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ffmpeg / libavformat / aviobuf.c @ d7fb5a18

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1
/*
2
 * Buffered I/O for ffmpeg system
3
 * Copyright (c) 2000,2001 Fabrice Bellard
4
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16
 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
19
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21

    
22
#include "libavutil/crc.h"
23
#include "avformat.h"
24
#include "avio.h"
25
#include <stdarg.h>
26

    
27
#define IO_BUFFER_SIZE 32768
28

    
29
static void fill_buffer(ByteIOContext *s);
30

    
31
int init_put_byte(ByteIOContext *s,
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                  unsigned char *buffer,
33
                  int buffer_size,
34
                  int write_flag,
35
                  void *opaque,
36
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
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                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
38
                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
39
{
40
    s->buffer = buffer;
41
    s->buffer_size = buffer_size;
42
    s->buf_ptr = buffer;
43
    url_resetbuf(s, write_flag ? URL_WRONLY : URL_RDONLY);
44
    s->opaque = opaque;
45
    s->write_packet = write_packet;
46
    s->read_packet = read_packet;
47
    s->seek = seek;
48
    s->pos = 0;
49
    s->must_flush = 0;
50
    s->eof_reached = 0;
51
    s->error = 0;
52
    s->is_streamed = 0;
53
    s->max_packet_size = 0;
54
    s->update_checksum= NULL;
55
    if(!read_packet && !write_flag){
56
        s->pos = buffer_size;
57
        s->buf_end = s->buffer + buffer_size;
58
    }
59
    s->read_pause = NULL;
60
    s->read_seek  = NULL;
61
    return 0;
62
}
63

    
64
ByteIOContext *av_alloc_put_byte(
65
                  unsigned char *buffer,
66
                  int buffer_size,
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                  int write_flag,
68
                  void *opaque,
69
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
70
                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
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                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
72
{
73
    ByteIOContext *s = av_mallocz(sizeof(ByteIOContext));
74
    init_put_byte(s, buffer, buffer_size, write_flag, opaque,
75
                  read_packet, write_packet, seek);
76
    return s;
77
}
78

    
79
static void flush_buffer(ByteIOContext *s)
80
{
81
    if (s->buf_ptr > s->buffer) {
82
        if (s->write_packet && !s->error){
83
            int ret= s->write_packet(s->opaque, s->buffer, s->buf_ptr - s->buffer);
84
            if(ret < 0){
85
                s->error = ret;
86
            }
87
        }
88
        if(s->update_checksum){
89
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
90
            s->checksum_ptr= s->buffer;
91
        }
92
        s->pos += s->buf_ptr - s->buffer;
93
    }
94
    s->buf_ptr = s->buffer;
95
}
96

    
97
void put_byte(ByteIOContext *s, int b)
98
{
99
    *(s->buf_ptr)++ = b;
100
    if (s->buf_ptr >= s->buf_end)
101
        flush_buffer(s);
102
}
103

    
104
void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
105
{
106
    int len;
107

    
108
    while (size > 0) {
109
        len = (s->buf_end - s->buf_ptr);
110
        if (len > size)
111
            len = size;
112
        memcpy(s->buf_ptr, buf, len);
113
        s->buf_ptr += len;
114

    
115
        if (s->buf_ptr >= s->buf_end)
116
            flush_buffer(s);
117

    
118
        buf += len;
119
        size -= len;
120
    }
121
}
122

    
123
void put_flush_packet(ByteIOContext *s)
124
{
125
    flush_buffer(s);
126
    s->must_flush = 0;
127
}
128

    
129
int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence)
130
{
131
    int64_t offset1;
132
    int64_t pos;
133

    
134
    if(!s)
135
        return AVERROR(EINVAL);
136

    
137
    pos = s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
138

    
139
    if (whence != SEEK_CUR && whence != SEEK_SET)
140
        return AVERROR(EINVAL);
141

    
142
    if (whence == SEEK_CUR) {
143
        offset1 = pos + (s->buf_ptr - s->buffer);
144
        if (offset == 0)
145
            return offset1;
146
        offset += offset1;
147
    }
148
    offset1 = offset - pos;
149
    if (!s->must_flush &&
150
        offset1 >= 0 && offset1 < (s->buf_end - s->buffer)) {
151
        /* can do the seek inside the buffer */
152
        s->buf_ptr = s->buffer + offset1;
153
    } else if(s->is_streamed && !s->write_flag &&
154
              offset1 >= 0 && offset1 < (s->buf_end - s->buffer) + (1<<16)){
155
        while(s->pos < offset && !s->eof_reached)
156
            fill_buffer(s);
157
        if (s->eof_reached)
158
            return AVERROR(EPIPE);
159
        s->buf_ptr = s->buf_end + offset - s->pos;
160
    } else {
161
        int64_t res = AVERROR(EPIPE);
162

    
163
#if defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK)
164
        if (s->write_flag) {
165
            flush_buffer(s);
166
            s->must_flush = 1;
167
        }
168
#endif /* defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK) */
169
        if (!s->seek || (res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
170
            return res;
171
        if (!s->write_flag)
172
            s->buf_end = s->buffer;
173
        s->buf_ptr = s->buffer;
174
        s->pos = offset;
175
    }
176
    s->eof_reached = 0;
177
    return offset;
178
}
179

    
180
void url_fskip(ByteIOContext *s, int64_t offset)
181
{
182
    url_fseek(s, offset, SEEK_CUR);
183
}
184

    
185
int64_t url_ftell(ByteIOContext *s)
186
{
187
    return url_fseek(s, 0, SEEK_CUR);
188
}
189

    
190
int64_t url_fsize(ByteIOContext *s)
191
{
192
    int64_t size;
193

    
194
    if(!s)
195
        return AVERROR(EINVAL);
196

    
197
    if (!s->seek)
198
        return AVERROR(EPIPE);
199
    size = s->seek(s->opaque, 0, AVSEEK_SIZE);
200
    if(size<0){
201
        if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
202
            return size;
203
        size++;
204
        s->seek(s->opaque, s->pos, SEEK_SET);
205
    }
206
    return size;
207
}
208

    
209
int url_feof(ByteIOContext *s)
210
{
211
    if(!s)
212
        return 0;
213
    return s->eof_reached;
214
}
215

    
216
int url_ferror(ByteIOContext *s)
217
{
218
    if(!s)
219
        return 0;
220
    return s->error;
221
}
222

    
223
void put_le32(ByteIOContext *s, unsigned int val)
224
{
225
    put_byte(s, val);
226
    put_byte(s, val >> 8);
227
    put_byte(s, val >> 16);
228
    put_byte(s, val >> 24);
229
}
230

    
231
void put_be32(ByteIOContext *s, unsigned int val)
232
{
233
    put_byte(s, val >> 24);
234
    put_byte(s, val >> 16);
235
    put_byte(s, val >> 8);
236
    put_byte(s, val);
237
}
238

    
239
void put_strz(ByteIOContext *s, const char *str)
240
{
241
    if (str)
242
        put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
243
    else
244
        put_byte(s, 0);
245
}
246

    
247
void put_le64(ByteIOContext *s, uint64_t val)
248
{
249
    put_le32(s, (uint32_t)(val & 0xffffffff));
250
    put_le32(s, (uint32_t)(val >> 32));
251
}
252

    
253
void put_be64(ByteIOContext *s, uint64_t val)
254
{
255
    put_be32(s, (uint32_t)(val >> 32));
256
    put_be32(s, (uint32_t)(val & 0xffffffff));
257
}
258

    
259
void put_le16(ByteIOContext *s, unsigned int val)
260
{
261
    put_byte(s, val);
262
    put_byte(s, val >> 8);
263
}
264

    
265
void put_be16(ByteIOContext *s, unsigned int val)
266
{
267
    put_byte(s, val >> 8);
268
    put_byte(s, val);
269
}
270

    
271
void put_le24(ByteIOContext *s, unsigned int val)
272
{
273
    put_le16(s, val & 0xffff);
274
    put_byte(s, val >> 16);
275
}
276

    
277
void put_be24(ByteIOContext *s, unsigned int val)
278
{
279
    put_be16(s, val >> 8);
280
    put_byte(s, val);
281
}
282

    
283
void put_tag(ByteIOContext *s, const char *tag)
284
{
285
    while (*tag) {
286
        put_byte(s, *tag++);
287
    }
288
}
289

    
290
/* Input stream */
291

    
292
static void fill_buffer(ByteIOContext *s)
293
{
294
    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : s->buffer;
295
    int len= s->buffer_size - (dst - s->buffer);
296

    
297
    assert(s->buf_ptr == s->buf_end);
298

    
299
    /* no need to do anything if EOF already reached */
300
    if (s->eof_reached)
301
        return;
302

    
303
    if(s->update_checksum && dst == s->buffer){
304
        if(s->buf_end > s->checksum_ptr)
305
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
306
        s->checksum_ptr= s->buffer;
307
    }
308

    
309
    if(s->read_packet)
310
        len = s->read_packet(s->opaque, dst, len);
311
    else
312
        len = 0;
313
    if (len <= 0) {
314
        /* do not modify buffer if EOF reached so that a seek back can
315
           be done without rereading data */
316
        s->eof_reached = 1;
317
        if(len<0)
318
            s->error= len;
319
    } else {
320
        s->pos += len;
321
        s->buf_ptr = dst;
322
        s->buf_end = dst + len;
323
    }
324
}
325

    
326
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
327
                                    unsigned int len)
328
{
329
    return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
330
}
331

    
332
unsigned long get_checksum(ByteIOContext *s)
333
{
334
    s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
335
    s->update_checksum= NULL;
336
    return s->checksum;
337
}
338

    
339
void init_checksum(ByteIOContext *s,
340
                   unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
341
                   unsigned long checksum)
342
{
343
    s->update_checksum= update_checksum;
344
    if(s->update_checksum){
345
        s->checksum= checksum;
346
        s->checksum_ptr= s->buf_ptr;
347
    }
348
}
349

    
350
/* XXX: put an inline version */
351
int get_byte(ByteIOContext *s)
352
{
353
    if (s->buf_ptr < s->buf_end) {
354
        return *s->buf_ptr++;
355
    } else {
356
        fill_buffer(s);
357
        if (s->buf_ptr < s->buf_end)
358
            return *s->buf_ptr++;
359
        else
360
            return 0;
361
    }
362
}
363

    
364
int url_fgetc(ByteIOContext *s)
365
{
366
    if (s->buf_ptr < s->buf_end) {
367
        return *s->buf_ptr++;
368
    } else {
369
        fill_buffer(s);
370
        if (s->buf_ptr < s->buf_end)
371
            return *s->buf_ptr++;
372
        else
373
            return URL_EOF;
374
    }
375
}
376

    
377
int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
378
{
379
    int len, size1;
380

    
381
    size1 = size;
382
    while (size > 0) {
383
        len = s->buf_end - s->buf_ptr;
384
        if (len > size)
385
            len = size;
386
        if (len == 0) {
387
            if(size > s->buffer_size && !s->update_checksum){
388
                if(s->read_packet)
389
                    len = s->read_packet(s->opaque, buf, size);
390
                if (len <= 0) {
391
                    /* do not modify buffer if EOF reached so that a seek back can
392
                    be done without rereading data */
393
                    s->eof_reached = 1;
394
                    if(len<0)
395
                        s->error= len;
396
                    break;
397
                } else {
398
                    s->pos += len;
399
                    size -= len;
400
                    buf += len;
401
                    s->buf_ptr = s->buffer;
402
                    s->buf_end = s->buffer/* + len*/;
403
                }
404
            }else{
405
                fill_buffer(s);
406
                len = s->buf_end - s->buf_ptr;
407
                if (len == 0)
408
                    break;
409
            }
410
        } else {
411
            memcpy(buf, s->buf_ptr, len);
412
            buf += len;
413
            s->buf_ptr += len;
414
            size -= len;
415
        }
416
    }
417
    return size1 - size;
418
}
419

    
420
int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
421
{
422
    int len;
423

    
424
    if(size<0)
425
        return -1;
426

    
427
    len = s->buf_end - s->buf_ptr;
428
    if (len == 0) {
429
        fill_buffer(s);
430
        len = s->buf_end - s->buf_ptr;
431
    }
432
    if (len > size)
433
        len = size;
434
    memcpy(buf, s->buf_ptr, len);
435
    s->buf_ptr += len;
436
    return len;
437
}
438

    
439
unsigned int get_le16(ByteIOContext *s)
440
{
441
    unsigned int val;
442
    val = get_byte(s);
443
    val |= get_byte(s) << 8;
444
    return val;
445
}
446

    
447
unsigned int get_le24(ByteIOContext *s)
448
{
449
    unsigned int val;
450
    val = get_le16(s);
451
    val |= get_byte(s) << 16;
452
    return val;
453
}
454

    
455
unsigned int get_le32(ByteIOContext *s)
456
{
457
    unsigned int val;
458
    val = get_le16(s);
459
    val |= get_le16(s) << 16;
460
    return val;
461
}
462

    
463
uint64_t get_le64(ByteIOContext *s)
464
{
465
    uint64_t val;
466
    val = (uint64_t)get_le32(s);
467
    val |= (uint64_t)get_le32(s) << 32;
468
    return val;
469
}
470

    
471
unsigned int get_be16(ByteIOContext *s)
472
{
473
    unsigned int val;
474
    val = get_byte(s) << 8;
475
    val |= get_byte(s);
476
    return val;
477
}
478

    
479
unsigned int get_be24(ByteIOContext *s)
480
{
481
    unsigned int val;
482
    val = get_be16(s) << 8;
483
    val |= get_byte(s);
484
    return val;
485
}
486
unsigned int get_be32(ByteIOContext *s)
487
{
488
    unsigned int val;
489
    val = get_be16(s) << 16;
490
    val |= get_be16(s);
491
    return val;
492
}
493

    
494
char *get_strz(ByteIOContext *s, char *buf, int maxlen)
495
{
496
    int i = 0;
497
    char c;
498

    
499
    while ((c = get_byte(s))) {
500
        if (i < maxlen-1)
501
            buf[i++] = c;
502
    }
503

    
504
    buf[i] = 0; /* Ensure null terminated, but may be truncated */
505

    
506
    return buf;
507
}
508

    
509
uint64_t get_be64(ByteIOContext *s)
510
{
511
    uint64_t val;
512
    val = (uint64_t)get_be32(s) << 32;
513
    val |= (uint64_t)get_be32(s);
514
    return val;
515
}
516

    
517
uint64_t ff_get_v(ByteIOContext *bc){
518
    uint64_t val = 0;
519
    int tmp;
520

    
521
    do{
522
        tmp = get_byte(bc);
523
        val= (val<<7) + (tmp&127);
524
    }while(tmp&128);
525
    return val;
526
}
527

    
528
int url_fdopen(ByteIOContext **s, URLContext *h)
529
{
530
    uint8_t *buffer;
531
    int buffer_size, max_packet_size;
532

    
533

    
534
    max_packet_size = url_get_max_packet_size(h);
535
    if (max_packet_size) {
536
        buffer_size = max_packet_size; /* no need to bufferize more than one packet */
537
    } else {
538
        buffer_size = IO_BUFFER_SIZE;
539
    }
540
    buffer = av_malloc(buffer_size);
541
    if (!buffer)
542
        return AVERROR(ENOMEM);
543

    
544
    *s = av_mallocz(sizeof(ByteIOContext));
545
    if(!*s) {
546
        av_free(buffer);
547
        return AVERROR(ENOMEM);
548
    }
549

    
550
    if (init_put_byte(*s, buffer, buffer_size,
551
                      (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
552
                      url_read, url_write, url_seek) < 0) {
553
        av_free(buffer);
554
        av_freep(s);
555
        return AVERROR(EIO);
556
    }
557
    (*s)->is_streamed = h->is_streamed;
558
    (*s)->max_packet_size = max_packet_size;
559
    if(h->prot) {
560
        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
561
        (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
562
    }
563
    return 0;
564
}
565

    
566
int url_setbufsize(ByteIOContext *s, int buf_size)
567
{
568
    uint8_t *buffer;
569
    buffer = av_malloc(buf_size);
570
    if (!buffer)
571
        return AVERROR(ENOMEM);
572

    
573
    av_free(s->buffer);
574
    s->buffer = buffer;
575
    s->buffer_size = buf_size;
576
    s->buf_ptr = buffer;
577
    url_resetbuf(s, s->write_flag ? URL_WRONLY : URL_RDONLY);
578
    return 0;
579
}
580

    
581
int url_resetbuf(ByteIOContext *s, int flags)
582
{
583
    URLContext *h = s->opaque;
584
    if ((flags & URL_RDWR) || (h && h->flags != flags && !h->flags & URL_RDWR))
585
        return AVERROR(EINVAL);
586

    
587
    if (flags & URL_WRONLY) {
588
        s->buf_end = s->buffer + s->buffer_size;
589
        s->write_flag = 1;
590
    } else {
591
        s->buf_end = s->buffer;
592
        s->write_flag = 0;
593
    }
594
    return 0;
595
}
596

    
597
int url_fopen(ByteIOContext **s, const char *filename, int flags)
598
{
599
    URLContext *h;
600
    int err;
601

    
602
    err = url_open(&h, filename, flags);
603
    if (err < 0)
604
        return err;
605
    err = url_fdopen(s, h);
606
    if (err < 0) {
607
        url_close(h);
608
        return err;
609
    }
610
    return 0;
611
}
612

    
613
int url_fclose(ByteIOContext *s)
614
{
615
    URLContext *h = s->opaque;
616

    
617
    av_free(s->buffer);
618
    av_free(s);
619
    return url_close(h);
620
}
621

    
622
URLContext *url_fileno(ByteIOContext *s)
623
{
624
    return s->opaque;
625
}
626

    
627
#ifdef CONFIG_MUXERS
628
int url_fprintf(ByteIOContext *s, const char *fmt, ...)
629
{
630
    va_list ap;
631
    char buf[4096];
632
    int ret;
633

    
634
    va_start(ap, fmt);
635
    ret = vsnprintf(buf, sizeof(buf), fmt, ap);
636
    va_end(ap);
637
    put_buffer(s, buf, strlen(buf));
638
    return ret;
639
}
640
#endif //CONFIG_MUXERS
641

    
642
char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
643
{
644
    int c;
645
    char *q;
646

    
647
    c = url_fgetc(s);
648
    if (c == EOF)
649
        return NULL;
650
    q = buf;
651
    for(;;) {
652
        if (c == EOF || c == '\n')
653
            break;
654
        if ((q - buf) < buf_size - 1)
655
            *q++ = c;
656
        c = url_fgetc(s);
657
    }
658
    if (buf_size > 0)
659
        *q = '\0';
660
    return buf;
661
}
662

    
663
int url_fget_max_packet_size(ByteIOContext *s)
664
{
665
    return s->max_packet_size;
666
}
667

    
668
int av_url_read_fpause(ByteIOContext *s, int pause)
669
{
670
    if (!s->read_pause)
671
        return AVERROR(ENOSYS);
672
    return s->read_pause(s->opaque, pause);
673
}
674

    
675
int64_t av_url_read_fseek(ByteIOContext *s, int stream_index,
676
                          int64_t timestamp, int flags)
677
{
678
    URLContext *h = s->opaque;
679
    int64_t ret;
680
    if (!s->read_seek)
681
        return AVERROR(ENOSYS);
682
    ret = s->read_seek(h, stream_index, timestamp, flags);
683
    if(ret >= 0) {
684
        s->buf_ptr = s->buf_end; // Flush buffer
685
        s->pos = s->seek(h, 0, SEEK_CUR);
686
    }
687
    return ret;
688
}
689

    
690
/* url_open_dyn_buf and url_close_dyn_buf are used in rtp.c to send a response
691
 * back to the server even if CONFIG_MUXERS is not set. */
692
#if defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK)
693
/* buffer handling */
694
int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags)
695
{
696
    int ret;
697
    *s = av_mallocz(sizeof(ByteIOContext));
698
    if(!*s)
699
        return AVERROR(ENOMEM);
700
    ret = init_put_byte(*s, buf, buf_size,
701
                        (flags & URL_WRONLY || flags & URL_RDWR),
702
                        NULL, NULL, NULL, NULL);
703
    if(ret != 0)
704
        av_freep(s);
705
    return ret;
706
}
707

    
708
int url_close_buf(ByteIOContext *s)
709
{
710
    put_flush_packet(s);
711
    return s->buf_ptr - s->buffer;
712
}
713

    
714
/* output in a dynamic buffer */
715

    
716
typedef struct DynBuffer {
717
    int pos, size, allocated_size;
718
    uint8_t *buffer;
719
    int io_buffer_size;
720
    uint8_t io_buffer[1];
721
} DynBuffer;
722

    
723
static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
724
{
725
    DynBuffer *d = opaque;
726
    unsigned new_size, new_allocated_size;
727

    
728
    /* reallocate buffer if needed */
729
    new_size = d->pos + buf_size;
730
    new_allocated_size = d->allocated_size;
731
    if(new_size < d->pos || new_size > INT_MAX/2)
732
        return -1;
733
    while (new_size > new_allocated_size) {
734
        if (!new_allocated_size)
735
            new_allocated_size = new_size;
736
        else
737
            new_allocated_size += new_allocated_size / 2 + 1;
738
    }
739

    
740
    if (new_allocated_size > d->allocated_size) {
741
        d->buffer = av_realloc(d->buffer, new_allocated_size);
742
        if(d->buffer == NULL)
743
             return -1234;
744
        d->allocated_size = new_allocated_size;
745
    }
746
    memcpy(d->buffer + d->pos, buf, buf_size);
747
    d->pos = new_size;
748
    if (d->pos > d->size)
749
        d->size = d->pos;
750
    return buf_size;
751
}
752

    
753
static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
754
{
755
    unsigned char buf1[4];
756
    int ret;
757

    
758
    /* packetized write: output the header */
759
    buf1[0] = (buf_size >> 24);
760
    buf1[1] = (buf_size >> 16);
761
    buf1[2] = (buf_size >> 8);
762
    buf1[3] = (buf_size);
763
    ret= dyn_buf_write(opaque, buf1, 4);
764
    if(ret < 0)
765
        return ret;
766

    
767
    /* then the data */
768
    return dyn_buf_write(opaque, buf, buf_size);
769
}
770

    
771
static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
772
{
773
    DynBuffer *d = opaque;
774

    
775
    if (whence == SEEK_CUR)
776
        offset += d->pos;
777
    else if (whence == SEEK_END)
778
        offset += d->size;
779
    if (offset < 0 || offset > 0x7fffffffLL)
780
        return -1;
781
    d->pos = offset;
782
    return 0;
783
}
784

    
785
static int url_open_dyn_buf_internal(ByteIOContext **s, int max_packet_size)
786
{
787
    DynBuffer *d;
788
    int io_buffer_size, ret;
789

    
790
    if (max_packet_size)
791
        io_buffer_size = max_packet_size;
792
    else
793
        io_buffer_size = 1024;
794

    
795
    if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
796
        return -1;
797
    d = av_malloc(sizeof(DynBuffer) + io_buffer_size);
798
    if (!d)
799
        return -1;
800
    *s = av_mallocz(sizeof(ByteIOContext));
801
    if(!*s) {
802
        av_free(d);
803
        return AVERROR(ENOMEM);
804
    }
805
    d->io_buffer_size = io_buffer_size;
806
    d->buffer = NULL;
807
    d->pos = 0;
808
    d->size = 0;
809
    d->allocated_size = 0;
810
    ret = init_put_byte(*s, d->io_buffer, io_buffer_size,
811
                        1, d, NULL,
812
                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
813
                        max_packet_size ? NULL : dyn_buf_seek);
814
    if (ret == 0) {
815
        (*s)->max_packet_size = max_packet_size;
816
    } else {
817
        av_free(d);
818
        av_freep(s);
819
    }
820
    return ret;
821
}
822

    
823
int url_open_dyn_buf(ByteIOContext **s)
824
{
825
    return url_open_dyn_buf_internal(s, 0);
826
}
827

    
828
int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size)
829
{
830
    if (max_packet_size <= 0)
831
        return -1;
832
    return url_open_dyn_buf_internal(s, max_packet_size);
833
}
834

    
835
int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
836
{
837
    DynBuffer *d = s->opaque;
838
    int size;
839

    
840
    put_flush_packet(s);
841

    
842
    *pbuffer = d->buffer;
843
    size = d->size;
844
    av_free(d);
845
    av_free(s);
846
    return size;
847
}
848
#endif /* CONFIG_MUXERS || CONFIG_NETWORK */