Libav
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 Libav.
8  *
9  * Libav 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  * Libav 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 Libav; 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 {
34  int64_t size;
35 };
36 
37 struct concat_data {
38  struct concat_nodes *nodes;
39  size_t length;
40  size_t current;
41 };
42 
44 {
45  int err = 0;
46  size_t i;
47  struct concat_data *data = h->priv_data;
48  struct concat_nodes *nodes = data->nodes;
49 
50  for (i = 0; i != data->length; i++)
51  err |= ffurl_close(nodes[i].uc);
52 
53  av_freep(&data->nodes);
54 
55  return err < 0 ? -1 : 0;
56 }
57 
58 static av_cold int concat_open(URLContext *h, const char *uri, int flags)
59 {
60  char *node_uri = NULL;
61  int err = 0;
62  int64_t size;
63  size_t len, i;
64  URLContext *uc;
65  struct concat_data *data = h->priv_data;
66  struct concat_nodes *nodes;
67 
68  av_strstart(uri, "concat:", &uri);
69 
70  for (i = 0, len = 1; uri[i]; i++) {
71  if (uri[i] == *AV_CAT_SEPARATOR) {
72  /* integer overflow */
73  if (++len == UINT_MAX / sizeof(*nodes)) {
74  av_freep(&h->priv_data);
75  return AVERROR(ENAMETOOLONG);
76  }
77  }
78  }
79 
80  if (!(nodes = av_realloc(NULL, sizeof(*nodes) * len)))
81  return AVERROR(ENOMEM);
82  else
83  data->nodes = nodes;
84 
85  /* handle input */
86  if (!*uri)
87  err = AVERROR(ENOENT);
88  for (i = 0; *uri; i++) {
89  /* parsing uri */
90  len = strcspn(uri, AV_CAT_SEPARATOR);
91  if ((err = av_reallocp(&node_uri, len + 1)) < 0)
92  break;
93  av_strlcpy(node_uri, uri, len + 1);
94  uri += len + strspn(uri + len, AV_CAT_SEPARATOR);
95 
96  /* creating URLContext */
97  if ((err = ffurl_open(&uc, node_uri, flags,
98  &h->interrupt_callback, NULL, h->protocols, h)) < 0)
99  break;
100 
101  /* creating size */
102  if ((size = ffurl_size(uc)) < 0) {
103  ffurl_close(uc);
104  err = AVERROR(ENOSYS);
105  break;
106  }
107 
108  /* assembling */
109  nodes[i].uc = uc;
110  nodes[i].size = size;
111  }
112  av_free(node_uri);
113  data->length = i;
114 
115  if (err < 0)
116  concat_close(h);
117  else if ((err = av_reallocp(&nodes, data->length * sizeof(*nodes))) < 0)
118  concat_close(h);
119  else
120  data->nodes = nodes;
121  return err;
122 }
123 
124 static int concat_read(URLContext *h, unsigned char *buf, int size)
125 {
126  int result, total = 0;
127  struct concat_data *data = h->priv_data;
128  struct concat_nodes *nodes = data->nodes;
129  size_t i = data->current;
130 
131  while (size > 0) {
132  result = ffurl_read(nodes[i].uc, buf, size);
133  if (result < 0)
134  return total ? total : result;
135  if (!result) {
136  if (i + 1 == data->length ||
137  ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)
138  break;
139  }
140  total += result;
141  buf += result;
142  size -= result;
143  }
144  data->current = i;
145  return total;
146 }
147 
148 static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
149 {
150  int64_t result;
151  struct concat_data *data = h->priv_data;
152  struct concat_nodes *nodes = data->nodes;
153  size_t i;
154 
155  switch (whence) {
156  case SEEK_END:
157  for (i = data->length - 1; i && pos < -nodes[i].size; i--)
158  pos += nodes[i].size;
159  break;
160  case SEEK_CUR:
161  /* get the absolute position */
162  for (i = 0; i != data->current; i++)
163  pos += nodes[i].size;
164  pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);
165  whence = SEEK_SET;
166  /* fall through with the absolute position */
167  case SEEK_SET:
168  for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)
169  pos -= nodes[i].size;
170  break;
171  default:
172  return AVERROR(EINVAL);
173  }
174 
175  result = ffurl_seek(nodes[i].uc, pos, whence);
176  if (result >= 0) {
177  data->current = i;
178  while (i)
179  result += nodes[--i].size;
180  }
181  return result;
182 }
183 
185  .name = "concat",
186  .url_open = concat_open,
187  .url_read = concat_read,
188  .url_seek = concat_seek,
189  .url_close = concat_close,
190  .priv_data_size = sizeof(struct concat_data),
191 };
static av_cold int concat_close(URLContext *h)
Definition: concat.c:43
memory handling functions
AVIOInterruptCB interrupt_callback
Definition: url.h:51
size_t length
number of cat&#39;ed nodes
Definition: concat.c:39
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:202
struct concat_nodes * nodes
list of nodes to concat
Definition: concat.c:38
#define av_cold
Definition: attributes.h:66
static int concat_read(URLContext *h, unsigned char *buf, int size)
Definition: concat.c:124
#define AV_CAT_SEPARATOR
Definition: concat.c:30
const char data[16]
Definition: mxf.c:70
int av_reallocp(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:140
static int flags
Definition: log.c:50
int ffurl_open(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const URLProtocol **protocols, URLContext *parent)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:175
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:190
#define AVERROR(e)
Definition: error.h:43
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:81
static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
Definition: concat.c:148
NULL
Definition: eval.c:55
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:330
static av_cold int concat_open(URLContext *h, const char *uri, int flags)
Definition: concat.c:58
Definition: url.h:38
void * priv_data
Definition: url.h:45
int64_t size
url filesize
Definition: concat.c:34
const char * name
Definition: url.h:56
int ffurl_close(URLContext *h)
Close the resource accessed by the URLContext h, and free the memory used by it.
Definition: avio.c:280
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:32
const struct URLProtocol ** protocols
A NULL-terminated list of protocols usable by the child contexts.
Definition: url.h:44
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:270
const URLProtocol ff_concat_protocol
Definition: concat.c:184
void * av_realloc(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:117
int len
size_t current
index of currently read node
Definition: concat.c:40
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:243
URLContext * uc
node&#39;s URLContext
Definition: concat.c:33