aboutsummaryrefslogtreecommitdiff
path: root/common/stream.h
blob: 14b1243ca0cbea5a4ffc873a07e8aa7d92c1465f (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
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
/* 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.
 *
 * $URL$
 * $Id$
 *
 */

#ifndef COMMON_STREAM_H
#define COMMON_STREAM_H

#include "common/types.h"
#include "common/endian.h"

namespace Common {

class String;
class MemoryReadStream;

/**
 * Virtual base class for both ReadStream and WriteStream.
 */
class Stream {
public:
	virtual ~Stream() {}

	/**
	 * Returns true if an I/O failure occurred.
	 * This flag is never cleared automatically. In order to clear it,
	 * client code has to call clearErr() explicitly.
	 */
	virtual bool err() const { return false; }

	/**
	 * Reset the I/O error status as returned by err().
	 * For a ReadStream, also reset the end-of-stream status returned by eos().
	 */
	virtual void clearErr() {}
};

/**
 * Generic interface for a writable data stream.
 */
class WriteStream : virtual public Stream {
public:
	/**
	 * Write data into the stream. Subclasses must implement this
	 * method; all other write methods are implemented using it.
	 *
	 * @param dataPtr	pointer to the data to be written
	 * @param dataSize	number of bytes to be written
	 * @return the number of bytes which were actually written.
	 */
	virtual uint32 write(const void *dataPtr, uint32 dataSize) = 0;

	/**
	 * Commit any buffered data to the underlying channel or
	 * storage medium; unbuffered streams can use the default
	 * implementation.
	 *
	 * @return true on success, false in case of a failure
	 */
	virtual bool flush() { return true; }

	/**
	 * Finalize and close this stream. To be called right before this
	 * stream instance is deleted. The goal here is to enable calling
	 * code to detect and handle I/O errors which might occur when
	 * closing (and this flushing, if buffered) the stream.
	 *
	 * After this method has been called, no further writes may be
	 * performed on the stream. Calling err() is allowed.
	 *
	 * By default, this just flushes the stream.
	 */
	virtual void finalize() {
		flush();
	}


	// The remaining methods all have default implementations; subclasses
	// need not (and should not) overload them.

	void writeByte(byte value) {
		write(&value, 1);
	}

	void writeSByte(int8 value) {
		write(&value, 1);
	}

	void writeUint16LE(uint16 value) {
		value = TO_LE_16(value);
		write(&value, 2);
	}

	void writeUint32LE(uint32 value) {
		value = TO_LE_32(value);
		write(&value, 4);
	}

	void writeUint16BE(uint16 value) {
		value = TO_BE_16(value);
		write(&value, 2);
	}

	void writeUint32BE(uint32 value) {
		value = TO_BE_32(value);
		write(&value, 4);
	}

	FORCEINLINE void writeSint16LE(int16 value) {
		writeUint16LE((uint16)value);
	}

	FORCEINLINE void writeSint32LE(int32 value) {
		writeUint32LE((uint32)value);
	}

	FORCEINLINE void writeSint16BE(int16 value) {
		writeUint16BE((uint16)value);
	}

	FORCEINLINE void writeSint32BE(int32 value) {
		writeUint32BE((uint32)value);
	}

	/**
	 * Write the given string to the stream.
	 * This writes str.size() characters, but no terminating zero byte.
	 */
	void writeString(const String &str);
};

/**
 * Generic interface for a readable data stream.
 */
class ReadStream : virtual public Stream {
public:
	/**
	 * Returns true if a read failed because the stream end has been reached.
	 * This flag is cleared by clearErr().
	 * For a SeekableReadStream, it is also cleared by a successful seek.
	 */
	virtual bool eos() const = 0;

	/**
	 * Read data from the stream. Subclasses must implement this
	 * method; all other read methods are implemented using it.
	 *
	 * @param dataPtr	pointer to a buffer into which the data is read
	 * @param dataSize	number of bytes to be read
	 * @return the number of bytes which were actually read.
	 */
	virtual uint32 read(void *dataPtr, uint32 dataSize) = 0;


	// The remaining methods all have default implementations; subclasses
	// in general should not overload them.

	/**
	 * Read an unsigned byte from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	byte readByte() {
		byte b = 0; // FIXME: remove initialisation
		read(&b, 1);
		return b;
	}

	/**
	 * Read a signed byte from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	FORCEINLINE int8 readSByte() {
		return (int8)readByte();
	}

	/**
	 * Read an unsigned 16-bit word stored in little endian (LSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	uint16 readUint16LE() {
		uint16 val;
		read(&val, 2);
		return FROM_LE_16(val);
	}

	/**
	 * Read an unsigned 32-bit word stored in little endian (LSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	uint32 readUint32LE() {
		uint32 val;
		read(&val, 4);
		return FROM_LE_32(val);
	}

	/**
	 * Read an unsigned 16-bit word stored in big endian (MSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	uint16 readUint16BE() {
		uint16 val;
		read(&val, 2);
		return FROM_BE_16(val);
	}

	/**
	 * Read an unsigned 32-bit word stored in big endian (MSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	uint32 readUint32BE() {
		uint32 val;
		read(&val, 4);
		return FROM_BE_32(val);
	}

	/**
	 * Read a signed 16-bit word stored in little endian (LSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	FORCEINLINE int16 readSint16LE() {
		return (int16)readUint16LE();
	}

	/**
	 * Read a signed 32-bit word stored in little endian (LSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	FORCEINLINE int32 readSint32LE() {
		return (int32)readUint32LE();
	}

	/**
	 * Read a signed 16-bit word stored in big endian (MSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	FORCEINLINE int16 readSint16BE() {
		return (int16)readUint16BE();
	}

	/**
	 * Read a signed 32-bit word stored in big endian (MSB first) order
	 * from the stream and return it.
	 * Performs no error checking. The return value is undefined
	 * if a read error occurred (for which client code can check by
	 * calling err() and eos() ).
	 */
	FORCEINLINE int32 readSint32BE() {
		return (int32)readUint32BE();
	}

	/**
	 * Read the specified amount of data into a malloc'ed buffer
	 * which then is wrapped into a MemoryReadStream.
	 * The returned stream might contain less data than requested,
	 * if reading more failed, because of an I/O error or because
	 * the end of the stream was reached. Which can be determined by
	 * calling err() and eos().
	 */
	MemoryReadStream *readStream(uint32 dataSize);

};


/**
 * Interface for a seekable & readable data stream.
 *
 * @todo Get rid of SEEK_SET, SEEK_CUR, or SEEK_END, use our own constants
 */
class SeekableReadStream : virtual public ReadStream {
public:

	/**
	 * Obtains the current value of the stream position indicator of the
	 * stream.
	 *
	 * @return the current position indicator, or -1 if an error occurred.
	 */
	virtual int32 pos() const = 0;

	/**
	 * Obtains the total size of the stream, measured in bytes.
	 * If this value is unknown or can not be computed, -1 is returned.
	 *
	 * @return the size of the stream, or -1 if an error occurred
	 */
	virtual int32 size() const = 0;

	/**
	 * Sets the stream position indicator for the stream. The new position,
	 * measured in bytes, is obtained by adding offset bytes to the position
	 * specified by whence. If whence is set to SEEK_SET, SEEK_CUR, or
	 * SEEK_END, the offset is relative to the start of the file, the current
	 * position indicator, or end-of-file, respectively. A successful call
	 * to the seek() method clears the end-of-file indicator for the stream.
	 *
	 * @param offset	the relative offset in bytes
	 * @param whence	the seek reference: SEEK_SET, SEEK_CUR, or SEEK_END
	 * @return true on success, false in case of a failure
	 */
	virtual bool seek(int32 offset, int whence = SEEK_SET) = 0;

	/**
	 * TODO: Get rid of this??? Or keep it and document it
	 * @return true on success, false in case of a failure
	 */
	virtual bool skip(uint32 offset) { return seek(offset, SEEK_CUR); }

	/**
	 * Reads at most one less than the number of characters specified
	 * by bufSize from the and stores them in the string buf. Reading
	 * stops when the end of a line is reached (CR, CR/LF or LF), and
	 * at end-of-file or error. The newline, if any, is retained (CR
	 * and CR/LF are translated to LF = 0xA = '\n'). If any characters
	 * are read and there is no error, a `\0' character is appended
	 * to end the string.
	 *
	 * Upon successful completion, return a pointer to the string. If
	 * end-of-file occurs before any characters are read, returns NULL
	 * and the buffer contents remain unchanged.  If an error occurs,
	 * returns NULL and the buffer contents are indeterminate.
	 * This method does not distinguish between end-of-file and error;
	 * callers must use err() or eos() to determine which occurred.
	 *
	 * @note This methods is closely modeled after the standard fgets()
	 *       function from stdio.h.
	 *
	 * @param buf	the buffer to store into
	 * @param bufSize	the size of the buffer
	 * @return a pointer to the read string, or NULL if an error occurred
	 */
	virtual char *readLine(char *s, size_t bufSize);


	/**
	 * Reads a full line and returns it as a Common::String. Reading
	 * stops when the end of a line is reached (CR, CR/LF or LF), and
	 * at end-of-file or error.
	 *
	 * Upon successful completion, return a string with the content
	 * of the line, *without* the end of a line marker. This method
	 * does not indicate whether an error occurred. Callers must use
	 * err() or eos() to determine whether an exception occurred.
	 */
	virtual String readLine();
};


/**
 * SubReadStream provides access to a ReadStream restricted to the range
 * [currentPosition, currentPosition+end).
 *
 * Manipulating the parent stream directly /will/ mess up a substream.
 * Likewise, manipulating two substreams of a parent stream will cause them to
 * step on each others toes.
 */
class SubReadStream : virtual public ReadStream {
protected:
	ReadStream *_parentStream;
	DisposeAfterUse::Flag _disposeParentStream;
	uint32 _pos;
	uint32 _end;
	bool _eos;
public:
	SubReadStream(ReadStream *parentStream, uint32 end, DisposeAfterUse::Flag disposeParentStream = DisposeAfterUse::NO)
		: _parentStream(parentStream),
		  _disposeParentStream(disposeParentStream),
		  _pos(0),
		  _end(end),
		  _eos(false) {
		assert(parentStream);
	}
	~SubReadStream() {
		if (_disposeParentStream)
			delete _parentStream;
	}

	virtual bool eos() const { return _eos; }
	virtual bool err() const { return _parentStream->err(); }
	virtual void clearErr() { _eos = false; _parentStream->clearErr(); }
	virtual uint32 read(void *dataPtr, uint32 dataSize);
};

/*
 * SeekableSubReadStream provides access to a SeekableReadStream restricted to
 * the range [begin, end).
 * The same caveats apply to SeekableSubReadStream as do to SeekableReadStream.
 *
 * Manipulating the parent stream directly /will/ mess up a substream.
 * @see SubReadStream
 */
class SeekableSubReadStream : public SubReadStream, public SeekableReadStream {
protected:
	SeekableReadStream *_parentStream;
	uint32 _begin;
public:
	SeekableSubReadStream(SeekableReadStream *parentStream, uint32 begin, uint32 end, DisposeAfterUse::Flag disposeParentStream = DisposeAfterUse::NO);

	virtual int32 pos() const { return _pos - _begin; }
	virtual int32 size() const { return _end - _begin; }

	virtual bool seek(int32 offset, int whence = SEEK_SET);
};

/**
 * This is a wrapper around SeekableSubReadStream, but it adds non-endian
 * read methods whose endianness is set on the stream creation.
 *
 * Manipulating the parent stream directly /will/ mess up a substream.
 * @see SubReadStream
 */
class SeekableSubReadStreamEndian : public SeekableSubReadStream {
private:
	const bool _bigEndian;

public:
	SeekableSubReadStreamEndian(SeekableReadStream *parentStream, uint32 begin, uint32 end, bool bigEndian = false, DisposeAfterUse::Flag disposeParentStream = DisposeAfterUse::NO)
		: SeekableSubReadStream(parentStream, begin, end, disposeParentStream), _bigEndian(bigEndian) {
	}

	uint16 readUint16() {
		uint16 val;
		read(&val, 2);
		return (_bigEndian) ? TO_BE_16(val) : TO_LE_16(val);
	}

	uint32 readUint32() {
		uint32 val;
		read(&val, 4);
		return (_bigEndian) ? TO_BE_32(val) : TO_LE_32(val);
	}

	FORCEINLINE int16 readSint16() {
		return (int16)readUint16();
	}

	FORCEINLINE int32 readSint32() {
		return (int32)readUint32();
	}
};

/**
 * Take an arbitrary ReadStream and wrap it in a custom stream which
 * transparently provides buffering.
 * Users can specify how big the buffer should be, and whether the wrapped
 * stream should be disposed when the wrapper is disposed.
 *
 * It is safe to call this with a NULL parameter (in this case, NULL is
 * returned).
 */
ReadStream *wrapBufferedReadStream(ReadStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream);

/**
 * Take an arbitrary SeekableReadStream and wrap it in a custom stream which
 * transparently provides buffering.
 * Users can specify how big the buffer should be, and whether the wrapped
 * stream should be disposed when the wrapper is disposed.
 *
 * It is safe to call this with a NULL parameter (in this case, NULL is
 * returned).
 */
SeekableReadStream *wrapBufferedSeekableReadStream(SeekableReadStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream);

/**
 * Take an arbitrary WriteStream and wrap it in a custom stream which
 * transparently provides buffering.
 * Users can specify how big the buffer should be, and whether the wrapped
 * stream should be disposed when the wrapper is disposed.
 *
 * It is safe to call this with a NULL parameter (in this case, NULL is
 * returned).
 */
WriteStream *wrapBufferedWriteStream(WriteStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream);

/**
 * Simple memory based 'stream', which implements the ReadStream interface for
 * a plain memory block.
 */
class MemoryReadStream : public SeekableReadStream {
private:
	const byte * const _ptrOrig;
	const byte *_ptr;
	const uint32 _size;
	uint32 _pos;
	byte _encbyte;
	DisposeAfterUse::Flag _disposeMemory;
	bool _eos;

public:

	/**
	 * This constructor takes a pointer to a memory buffer and a length, and
	 * wraps it. If disposeMemory is true, the MemoryReadStream takes ownership
	 * of the buffer and hence free's it when destructed.
	 */
	MemoryReadStream(const byte *dataPtr, uint32 dataSize, DisposeAfterUse::Flag disposeMemory = DisposeAfterUse::NO) :
		_ptrOrig(dataPtr),
		_ptr(dataPtr),
		_size(dataSize),
		_pos(0),
		_encbyte(0),
		_disposeMemory(disposeMemory),
		_eos(false) {}

	~MemoryReadStream() {
		if (_disposeMemory)
			free(const_cast<byte *>(_ptrOrig));
	}

	void setEnc(byte value) { _encbyte = value; }

	uint32 read(void *dataPtr, uint32 dataSize);

	bool eos() const { return _eos; }
	void clearErr() { _eos = false; }

	int32 pos() const { return _pos; }
	int32 size() const { return _size; }

	bool seek(int32 offs, int whence = SEEK_SET);
};


/**
 * This is a wrapper around MemoryReadStream, but it adds non-endian
 * read methods whose endianness is set on the stream creation.
 */
class MemoryReadStreamEndian : public MemoryReadStream {
private:
	const bool _bigEndian;

public:
	MemoryReadStreamEndian(const byte *buf, uint32 len, bool bigEndian = false) : MemoryReadStream(buf, len), _bigEndian(bigEndian) {}

	uint16 readUint16() {
		uint16 val;
		read(&val, 2);
		return (_bigEndian) ? TO_BE_16(val) : TO_LE_16(val);
	}

	uint32 readUint32() {
		uint32 val;
		read(&val, 4);
		return (_bigEndian) ? TO_BE_32(val) : TO_LE_32(val);
	}

	FORCEINLINE int16 readSint16() {
		return (int16)readUint16();
	}

	FORCEINLINE int32 readSint32() {
		return (int32)readUint32();
	}
};

/**
 * Simple memory based 'stream', which implements the WriteStream interface for
 * a plain memory block.
 */
class MemoryWriteStream : public WriteStream {
private:
	byte *_ptr;
	const uint32 _bufSize;
	uint32 _pos;
public:
	MemoryWriteStream(byte *buf, uint32 len) : _ptr(buf), _bufSize(len), _pos(0) {}

	uint32 write(const void *dataPtr, uint32 dataSize) {
		// Write at most as many bytes as are still available...
		if (dataSize > _bufSize - _pos)
			dataSize = _bufSize - _pos;
		memcpy(_ptr, dataPtr, dataSize);
		_ptr += dataSize;
		_pos += dataSize;
		return dataSize;
	}

	uint32 pos() const { return _pos; }
	uint32 size() const { return _bufSize; }
};

/**
 * A sort of hybrid between MemoryWriteStream and Array classes. A stream
 * that grows as it's written to.
 */
class MemoryWriteStreamDynamic : public WriteStream {
private:
	uint32 _capacity;
	uint32 _size;
	byte *_ptr;
	byte *_data;
	uint32 _pos;
	DisposeAfterUse::Flag _disposeMemory;

	void ensureCapacity(uint32 new_len) {
		if (new_len <= _capacity)
			return;

		byte *old_data = _data;

		_capacity = new_len + 32;
		_data = (byte *)malloc(_capacity);
		_ptr = _data + _pos;

		if (old_data) {
			// Copy old data
			memcpy(_data, old_data, _size);
			free(old_data);
		}

		_size = new_len;
	}
public:
	MemoryWriteStreamDynamic(DisposeAfterUse::Flag disposeMemory = DisposeAfterUse::NO) : _capacity(0), _size(0), _ptr(0), _data(0), _pos(0), _disposeMemory(disposeMemory) {}

	~MemoryWriteStreamDynamic() {
		if (_disposeMemory)
			free(_data);
	}

	uint32 write(const void *dataPtr, uint32 dataSize) {
		ensureCapacity(_pos + dataSize);
		memcpy(_ptr, dataPtr, dataSize);
		_ptr += dataSize;
		_pos += dataSize;
		if (_pos > _size)
			_size = _pos;
		return dataSize;
	}

	uint32 pos() const { return _pos; }
	uint32 size() const { return _size; }

	byte *getData() { return _data; }

	bool seek(int32 offset, int whence = SEEK_SET);
};

}	// End of namespace Common

#endif