path: root/libavformat/concat.c (plain)
blob: 46b520fe8044364d770b34561eac3f66dc29c78c

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	};
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	if (!av_strstart(uri, "concat:", &uri)) {
69	av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);
70	return AVERROR(EINVAL);
71	}
72
73	for (i = 0, len = 1; uri[i]; i++) {
74	if (uri[i] == *AV_CAT_SEPARATOR) {
75	/* integer overflow */
76	if (++len == UINT_MAX / sizeof(*nodes)) {
77	av_freep(&h->priv_data);
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,
101	&h->interrupt_callback, NULL, h->protocol_whitelist, h->protocol_blacklist, h);
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	}
116	av_free(node_uri);
117	data->length = i;
118
119	if (err < 0)
120	concat_close(h);
121	else if (!(nodes = av_realloc(nodes, data->length * sizeof(*nodes)))) {
122	concat_close(h);
123	err = AVERROR(ENOMEM);
124	} else
125	data->nodes = nodes;
126	return err;
127	}
128
129	static int concat_read(URLContext *h, unsigned char *buf, int size)
130	{
131	int result, total = 0;
132	struct concat_data *data = h->priv_data;
133	struct concat_nodes *nodes = data->nodes;
134	size_t i = data->current;
135
136	while (size > 0) {
137	result = ffurl_read(nodes[i].uc, buf, size);
138	if (result < 0)
139	return total ? total : result;
140	if (!result) {
141	if (i + 1 == data->length ||
142	ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)
143	break;
144	}
145	total += result;
146	buf += result;
147	size -= result;
148	}
149	data->current = i;
150	return total;
151	}
152
153	static int64_t concat_seek(URLContext *h, int64_t pos, int whence)
154	{
155	int64_t result;
156	struct concat_data *data = h->priv_data;
157	struct concat_nodes *nodes = data->nodes;
158	size_t i;
159
160	switch (whence) {
161	case SEEK_END:
162	for (i = data->length - 1; i && pos < -nodes[i].size; i--)
163	pos += nodes[i].size;
164	break;
165	case SEEK_CUR:
166	/* get the absolute position */
167	for (i = 0; i != data->current; i++)
168	pos += nodes[i].size;
169	pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);
170	whence = SEEK_SET;
171	/* fall through with the absolute position */
172	case SEEK_SET:
173	for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)
174	pos -= nodes[i].size;
175	break;
176	default:
177	return AVERROR(EINVAL);
178	}
179
180	result = ffurl_seek(nodes[i].uc, pos, whence);
181	if (result >= 0) {
182	data->current = i;
183	while (i)
184	result += nodes[--i].size;
185	}
186	return result;
187	}
188
189	const URLProtocol ff_concat_protocol = {
190	.name = "concat",
191	.url_open = concat_open,
192	.url_read = concat_read,
193	.url_seek = concat_seek,
194	.url_close = concat_close,
195	.priv_data_size = sizeof(struct concat_data),
196	.default_whitelist = "concat,file,subfile",
197	};
198