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
30static void fill_buffer(ByteIOContext *s);
31#if LIBAVFORMAT_VERSION_MAJOR >= 53
32static int url_resetbuf(ByteIOContext *s, int flags);
33#endif
34
35int 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
68ByteIOContext *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
83static 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
101void 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
108void 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
123void put_flush_packet(ByteIOContext *s)
124{
125    flush_buffer(s);
126    s->must_flush = 0;
127}
128
129int64_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;
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)
172            return AVERROR(EPIPE);
173        if ((res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
174            return res;
175        if (!s->write_flag)
176            s->buf_end = s->buffer;
177        s->buf_ptr = s->buffer;
178        s->pos = offset;
179    }
180    s->eof_reached = 0;
181    return offset;
182}
183
184void url_fskip(ByteIOContext *s, int64_t offset)
185{
186    url_fseek(s, offset, SEEK_CUR);
187}
188
189int64_t url_ftell(ByteIOContext *s)
190{
191    return url_fseek(s, 0, SEEK_CUR);
192}
193
194int64_t url_fsize(ByteIOContext *s)
195{
196    int64_t size;
197
198    if(!s)
199        return AVERROR(EINVAL);
200
201    if (!s->seek)
202        return AVERROR(ENOSYS);
203    size = s->seek(s->opaque, 0, AVSEEK_SIZE);
204    if(size<0){
205        if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
206            return size;
207        size++;
208        s->seek(s->opaque, s->pos, SEEK_SET);
209    }
210    return size;
211}
212
213int url_feof(ByteIOContext *s)
214{
215    if(!s)
216        return 0;
217    return s->eof_reached;
218}
219
220int url_ferror(ByteIOContext *s)
221{
222    if(!s)
223        return 0;
224    return s->error;
225}
226
227void put_le32(ByteIOContext *s, unsigned int val)
228{
229    put_byte(s, val);
230    put_byte(s, val >> 8);
231    put_byte(s, val >> 16);
232    put_byte(s, val >> 24);
233}
234
235void put_be32(ByteIOContext *s, unsigned int val)
236{
237    put_byte(s, val >> 24);
238    put_byte(s, val >> 16);
239    put_byte(s, val >> 8);
240    put_byte(s, val);
241}
242
243void put_strz(ByteIOContext *s, const char *str)
244{
245    if (str)
246        put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
247    else
248        put_byte(s, 0);
249}
250
251void put_le64(ByteIOContext *s, uint64_t val)
252{
253    put_le32(s, (uint32_t)(val & 0xffffffff));
254    put_le32(s, (uint32_t)(val >> 32));
255}
256
257void put_be64(ByteIOContext *s, uint64_t val)
258{
259    put_be32(s, (uint32_t)(val >> 32));
260    put_be32(s, (uint32_t)(val & 0xffffffff));
261}
262
263void put_le16(ByteIOContext *s, unsigned int val)
264{
265    put_byte(s, val);
266    put_byte(s, val >> 8);
267}
268
269void put_be16(ByteIOContext *s, unsigned int val)
270{
271    put_byte(s, val >> 8);
272    put_byte(s, val);
273}
274
275void put_le24(ByteIOContext *s, unsigned int val)
276{
277    put_le16(s, val & 0xffff);
278    put_byte(s, val >> 16);
279}
280
281void put_be24(ByteIOContext *s, unsigned int val)
282{
283    put_be16(s, val >> 8);
284    put_byte(s, val);
285}
286
287void put_tag(ByteIOContext *s, const char *tag)
288{
289    while (*tag) {
290        put_byte(s, *tag++);
291    }
292}
293
294/* Input stream */
295
296static void fill_buffer(ByteIOContext *s)
297{
298    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : s->buffer;
299    int len= s->buffer_size - (dst - s->buffer);
300    int max_buffer_size = s->max_packet_size ? s->max_packet_size : IO_BUFFER_SIZE;
301
302    assert(s->buf_ptr == s->buf_end);
303
304    /* no need to do anything if EOF already reached */
305    if (s->eof_reached)
306        return;
307
308    if(s->update_checksum && dst == s->buffer){
309        if(s->buf_end > s->checksum_ptr)
310            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
311        s->checksum_ptr= s->buffer;
312    }
313
314    /* make buffer smaller in case it ended up large after probing */
315    if (s->buffer_size > max_buffer_size) {
316        url_setbufsize(s, max_buffer_size);
317
318        s->checksum_ptr = dst = s->buffer;
319        len = s->buffer_size;
320    }
321
322    if(s->read_packet)
323        len = s->read_packet(s->opaque, dst, len);
324    else
325        len = 0;
326    if (len <= 0) {
327        /* do not modify buffer if EOF reached so that a seek back can
328           be done without rereading data */
329        s->eof_reached = 1;
330        if(len<0)
331            s->error= len;
332    } else {
333        s->pos += len;
334        s->buf_ptr = dst;
335        s->buf_end = dst + len;
336    }
337}
338
339unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
340                                    unsigned int len)
341{
342    return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
343}
344
345unsigned long get_checksum(ByteIOContext *s)
346{
347    s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
348    s->update_checksum= NULL;
349    return s->checksum;
350}
351
352void init_checksum(ByteIOContext *s,
353                   unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
354                   unsigned long checksum)
355{
356    s->update_checksum= update_checksum;
357    if(s->update_checksum){
358        s->checksum= checksum;
359        s->checksum_ptr= s->buf_ptr;
360    }
361}
362
363/* XXX: put an inline version */
364int get_byte(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 0;
374    }
375}
376
377int url_fgetc(ByteIOContext *s)
378{
379    if (s->buf_ptr < s->buf_end) {
380        return *s->buf_ptr++;
381    } else {
382        fill_buffer(s);
383        if (s->buf_ptr < s->buf_end)
384            return *s->buf_ptr++;
385        else
386            return URL_EOF;
387    }
388}
389
390int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
391{
392    int len, size1;
393
394    size1 = size;
395    while (size > 0) {
396        len = s->buf_end - s->buf_ptr;
397        if (len > size)
398            len = size;
399        if (len == 0) {
400            if(size > s->buffer_size && !s->update_checksum){
401                if(s->read_packet)
402                    len = s->read_packet(s->opaque, buf, size);
403                if (len <= 0) {
404                    /* do not modify buffer if EOF reached so that a seek back can
405                    be done without rereading data */
406                    s->eof_reached = 1;
407                    if(len<0)
408                        s->error= len;
409                    break;
410                } else {
411                    s->pos += len;
412                    size -= len;
413                    buf += len;
414                    s->buf_ptr = s->buffer;
415                    s->buf_end = s->buffer/* + len*/;
416                }
417            }else{
418                fill_buffer(s);
419                len = s->buf_end - s->buf_ptr;
420                if (len == 0)
421                    break;
422            }
423        } else {
424            memcpy(buf, s->buf_ptr, len);
425            buf += len;
426            s->buf_ptr += len;
427            size -= len;
428        }
429    }
430    if (size1 == size) {
431        if (url_ferror(s)) return url_ferror(s);
432        if (url_feof(s))   return AVERROR_EOF;
433    }
434    return size1 - size;
435}
436
437int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
438{
439    int len;
440
441    if(size<0)
442        return -1;
443
444    len = s->buf_end - s->buf_ptr;
445    if (len == 0) {
446        fill_buffer(s);
447        len = s->buf_end - s->buf_ptr;
448    }
449    if (len > size)
450        len = size;
451    memcpy(buf, s->buf_ptr, len);
452    s->buf_ptr += len;
453    if (!len) {
454        if (url_ferror(s)) return url_ferror(s);
455        if (url_feof(s))   return AVERROR_EOF;
456    }
457    return len;
458}
459
460unsigned int get_le16(ByteIOContext *s)
461{
462    unsigned int val;
463    val = get_byte(s);
464    val |= get_byte(s) << 8;
465    return val;
466}
467
468unsigned int get_le24(ByteIOContext *s)
469{
470    unsigned int val;
471    val = get_le16(s);
472    val |= get_byte(s) << 16;
473    return val;
474}
475
476unsigned int get_le32(ByteIOContext *s)
477{
478    unsigned int val;
479    val = get_le16(s);
480    val |= get_le16(s) << 16;
481    return val;
482}
483
484uint64_t get_le64(ByteIOContext *s)
485{
486    uint64_t val;
487    val = (uint64_t)get_le32(s);
488    val |= (uint64_t)get_le32(s) << 32;
489    return val;
490}
491
492unsigned int get_be16(ByteIOContext *s)
493{
494    unsigned int val;
495    val = get_byte(s) << 8;
496    val |= get_byte(s);
497    return val;
498}
499
500unsigned int get_be24(ByteIOContext *s)
501{
502    unsigned int val;
503    val = get_be16(s) << 8;
504    val |= get_byte(s);
505    return val;
506}
507unsigned int get_be32(ByteIOContext *s)
508{
509    unsigned int val;
510    val = get_be16(s) << 16;
511    val |= get_be16(s);
512    return val;
513}
514
515char *get_strz(ByteIOContext *s, char *buf, int maxlen)
516{
517    int i = 0;
518    char c;
519
520    while ((c = get_byte(s))) {
521        if (i < maxlen-1)
522            buf[i++] = c;
523    }
524
525    buf[i] = 0; /* Ensure null terminated, but may be truncated */
526
527    return buf;
528}
529
530uint64_t get_be64(ByteIOContext *s)
531{
532    uint64_t val;
533    val = (uint64_t)get_be32(s) << 32;
534    val |= (uint64_t)get_be32(s);
535    return val;
536}
537
538uint64_t ff_get_v(ByteIOContext *bc){
539    uint64_t val = 0;
540    int tmp;
541
542    do{
543        tmp = get_byte(bc);
544        val= (val<<7) + (tmp&127);
545    }while(tmp&128);
546    return val;
547}
548
549int url_fdopen(ByteIOContext **s, URLContext *h)
550{
551    uint8_t *buffer;
552    int buffer_size, max_packet_size;
553
554    max_packet_size = url_get_max_packet_size(h);
555    if (max_packet_size) {
556        buffer_size = max_packet_size; /* no need to bufferize more than one packet */
557    } else {
558        buffer_size = IO_BUFFER_SIZE;
559    }
560    buffer = av_malloc(buffer_size);
561    if (!buffer)
562        return AVERROR(ENOMEM);
563
564    *s = av_mallocz(sizeof(ByteIOContext));
565    if(!*s) {
566        av_free(buffer);
567        return AVERROR(ENOMEM);
568    }
569
570    if (init_put_byte(*s, buffer, buffer_size,
571                      (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
572                      url_read, url_write, url_seek) < 0) {
573        av_free(buffer);
574        av_freep(s);
575        return AVERROR(EIO);
576    }
577    (*s)->is_streamed = h->is_streamed;
578    (*s)->max_packet_size = max_packet_size;
579    if(h->prot) {
580        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
581        (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
582    }
583    return 0;
584}
585
586int url_setbufsize(ByteIOContext *s, int buf_size)
587{
588    uint8_t *buffer;
589    buffer = av_malloc(buf_size);
590    if (!buffer)
591        return AVERROR(ENOMEM);
592
593    av_free(s->buffer);
594    s->buffer = buffer;
595    s->buffer_size = buf_size;
596    s->buf_ptr = buffer;
597    url_resetbuf(s, s->write_flag ? URL_WRONLY : URL_RDONLY);
598    return 0;
599}
600
601#if LIBAVFORMAT_VERSION_MAJOR < 53
602int url_resetbuf(ByteIOContext *s, int flags)
603#else
604static int url_resetbuf(ByteIOContext *s, int flags)
605#endif
606{
607#if LIBAVFORMAT_VERSION_MAJOR < 53
608    URLContext *h = s->opaque;
609    if ((flags & URL_RDWR) || (h && h->flags != flags && !h->flags & URL_RDWR))
610        return AVERROR(EINVAL);
611#else
612    assert(flags == URL_WRONLY || flags == URL_RDONLY);
613#endif
614
615    if (flags & URL_WRONLY) {
616        s->buf_end = s->buffer + s->buffer_size;
617        s->write_flag = 1;
618    } else {
619        s->buf_end = s->buffer;
620        s->write_flag = 0;
621    }
622    return 0;
623}
624
625int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size)
626{
627    int64_t buffer_start;
628    int buffer_size;
629    int overlap, new_size;
630
631    if (s->write_flag)
632        return AVERROR(EINVAL);
633
634    buffer_size = s->buf_end - s->buffer;
635
636    /* the buffers must touch or overlap */
637    if ((buffer_start = s->pos - buffer_size) > buf_size)
638        return AVERROR(EINVAL);
639
640    overlap = buf_size - buffer_start;
641    new_size = buf_size + buffer_size - overlap;
642
643    if (new_size > buf_size) {
644        if (!(buf = av_realloc(buf, new_size)))
645            return AVERROR(ENOMEM);
646
647        memcpy(buf + buf_size, s->buffer + overlap, buffer_size - overlap);
648        buf_size = new_size;
649    }
650
651    av_free(s->buffer);
652    s->buf_ptr = s->buffer = buf;
653    s->pos = s->buffer_size = buf_size;
654    s->buf_end = s->buf_ptr + buf_size;
655    s->eof_reached = 0;
656    s->must_flush = 0;
657
658    return 0;
659}
660
661int url_fopen(ByteIOContext **s, const char *filename, int flags)
662{
663    URLContext *h;
664    int err;
665
666    err = url_open(&h, filename, flags);
667    if (err < 0)
668        return err;
669    err = url_fdopen(s, h);
670    if (err < 0) {
671        url_close(h);
672        return err;
673    }
674    return 0;
675}
676
677int url_fclose(ByteIOContext *s)
678{
679    URLContext *h = s->opaque;
680
681    av_free(s->buffer);
682    av_free(s);
683    return url_close(h);
684}
685
686URLContext *url_fileno(ByteIOContext *s)
687{
688    return s->opaque;
689}
690
691#if CONFIG_MUXERS
692int url_fprintf(ByteIOContext *s, const char *fmt, ...)
693{
694    va_list ap;
695    char buf[4096];
696    int ret;
697
698    va_start(ap, fmt);
699    ret = vsnprintf(buf, sizeof(buf), fmt, ap);
700    va_end(ap);
701    put_buffer(s, buf, strlen(buf));
702    return ret;
703}
704#endif //CONFIG_MUXERS
705
706char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
707{
708    int c;
709    char *q;
710
711    c = url_fgetc(s);
712    if (c == EOF)
713        return NULL;
714    q = buf;
715    for(;;) {
716        if (c == EOF || c == '\n')
717            break;
718        if ((q - buf) < buf_size - 1)
719            *q++ = c;
720        c = url_fgetc(s);
721    }
722    if (buf_size > 0)
723        *q = '\0';
724    return buf;
725}
726
727int url_fget_max_packet_size(ByteIOContext *s)
728{
729    return s->max_packet_size;
730}
731
732int av_url_read_fpause(ByteIOContext *s, int pause)
733{
734    if (!s->read_pause)
735        return AVERROR(ENOSYS);
736    return s->read_pause(s->opaque, pause);
737}
738
739int64_t av_url_read_fseek(ByteIOContext *s, int stream_index,
740                          int64_t timestamp, int flags)
741{
742    URLContext *h = s->opaque;
743    int64_t ret;
744    if (!s->read_seek)
745        return AVERROR(ENOSYS);
746    ret = s->read_seek(h, stream_index, timestamp, flags);
747    if(ret >= 0) {
748        int64_t pos;
749        s->buf_ptr = s->buf_end; // Flush buffer
750        pos = s->seek(h, 0, SEEK_CUR);
751        if (pos >= 0)
752            s->pos = pos;
753        else if (pos != AVERROR(ENOSYS))
754            ret = pos;
755    }
756    return ret;
757}
758
759/* url_open_dyn_buf and url_close_dyn_buf are used in rtp.c to send a response
760 * back to the server even if CONFIG_MUXERS is false. */
761#if CONFIG_MUXERS || CONFIG_NETWORK
762/* buffer handling */
763int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags)
764{
765    int ret;
766    *s = av_mallocz(sizeof(ByteIOContext));
767    if(!*s)
768        return AVERROR(ENOMEM);
769    ret = init_put_byte(*s, buf, buf_size,
770                        (flags & URL_WRONLY || flags & URL_RDWR),
771                        NULL, NULL, NULL, NULL);
772    if(ret != 0)
773        av_freep(s);
774    return ret;
775}
776
777int url_close_buf(ByteIOContext *s)
778{
779    put_flush_packet(s);
780    return s->buf_ptr - s->buffer;
781}
782
783/* output in a dynamic buffer */
784
785typedef struct DynBuffer {
786    int pos, size, allocated_size;
787    uint8_t *buffer;
788    int io_buffer_size;
789    uint8_t io_buffer[1];
790} DynBuffer;
791
792static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
793{
794    DynBuffer *d = opaque;
795    unsigned new_size, new_allocated_size;
796
797    /* reallocate buffer if needed */
798    new_size = d->pos + buf_size;
799    new_allocated_size = d->allocated_size;
800    if(new_size < d->pos || new_size > INT_MAX/2)
801        return -1;
802    while (new_size > new_allocated_size) {
803        if (!new_allocated_size)
804            new_allocated_size = new_size;
805        else
806            new_allocated_size += new_allocated_size / 2 + 1;
807    }
808
809    if (new_allocated_size > d->allocated_size) {
810        d->buffer = av_realloc(d->buffer, new_allocated_size);
811        if(d->buffer == NULL)
812             return AVERROR(ENOMEM);
813        d->allocated_size = new_allocated_size;
814    }
815    memcpy(d->buffer + d->pos, buf, buf_size);
816    d->pos = new_size;
817    if (d->pos > d->size)
818        d->size = d->pos;
819    return buf_size;
820}
821
822static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
823{
824    unsigned char buf1[4];
825    int ret;
826
827    /* packetized write: output the header */
828    AV_WB32(buf1, buf_size);
829    ret= dyn_buf_write(opaque, buf1, 4);
830    if(ret < 0)
831        return ret;
832
833    /* then the data */
834    return dyn_buf_write(opaque, buf, buf_size);
835}
836
837static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
838{
839    DynBuffer *d = opaque;
840
841    if (whence == SEEK_CUR)
842        offset += d->pos;
843    else if (whence == SEEK_END)
844        offset += d->size;
845    if (offset < 0 || offset > 0x7fffffffLL)
846        return -1;
847    d->pos = offset;
848    return 0;
849}
850
851static int url_open_dyn_buf_internal(ByteIOContext **s, int max_packet_size)
852{
853    DynBuffer *d;
854    int ret;
855    unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
856
857    if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
858        return -1;
859    d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
860    if (!d)
861        return AVERROR(ENOMEM);
862    *s = av_mallocz(sizeof(ByteIOContext));
863    if(!*s) {
864        av_free(d);
865        return AVERROR(ENOMEM);
866    }
867    d->io_buffer_size = io_buffer_size;
868    ret = init_put_byte(*s, d->io_buffer, io_buffer_size,
869                        1, d, NULL,
870                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
871                        max_packet_size ? NULL : dyn_buf_seek);
872    if (ret == 0) {
873        (*s)->max_packet_size = max_packet_size;
874    } else {
875        av_free(d);
876        av_freep(s);
877    }
878    return ret;
879}
880
881int url_open_dyn_buf(ByteIOContext **s)
882{
883    return url_open_dyn_buf_internal(s, 0);
884}
885
886int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size)
887{
888    if (max_packet_size <= 0)
889        return -1;
890    return url_open_dyn_buf_internal(s, max_packet_size);
891}
892
893int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
894{
895    DynBuffer *d = s->opaque;
896    int size;
897
898    put_flush_packet(s);
899
900    *pbuffer = d->buffer;
901    size = d->size;
902    av_free(d);
903    av_free(s);
904    return size;
905}
906#endif /* CONFIG_MUXERS || CONFIG_NETWORK */
907