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ffmpeg / libavformat / aviobuf.c @ c007c687

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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
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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 "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
#if LIBAVFORMAT_VERSION_MAJOR >= 53
32
static int url_resetbuf(ByteIOContext *s, int flags);
33
#endif
34

    
35
int init_put_byte(ByteIOContext *s,
36
                  unsigned char *buffer,
37
                  int buffer_size,
38
                  int write_flag,
39
                  void *opaque,
40
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
41
                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
42
                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
43
{
44
    s->buffer = buffer;
45
    s->buffer_size = buffer_size;
46
    s->buf_ptr = buffer;
47
    s->opaque = opaque;
48
    url_resetbuf(s, write_flag ? URL_WRONLY : URL_RDONLY);
49
    s->write_packet = write_packet;
50
    s->read_packet = read_packet;
51
    s->seek = seek;
52
    s->pos = 0;
53
    s->must_flush = 0;
54
    s->eof_reached = 0;
55
    s->error = 0;
56
    s->is_streamed = 0;
57
    s->max_packet_size = 0;
58
    s->update_checksum= NULL;
59
    if(!read_packet && !write_flag){
60
        s->pos = buffer_size;
61
        s->buf_end = s->buffer + buffer_size;
62
    }
63
    s->read_pause = NULL;
64
    s->read_seek  = NULL;
65
    return 0;
66
}
67

    
68
ByteIOContext *av_alloc_put_byte(
69
                  unsigned char *buffer,
70
                  int buffer_size,
71
                  int write_flag,
72
                  void *opaque,
73
                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
74
                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
75
                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
76
{
77
    ByteIOContext *s = av_mallocz(sizeof(ByteIOContext));
78
    init_put_byte(s, buffer, buffer_size, write_flag, opaque,
79
                  read_packet, write_packet, seek);
80
    return s;
81
}
82

    
83
static void flush_buffer(ByteIOContext *s)
84
{
85
    if (s->buf_ptr > s->buffer) {
86
        if (s->write_packet && !s->error){
87
            int ret= s->write_packet(s->opaque, s->buffer, s->buf_ptr - s->buffer);
88
            if(ret < 0){
89
                s->error = ret;
90
            }
91
        }
92
        if(s->update_checksum){
93
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
94
            s->checksum_ptr= s->buffer;
95
        }
96
        s->pos += s->buf_ptr - s->buffer;
97
    }
98
    s->buf_ptr = s->buffer;
99
}
100

    
101
void put_byte(ByteIOContext *s, int b)
102
{
103
    *(s->buf_ptr)++ = b;
104
    if (s->buf_ptr >= s->buf_end)
105
        flush_buffer(s);
106
}
107

    
108
void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
109
{
110
    while (size > 0) {
111
        int len = FFMIN(s->buf_end - s->buf_ptr, 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
    int force = whence & AVSEEK_FORCE;
134
    whence &= ~AVSEEK_FORCE;
135

    
136
    if(!s)
137
        return AVERROR(EINVAL);
138

    
139
    pos = s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
140

    
141
    if (whence != SEEK_CUR && whence != SEEK_SET)
142
        return AVERROR(EINVAL);
143

    
144
    if (whence == SEEK_CUR) {
145
        offset1 = pos + (s->buf_ptr - s->buffer);
146
        if (offset == 0)
147
            return offset1;
148
        offset += offset1;
149
    }
150
    offset1 = offset - pos;
151
    if (!s->must_flush &&
152
        offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
153
        /* can do the seek inside the buffer */
154
        s->buf_ptr = s->buffer + offset1;
155
    } else if(s->is_streamed && !s->write_flag && offset1 >= 0 &&
156
              (whence != SEEK_END || force)) {
157
        while(s->pos < offset && !s->eof_reached)
158
            fill_buffer(s);
159
        if (s->eof_reached)
160
            return AVERROR_EOF;
161
        s->buf_ptr = s->buf_end + offset - s->pos;
162
    } else {
163
        int64_t res = AVERROR(EPIPE);
164

    
165
#if CONFIG_MUXERS || CONFIG_NETWORK
166
        if (s->write_flag) {
167
            flush_buffer(s);
168
            s->must_flush = 1;
169
        }
170
#endif /* CONFIG_MUXERS || CONFIG_NETWORK */
171
        if (!s->seek || (res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
172
            return res;
173
        if (!s->write_flag)
174
            s->buf_end = s->buffer;
175
        s->buf_ptr = s->buffer;
176
        s->pos = offset;
177
    }
178
    s->eof_reached = 0;
179
    return offset;
180
}
181

    
182
void url_fskip(ByteIOContext *s, int64_t offset)
183
{
184
    url_fseek(s, offset, SEEK_CUR);
185
}
186

    
187
int64_t url_ftell(ByteIOContext *s)
188
{
189
    return url_fseek(s, 0, SEEK_CUR);
190
}
191

    
192
int64_t url_fsize(ByteIOContext *s)
193
{
194
    int64_t size;
195

    
196
    if(!s)
197
        return AVERROR(EINVAL);
198

    
199
    if (!s->seek)
200
        return AVERROR(EPIPE);
201
    size = s->seek(s->opaque, 0, AVSEEK_SIZE);
202
    if(size<0){
203
        if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
204
            return size;
205
        size++;
206
        s->seek(s->opaque, s->pos, SEEK_SET);
207
    }
208
    return size;
209
}
210

    
211
int url_feof(ByteIOContext *s)
212
{
213
    if(!s)
214
        return 0;
215
    return s->eof_reached;
216
}
217

    
218
int url_ferror(ByteIOContext *s)
219
{
220
    if(!s)
221
        return 0;
222
    return s->error;
223
}
224

    
225
void put_le32(ByteIOContext *s, unsigned int val)
226
{
227
    put_byte(s, val);
228
    put_byte(s, val >> 8);
229
    put_byte(s, val >> 16);
230
    put_byte(s, val >> 24);
231
}
232

    
233
void put_be32(ByteIOContext *s, unsigned int val)
234
{
235
    put_byte(s, val >> 24);
236
    put_byte(s, val >> 16);
237
    put_byte(s, val >> 8);
238
    put_byte(s, val);
239
}
240

    
241
void put_strz(ByteIOContext *s, const char *str)
242
{
243
    if (str)
244
        put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
245
    else
246
        put_byte(s, 0);
247
}
248

    
249
void put_le64(ByteIOContext *s, uint64_t val)
250
{
251
    put_le32(s, (uint32_t)(val & 0xffffffff));
252
    put_le32(s, (uint32_t)(val >> 32));
253
}
254

    
255
void put_be64(ByteIOContext *s, uint64_t val)
256
{
257
    put_be32(s, (uint32_t)(val >> 32));
258
    put_be32(s, (uint32_t)(val & 0xffffffff));
259
}
260

    
261
void put_le16(ByteIOContext *s, unsigned int val)
262
{
263
    put_byte(s, val);
264
    put_byte(s, val >> 8);
265
}
266

    
267
void put_be16(ByteIOContext *s, unsigned int val)
268
{
269
    put_byte(s, val >> 8);
270
    put_byte(s, val);
271
}
272

    
273
void put_le24(ByteIOContext *s, unsigned int val)
274
{
275
    put_le16(s, val & 0xffff);
276
    put_byte(s, val >> 16);
277
}
278

    
279
void put_be24(ByteIOContext *s, unsigned int val)
280
{
281
    put_be16(s, val >> 8);
282
    put_byte(s, val);
283
}
284

    
285
void put_tag(ByteIOContext *s, const char *tag)
286
{
287
    while (*tag) {
288
        put_byte(s, *tag++);
289
    }
290
}
291

    
292
/* Input stream */
293

    
294
static void fill_buffer(ByteIOContext *s)
295
{
296
    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : s->buffer;
297
    int len= s->buffer_size - (dst - s->buffer);
298
    int max_buffer_size = s->max_packet_size ? s->max_packet_size : IO_BUFFER_SIZE;
299

    
300
    assert(s->buf_ptr == s->buf_end);
301

    
302
    /* no need to do anything if EOF already reached */
303
    if (s->eof_reached)
304
        return;
305

    
306
    if(s->update_checksum && dst == s->buffer){
307
        if(s->buf_end > s->checksum_ptr)
308
            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
309
        s->checksum_ptr= s->buffer;
310
    }
311

    
312
    /* make buffer smaller in case it ended up large after probing */
313
    if (s->buffer_size > max_buffer_size) {
314
        url_setbufsize(s, max_buffer_size);
315

    
316
        s->checksum_ptr = dst = s->buffer;
317
        len = s->buffer_size;
318
    }
319

    
320
    if(s->read_packet)
321
        len = s->read_packet(s->opaque, dst, len);
322
    else
323
        len = 0;
324
    if (len <= 0) {
325
        /* do not modify buffer if EOF reached so that a seek back can
326
           be done without rereading data */
327
        s->eof_reached = 1;
328
        if(len<0)
329
            s->error= len;
330
    } else {
331
        s->pos += len;
332
        s->buf_ptr = dst;
333
        s->buf_end = dst + len;
334
    }
335
}
336

    
337
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
338
                                    unsigned int len)
339
{
340
    return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
341
}
342

    
343
unsigned long get_checksum(ByteIOContext *s)
344
{
345
    s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
346
    s->update_checksum= NULL;
347
    return s->checksum;
348
}
349

    
350
void init_checksum(ByteIOContext *s,
351
                   unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
352
                   unsigned long checksum)
353
{
354
    s->update_checksum= update_checksum;
355
    if(s->update_checksum){
356
        s->checksum= checksum;
357
        s->checksum_ptr= s->buf_ptr;
358
    }
359
}
360

    
361
/* XXX: put an inline version */
362
int get_byte(ByteIOContext *s)
363
{
364
    if (s->buf_ptr < s->buf_end) {
365
        return *s->buf_ptr++;
366
    } else {
367
        fill_buffer(s);
368
        if (s->buf_ptr < s->buf_end)
369
            return *s->buf_ptr++;
370
        else
371
            return 0;
372
    }
373
}
374

    
375
int url_fgetc(ByteIOContext *s)
376
{
377
    if (s->buf_ptr < s->buf_end) {
378
        return *s->buf_ptr++;
379
    } else {
380
        fill_buffer(s);
381
        if (s->buf_ptr < s->buf_end)
382
            return *s->buf_ptr++;
383
        else
384
            return URL_EOF;
385
    }
386
}
387

    
388
int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
389
{
390
    int len, size1;
391

    
392
    size1 = size;
393
    while (size > 0) {
394
        len = s->buf_end - s->buf_ptr;
395
        if (len > size)
396
            len = size;
397
        if (len == 0) {
398
            if(size > s->buffer_size && !s->update_checksum){
399
                if(s->read_packet)
400
                    len = s->read_packet(s->opaque, buf, size);
401
                if (len <= 0) {
402
                    /* do not modify buffer if EOF reached so that a seek back can
403
                    be done without rereading data */
404
                    s->eof_reached = 1;
405
                    if(len<0)
406
                        s->error= len;
407
                    break;
408
                } else {
409
                    s->pos += len;
410
                    size -= len;
411
                    buf += len;
412
                    s->buf_ptr = s->buffer;
413
                    s->buf_end = s->buffer/* + len*/;
414
                }
415
            }else{
416
                fill_buffer(s);
417
                len = s->buf_end - s->buf_ptr;
418
                if (len == 0)
419
                    break;
420
            }
421
        } else {
422
            memcpy(buf, s->buf_ptr, len);
423
            buf += len;
424
            s->buf_ptr += len;
425
            size -= len;
426
        }
427
    }
428
    if (size1 == size) {
429
        if (url_ferror(s)) return url_ferror(s);
430
        if (url_feof(s))   return AVERROR_EOF;
431
    }
432
    return size1 - size;
433
}
434

    
435
int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
436
{
437
    int len;
438

    
439
    if(size<0)
440
        return -1;
441

    
442
    len = s->buf_end - s->buf_ptr;
443
    if (len == 0) {
444
        fill_buffer(s);
445
        len = s->buf_end - s->buf_ptr;
446
    }
447
    if (len > size)
448
        len = size;
449
    memcpy(buf, s->buf_ptr, len);
450
    s->buf_ptr += len;
451
    if (!len) {
452
        if (url_ferror(s)) return url_ferror(s);
453
        if (url_feof(s))   return AVERROR_EOF;
454
    }
455
    return len;
456
}
457

    
458
unsigned int get_le16(ByteIOContext *s)
459
{
460
    unsigned int val;
461
    val = get_byte(s);
462
    val |= get_byte(s) << 8;
463
    return val;
464
}
465

    
466
unsigned int get_le24(ByteIOContext *s)
467
{
468
    unsigned int val;
469
    val = get_le16(s);
470
    val |= get_byte(s) << 16;
471
    return val;
472
}
473

    
474
unsigned int get_le32(ByteIOContext *s)
475
{
476
    unsigned int val;
477
    val = get_le16(s);
478
    val |= get_le16(s) << 16;
479
    return val;
480
}
481

    
482
uint64_t get_le64(ByteIOContext *s)
483
{
484
    uint64_t val;
485
    val = (uint64_t)get_le32(s);
486
    val |= (uint64_t)get_le32(s) << 32;
487
    return val;
488
}
489

    
490
unsigned int get_be16(ByteIOContext *s)
491
{
492
    unsigned int val;
493
    val = get_byte(s) << 8;
494
    val |= get_byte(s);
495
    return val;
496
}
497

    
498
unsigned int get_be24(ByteIOContext *s)
499
{
500
    unsigned int val;
501
    val = get_be16(s) << 8;
502
    val |= get_byte(s);
503
    return val;
504
}
505
unsigned int get_be32(ByteIOContext *s)
506
{
507
    unsigned int val;
508
    val = get_be16(s) << 16;
509
    val |= get_be16(s);
510
    return val;
511
}
512

    
513
char *get_strz(ByteIOContext *s, char *buf, int maxlen)
514
{
515
    int i = 0;
516
    char c;
517

    
518
    while ((c = get_byte(s))) {
519
        if (i < maxlen-1)
520
            buf[i++] = c;
521
    }
522

    
523
    buf[i] = 0; /* Ensure null terminated, but may be truncated */
524

    
525
    return buf;
526
}
527

    
528
uint64_t get_be64(ByteIOContext *s)
529
{
530
    uint64_t val;
531
    val = (uint64_t)get_be32(s) << 32;
532
    val |= (uint64_t)get_be32(s);
533
    return val;
534
}
535

    
536
uint64_t ff_get_v(ByteIOContext *bc){
537
    uint64_t val = 0;
538
    int tmp;
539

    
540
    do{
541
        tmp = get_byte(bc);
542
        val= (val<<7) + (tmp&127);
543
    }while(tmp&128);
544
    return val;
545
}
546

    
547
int url_fdopen(ByteIOContext **s, URLContext *h)
548
{
549
    uint8_t *buffer;
550
    int buffer_size, max_packet_size;
551

    
552
    max_packet_size = url_get_max_packet_size(h);
553
    if (max_packet_size) {
554
        buffer_size = max_packet_size; /* no need to bufferize more than one packet */
555
    } else {
556
        buffer_size = IO_BUFFER_SIZE;
557
    }
558
    buffer = av_malloc(buffer_size);
559
    if (!buffer)
560
        return AVERROR(ENOMEM);
561

    
562
    *s = av_mallocz(sizeof(ByteIOContext));
563
    if(!*s) {
564
        av_free(buffer);
565
        return AVERROR(ENOMEM);
566
    }
567

    
568
    if (init_put_byte(*s, buffer, buffer_size,
569
                      (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
570
                      url_read, url_write, url_seek) < 0) {
571
        av_free(buffer);
572
        av_freep(s);
573
        return AVERROR(EIO);
574
    }
575
    (*s)->is_streamed = h->is_streamed;
576
    (*s)->max_packet_size = max_packet_size;
577
    if(h->prot) {
578
        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
579
        (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
580
    }
581
    return 0;
582
}
583

    
584
int url_setbufsize(ByteIOContext *s, int buf_size)
585
{
586
    uint8_t *buffer;
587
    buffer = av_malloc(buf_size);
588
    if (!buffer)
589
        return AVERROR(ENOMEM);
590

    
591
    av_free(s->buffer);
592
    s->buffer = buffer;
593
    s->buffer_size = buf_size;
594
    s->buf_ptr = buffer;
595
    url_resetbuf(s, s->write_flag ? URL_WRONLY : URL_RDONLY);
596
    return 0;
597
}
598

    
599
#if LIBAVFORMAT_VERSION_MAJOR < 53
600
int url_resetbuf(ByteIOContext *s, int flags)
601
#else
602
static int url_resetbuf(ByteIOContext *s, int flags)
603
#endif
604
{
605
#if LIBAVFORMAT_VERSION_MAJOR < 53
606
    URLContext *h = s->opaque;
607
    if ((flags & URL_RDWR) || (h && h->flags != flags && !h->flags & URL_RDWR))
608
        return AVERROR(EINVAL);
609
#else
610
    assert(flags == URL_WRONLY || flags == URL_RDONLY);
611
#endif
612

    
613
    if (flags & URL_WRONLY) {
614
        s->buf_end = s->buffer + s->buffer_size;
615
        s->write_flag = 1;
616
    } else {
617
        s->buf_end = s->buffer;
618
        s->write_flag = 0;
619
    }
620
    return 0;
621
}
622

    
623
int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size)
624
{
625
    int64_t buffer_start;
626
    int buffer_size;
627
    int overlap, new_size;
628

    
629
    if (s->write_flag)
630
        return AVERROR(EINVAL);
631

    
632
    buffer_size = s->buf_end - s->buffer;
633

    
634
    /* the buffers must touch or overlap */
635
    if ((buffer_start = s->pos - buffer_size) > buf_size)
636
        return AVERROR(EINVAL);
637

    
638
    overlap = buf_size - buffer_start;
639
    new_size = buf_size + buffer_size - overlap;
640

    
641
    if (new_size > buf_size) {
642
        if (!(buf = av_realloc(buf, new_size)))
643
            return AVERROR(ENOMEM);
644

    
645
        memcpy(buf + buf_size, s->buffer + overlap, buffer_size - overlap);
646
        buf_size = new_size;
647
    }
648

    
649
    av_free(s->buffer);
650
    s->buf_ptr = s->buffer = buf;
651
    s->pos = s->buffer_size = buf_size;
652
    s->buf_end = s->buf_ptr + buf_size;
653
    s->eof_reached = 0;
654
    s->must_flush = 0;
655

    
656
    return 0;
657
}
658

    
659
int url_fopen(ByteIOContext **s, const char *filename, int flags)
660
{
661
    URLContext *h;
662
    int err;
663

    
664
    err = url_open(&h, filename, flags);
665
    if (err < 0)
666
        return err;
667
    err = url_fdopen(s, h);
668
    if (err < 0) {
669
        url_close(h);
670
        return err;
671
    }
672
    return 0;
673
}
674

    
675
int url_fclose(ByteIOContext *s)
676
{
677
    URLContext *h = s->opaque;
678

    
679
    av_free(s->buffer);
680
    av_free(s);
681
    return url_close(h);
682
}
683

    
684
URLContext *url_fileno(ByteIOContext *s)
685
{
686
    return s->opaque;
687
}
688

    
689
#if CONFIG_MUXERS
690
int url_fprintf(ByteIOContext *s, const char *fmt, ...)
691
{
692
    va_list ap;
693
    char buf[4096];
694
    int ret;
695

    
696
    va_start(ap, fmt);
697
    ret = vsnprintf(buf, sizeof(buf), fmt, ap);
698
    va_end(ap);
699
    put_buffer(s, buf, strlen(buf));
700
    return ret;
701
}
702
#endif //CONFIG_MUXERS
703

    
704
char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
705
{
706
    int c;
707
    char *q;
708

    
709
    c = url_fgetc(s);
710
    if (c == EOF)
711
        return NULL;
712
    q = buf;
713
    for(;;) {
714
        if (c == EOF || c == '\n')
715
            break;
716
        if ((q - buf) < buf_size - 1)
717
            *q++ = c;
718
        c = url_fgetc(s);
719
    }
720
    if (buf_size > 0)
721
        *q = '\0';
722
    return buf;
723
}
724

    
725
int url_fget_max_packet_size(ByteIOContext *s)
726
{
727
    return s->max_packet_size;
728
}
729

    
730
int av_url_read_fpause(ByteIOContext *s, int pause)
731
{
732
    if (!s->read_pause)
733
        return AVERROR(ENOSYS);
734
    return s->read_pause(s->opaque, pause);
735
}
736

    
737
int64_t av_url_read_fseek(ByteIOContext *s, int stream_index,
738
                          int64_t timestamp, int flags)
739
{
740
    URLContext *h = s->opaque;
741
    int64_t ret;
742
    if (!s->read_seek)
743
        return AVERROR(ENOSYS);
744
    ret = s->read_seek(h, stream_index, timestamp, flags);
745
    if(ret >= 0) {
746
        int64_t pos;
747
        s->buf_ptr = s->buf_end; // Flush buffer
748
        pos = s->seek(h, 0, SEEK_CUR);
749
        if (pos >= 0)
750
            s->pos = pos;
751
        else if (pos != AVERROR(ENOSYS))
752
            ret = pos;
753
    }
754
    return ret;
755
}
756

    
757
/* url_open_dyn_buf and url_close_dyn_buf are used in rtp.c to send a response
758
 * back to the server even if CONFIG_MUXERS is false. */
759
#if CONFIG_MUXERS || CONFIG_NETWORK
760
/* buffer handling */
761
int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags)
762
{
763
    int ret;
764
    *s = av_mallocz(sizeof(ByteIOContext));
765
    if(!*s)
766
        return AVERROR(ENOMEM);
767
    ret = init_put_byte(*s, buf, buf_size,
768
                        (flags & URL_WRONLY || flags & URL_RDWR),
769
                        NULL, NULL, NULL, NULL);
770
    if(ret != 0)
771
        av_freep(s);
772
    return ret;
773
}
774

    
775
int url_close_buf(ByteIOContext *s)
776
{
777
    put_flush_packet(s);
778
    return s->buf_ptr - s->buffer;
779
}
780

    
781
/* output in a dynamic buffer */
782

    
783
typedef struct DynBuffer {
784
    int pos, size, allocated_size;
785
    uint8_t *buffer;
786
    int io_buffer_size;
787
    uint8_t io_buffer[1];
788
} DynBuffer;
789

    
790
static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
791
{
792
    DynBuffer *d = opaque;
793
    unsigned new_size, new_allocated_size;
794

    
795
    /* reallocate buffer if needed */
796
    new_size = d->pos + buf_size;
797
    new_allocated_size = d->allocated_size;
798
    if(new_size < d->pos || new_size > INT_MAX/2)
799
        return -1;
800
    while (new_size > new_allocated_size) {
801
        if (!new_allocated_size)
802
            new_allocated_size = new_size;
803
        else
804
            new_allocated_size += new_allocated_size / 2 + 1;
805
    }
806

    
807
    if (new_allocated_size > d->allocated_size) {
808
        d->buffer = av_realloc(d->buffer, new_allocated_size);
809
        if(d->buffer == NULL)
810
             return AVERROR(ENOMEM);
811
        d->allocated_size = new_allocated_size;
812
    }
813
    memcpy(d->buffer + d->pos, buf, buf_size);
814
    d->pos = new_size;
815
    if (d->pos > d->size)
816
        d->size = d->pos;
817
    return buf_size;
818
}
819

    
820
static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
821
{
822
    unsigned char buf1[4];
823
    int ret;
824

    
825
    /* packetized write: output the header */
826
    AV_WB32(buf1, buf_size);
827
    ret= dyn_buf_write(opaque, buf1, 4);
828
    if(ret < 0)
829
        return ret;
830

    
831
    /* then the data */
832
    return dyn_buf_write(opaque, buf, buf_size);
833
}
834

    
835
static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
836
{
837
    DynBuffer *d = opaque;
838

    
839
    if (whence == SEEK_CUR)
840
        offset += d->pos;
841
    else if (whence == SEEK_END)
842
        offset += d->size;
843
    if (offset < 0 || offset > 0x7fffffffLL)
844
        return -1;
845
    d->pos = offset;
846
    return 0;
847
}
848

    
849
static int url_open_dyn_buf_internal(ByteIOContext **s, int max_packet_size)
850
{
851
    DynBuffer *d;
852
    int ret;
853
    unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
854

    
855
    if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
856
        return -1;
857
    d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
858
    if (!d)
859
        return AVERROR(ENOMEM);
860
    *s = av_mallocz(sizeof(ByteIOContext));
861
    if(!*s) {
862
        av_free(d);
863
        return AVERROR(ENOMEM);
864
    }
865
    d->io_buffer_size = io_buffer_size;
866
    ret = init_put_byte(*s, d->io_buffer, io_buffer_size,
867
                        1, d, NULL,
868
                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
869
                        max_packet_size ? NULL : dyn_buf_seek);
870
    if (ret == 0) {
871
        (*s)->max_packet_size = max_packet_size;
872
    } else {
873
        av_free(d);
874
        av_freep(s);
875
    }
876
    return ret;
877
}
878

    
879
int url_open_dyn_buf(ByteIOContext **s)
880
{
881
    return url_open_dyn_buf_internal(s, 0);
882
}
883

    
884
int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size)
885
{
886
    if (max_packet_size <= 0)
887
        return -1;
888
    return url_open_dyn_buf_internal(s, max_packet_size);
889
}
890

    
891
int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
892
{
893
    DynBuffer *d = s->opaque;
894
    int size;
895

    
896
    put_flush_packet(s);
897

    
898
    *pbuffer = d->buffer;
899
    size = d->size;
900
    av_free(d);
901
    av_free(s);
902
    return size;
903
}
904
#endif /* CONFIG_MUXERS || CONFIG_NETWORK */