2fb3ba9059a857f8f92cb40d0d006940f70109aa
[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 "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 };
42
43 static av_cold int concat_close(URLContext *h)
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)) < 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
184 URLProtocol ff_concat_protocol = {
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 };