FFmpeg
concat.c
Go to the documentation of this file.
1 /*
2  * Concat URL protocol
3  * Copyright (c) 2006 Steve Lhomme
4  * Copyright (c) 2007 Wolfram Gloger
5  * Copyright (c) 2010 Michele Orrù
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_close(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  av_freep(&h->priv_data);
79  return AVERROR(ENAMETOOLONG);
80  }
81  }
82  }
83 
84  if (!(nodes = av_realloc(NULL, sizeof(*nodes) * len)))
85  return AVERROR(ENOMEM);
86  else
87  data->nodes = nodes;
88 
89  /* handle input */
90  if (!*uri)
91  err = AVERROR(ENOENT);
92  for (i = 0; *uri; i++) {
93  /* parsing uri */
94  len = strcspn(uri, AV_CAT_SEPARATOR);
95  if ((err = av_reallocp(&node_uri, len + 1)) < 0)
96  break;
97  av_strlcpy(node_uri, uri, len + 1);
98  uri += len + strspn(uri + len, AV_CAT_SEPARATOR);
99 
100  /* creating URLContext */
101  err = ffurl_open_whitelist(&uc, node_uri, flags,
103  if (err < 0)
104  break;
105 
106  /* creating size */
107  if ((size = ffurl_size(uc)) < 0) {
108  ffurl_close(uc);
109  err = AVERROR(ENOSYS);
110  break;
111  }
112 
113  /* assembling */
114  nodes[i].uc = uc;
115  nodes[i].size = size;
116  total_size += size;
117  }
118  av_free(node_uri);
119  data->length = i;
120 
121  if (err < 0)
122  concat_close(h);
123  else if (!(nodes = av_realloc(nodes, data->length * sizeof(*nodes)))) {
124  concat_close(h);
125  err = AVERROR(ENOMEM);
126  } else
127  data->nodes = nodes;
128  data->total_size = total_size;
129  return err;
130 }
131 
132 static int concat_read(URLContext *h, unsigned char *buf, int size)
133 {
134  int result, total = 0;
135  struct concat_data *data = h->priv_data;
136  struct concat_nodes *nodes = data->nodes;
137  size_t i = data->current;
138 
139  while (size > 0) {
140  result = ffurl_read(nodes[i].uc, buf, size);
141  if (result == AVERROR_EOF) {
142  if (i + 1 == data->length ||
143  ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)
144  break;
145  result = 0;
146  }
147  if (result < 0)
148  return total ? total : result;
149  total += result;
150  buf += result;
151  size -= result;
152  }
153  data->current = i;
154  return total ? total : result;
155 }
156 
157 static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
158 {
159  int64_t result;
160  struct concat_data *data = h->priv_data;
161  struct concat_nodes *nodes = data->nodes;
162  size_t i;
163 
164  if ((whence & AVSEEK_SIZE))
165  return data->total_size;
166  switch (whence) {
167  case SEEK_END:
168  for (i = data->length - 1; i && pos < -nodes[i].size; i--)
169  pos += nodes[i].size;
170  break;
171  case SEEK_CUR:
172  /* get the absolute position */
173  for (i = 0; i != data->current; i++)
174  pos += nodes[i].size;
175  pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);
176  whence = SEEK_SET;
177  /* fall through with the absolute position */
178  case SEEK_SET:
179  for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)
180  pos -= nodes[i].size;
181  break;
182  default:
183  return AVERROR(EINVAL);
184  }
185 
186  result = ffurl_seek(nodes[i].uc, pos, whence);
187  if (result >= 0) {
188  data->current = i;
189  while (i)
190  result += nodes[--i].size;
191  }
192  return result;
193 }
194 
196  .name = "concat",
197  .url_open = concat_open,
198  .url_read = concat_read,
199  .url_seek = concat_seek,
200  .url_close = concat_close,
201  .priv_data_size = sizeof(struct concat_data),
202  .default_whitelist = "concat,file,subfile",
203 };
#define NULL
Definition: coverity.c:32
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
void * av_realloc(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory.
Definition: mem.c:135
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
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:82
static int concat_read(URLContext *h, unsigned char *buf, int size)
Definition: concat.c:132
#define AV_CAT_SEPARATOR
Definition: concat.c:30
#define AVERROR_EOF
End of file.
Definition: error.h:55
ptrdiff_t size
Definition: opengl_enc.c:100
#define av_log(a,...)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
const char * protocol_whitelist
Definition: url.h:49
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:157
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:163
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:611
static av_cold int concat_open(URLContext *h, const char *uri, int flags)
Definition: concat.c:59
void * buf
Definition: avisynth_c.h:766
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:561
int ffurl_close(URLContext *h)
Definition: avio.c:467
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:434
const URLProtocol ff_concat_protocol
Definition: concat.c:195
#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
and forward the result(frame or status change) to the corresponding input.If nothing is possible
#define av_freep(p)
unbuffered private I/O API
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
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:407
URLContext * uc
node&#39;s URLContext
Definition: concat.c:33