dc40384fc504588116593e693e5b6b57ea7726ee
[libav.git] / libavformat / avio.c
1 /*
2 * Unbuffered io for ffmpeg system
3 * Copyright (c) 2001 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21 #include "avformat.h"
22
23 static int default_interrupt_cb(void);
24
25 URLProtocol *first_protocol = NULL;
26 URLInterruptCB *url_interrupt_cb = default_interrupt_cb;
27
28 int register_protocol(URLProtocol *protocol)
29 {
30 URLProtocol **p;
31 p = &first_protocol;
32 while (*p != NULL) p = &(*p)->next;
33 *p = protocol;
34 protocol->next = NULL;
35 return 0;
36 }
37
38 int url_open(URLContext **puc, const char *filename, int flags)
39 {
40 URLContext *uc;
41 URLProtocol *up;
42 const char *p;
43 char proto_str[128], *q;
44 int err;
45
46 p = filename;
47 q = proto_str;
48 while (*p != '\0' && *p != ':') {
49 /* protocols can only contain alphabetic chars */
50 if (!isalpha(*p))
51 goto file_proto;
52 if ((q - proto_str) < sizeof(proto_str) - 1)
53 *q++ = *p;
54 p++;
55 }
56 /* if the protocol has length 1, we consider it is a dos drive */
57 if (*p == '\0' || (q - proto_str) <= 1) {
58 file_proto:
59 strcpy(proto_str, "file");
60 } else {
61 *q = '\0';
62 }
63
64 up = first_protocol;
65 while (up != NULL) {
66 if (!strcmp(proto_str, up->name))
67 goto found;
68 up = up->next;
69 }
70 err = -ENOENT;
71 goto fail;
72 found:
73 uc = av_malloc(sizeof(URLContext) + strlen(filename));
74 if (!uc) {
75 err = -ENOMEM;
76 goto fail;
77 }
78 strcpy(uc->filename, filename);
79 uc->prot = up;
80 uc->flags = flags;
81 uc->is_streamed = 0; /* default = not streamed */
82 uc->max_packet_size = 0; /* default: stream file */
83 err = up->url_open(uc, filename, flags);
84 if (err < 0) {
85 av_free(uc);
86 *puc = NULL;
87 return err;
88 }
89 *puc = uc;
90 return 0;
91 fail:
92 *puc = NULL;
93 return err;
94 }
95
96 int url_read(URLContext *h, unsigned char *buf, int size)
97 {
98 int ret;
99 if (h->flags & URL_WRONLY)
100 return AVERROR_IO;
101 ret = h->prot->url_read(h, buf, size);
102 return ret;
103 }
104
105 #if defined(CONFIG_MUXERS) || defined(CONFIG_PROTOCOLS)
106 int url_write(URLContext *h, unsigned char *buf, int size)
107 {
108 int ret;
109 if (!(h->flags & (URL_WRONLY | URL_RDWR)))
110 return AVERROR_IO;
111 /* avoid sending too big packets */
112 if (h->max_packet_size && size > h->max_packet_size)
113 return AVERROR_IO;
114 ret = h->prot->url_write(h, buf, size);
115 return ret;
116 }
117 #endif //CONFIG_MUXERS || CONFIG_PROTOCOLS
118
119 offset_t url_seek(URLContext *h, offset_t pos, int whence)
120 {
121 offset_t ret;
122
123 if (!h->prot->url_seek)
124 return -EPIPE;
125 ret = h->prot->url_seek(h, pos, whence);
126 return ret;
127 }
128
129 int url_close(URLContext *h)
130 {
131 int ret;
132
133 ret = h->prot->url_close(h);
134 av_free(h);
135 return ret;
136 }
137
138 int url_exist(const char *filename)
139 {
140 URLContext *h;
141 if (url_open(&h, filename, URL_RDONLY) < 0)
142 return 0;
143 url_close(h);
144 return 1;
145 }
146
147 offset_t url_filesize(URLContext *h)
148 {
149 offset_t pos, size;
150
151 size= url_seek(h, 0, AVSEEK_SIZE);
152 if(size<0){
153 pos = url_seek(h, 0, SEEK_CUR);
154 size = url_seek(h, -1, SEEK_END)+1;
155 url_seek(h, pos, SEEK_SET);
156 }
157 return size;
158 }
159
160 /*
161 * Return the maximum packet size associated to packetized file
162 * handle. If the file is not packetized (stream like http or file on
163 * disk), then 0 is returned.
164 *
165 * @param h file handle
166 * @return maximum packet size in bytes
167 */
168 int url_get_max_packet_size(URLContext *h)
169 {
170 return h->max_packet_size;
171 }
172
173 void url_get_filename(URLContext *h, char *buf, int buf_size)
174 {
175 pstrcpy(buf, buf_size, h->filename);
176 }
177
178
179 static int default_interrupt_cb(void)
180 {
181 return 0;
182 }
183
184 /**
185 * The callback is called in blocking functions to test regulary if
186 * asynchronous interruption is needed. -EINTR is returned in this
187 * case by the interrupted function. 'NULL' means no interrupt
188 * callback is given.
189 */
190 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
191 {
192 if (!interrupt_cb)
193 interrupt_cb = default_interrupt_cb;
194 url_interrupt_cb = interrupt_cb;
195 }