FFmpeg  4.3.6
concat.c
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1 /*
2  * Concat URL protocol
3  * Copyright (c) 2006 Steve Lhomme
4  * Copyright (c) 2007 Wolfram Gloger
5  * Copyright (c) 2010 Michele OrrĂ¹
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include "libavutil/avstring.h"
25 #include "libavutil/mem.h"
26 
27 #include "avformat.h"
28 #include "url.h"
29 
30 #define AV_CAT_SEPARATOR "|"
31 
32 struct concat_nodes {
33  URLContext *uc; ///< node's URLContext
34  int64_t size; ///< url filesize
35 };
36 
37 struct concat_data {
38  struct concat_nodes *nodes; ///< list of nodes to concat
39  size_t length; ///< number of cat'ed nodes
40  size_t current; ///< index of currently read node
41  uint64_t total_size;
42 };
43 
45 {
46  int err = 0;
47  size_t i;
48  struct concat_data *data = h->priv_data;
49  struct concat_nodes *nodes = data->nodes;
50 
51  for (i = 0; i != data->length; i++)
52  err |= ffurl_closep(&nodes[i].uc);
53 
54  av_freep(&data->nodes);
55 
56  return err < 0 ? -1 : 0;
57 }
58 
59 static av_cold int concat_open(URLContext *h, const char *uri, int flags)
60 {
61  char *node_uri = NULL;
62  int err = 0;
63  int64_t size, total_size = 0;
64  size_t len, i;
65  URLContext *uc;
66  struct concat_data *data = h->priv_data;
67  struct concat_nodes *nodes;
68 
69  if (!av_strstart(uri, "concat:", &uri)) {
70  av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);
71  return AVERROR(EINVAL);
72  }
73 
74  for (i = 0, len = 1; uri[i]; i++) {
75  if (uri[i] == *AV_CAT_SEPARATOR) {
76  /* integer overflow */
77  if (++len == UINT_MAX / sizeof(*nodes)) {
78  return AVERROR(ENAMETOOLONG);
79  }
80  }
81  }
82 
83  if (!(nodes = av_realloc(NULL, sizeof(*nodes) * len)))
84  return AVERROR(ENOMEM);
85  else
86  data->nodes = nodes;
87 
88  /* handle input */
89  if (!*uri)
90  err = AVERROR(ENOENT);
91  for (i = 0; *uri; i++) {
92  /* parsing uri */
93  len = strcspn(uri, AV_CAT_SEPARATOR);
94  if ((err = av_reallocp(&node_uri, len + 1)) < 0)
95  break;
96  av_strlcpy(node_uri, uri, len + 1);
97  uri += len + strspn(uri + len, AV_CAT_SEPARATOR);
98 
99  /* creating URLContext */
100  err = ffurl_open_whitelist(&uc, node_uri, flags,
102  if (err < 0)
103  break;
104 
105  /* creating size */
106  if ((size = ffurl_size(uc)) < 0) {
107  ffurl_close(uc);
108  err = AVERROR(ENOSYS);
109  break;
110  }
111 
112  /* assembling */
113  nodes[i].uc = uc;
114  nodes[i].size = size;
115  total_size += size;
116  }
117  av_free(node_uri);
118  data->length = i;
119 
120  if (err < 0)
121  concat_close(h);
122  else if (!(nodes = av_realloc(nodes, data->length * sizeof(*nodes)))) {
123  concat_close(h);
124  err = AVERROR(ENOMEM);
125  } else
126  data->nodes = nodes;
127  data->total_size = total_size;
128  return err;
129 }
130 
131 static int concat_read(URLContext *h, unsigned char *buf, int size)
132 {
133  int result, total = 0;
134  struct concat_data *data = h->priv_data;
135  struct concat_nodes *nodes = data->nodes;
136  size_t i = data->current;
137 
138  while (size > 0) {
139  result = ffurl_read(nodes[i].uc, buf, size);
140  if (result == AVERROR_EOF) {
141  if (i + 1 == data->length ||
142  ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)
143  break;
144  result = 0;
145  }
146  if (result < 0)
147  return total ? total : result;
148  total += result;
149  buf += result;
150  size -= result;
151  }
152  data->current = i;
153  return total ? total : result;
154 }
155 
156 static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
157 {
158  int64_t result;
159  struct concat_data *data = h->priv_data;
160  struct concat_nodes *nodes = data->nodes;
161  size_t i;
162 
163  if ((whence & AVSEEK_SIZE))
164  return data->total_size;
165  switch (whence) {
166  case SEEK_END:
167  for (i = data->length - 1; i && pos < -nodes[i].size; i--)
168  pos += nodes[i].size;
169  break;
170  case SEEK_CUR:
171  /* get the absolute position */
172  for (i = 0; i != data->current; i++)
173  pos += nodes[i].size;
174  pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);
175  whence = SEEK_SET;
176  /* fall through with the absolute position */
177  case SEEK_SET:
178  for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)
179  pos -= nodes[i].size;
180  break;
181  default:
182  return AVERROR(EINVAL);
183  }
184 
185  result = ffurl_seek(nodes[i].uc, pos, whence);
186  if (result >= 0) {
187  data->current = i;
188  while (i)
189  result += nodes[--i].size;
190  }
191  return result;
192 }
193 
195  .name = "concat",
196  .url_open = concat_open,
197  .url_read = concat_read,
198  .url_seek = concat_seek,
199  .url_close = concat_close,
200  .priv_data_size = sizeof(struct concat_data),
201  .default_whitelist = "concat,file,subfile",
202 };
#define NULL
Definition: coverity.c:32
void * av_realloc(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory.
Definition: mem.c:134
int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const char *whitelist, const char *blacklist, URLContext *parent)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:307
static av_cold int concat_close(URLContext *h)
Definition: concat.c:44
Memory handling functions.
AVIOInterruptCB interrupt_callback
Definition: url.h:47
size_t length
number of cat&#39;ed nodes
Definition: concat.c:39
struct concat_nodes * nodes
list of nodes to concat
Definition: concat.c:38
#define av_cold
Definition: attributes.h:88
static int concat_read(URLContext *h, unsigned char *buf, int size)
Definition: concat.c:131
#define AV_CAT_SEPARATOR
Definition: concat.c:30
const char data[16]
Definition: mxf.c:91
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define av_log(a,...)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
const char * protocol_whitelist
Definition: url.h:49
#define AVERROR(e)
Definition: error.h:43
unsigned int pos
Definition: spdifenc.c:412
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:83
static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
Definition: concat.c:156
int ffurl_closep(URLContext **hh)
Close the resource accessed by the URLContext h, and free the memory used by it.
Definition: avio.c:446
int av_reallocp(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory through a pointer to a pointer.
Definition: mem.c:161
const char * protocol_blacklist
Definition: url.h:50
int64_t ffurl_size(URLContext *h)
Return the filesize of the resource accessed by h, AVERROR(ENOSYS) if the operation is not supported ...
Definition: avio.c:613
static av_cold int concat_open(URLContext *h, const char *uri, int flags)
Definition: concat.c:59
Definition: url.h:38
uint64_t total_size
Definition: concat.c:41
void * priv_data
Definition: url.h:41
int64_t size
url filesize
Definition: concat.c:34
const char * name
Definition: url.h:55
#define flags(name, subs,...)
Definition: cbs_av1.c:565
int ffurl_close(URLContext *h)
Definition: avio.c:469
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
Main libavformat public API header.
int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
Change the position that will be used by the next read/write operation on the resource accessed by h...
Definition: avio.c:436
const URLProtocol ff_concat_protocol
Definition: concat.c:194
#define AVSEEK_SIZE
ORing this as the "whence" parameter to a seek function causes it to return the filesize without seek...
Definition: avio.h:531
#define av_free(p)
int len
size_t current
index of currently read node
Definition: concat.c:40
#define av_freep(p)
unbuffered private I/O API
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf...
Definition: avio.c:409
URLContext * uc
node&#39;s URLContext
Definition: concat.c:33