416bbf5fc3bef1fcc36846f7c7fcc4194597836f
[libav.git] / libavformat / concat.c
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 "avformat.h"
25 #include "libavutil/avstring.h"
26 #include "libavutil/mem.h"
27 #include "url.h"
28
29 #define AV_CAT_SEPARATOR "|"
30
31 struct concat_nodes {
32 URLContext *uc; ///< node's URLContext
33 int64_t size; ///< url filesize
34 };
35
36 struct concat_data {
37 struct concat_nodes *nodes; ///< list of nodes to concat
38 size_t length; ///< number of cat'ed nodes
39 size_t current; ///< index of currently read node
40 };
41
42 static av_cold int concat_close(URLContext *h)
43 {
44 int err = 0;
45 size_t i;
46 struct concat_data *data = h->priv_data;
47 struct concat_nodes *nodes = data->nodes;
48
49 for (i = 0; i != data->length; i++)
50 err |= ffurl_close(nodes[i].uc);
51
52 av_freep(&data->nodes);
53
54 return err < 0 ? -1 : 0;
55 }
56
57 static av_cold int concat_open(URLContext *h, const char *uri, int flags)
58 {
59 char *node_uri = NULL;
60 int err = 0;
61 int64_t size;
62 size_t len, i;
63 URLContext *uc;
64 struct concat_data *data = h->priv_data;
65 struct concat_nodes *nodes;
66
67 av_strstart(uri, "concat:", &uri);
68
69 for (i = 0, len = 1; uri[i]; i++)
70 if (uri[i] == *AV_CAT_SEPARATOR)
71 /* integer overflow */
72 if (++len == UINT_MAX / sizeof(*nodes)) {
73 av_freep(&h->priv_data);
74 return AVERROR(ENAMETOOLONG);
75 }
76
77 if (!(nodes = av_realloc(NULL, sizeof(*nodes) * len))) {
78 return AVERROR(ENOMEM);
79 } else
80 data->nodes = nodes;
81
82 /* handle input */
83 if (!*uri)
84 err = AVERROR(ENOENT);
85 for (i = 0; *uri; i++) {
86 /* parsing uri */
87 len = strcspn(uri, AV_CAT_SEPARATOR);
88 if ((err = av_reallocp(&node_uri, len + 1)) < 0)
89 break;
90 av_strlcpy(node_uri, uri, len+1);
91 uri += len + strspn(uri+len, AV_CAT_SEPARATOR);
92
93 /* creating URLContext */
94 if ((err = ffurl_open(&uc, node_uri, flags,
95 &h->interrupt_callback, NULL)) < 0)
96 break;
97
98 /* creating size */
99 if ((size = ffurl_size(uc)) < 0) {
100 ffurl_close(uc);
101 err = AVERROR(ENOSYS);
102 break;
103 }
104
105 /* assembling */
106 nodes[i].uc = uc;
107 nodes[i].size = size;
108 }
109 av_free(node_uri);
110 data->length = i;
111
112 if (err < 0)
113 concat_close(h);
114 else if ((err = av_reallocp(&nodes, data->length * sizeof(*nodes))) < 0)
115 concat_close(h);
116 else
117 data->nodes = nodes;
118 return err;
119 }
120
121 static int concat_read(URLContext *h, unsigned char *buf, int size)
122 {
123 int result, total = 0;
124 struct concat_data *data = h->priv_data;
125 struct concat_nodes *nodes = data->nodes;
126 size_t i = data->current;
127
128 while (size > 0) {
129 result = ffurl_read(nodes[i].uc, buf, size);
130 if (result < 0)
131 return total ? total : result;
132 if (!result)
133 if (i + 1 == data->length ||
134 ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)
135 break;
136 total += result;
137 buf += result;
138 size -= result;
139 }
140 data->current = i;
141 return total;
142 }
143
144 static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
145 {
146 int64_t result;
147 struct concat_data *data = h->priv_data;
148 struct concat_nodes *nodes = data->nodes;
149 size_t i;
150
151 switch (whence) {
152 case SEEK_END:
153 for (i = data->length - 1;
154 i && pos < -nodes[i].size;
155 i--)
156 pos += nodes[i].size;
157 break;
158 case SEEK_CUR:
159 /* get the absolute position */
160 for (i = 0; i != data->current; i++)
161 pos += nodes[i].size;
162 pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);
163 whence = SEEK_SET;
164 /* fall through with the absolute position */
165 case SEEK_SET:
166 for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)
167 pos -= nodes[i].size;
168 break;
169 default:
170 return AVERROR(EINVAL);
171 }
172
173 result = ffurl_seek(nodes[i].uc, pos, whence);
174 if (result >= 0) {
175 data->current = i;
176 while (i)
177 result += nodes[--i].size;
178 }
179 return result;
180 }
181
182 URLProtocol ff_concat_protocol = {
183 .name = "concat",
184 .url_open = concat_open,
185 .url_read = concat_read,
186 .url_seek = concat_seek,
187 .url_close = concat_close,
188 .priv_data_size = sizeof(struct concat_data),
189 };