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
  22 #include "libavutil/avstring.h"
  23 #include "libavcodec/opt.h"
  24 #include "avformat.h"
  25
  26 #if LIBAVFORMAT_VERSION_MAJOR >= 53
  27 /** @name Logging context. */
  28 /*@{*/
  29 static const char *urlcontext_to_name(void *ptr)
  30 {
  31     URLContext *h = (URLContext *)ptr;
  32     if(h->prot) return h->prot->name;
  33     else        return "NULL";
  34 }
  35 static const AVOption options[] = {{NULL}};
  36 static const AVClass urlcontext_class =
  37         { "URLContext", urlcontext_to_name, options };
  38 /*@}*/
  39 #endif
  40
  41 static int default_interrupt_cb(void);
  42
  43 URLProtocol *first_protocol = NULL;
  44 URLInterruptCB *url_interrupt_cb = default_interrupt_cb;
  45
  46 URLProtocol *av_protocol_next(URLProtocol *p)
  47 {
  48     if(p) return p->next;
  49     else  return first_protocol;
  50 }
  51
  52 int register_protocol(URLProtocol *protocol)
  53 {
  54     URLProtocol **p;
  55     p = &first_protocol;
  56     while (*p != NULL) p = &(*p)->next;
  57     *p = protocol;
  58     protocol->next = NULL;
  59     return 0;
  60 }
  61
  62 int url_open(URLContext **puc, const char *filename, int flags)
  63 {
  64     URLContext *uc;
  65     URLProtocol *up;
  66     const char *p;
  67     char proto_str[128], *q;
  68     int err;
  69
  70     p = filename;
  71     q = proto_str;
  72     while (*p != '\0' && *p != ':') {
  73         /* protocols can only contain alphabetic chars */
  74         if (!isalpha(*p))
  75             goto file_proto;
  76         if ((q - proto_str) < sizeof(proto_str) - 1)
  77             *q++ = *p;
  78         p++;
  79     }
  80     /* if the protocol has length 1, we consider it is a dos drive */
  81     if (*p == '\0' || (q - proto_str) <= 1) {
  82     file_proto:
  83         strcpy(proto_str, "file");
  84     } else {
  85         *q = '\0';
  86     }
  87
  88     up = first_protocol;
  89     while (up != NULL) {
  90         if (!strcmp(proto_str, up->name))
  91             goto found;
  92         up = up->next;
  93     }
  94     err = AVERROR(ENOENT);
  95     goto fail;
  96  found:
  97     uc = av_malloc(sizeof(URLContext) + strlen(filename) + 1);
  98     if (!uc) {
  99         err = AVERROR(ENOMEM);
 100         goto fail;
 101     }
 102 #if LIBAVFORMAT_VERSION_MAJOR >= 53
 103     uc->av_class = &urlcontext_class;
 104 #endif
 105     uc->filename = (char *) &uc[1];
 106     strcpy(uc->filename, filename);
 107     uc->prot = up;
 108     uc->flags = flags;
 109     uc->is_streamed = 0; /* default = not streamed */
 110     uc->max_packet_size = 0; /* default: stream file */
 111     err = up->url_open(uc, filename, flags);
 112     if (err < 0) {
 113         av_free(uc);
 114         *puc = NULL;
 115         return err;
 116     }
 117
 118     //We must be carefull here as url_seek() could be slow, for example for http
 119     if(   (flags & (URL_WRONLY | URL_RDWR))
 120        || !strcmp(proto_str, "file"))
 121         if(!uc->is_streamed && url_seek(uc, 0, SEEK_SET) < 0)
 122             uc->is_streamed= 1;
 123     *puc = uc;
 124     return 0;
 125  fail:
 126     *puc = NULL;
 127     return err;
 128 }
 129
 130 int url_read(URLContext *h, unsigned char *buf, int size)
 131 {
 132     int ret;
 133     if (h->flags & URL_WRONLY)
 134         return AVERROR(EIO);
 135     ret = h->prot->url_read(h, buf, size);
 136     return ret;
 137 }
 138
 139 int url_write(URLContext *h, unsigned char *buf, int size)
 140 {
 141     int ret;
 142     if (!(h->flags & (URL_WRONLY | URL_RDWR)))
 143         return AVERROR(EIO);
 144     /* avoid sending too big packets */
 145     if (h->max_packet_size && size > h->max_packet_size)
 146         return AVERROR(EIO);
 147     ret = h->prot->url_write(h, buf, size);
 148     return ret;
 149 }
 150
 151 offset_t url_seek(URLContext *h, offset_t pos, int whence)
 152 {
 153     offset_t ret;
 154
 155     if (!h->prot->url_seek)
 156         return AVERROR(EPIPE);
 157     ret = h->prot->url_seek(h, pos, whence);
 158     return ret;
 159 }
 160
 161 int url_close(URLContext *h)
 162 {
 163     int ret = 0;
 164     if (!h) return 0; /* can happen when url_open fails */
 165
 166     if (h->prot->url_close)
 167         ret = h->prot->url_close(h);
 168     av_free(h);
 169     return ret;
 170 }
 171
 172 int url_exist(const char *filename)
 173 {
 174     URLContext *h;
 175     if (url_open(&h, filename, URL_RDONLY) < 0)
 176         return 0;
 177     url_close(h);
 178     return 1;
 179 }
 180
 181 offset_t url_filesize(URLContext *h)
 182 {
 183     offset_t pos, size;
 184
 185     size= url_seek(h, 0, AVSEEK_SIZE);
 186     if(size<0){
 187         pos = url_seek(h, 0, SEEK_CUR);
 188         if ((size = url_seek(h, -1, SEEK_END)) < 0)
 189             return size;
 190         size++;
 191         url_seek(h, pos, SEEK_SET);
 192     }
 193     return size;
 194 }
 195
 196 int url_get_max_packet_size(URLContext *h)
 197 {
 198     return h->max_packet_size;
 199 }
 200
 201 void url_get_filename(URLContext *h, char *buf, int buf_size)
 202 {
 203     av_strlcpy(buf, h->filename, buf_size);
 204 }
 205
 206
 207 static int default_interrupt_cb(void)
 208 {
 209     return 0;
 210 }
 211
 212 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
 213 {
 214     if (!interrupt_cb)
 215         interrupt_cb = default_interrupt_cb;
 216     url_interrupt_cb = interrupt_cb;
 217 }
 218
 219 int av_url_read_pause(URLContext *h, int pause)
 220 {
 221     if (!h->prot->url_read_pause)
 222         return AVERROR(ENOSYS);
 223     return h->prot->url_read_pause(h, pause);
 224 }
 225
 226 offset_t av_url_read_seek(URLContext *h,
 227         int stream_index, int64_t timestamp, int flags)
 228 {
 229     if (!h->prot->url_read_seek)
 230         return AVERROR(ENOSYS);
 231     return h->prot->url_read_seek(h, stream_index, timestamp, flags);
 232 }