aboutsummaryrefslogtreecommitdiff
path: root/common/zlib.cpp
blob: 98f319f351565fdcacdfe000720b09d2366006e2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/* 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/ptr.h"
#include "common/util.h"
#include "common/stream.h"

#if defined(USE_ZLIB)
  #ifdef __SYMBIAN32__
    #include <zlib\zlib.h>
  #else
    #include <zlib.h>
  #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);
}

bool inflateZlibHeaderless(byte *dst, uint dstLen, const byte *src, uint srcLen, const byte *dict, uint dictLen) {
	if (!dst || !dstLen || !src || !srcLen)
		return false;

	// Initialize zlib
	z_stream stream;
	stream.next_in = const_cast<byte *>(src);
	stream.avail_in = srcLen;
	stream.next_out = dst;
	stream.avail_out = dstLen;
	stream.zalloc = Z_NULL;
	stream.zfree = Z_NULL;
	stream.opaque = Z_NULL;

	// Negative MAX_WBITS tells zlib there's no zlib header
	int err = inflateInit2(&stream, -MAX_WBITS);
	if (err != Z_OK)
		return false;

	// Set the dictionary, if provided
	if (dict != 0) {
		err = inflateSetDictionary(&stream, const_cast<byte *>(dict), dictLen);
		if (err != Z_OK)
			return false;
	}

	err = inflate(&stream, Z_SYNC_FLUSH);
	if (err != Z_OK && err != Z_STREAM_END) {
		inflateEnd(&stream);
		return false;
	}

	inflateEnd(&stream);
	return true;
}

enum {
	kTempBufSize = 65536
};

bool inflateZlibInstallShield(byte *dst, uint dstLen, const byte *src, uint srcLen) {
	if (!dst || !dstLen || !src || !srcLen)
		return false;

	// See if we have sync bytes. If so, just use our function for that.
	if (srcLen >= 4 && READ_BE_UINT32(src + srcLen - 4) == 0xFFFF)
		return inflateZlibHeaderless(dst, dstLen, src, srcLen);

	// Otherwise, we have some custom code we get to use here.

	byte *temp = (byte *)malloc(kTempBufSize);

	uint32 bytesRead = 0, bytesProcessed = 0;
	while (bytesRead < srcLen) {
		uint16 chunkSize = READ_LE_UINT16(src + bytesRead);
		bytesRead += 2;

		// Initialize zlib
		z_stream stream;
		stream.next_in = const_cast<byte *>(src + bytesRead);
		stream.avail_in = chunkSize;
		stream.next_out = temp;
		stream.avail_out = kTempBufSize;
		stream.zalloc = Z_NULL;
		stream.zfree = Z_NULL;
		stream.opaque = Z_NULL;

		// Negative MAX_WBITS tells zlib there's no zlib header
		int err = inflateInit2(&stream, -MAX_WBITS);
		if (err != Z_OK)
			return false;

		err = inflate(&stream, Z_FINISH);
		if (err != Z_OK && err != Z_STREAM_END) {
			inflateEnd(&stream);
			free(temp);
			return false;
		}

		memcpy(dst + bytesProcessed, temp, stream.total_out);
		bytesProcessed += stream.total_out;

		inflateEnd(&stream);
		bytesRead += chunkSize;
	}

	free(temp);
	return true;
}

/**
 * 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 SeekableReadStream {
protected:
	enum {
		BUFSIZE = 16384		// 1 << MAX_WBITS
	};

	byte	_buf[BUFSIZE];

	ScopedPtr<SeekableReadStream> _wrapped;
	z_stream _stream;
	int _zlibErr;
	uint32 _pos;
	uint32 _origSize;
	bool _eos;

public:

	GZipReadStream(SeekableReadStream *w) : _wrapped(w), _stream() {
		assert(w != 0);

		// 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);
	}

	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 WriteStream {
protected:
	enum {
		BUFSIZE = 16384		// 1 << MAX_WBITS
	};

	byte	_buf[BUFSIZE];
	ScopedPtr<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(WriteStream *w) : _wrapped(w), _stream() {
		assert(w != 0);

		// 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);
	}

	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<byte *>((const byte *)dataPtr);
		_stream.avail_in = dataSize;

		// ... and flush it to disk
		processData(Z_NO_FLUSH);

		return dataSize - _stream.avail_in;
	}
};

#endif	// USE_ZLIB

SeekableReadStream *wrapCompressedReadStream(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;
}

WriteStream *wrapCompressedWriteStream(WriteStream *toBeWrapped) {
#if defined(USE_ZLIB)
	if (toBeWrapped)
		return new GZipWriteStream(toBeWrapped);
#endif
	return toBeWrapped;
}


}	// End of namespace Common