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ffmpeg / libavformat / aviobuf.c @ b3eab9fb

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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
 *
17
 * You should have received a copy of the GNU Lesser General Public
18
 * 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 "libavutil/intreadwrite.h"
24
#include "avformat.h"
25
#include "avio.h"
26
#include <stdarg.h>
27

    
28
#define IO_BUFFER_SIZE 32768
29

    
30
static void fill_buffer(ByteIOContext *s);
31

    
32
int init_put_byte(ByteIOContext *s,
33
                  unsigned char *buffer,
34
                  int buffer_size,
35
                  int write_flag,
36
                  void *opaque,
37
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
38
                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
39
                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
40
{
41
    s->buffer = buffer;
42
    s->buffer_size = buffer_size;
43
    s->buf_ptr = buffer;
44
    s->opaque = opaque;
45
    url_resetbuf(s, write_flag ? URL_WRONLY : URL_RDONLY);
46
    s->write_packet = write_packet;
47
    s->read_packet = read_packet;
48
    s->seek = seek;
49
    s->pos = 0;
50
    s->must_flush = 0;
51
    s->eof_reached = 0;
52
    s->error = 0;
53
    s->is_streamed = 0;
54
    s->max_packet_size = 0;
55
    s->update_checksum= NULL;
56
    if(!read_packet && !write_flag){
57
        s->pos = buffer_size;
58
        s->buf_end = s->buffer + buffer_size;
59
    }
60
    s->read_pause = NULL;
61
    s->read_seek  = NULL;
62
    return 0;
63
}
64

    
65
ByteIOContext *av_alloc_put_byte(
66
                  unsigned char *buffer,
67
                  int buffer_size,
68
                  int write_flag,
69
                  void *opaque,
70
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
71
                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
72
                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
73
{
74
    ByteIOContext *s = av_mallocz(sizeof(ByteIOContext));
75
    init_put_byte(s, buffer, buffer_size, write_flag, opaque,
76
                  read_packet, write_packet, seek);
77
    return s;
78
}
79

    
80
static void flush_buffer(ByteIOContext *s)
81
{
82
    if (s->buf_ptr > s->buffer) {
83
        if (s->write_packet && !s->error){
84
            int ret= s->write_packet(s->opaque, s->buffer, s->buf_ptr - s->buffer);
85
            if(ret < 0){
86
                s->error = ret;
87
            }
88
        }
89
        if(s->update_checksum){
90
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
91
            s->checksum_ptr= s->buffer;
92
        }
93
        s->pos += s->buf_ptr - s->buffer;
94
    }
95
    s->buf_ptr = s->buffer;
96
}
97

    
98
void put_byte(ByteIOContext *s, int b)
99
{
100
    *(s->buf_ptr)++ = b;
101
    if (s->buf_ptr >= s->buf_end)
102
        flush_buffer(s);
103
}
104

    
105
void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
106
{
107
    int len;
108

    
109
    while (size > 0) {
110
        len = (s->buf_end - s->buf_ptr);
111
        if (len > size)
112
            len = size;
113
        memcpy(s->buf_ptr, buf, len);
114
        s->buf_ptr += len;
115

    
116
        if (s->buf_ptr >= s->buf_end)
117
            flush_buffer(s);
118

    
119
        buf += len;
120
        size -= len;
121
    }
122
}
123

    
124
void put_flush_packet(ByteIOContext *s)
125
{
126
    flush_buffer(s);
127
    s->must_flush = 0;
128
}
129

    
130
int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence)
131
{
132
    int64_t offset1;
133
    int64_t pos;
134

    
135
    if(!s)
136
        return AVERROR(EINVAL);
137

    
138
    pos = s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
139

    
140
    if (whence != SEEK_CUR && whence != SEEK_SET)
141
        return AVERROR(EINVAL);
142

    
143
    if (whence == SEEK_CUR) {
144
        offset1 = pos + (s->buf_ptr - s->buffer);
145
        if (offset == 0)
146
            return offset1;
147
        offset += offset1;
148
    }
149
    offset1 = offset - pos;
150
    if (!s->must_flush &&
151
        offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
152
        /* can do the seek inside the buffer */
153
        s->buf_ptr = s->buffer + offset1;
154
    } else if(s->is_streamed && !s->write_flag &&
155
              offset1 >= 0 && offset1 < (s->buf_end - s->buffer) + (1<<16)){
156
        while(s->pos < offset && !s->eof_reached)
157
            fill_buffer(s);
158
        if (s->eof_reached)
159
            return AVERROR(EPIPE);
160
        s->buf_ptr = s->buf_end + offset - s->pos;
161
    } else {
162
        int64_t res = AVERROR(EPIPE);
163

    
164
#if CONFIG_MUXERS || CONFIG_NETWORK
165
        if (s->write_flag) {
166
            flush_buffer(s);
167
            s->must_flush = 1;
168
        }
169
#endif /* CONFIG_MUXERS || CONFIG_NETWORK */
170
        if (!s->seek || (res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
171
            return res;
172
        if (!s->write_flag)
173
            s->buf_end = s->buffer;
174
        s->buf_ptr = s->buffer;
175
        s->pos = offset;
176
    }
177
    s->eof_reached = 0;
178
    return offset;
179
}
180

    
181
void url_fskip(ByteIOContext *s, int64_t offset)
182
{
183
    url_fseek(s, offset, SEEK_CUR);
184
}
185

    
186
int64_t url_ftell(ByteIOContext *s)
187
{
188
    return url_fseek(s, 0, SEEK_CUR);
189
}
190

    
191
int64_t url_fsize(ByteIOContext *s)
192
{
193
    int64_t size;
194

    
195
    if(!s)
196
        return AVERROR(EINVAL);
197

    
198
    if (!s->seek)
199
        return AVERROR(EPIPE);
200
    size = s->seek(s->opaque, 0, AVSEEK_SIZE);
201
    if(size<0){
202
        if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
203
            return size;
204
        size++;
205
        s->seek(s->opaque, s->pos, SEEK_SET);
206
    }
207
    return size;
208
}
209

    
210
int url_feof(ByteIOContext *s)
211
{
212
    if(!s)
213
        return 0;
214
    return s->eof_reached;
215
}
216

    
217
int url_ferror(ByteIOContext *s)
218
{
219
    if(!s)
220
        return 0;
221
    return s->error;
222
}
223

    
224
void put_le32(ByteIOContext *s, unsigned int val)
225
{
226
    put_byte(s, val);
227
    put_byte(s, val >> 8);
228
    put_byte(s, val >> 16);
229
    put_byte(s, val >> 24);
230
}
231

    
232
void put_be32(ByteIOContext *s, unsigned int val)
233
{
234
    put_byte(s, val >> 24);
235
    put_byte(s, val >> 16);
236
    put_byte(s, val >> 8);
237
    put_byte(s, val);
238
}
239

    
240
void put_strz(ByteIOContext *s, const char *str)
241
{
242
    if (str)
243
        put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
244
    else
245
        put_byte(s, 0);
246
}
247

    
248
void put_le64(ByteIOContext *s, uint64_t val)
249
{
250
    put_le32(s, (uint32_t)(val & 0xffffffff));
251
    put_le32(s, (uint32_t)(val >> 32));
252
}
253

    
254
void put_be64(ByteIOContext *s, uint64_t val)
255
{
256
    put_be32(s, (uint32_t)(val >> 32));
257
    put_be32(s, (uint32_t)(val & 0xffffffff));
258
}
259

    
260
void put_le16(ByteIOContext *s, unsigned int val)
261
{
262
    put_byte(s, val);
263
    put_byte(s, val >> 8);
264
}
265

    
266
void put_be16(ByteIOContext *s, unsigned int val)
267
{
268
    put_byte(s, val >> 8);
269
    put_byte(s, val);
270
}
271

    
272
void put_le24(ByteIOContext *s, unsigned int val)
273
{
274
    put_le16(s, val & 0xffff);
275
    put_byte(s, val >> 16);
276
}
277

    
278
void put_be24(ByteIOContext *s, unsigned int val)
279
{
280
    put_be16(s, val >> 8);
281
    put_byte(s, val);
282
}
283

    
284
void put_tag(ByteIOContext *s, const char *tag)
285
{
286
    while (*tag) {
287
        put_byte(s, *tag++);
288
    }
289
}
290

    
291
/* Input stream */
292

    
293
static void fill_buffer(ByteIOContext *s)
294
{
295
    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : s->buffer;
296
    int len= s->buffer_size - (dst - s->buffer);
297

    
298
    assert(s->buf_ptr == s->buf_end);
299

    
300
    /* no need to do anything if EOF already reached */
301
    if (s->eof_reached)
302
        return;
303

    
304
    if(s->update_checksum && dst == s->buffer){
305
        if(s->buf_end > s->checksum_ptr)
306
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
307
        s->checksum_ptr= s->buffer;
308
    }
309

    
310
    if(s->read_packet)
311
        len = s->read_packet(s->opaque, dst, len);
312
    else
313
        len = 0;
314
    if (len <= 0) {
315
        /* do not modify buffer if EOF reached so that a seek back can
316
           be done without rereading data */
317
        s->eof_reached = 1;
318
        if(len<0)
319
            s->error= len;
320
    } else {
321
        s->pos += len;
322
        s->buf_ptr = dst;
323
        s->buf_end = dst + len;
324
    }
325
}
326

    
327
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
328
                                    unsigned int len)
329
{
330
    return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
331
}
332

    
333
unsigned long get_checksum(ByteIOContext *s)
334
{
335
    s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
336
    s->update_checksum= NULL;
337
    return s->checksum;
338
}
339

    
340
void init_checksum(ByteIOContext *s,
341
                   unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
342
                   unsigned long checksum)
343
{
344
    s->update_checksum= update_checksum;
345
    if(s->update_checksum){
346
        s->checksum= checksum;
347
        s->checksum_ptr= s->buf_ptr;
348
    }
349
}
350

    
351
/* XXX: put an inline version */
352
int get_byte(ByteIOContext *s)
353
{
354
    if (s->buf_ptr < s->buf_end) {
355
        return *s->buf_ptr++;
356
    } else {
357
        fill_buffer(s);
358
        if (s->buf_ptr < s->buf_end)
359
            return *s->buf_ptr++;
360
        else
361
            return 0;
362
    }
363
}
364

    
365
int url_fgetc(ByteIOContext *s)
366
{
367
    if (s->buf_ptr < s->buf_end) {
368
        return *s->buf_ptr++;
369
    } else {
370
        fill_buffer(s);
371
        if (s->buf_ptr < s->buf_end)
372
            return *s->buf_ptr++;
373
        else
374
            return URL_EOF;
375
    }
376
}
377

    
378
int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
379
{
380
    int len, size1;
381

    
382
    size1 = size;
383
    while (size > 0) {
384
        len = s->buf_end - s->buf_ptr;
385
        if (len > size)
386
            len = size;
387
        if (len == 0) {
388
            if(size > s->buffer_size && !s->update_checksum){
389
                if(s->read_packet)
390
                    len = s->read_packet(s->opaque, buf, size);
391
                if (len <= 0) {
392
                    /* do not modify buffer if EOF reached so that a seek back can
393
                    be done without rereading data */
394
                    s->eof_reached = 1;
395
                    if(len<0)
396
                        s->error= len;
397
                    break;
398
                } else {
399
                    s->pos += len;
400
                    size -= len;
401
                    buf += len;
402
                    s->buf_ptr = s->buffer;
403
                    s->buf_end = s->buffer/* + len*/;
404
                }
405
            }else{
406
                fill_buffer(s);
407
                len = s->buf_end - s->buf_ptr;
408
                if (len == 0)
409
                    break;
410
            }
411
        } else {
412
            memcpy(buf, s->buf_ptr, len);
413
            buf += len;
414
            s->buf_ptr += len;
415
            size -= len;
416
        }
417
    }
418
    return size1 - size;
419
}
420

    
421
int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
422
{
423
    int len;
424

    
425
    if(size<0)
426
        return -1;
427

    
428
    len = s->buf_end - s->buf_ptr;
429
    if (len == 0) {
430
        fill_buffer(s);
431
        len = s->buf_end - s->buf_ptr;
432
    }
433
    if (len > size)
434
        len = size;
435
    memcpy(buf, s->buf_ptr, len);
436
    s->buf_ptr += len;
437
    return len;
438
}
439

    
440
unsigned int get_le16(ByteIOContext *s)
441
{
442
    unsigned int val;
443
    val = get_byte(s);
444
    val |= get_byte(s) << 8;
445
    return val;
446
}
447

    
448
unsigned int get_le24(ByteIOContext *s)
449
{
450
    unsigned int val;
451
    val = get_le16(s);
452
    val |= get_byte(s) << 16;
453
    return val;
454
}
455

    
456
unsigned int get_le32(ByteIOContext *s)
457
{
458
    unsigned int val;
459
    val = get_le16(s);
460
    val |= get_le16(s) << 16;
461
    return val;
462
}
463

    
464
uint64_t get_le64(ByteIOContext *s)
465
{
466
    uint64_t val;
467
    val = (uint64_t)get_le32(s);
468
    val |= (uint64_t)get_le32(s) << 32;
469
    return val;
470
}
471

    
472
unsigned int get_be16(ByteIOContext *s)
473
{
474
    unsigned int val;
475
    val = get_byte(s) << 8;
476
    val |= get_byte(s);
477
    return val;
478
}
479

    
480
unsigned int get_be24(ByteIOContext *s)
481
{
482
    unsigned int val;
483
    val = get_be16(s) << 8;
484
    val |= get_byte(s);
485
    return val;
486
}
487
unsigned int get_be32(ByteIOContext *s)
488
{
489
    unsigned int val;
490
    val = get_be16(s) << 16;
491
    val |= get_be16(s);
492
    return val;
493
}
494

    
495
char *get_strz(ByteIOContext *s, char *buf, int maxlen)
496
{
497
    int i = 0;
498
    char c;
499

    
500
    while ((c = get_byte(s))) {
501
        if (i < maxlen-1)
502
            buf[i++] = c;
503
    }
504

    
505
    buf[i] = 0; /* Ensure null terminated, but may be truncated */
506

    
507
    return buf;
508
}
509

    
510
uint64_t get_be64(ByteIOContext *s)
511
{
512
    uint64_t val;
513
    val = (uint64_t)get_be32(s) << 32;
514
    val |= (uint64_t)get_be32(s);
515
    return val;
516
}
517

    
518
uint64_t ff_get_v(ByteIOContext *bc){
519
    uint64_t val = 0;
520
    int tmp;
521

    
522
    do{
523
        tmp = get_byte(bc);
524
        val= (val<<7) + (tmp&127);
525
    }while(tmp&128);
526
    return val;
527
}
528

    
529
int url_fdopen(ByteIOContext **s, URLContext *h)
530
{
531
    uint8_t *buffer;
532
    int buffer_size, max_packet_size;
533

    
534

    
535
    max_packet_size = url_get_max_packet_size(h);
536
    if (max_packet_size) {
537
        buffer_size = max_packet_size; /* no need to bufferize more than one packet */
538
    } else {
539
        buffer_size = IO_BUFFER_SIZE;
540
    }
541
    buffer = av_malloc(buffer_size);
542
    if (!buffer)
543
        return AVERROR(ENOMEM);
544

    
545
    *s = av_mallocz(sizeof(ByteIOContext));
546
    if(!*s) {
547
        av_free(buffer);
548
        return AVERROR(ENOMEM);
549
    }
550

    
551
    if (init_put_byte(*s, buffer, buffer_size,
552
                      (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
553
                      url_read, url_write, url_seek) < 0) {
554
        av_free(buffer);
555
        av_freep(s);
556
        return AVERROR(EIO);
557
    }
558
    (*s)->is_streamed = h->is_streamed;
559
    (*s)->max_packet_size = max_packet_size;
560
    if(h->prot) {
561
        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
562
        (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
563
    }
564
    return 0;
565
}
566

    
567
int url_setbufsize(ByteIOContext *s, int buf_size)
568
{
569
    uint8_t *buffer;
570
    buffer = av_malloc(buf_size);
571
    if (!buffer)
572
        return AVERROR(ENOMEM);
573

    
574
    av_free(s->buffer);
575
    s->buffer = buffer;
576
    s->buffer_size = buf_size;
577
    s->buf_ptr = buffer;
578
    url_resetbuf(s, s->write_flag ? URL_WRONLY : URL_RDONLY);
579
    return 0;
580
}
581

    
582
int url_resetbuf(ByteIOContext *s, int flags)
583
{
584
    URLContext *h = s->opaque;
585
    if ((flags & URL_RDWR) || (h && h->flags != flags && !h->flags & URL_RDWR))
586
        return AVERROR(EINVAL);
587

    
588
    if (flags & URL_WRONLY) {
589
        s->buf_end = s->buffer + s->buffer_size;
590
        s->write_flag = 1;
591
    } else {
592
        s->buf_end = s->buffer;
593
        s->write_flag = 0;
594
    }
595
    return 0;
596
}
597

    
598
int url_fopen(ByteIOContext **s, const char *filename, int flags)
599
{
600
    URLContext *h;
601
    int err;
602

    
603
    err = url_open(&h, filename, flags);
604
    if (err < 0)
605
        return err;
606
    err = url_fdopen(s, h);
607
    if (err < 0) {
608
        url_close(h);
609
        return err;
610
    }
611
    return 0;
612
}
613

    
614
int url_fclose(ByteIOContext *s)
615
{
616
    URLContext *h = s->opaque;
617

    
618
    av_free(s->buffer);
619
    av_free(s);
620
    return url_close(h);
621
}
622

    
623
URLContext *url_fileno(ByteIOContext *s)
624
{
625
    return s->opaque;
626
}
627

    
628
#if CONFIG_MUXERS
629
int url_fprintf(ByteIOContext *s, const char *fmt, ...)
630
{
631
    va_list ap;
632
    char buf[4096];
633
    int ret;
634

    
635
    va_start(ap, fmt);
636
    ret = vsnprintf(buf, sizeof(buf), fmt, ap);
637
    va_end(ap);
638
    put_buffer(s, buf, strlen(buf));
639
    return ret;
640
}
641
#endif //CONFIG_MUXERS
642

    
643
char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
644
{
645
    int c;
646
    char *q;
647

    
648
    c = url_fgetc(s);
649
    if (c == EOF)
650
        return NULL;
651
    q = buf;
652
    for(;;) {
653
        if (c == EOF || c == '\n')
654
            break;
655
        if ((q - buf) < buf_size - 1)
656
            *q++ = c;
657
        c = url_fgetc(s);
658
    }
659
    if (buf_size > 0)
660
        *q = '\0';
661
    return buf;
662
}
663

    
664
int url_fget_max_packet_size(ByteIOContext *s)
665
{
666
    return s->max_packet_size;
667
}
668

    
669
int av_url_read_fpause(ByteIOContext *s, int pause)
670
{
671
    if (!s->read_pause)
672
        return AVERROR(ENOSYS);
673
    return s->read_pause(s->opaque, pause);
674
}
675

    
676
int64_t av_url_read_fseek(ByteIOContext *s, int stream_index,
677
                          int64_t timestamp, int flags)
678
{
679
    URLContext *h = s->opaque;
680
    int64_t ret;
681
    if (!s->read_seek)
682
        return AVERROR(ENOSYS);
683
    ret = s->read_seek(h, stream_index, timestamp, flags);
684
    if(ret >= 0) {
685
        s->buf_ptr = s->buf_end; // Flush buffer
686
        s->pos = s->seek(h, 0, SEEK_CUR);
687
    }
688
    return ret;
689
}
690

    
691
/* url_open_dyn_buf and url_close_dyn_buf are used in rtp.c to send a response
692
 * back to the server even if CONFIG_MUXERS is false. */
693
#if CONFIG_MUXERS || CONFIG_NETWORK
694
/* buffer handling */
695
int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags)
696
{
697
    int ret;
698
    *s = av_mallocz(sizeof(ByteIOContext));
699
    if(!*s)
700
        return AVERROR(ENOMEM);
701
    ret = init_put_byte(*s, buf, buf_size,
702
                        (flags & URL_WRONLY || flags & URL_RDWR),
703
                        NULL, NULL, NULL, NULL);
704
    if(ret != 0)
705
        av_freep(s);
706
    return ret;
707
}
708

    
709
int url_close_buf(ByteIOContext *s)
710
{
711
    put_flush_packet(s);
712
    return s->buf_ptr - s->buffer;
713
}
714

    
715
/* output in a dynamic buffer */
716

    
717
typedef struct DynBuffer {
718
    int pos, size, allocated_size;
719
    uint8_t *buffer;
720
    int io_buffer_size;
721
    uint8_t io_buffer[1];
722
} DynBuffer;
723

    
724
static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
725
{
726
    DynBuffer *d = opaque;
727
    unsigned new_size, new_allocated_size;
728

    
729
    /* reallocate buffer if needed */
730
    new_size = d->pos + buf_size;
731
    new_allocated_size = d->allocated_size;
732
    if(new_size < d->pos || new_size > INT_MAX/2)
733
        return -1;
734
    while (new_size > new_allocated_size) {
735
        if (!new_allocated_size)
736
            new_allocated_size = new_size;
737
        else
738
            new_allocated_size += new_allocated_size / 2 + 1;
739
    }
740

    
741
    if (new_allocated_size > d->allocated_size) {
742
        d->buffer = av_realloc(d->buffer, new_allocated_size);
743
        if(d->buffer == NULL)
744
             return AVERROR(ENOMEM);
745
        d->allocated_size = new_allocated_size;
746
    }
747
    memcpy(d->buffer + d->pos, buf, buf_size);
748
    d->pos = new_size;
749
    if (d->pos > d->size)
750
        d->size = d->pos;
751
    return buf_size;
752
}
753

    
754
static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
755
{
756
    unsigned char buf1[4];
757
    int ret;
758

    
759
    /* packetized write: output the header */
760
    AV_WB32(buf1, buf_size);
761
    ret= dyn_buf_write(opaque, buf1, 4);
762
    if(ret < 0)
763
        return ret;
764

    
765
    /* then the data */
766
    return dyn_buf_write(opaque, buf, buf_size);
767
}
768

    
769
static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
770
{
771
    DynBuffer *d = opaque;
772

    
773
    if (whence == SEEK_CUR)
774
        offset += d->pos;
775
    else if (whence == SEEK_END)
776
        offset += d->size;
777
    if (offset < 0 || offset > 0x7fffffffLL)
778
        return -1;
779
    d->pos = offset;
780
    return 0;
781
}
782

    
783
static int url_open_dyn_buf_internal(ByteIOContext **s, int max_packet_size)
784
{
785
    DynBuffer *d;
786
    int ret;
787
    unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
788

    
789
    if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
790
        return -1;
791
    d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
792
    if (!d)
793
        return AVERROR(ENOMEM);
794
    *s = av_mallocz(sizeof(ByteIOContext));
795
    if(!*s) {
796
        av_free(d);
797
        return AVERROR(ENOMEM);
798
    }
799
    d->io_buffer_size = io_buffer_size;
800
    ret = init_put_byte(*s, d->io_buffer, io_buffer_size,
801
                        1, d, NULL,
802
                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
803
                        max_packet_size ? NULL : dyn_buf_seek);
804
    if (ret == 0) {
805
        (*s)->max_packet_size = max_packet_size;
806
    } else {
807
        av_free(d);
808
        av_freep(s);
809
    }
810
    return ret;
811
}
812

    
813
int url_open_dyn_buf(ByteIOContext **s)
814
{
815
    return url_open_dyn_buf_internal(s, 0);
816
}
817

    
818
int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size)
819
{
820
    if (max_packet_size <= 0)
821
        return -1;
822
    return url_open_dyn_buf_internal(s, max_packet_size);
823
}
824

    
825
int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
826
{
827
    DynBuffer *d = s->opaque;
828
    int size;
829

    
830
    put_flush_packet(s);
831

    
832
    *pbuffer = d->buffer;
833
    size = d->size;
834
    av_free(d);
835
    av_free(s);
836
    return size;
837
}
838
#endif /* CONFIG_MUXERS || CONFIG_NETWORK */