.opaque = Z_NULL;
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// Adding 16 to windowBits indicates to zlib that it is supposed to
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// write gzip headers. This feature was added in zlib 1.2.0.4,
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// released 10 August 2003.
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// Note: This is *crucial* for savegame compatibility, do *not* remove!
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_zlibErr = deflateInit2(&_stream,
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Z_DEFAULT_COMPRESSION,
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Z_DEFLATED,
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MAX_WBITS + 16,
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8,
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Z_DEFAULT_STRATEGY);
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assert(_zlibErr == Z_OK);
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_stream.next_out = _buf;
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_stream.avail_out = BUFSIZE;
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_stream.avail_in = 0;
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_stream.next_in = 0;
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}
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~GZipWriteStream() {
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finalize();
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deflateEnd(&_stream);
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delete _wrapped;
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}
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bool err() const {
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// CHECKME: does Z_STREAM_END make sense here?
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return (_zlibErr != Z_OK && _zlibErr != Z_STREAM_END) || _wrapped->err();
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}
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void clearErr() {
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// Note: we don't reset the _zlibErr here, as it is not
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// clear in general how
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_wrapped->clearErr();
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}
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void finalize() {
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if (_zlibErr != Z_OK)
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return;
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// Process whatever remaining data there is.
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processData(Z_FINISH);
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// Since processData only writes out blocks of size BUFSIZE,
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// we may have to flush some stragglers.
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uint remainder = BUFSIZE - _stream.avail_out;
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if (remainder > 0) {
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if (_wrapped->write(_buf, remainder) != remainder) {
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_zlibErr = Z_ERRNO;
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}
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}
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// Finalize the wrapped savefile, too
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_wrapped->finalize();
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}
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uint32 write(const void *dataPtr, uint32 dataSize) {
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if (err())
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return 0;
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// Hook in the new data ...
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// Note: We need to make a const_cast here, as zlib is not aware
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// of the const keyword.
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_stream.next_in = const_cast<byte *>((const byte *)dataPtr);
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_stream.avail_in = dataSize;
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// ... and flush it to disk
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processData(Z_NO_FLUSH);
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return dataSize - _stream.avail_in;
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}
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};
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#endif // USE_ZLIB
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Common::SeekableReadStream *wrapCompressedReadStream(Common::SeekableReadStream *toBeWrapped) {
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#if defined(USE_ZLIB)
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if (toBeWrapped) {
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uint16 header = toBeWrapped->readUint16BE();
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bool isCompressed = (header == 0x1F8B ||
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((header & 0x0F00) == 0x0800 &&
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header % 31 == 0));
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toBeWrapped->seek(-2, SEEK_CUR);
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if (isCompressed)
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return new GZipReadStream(toBeWrapped);
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}
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#endif
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return toBeWrapped;
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}
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Common::WriteStream *wrapCompressedWriteStream(Common::WriteStream *toBeWrapped) {
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#if defined(USE_ZLIB)
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if (toBeWrapped)
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return new GZipWriteStream(toBeWrapped);
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#endif
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return toBeWrapped;
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}
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} // End of namespace Common
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