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aviobuf.c
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1 /*
2  * buffered I/O
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/bprint.h"
23 #include "libavutil/crc.h"
24 #include "libavutil/dict.h"
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/log.h"
27 #include "libavutil/opt.h"
28 #include "libavutil/avassert.h"
29 #include "avformat.h"
30 #include "avio.h"
31 #include "avio_internal.h"
32 #include "internal.h"
33 #include "url.h"
34 #include <stdarg.h>
35 
36 #define IO_BUFFER_SIZE 32768
37 
38 /**
39  * Do seeks within this distance ahead of the current buffer by skipping
40  * data instead of calling the protocol seek function, for seekable
41  * protocols.
42  */
43 #define SHORT_SEEK_THRESHOLD 4096
44 
45 static void *ff_avio_child_next(void *obj, void *prev)
46 {
47  AVIOContext *s = obj;
48  return prev ? NULL : s->opaque;
49 }
50 
51 static const AVClass *ff_avio_child_class_next(const AVClass *prev)
52 {
53  return prev ? NULL : &ffurl_context_class;
54 }
55 
56 static const AVOption ff_avio_options[] = {
57  { NULL },
58 };
59 
61  .class_name = "AVIOContext",
62  .item_name = av_default_item_name,
63  .version = LIBAVUTIL_VERSION_INT,
64  .option = ff_avio_options,
65  .child_next = ff_avio_child_next,
66  .child_class_next = ff_avio_child_class_next,
67 };
68 
69 static void fill_buffer(AVIOContext *s);
70 static int url_resetbuf(AVIOContext *s, int flags);
71 
73  unsigned char *buffer,
74  int buffer_size,
75  int write_flag,
76  void *opaque,
77  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
78  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
79  int64_t (*seek)(void *opaque, int64_t offset, int whence))
80 {
81  s->buffer = buffer;
82  s->orig_buffer_size =
83  s->buffer_size = buffer_size;
84  s->buf_ptr = buffer;
85  s->opaque = opaque;
86  s->direct = 0;
87 
88  url_resetbuf(s, write_flag ? AVIO_FLAG_WRITE : AVIO_FLAG_READ);
89 
92  s->seek = seek;
93  s->pos = 0;
94  s->must_flush = 0;
95  s->eof_reached = 0;
96  s->error = 0;
97  s->seekable = seek ? AVIO_SEEKABLE_NORMAL : 0;
98  s->max_packet_size = 0;
99  s->update_checksum = NULL;
100 
101  if (!read_packet && !write_flag) {
102  s->pos = buffer_size;
103  s->buf_end = s->buffer + buffer_size;
104  }
105  s->read_pause = NULL;
106  s->read_seek = NULL;
107 
108  return 0;
109 }
110 
112  unsigned char *buffer,
113  int buffer_size,
114  int write_flag,
115  void *opaque,
116  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
117  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
118  int64_t (*seek)(void *opaque, int64_t offset, int whence))
119 {
120  AVIOContext *s = av_mallocz(sizeof(AVIOContext));
121  if (!s)
122  return NULL;
123  ffio_init_context(s, buffer, buffer_size, write_flag, opaque,
124  read_packet, write_packet, seek);
125  return s;
126 }
127 
128 static void writeout(AVIOContext *s, const uint8_t *data, int len)
129 {
130  if (s->write_packet && !s->error) {
131  int ret = s->write_packet(s->opaque, (uint8_t *)data, len);
132  if (ret < 0) {
133  s->error = ret;
134  }
135  }
136  s->writeout_count ++;
137  s->pos += len;
138 }
139 
140 static void flush_buffer(AVIOContext *s)
141 {
142  if (s->write_flag && s->buf_ptr > s->buffer) {
143  writeout(s, s->buffer, s->buf_ptr - s->buffer);
144  if (s->update_checksum) {
146  s->buf_ptr - s->checksum_ptr);
147  s->checksum_ptr = s->buffer;
148  }
149  }
150  s->buf_ptr = s->buffer;
151  if (!s->write_flag)
152  s->buf_end = s->buffer;
153 }
154 
155 void avio_w8(AVIOContext *s, int b)
156 {
157  av_assert2(b>=-128 && b<=255);
158  *s->buf_ptr++ = b;
159  if (s->buf_ptr >= s->buf_end)
160  flush_buffer(s);
161 }
162 
163 void ffio_fill(AVIOContext *s, int b, int count)
164 {
165  while (count > 0) {
166  int len = FFMIN(s->buf_end - s->buf_ptr, count);
167  memset(s->buf_ptr, b, len);
168  s->buf_ptr += len;
169 
170  if (s->buf_ptr >= s->buf_end)
171  flush_buffer(s);
172 
173  count -= len;
174  }
175 }
176 
177 void avio_write(AVIOContext *s, const unsigned char *buf, int size)
178 {
179  if (s->direct && !s->update_checksum) {
180  avio_flush(s);
181  writeout(s, buf, size);
182  return;
183  }
184  while (size > 0) {
185  int len = FFMIN(s->buf_end - s->buf_ptr, size);
186  memcpy(s->buf_ptr, buf, len);
187  s->buf_ptr += len;
188 
189  if (s->buf_ptr >= s->buf_end)
190  flush_buffer(s);
191 
192  buf += len;
193  size -= len;
194  }
195 }
196 
198 {
199  flush_buffer(s);
200  s->must_flush = 0;
201 }
202 
203 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
204 {
205  int64_t offset1;
206  int64_t pos;
207  int force = whence & AVSEEK_FORCE;
208  int buffer_size;
209  whence &= ~AVSEEK_FORCE;
210 
211  if(!s)
212  return AVERROR(EINVAL);
213 
214  buffer_size = s->buf_end - s->buffer;
215  pos = s->pos - (s->write_flag ? 0 : buffer_size);
216 
217  if (whence != SEEK_CUR && whence != SEEK_SET)
218  return AVERROR(EINVAL);
219 
220  if (whence == SEEK_CUR) {
221  offset1 = pos + (s->buf_ptr - s->buffer);
222  if (offset == 0)
223  return offset1;
224  offset += offset1;
225  }
226  if (offset < 0)
227  return AVERROR(EINVAL);
228 
229  offset1 = offset - pos;
230  if (!s->must_flush && (!s->direct || !s->seek) &&
231  offset1 >= 0 && offset1 <= buffer_size - s->write_flag) {
232  /* can do the seek inside the buffer */
233  s->buf_ptr = s->buffer + offset1;
234  } else if ((!s->seekable ||
235  offset1 <= s->buf_end + SHORT_SEEK_THRESHOLD - s->buffer) &&
236  !s->write_flag && offset1 >= 0 &&
237  (!s->direct || !s->seek) &&
238  (whence != SEEK_END || force)) {
239  while(s->pos < offset && !s->eof_reached)
240  fill_buffer(s);
241  if (s->eof_reached)
242  return AVERROR_EOF;
243  s->buf_ptr = s->buf_end + offset - s->pos;
244  } else if(!s->write_flag && offset1 < 0 && -offset1 < buffer_size>>1 && s->seek && offset > 0) {
245  int64_t res;
246 
247  pos -= FFMIN(buffer_size>>1, pos);
248  if ((res = s->seek(s->opaque, pos, SEEK_SET)) < 0)
249  return res;
250  s->buf_end =
251  s->buf_ptr = s->buffer;
252  s->pos = pos;
253  s->eof_reached = 0;
254  fill_buffer(s);
255  return avio_seek(s, offset, SEEK_SET | force);
256  } else {
257  int64_t res;
258  if (s->write_flag) {
259  flush_buffer(s);
260  s->must_flush = 1;
261  }
262  if (!s->seek)
263  return AVERROR(EPIPE);
264  if ((res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
265  return res;
266  s->seek_count ++;
267  if (!s->write_flag)
268  s->buf_end = s->buffer;
269  s->buf_ptr = s->buffer;
270  s->pos = offset;
271  }
272  s->eof_reached = 0;
273  return offset;
274 }
275 
276 int64_t avio_skip(AVIOContext *s, int64_t offset)
277 {
278  return avio_seek(s, offset, SEEK_CUR);
279 }
280 
282 {
283  int64_t size;
284 
285  if (!s)
286  return AVERROR(EINVAL);
287 
288  if (!s->seek)
289  return AVERROR(ENOSYS);
290  size = s->seek(s->opaque, 0, AVSEEK_SIZE);
291  if (size < 0) {
292  if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
293  return size;
294  size++;
295  s->seek(s->opaque, s->pos, SEEK_SET);
296  }
297  return size;
298 }
299 
301 {
302  if(!s)
303  return 0;
304  if(s->eof_reached){
305  s->eof_reached=0;
306  fill_buffer(s);
307  }
308  return s->eof_reached;
309 }
310 
311 #if FF_API_URL_FEOF
312 int url_feof(AVIOContext *s)
313 {
314  return avio_feof(s);
315 }
316 #endif
317 
318 void avio_wl32(AVIOContext *s, unsigned int val)
319 {
320  avio_w8(s, (uint8_t) val );
321  avio_w8(s, (uint8_t)(val >> 8 ));
322  avio_w8(s, (uint8_t)(val >> 16));
323  avio_w8(s, val >> 24 );
324 }
325 
326 void avio_wb32(AVIOContext *s, unsigned int val)
327 {
328  avio_w8(s, val >> 24 );
329  avio_w8(s, (uint8_t)(val >> 16));
330  avio_w8(s, (uint8_t)(val >> 8 ));
331  avio_w8(s, (uint8_t) val );
332 }
333 
334 int avio_put_str(AVIOContext *s, const char *str)
335 {
336  int len = 1;
337  if (str) {
338  len += strlen(str);
339  avio_write(s, (const unsigned char *) str, len);
340  } else
341  avio_w8(s, 0);
342  return len;
343 }
344 
345 static inline int put_str16(AVIOContext *s, const char *str, const int be)
346 {
347  const uint8_t *q = str;
348  int ret = 0;
349  int err = 0;
350 
351  while (*q) {
352  uint32_t ch;
353  uint16_t tmp;
354 
355  GET_UTF8(ch, *q++, goto invalid;)
356  PUT_UTF16(ch, tmp, be ? avio_wb16(s, tmp) : avio_wl16(s, tmp);
357  ret += 2;)
358  continue;
359 invalid:
360  av_log(s, AV_LOG_ERROR, "Invaid UTF8 sequence in avio_put_str16%s\n", be ? "be" : "le");
361  err = AVERROR(EINVAL);
362  if (!*(q-1))
363  break;
364  }
365  if (be)
366  avio_wb16(s, 0);
367  else
368  avio_wl16(s, 0);
369  if (err)
370  return err;
371  ret += 2;
372  return ret;
373 }
374 
375 #define PUT_STR16(type, big_endian) \
376 int avio_put_str16 ## type(AVIOContext *s, const char *str) \
377 { \
378 return put_str16(s, str, big_endian); \
379 }
380 
381 PUT_STR16(le, 0)
382 PUT_STR16(be, 1)
383 
384 #undef PUT_STR16
385 
386 int ff_get_v_length(uint64_t val)
387 {
388  int i = 1;
389 
390  while (val >>= 7)
391  i++;
392 
393  return i;
394 }
395 
396 void ff_put_v(AVIOContext *bc, uint64_t val)
397 {
398  int i = ff_get_v_length(val);
399 
400  while (--i > 0)
401  avio_w8(bc, 128 | (uint8_t)(val >> (7*i)));
402 
403  avio_w8(bc, val & 127);
404 }
405 
406 void avio_wl64(AVIOContext *s, uint64_t val)
407 {
408  avio_wl32(s, (uint32_t)(val & 0xffffffff));
409  avio_wl32(s, (uint32_t)(val >> 32));
410 }
411 
412 void avio_wb64(AVIOContext *s, uint64_t val)
413 {
414  avio_wb32(s, (uint32_t)(val >> 32));
415  avio_wb32(s, (uint32_t)(val & 0xffffffff));
416 }
417 
418 void avio_wl16(AVIOContext *s, unsigned int val)
419 {
420  avio_w8(s, (uint8_t)val);
421  avio_w8(s, (int)val >> 8);
422 }
423 
424 void avio_wb16(AVIOContext *s, unsigned int val)
425 {
426  avio_w8(s, (int)val >> 8);
427  avio_w8(s, (uint8_t)val);
428 }
429 
430 void avio_wl24(AVIOContext *s, unsigned int val)
431 {
432  avio_wl16(s, val & 0xffff);
433  avio_w8(s, (int)val >> 16);
434 }
435 
436 void avio_wb24(AVIOContext *s, unsigned int val)
437 {
438  avio_wb16(s, (int)val >> 8);
439  avio_w8(s, (uint8_t)val);
440 }
441 
442 /* Input stream */
443 
444 static void fill_buffer(AVIOContext *s)
445 {
446  int max_buffer_size = s->max_packet_size ?
448  uint8_t *dst = s->buf_end - s->buffer + max_buffer_size < s->buffer_size ?
449  s->buf_end : s->buffer;
450  int len = s->buffer_size - (dst - s->buffer);
451 
452  /* can't fill the buffer without read_packet, just set EOF if appropriate */
453  if (!s->read_packet && s->buf_ptr >= s->buf_end)
454  s->eof_reached = 1;
455 
456  /* no need to do anything if EOF already reached */
457  if (s->eof_reached)
458  return;
459 
460  if (s->update_checksum && dst == s->buffer) {
461  if (s->buf_end > s->checksum_ptr)
463  s->buf_end - s->checksum_ptr);
464  s->checksum_ptr = s->buffer;
465  }
466 
467  /* make buffer smaller in case it ended up large after probing */
468  if (s->read_packet && s->orig_buffer_size && s->buffer_size > s->orig_buffer_size) {
469  if (dst == s->buffer) {
471 
472  s->checksum_ptr = dst = s->buffer;
473  }
474  av_assert0(len >= s->orig_buffer_size);
475  len = s->orig_buffer_size;
476  }
477 
478  if (s->read_packet)
479  len = s->read_packet(s->opaque, dst, len);
480  else
481  len = 0;
482  if (len <= 0) {
483  /* do not modify buffer if EOF reached so that a seek back can
484  be done without rereading data */
485  s->eof_reached = 1;
486  if (len < 0)
487  s->error = len;
488  } else {
489  s->pos += len;
490  s->buf_ptr = dst;
491  s->buf_end = dst + len;
492  s->bytes_read += len;
493  }
494 }
495 
496 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
497  unsigned int len)
498 {
499  return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
500 }
501 
502 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
503  unsigned int len)
504 {
505  return av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE), checksum, buf, len);
506 }
507 
509 {
511  s->buf_ptr - s->checksum_ptr);
512  s->update_checksum = NULL;
513  return s->checksum;
514 }
515 
517  unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
518  unsigned long checksum)
519 {
520  s->update_checksum = update_checksum;
521  if (s->update_checksum) {
522  s->checksum = checksum;
523  s->checksum_ptr = s->buf_ptr;
524  }
525 }
526 
527 /* XXX: put an inline version */
529 {
530  if (s->buf_ptr >= s->buf_end)
531  fill_buffer(s);
532  if (s->buf_ptr < s->buf_end)
533  return *s->buf_ptr++;
534  return 0;
535 }
536 
537 int avio_read(AVIOContext *s, unsigned char *buf, int size)
538 {
539  int len, size1;
540 
541  size1 = size;
542  while (size > 0) {
543  len = s->buf_end - s->buf_ptr;
544  if (len > size)
545  len = size;
546  if (len == 0 || s->write_flag) {
547  if((s->direct || size > s->buffer_size) && !s->update_checksum){
548  if(s->read_packet)
549  len = s->read_packet(s->opaque, buf, size);
550  if (len <= 0) {
551  /* do not modify buffer if EOF reached so that a seek back can
552  be done without rereading data */
553  s->eof_reached = 1;
554  if(len<0)
555  s->error= len;
556  break;
557  } else {
558  s->pos += len;
559  s->bytes_read += len;
560  size -= len;
561  buf += len;
562  s->buf_ptr = s->buffer;
563  s->buf_end = s->buffer/* + len*/;
564  }
565  } else {
566  fill_buffer(s);
567  len = s->buf_end - s->buf_ptr;
568  if (len == 0)
569  break;
570  }
571  } else {
572  memcpy(buf, s->buf_ptr, len);
573  buf += len;
574  s->buf_ptr += len;
575  size -= len;
576  }
577  }
578  if (size1 == size) {
579  if (s->error) return s->error;
580  if (avio_feof(s)) return AVERROR_EOF;
581  }
582  return size1 - size;
583 }
584 
585 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data)
586 {
587  if (s->buf_end - s->buf_ptr >= size && !s->write_flag) {
588  *data = s->buf_ptr;
589  s->buf_ptr += size;
590  return size;
591  } else {
592  *data = buf;
593  return avio_read(s, buf, size);
594  }
595 }
596 
597 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size)
598 {
599  int len;
600 
601  if (size < 0)
602  return -1;
603 
604  if (s->read_packet && s->write_flag) {
605  len = s->read_packet(s->opaque, buf, size);
606  if (len > 0)
607  s->pos += len;
608  return len;
609  }
610 
611  len = s->buf_end - s->buf_ptr;
612  if (len == 0) {
613  /* Reset the buf_end pointer to the start of the buffer, to make sure
614  * the fill_buffer call tries to read as much data as fits into the
615  * full buffer, instead of just what space is left after buf_end.
616  * This avoids returning partial packets at the end of the buffer,
617  * for packet based inputs.
618  */
619  s->buf_end = s->buf_ptr = s->buffer;
620  fill_buffer(s);
621  len = s->buf_end - s->buf_ptr;
622  }
623  if (len > size)
624  len = size;
625  memcpy(buf, s->buf_ptr, len);
626  s->buf_ptr += len;
627  if (!len) {
628  if (s->error) return s->error;
629  if (avio_feof(s)) return AVERROR_EOF;
630  }
631  return len;
632 }
633 
634 unsigned int avio_rl16(AVIOContext *s)
635 {
636  unsigned int val;
637  val = avio_r8(s);
638  val |= avio_r8(s) << 8;
639  return val;
640 }
641 
642 unsigned int avio_rl24(AVIOContext *s)
643 {
644  unsigned int val;
645  val = avio_rl16(s);
646  val |= avio_r8(s) << 16;
647  return val;
648 }
649 
650 unsigned int avio_rl32(AVIOContext *s)
651 {
652  unsigned int val;
653  val = avio_rl16(s);
654  val |= avio_rl16(s) << 16;
655  return val;
656 }
657 
658 uint64_t avio_rl64(AVIOContext *s)
659 {
660  uint64_t val;
661  val = (uint64_t)avio_rl32(s);
662  val |= (uint64_t)avio_rl32(s) << 32;
663  return val;
664 }
665 
666 unsigned int avio_rb16(AVIOContext *s)
667 {
668  unsigned int val;
669  val = avio_r8(s) << 8;
670  val |= avio_r8(s);
671  return val;
672 }
673 
674 unsigned int avio_rb24(AVIOContext *s)
675 {
676  unsigned int val;
677  val = avio_rb16(s) << 8;
678  val |= avio_r8(s);
679  return val;
680 }
681 unsigned int avio_rb32(AVIOContext *s)
682 {
683  unsigned int val;
684  val = avio_rb16(s) << 16;
685  val |= avio_rb16(s);
686  return val;
687 }
688 
689 int ff_get_line(AVIOContext *s, char *buf, int maxlen)
690 {
691  int i = 0;
692  char c;
693 
694  do {
695  c = avio_r8(s);
696  if (c && i < maxlen-1)
697  buf[i++] = c;
698  } while (c != '\n' && c != '\r' && c);
699  if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))
700  avio_skip(s, -1);
701 
702  buf[i] = 0;
703  return i;
704 }
705 
706 int avio_get_str(AVIOContext *s, int maxlen, char *buf, int buflen)
707 {
708  int i;
709 
710  if (buflen <= 0)
711  return AVERROR(EINVAL);
712  // reserve 1 byte for terminating 0
713  buflen = FFMIN(buflen - 1, maxlen);
714  for (i = 0; i < buflen; i++)
715  if (!(buf[i] = avio_r8(s)))
716  return i + 1;
717  buf[i] = 0;
718  for (; i < maxlen; i++)
719  if (!avio_r8(s))
720  return i + 1;
721  return maxlen;
722 }
723 
724 #define GET_STR16(type, read) \
725  int avio_get_str16 ##type(AVIOContext *pb, int maxlen, char *buf, int buflen)\
726 {\
727  char* q = buf;\
728  int ret = 0;\
729  if (buflen <= 0) \
730  return AVERROR(EINVAL); \
731  while (ret + 1 < maxlen) {\
732  uint8_t tmp;\
733  uint32_t ch;\
734  GET_UTF16(ch, (ret += 2) <= maxlen ? read(pb) : 0, break;)\
735  if (!ch)\
736  break;\
737  PUT_UTF8(ch, tmp, if (q - buf < buflen - 1) *q++ = tmp;)\
738  }\
739  *q = 0;\
740  return ret;\
741 }\
742 
744 GET_STR16(be, avio_rb16)
745 
746 #undef GET_STR16
747 
748 uint64_t avio_rb64(AVIOContext *s)
749 {
750  uint64_t val;
751  val = (uint64_t)avio_rb32(s) << 32;
752  val |= (uint64_t)avio_rb32(s);
753  return val;
754 }
755 
757  uint64_t val = 0;
758  int tmp;
759 
760  do{
761  tmp = avio_r8(bc);
762  val= (val<<7) + (tmp&127);
763  }while(tmp&128);
764  return val;
765 }
766 
768 {
769  uint8_t *buffer;
770  int buffer_size, max_packet_size;
771 
772  max_packet_size = h->max_packet_size;
773  if (max_packet_size) {
774  buffer_size = max_packet_size; /* no need to bufferize more than one packet */
775  } else {
776  buffer_size = IO_BUFFER_SIZE;
777  }
778  buffer = av_malloc(buffer_size);
779  if (!buffer)
780  return AVERROR(ENOMEM);
781 
782  *s = avio_alloc_context(buffer, buffer_size, h->flags & AVIO_FLAG_WRITE, h,
783  (void*)ffurl_read, (void*)ffurl_write, (void*)ffurl_seek);
784  if (!*s) {
785  av_free(buffer);
786  return AVERROR(ENOMEM);
787  }
788  (*s)->direct = h->flags & AVIO_FLAG_DIRECT;
789  (*s)->seekable = h->is_streamed ? 0 : AVIO_SEEKABLE_NORMAL;
790  (*s)->max_packet_size = max_packet_size;
791  if(h->prot) {
792  (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
793  (*s)->read_seek = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
794  }
795  (*s)->av_class = &ff_avio_class;
796  return 0;
797 }
798 
799 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
800 {
801  uint8_t *buffer;
802  int max_buffer_size = s->max_packet_size ?
804  int filled = s->buf_end - s->buffer;
805  ptrdiff_t checksum_ptr_offset = s->checksum_ptr ? s->checksum_ptr - s->buffer : -1;
806 
807  buf_size += s->buf_ptr - s->buffer + max_buffer_size;
808 
809  if (buf_size < filled || s->seekable)
810  return 0;
811  av_assert0(!s->write_flag);
812 
813  buffer = av_malloc(buf_size);
814  if (!buffer)
815  return AVERROR(ENOMEM);
816 
817  memcpy(buffer, s->buffer, filled);
818  av_free(s->buffer);
819  s->buf_ptr = buffer + (s->buf_ptr - s->buffer);
820  s->buf_end = buffer + (s->buf_end - s->buffer);
821  s->buffer = buffer;
822  s->buffer_size = buf_size;
823  if (checksum_ptr_offset >= 0)
824  s->checksum_ptr = s->buffer + checksum_ptr_offset;
825  return 0;
826 }
827 
828 int ffio_set_buf_size(AVIOContext *s, int buf_size)
829 {
830  uint8_t *buffer;
831  buffer = av_malloc(buf_size);
832  if (!buffer)
833  return AVERROR(ENOMEM);
834 
835  av_free(s->buffer);
836  s->buffer = buffer;
837  s->orig_buffer_size =
838  s->buffer_size = buf_size;
839  s->buf_ptr = buffer;
841  return 0;
842 }
843 
844 static int url_resetbuf(AVIOContext *s, int flags)
845 {
846  av_assert1(flags == AVIO_FLAG_WRITE || flags == AVIO_FLAG_READ);
847 
848  if (flags & AVIO_FLAG_WRITE) {
849  s->buf_end = s->buffer + s->buffer_size;
850  s->write_flag = 1;
851  } else {
852  s->buf_end = s->buffer;
853  s->write_flag = 0;
854  }
855  return 0;
856 }
857 
858 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **bufp, int buf_size)
859 {
860  int64_t buffer_start;
861  int buffer_size;
862  int overlap, new_size, alloc_size;
863  uint8_t *buf = *bufp;
864 
865  if (s->write_flag) {
866  av_freep(bufp);
867  return AVERROR(EINVAL);
868  }
869 
870  buffer_size = s->buf_end - s->buffer;
871 
872  /* the buffers must touch or overlap */
873  if ((buffer_start = s->pos - buffer_size) > buf_size) {
874  av_freep(bufp);
875  return AVERROR(EINVAL);
876  }
877 
878  overlap = buf_size - buffer_start;
879  new_size = buf_size + buffer_size - overlap;
880 
881  alloc_size = FFMAX(s->buffer_size, new_size);
882  if (alloc_size > buf_size)
883  if (!(buf = (*bufp) = av_realloc_f(buf, 1, alloc_size)))
884  return AVERROR(ENOMEM);
885 
886  if (new_size > buf_size) {
887  memcpy(buf + buf_size, s->buffer + overlap, buffer_size - overlap);
888  buf_size = new_size;
889  }
890 
891  av_free(s->buffer);
892  s->buf_ptr = s->buffer = buf;
893  s->buffer_size = alloc_size;
894  s->pos = buf_size;
895  s->buf_end = s->buf_ptr + buf_size;
896  s->eof_reached = 0;
897  s->must_flush = 0;
898 
899  return 0;
900 }
901 
902 int avio_open(AVIOContext **s, const char *filename, int flags)
903 {
904  return avio_open2(s, filename, flags, NULL, NULL);
905 }
906 
907 int avio_open2(AVIOContext **s, const char *filename, int flags,
909 {
910  URLContext *h;
911  int err;
912 
913  err = ffurl_open(&h, filename, flags, int_cb, options);
914  if (err < 0)
915  return err;
916  err = ffio_fdopen(s, h);
917  if (err < 0) {
918  ffurl_close(h);
919  return err;
920  }
921  return 0;
922 }
923 
925 {
926  URLContext *h;
927 
928  if (!s)
929  return 0;
930 
931  avio_flush(s);
932  h = s->opaque;
933  av_freep(&s->buffer);
934  if (s->write_flag)
935  av_log(s, AV_LOG_DEBUG, "Statistics: %d seeks, %d writeouts\n", s->seek_count, s->writeout_count);
936  else
937  av_log(s, AV_LOG_DEBUG, "Statistics: %"PRId64" bytes read, %d seeks\n", s->bytes_read, s->seek_count);
938  av_free(s);
939  return ffurl_close(h);
940 }
941 
943 {
944  int ret = avio_close(*s);
945  *s = NULL;
946  return ret;
947 }
948 
949 int avio_printf(AVIOContext *s, const char *fmt, ...)
950 {
951  va_list ap;
952  char buf[4096];
953  int ret;
954 
955  va_start(ap, fmt);
956  ret = vsnprintf(buf, sizeof(buf), fmt, ap);
957  va_end(ap);
958  avio_write(s, buf, strlen(buf));
959  return ret;
960 }
961 
962 int avio_pause(AVIOContext *s, int pause)
963 {
964  if (!s->read_pause)
965  return AVERROR(ENOSYS);
966  return s->read_pause(s->opaque, pause);
967 }
968 
969 int64_t avio_seek_time(AVIOContext *s, int stream_index,
970  int64_t timestamp, int flags)
971 {
972  URLContext *h = s->opaque;
973  int64_t ret;
974  if (!s->read_seek)
975  return AVERROR(ENOSYS);
976  ret = s->read_seek(h, stream_index, timestamp, flags);
977  if (ret >= 0) {
978  int64_t pos;
979  s->buf_ptr = s->buf_end; // Flush buffer
980  pos = s->seek(h, 0, SEEK_CUR);
981  if (pos >= 0)
982  s->pos = pos;
983  else if (pos != AVERROR(ENOSYS))
984  ret = pos;
985  }
986  return ret;
987 }
988 
989 int avio_read_to_bprint(AVIOContext *h, AVBPrint *pb, size_t max_size)
990 {
991  int ret;
992  char buf[1024];
993  while (max_size) {
994  ret = avio_read(h, buf, FFMIN(max_size, sizeof(buf)));
995  if (ret == AVERROR_EOF)
996  return 0;
997  if (ret <= 0)
998  return ret;
999  av_bprint_append_data(pb, buf, ret);
1000  if (!av_bprint_is_complete(pb))
1001  return AVERROR(ENOMEM);
1002  max_size -= ret;
1003  }
1004  return 0;
1005 }
1006 
1007 /* output in a dynamic buffer */
1008 
1009 typedef struct DynBuffer {
1014 } DynBuffer;
1015 
1016 static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
1017 {
1018  DynBuffer *d = opaque;
1019  unsigned new_size, new_allocated_size;
1020 
1021  /* reallocate buffer if needed */
1022  new_size = d->pos + buf_size;
1023  new_allocated_size = d->allocated_size;
1024  if (new_size < d->pos || new_size > INT_MAX/2)
1025  return -1;
1026  while (new_size > new_allocated_size) {
1027  if (!new_allocated_size)
1028  new_allocated_size = new_size;
1029  else
1030  new_allocated_size += new_allocated_size / 2 + 1;
1031  }
1032 
1033  if (new_allocated_size > d->allocated_size) {
1034  int err;
1035  if ((err = av_reallocp(&d->buffer, new_allocated_size)) < 0) {
1036  d->allocated_size = 0;
1037  d->size = 0;
1038  return err;
1039  }
1040  d->allocated_size = new_allocated_size;
1041  }
1042  memcpy(d->buffer + d->pos, buf, buf_size);
1043  d->pos = new_size;
1044  if (d->pos > d->size)
1045  d->size = d->pos;
1046  return buf_size;
1047 }
1048 
1049 static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
1050 {
1051  unsigned char buf1[4];
1052  int ret;
1053 
1054  /* packetized write: output the header */
1055  AV_WB32(buf1, buf_size);
1056  ret = dyn_buf_write(opaque, buf1, 4);
1057  if (ret < 0)
1058  return ret;
1059 
1060  /* then the data */
1061  return dyn_buf_write(opaque, buf, buf_size);
1062 }
1063 
1064 static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
1065 {
1066  DynBuffer *d = opaque;
1067 
1068  if (whence == SEEK_CUR)
1069  offset += d->pos;
1070  else if (whence == SEEK_END)
1071  offset += d->size;
1072  if (offset < 0 || offset > 0x7fffffffLL)
1073  return -1;
1074  d->pos = offset;
1075  return 0;
1076 }
1077 
1078 static int url_open_dyn_buf_internal(AVIOContext **s, int max_packet_size)
1079 {
1080  DynBuffer *d;
1081  unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
1082 
1083  if (sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
1084  return -1;
1085  d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
1086  if (!d)
1087  return AVERROR(ENOMEM);
1088  d->io_buffer_size = io_buffer_size;
1089  *s = avio_alloc_context(d->io_buffer, d->io_buffer_size, 1, d, NULL,
1090  max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
1091  max_packet_size ? NULL : dyn_buf_seek);
1092  if(!*s) {
1093  av_free(d);
1094  return AVERROR(ENOMEM);
1095  }
1096  (*s)->max_packet_size = max_packet_size;
1097  return 0;
1098 }
1099 
1101 {
1102  return url_open_dyn_buf_internal(s, 0);
1103 }
1104 
1105 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size)
1106 {
1107  if (max_packet_size <= 0)
1108  return -1;
1109  return url_open_dyn_buf_internal(s, max_packet_size);
1110 }
1111 
1113 {
1114  DynBuffer *d;
1115  int size;
1116  static const char padbuf[FF_INPUT_BUFFER_PADDING_SIZE] = {0};
1117  int padding = 0;
1118 
1119  if (!s) {
1120  *pbuffer = NULL;
1121  return 0;
1122  }
1123 
1124  /* don't attempt to pad fixed-size packet buffers */
1125  if (!s->max_packet_size) {
1126  avio_write(s, padbuf, sizeof(padbuf));
1127  padding = FF_INPUT_BUFFER_PADDING_SIZE;
1128  }
1129 
1130  avio_flush(s);
1131 
1132  d = s->opaque;
1133  *pbuffer = d->buffer;
1134  size = d->size;
1135  av_free(d);
1136  av_free(s);
1137  return size - padding;
1138 }
1139 
1141 {
1142  uint8_t *tmp;
1143  if (!*s)
1144  return;
1145  avio_close_dyn_buf(*s, &tmp);
1146  av_free(tmp);
1147  *s = NULL;
1148 }
1149 
1150 static int null_buf_write(void *opaque, uint8_t *buf, int buf_size)
1151 {
1152  DynBuffer *d = opaque;
1153 
1154  d->pos += buf_size;
1155  if (d->pos > d->size)
1156  d->size = d->pos;
1157  return buf_size;
1158 }
1159 
1161 {
1162  int ret = url_open_dyn_buf_internal(s, 0);
1163  if (ret >= 0) {
1164  AVIOContext *pb = *s;
1166  }
1167  return ret;
1168 }
1169 
1171 {
1172  DynBuffer *d = s->opaque;
1173  int size;
1174 
1175  avio_flush(s);
1176 
1177  size = d->size;
1178  av_free(d);
1179  av_free(s);
1180  return size;
1181 }