libav/avio.c

   1 /*
   2  * Unbuffered io for ffmpeg system
   3  * Copyright (c) 2001 Fabrice Bellard
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avformat.h"
  20
  21 URLProtocol *first_protocol = NULL;
  22
  23 int register_protocol(URLProtocol *protocol)
  24 {
  25     URLProtocol **p;
  26     p = &first_protocol;
  27     while (*p != NULL) p = &(*p)->next;
  28     *p = protocol;
  29     protocol->next = NULL;
  30     return 0;
  31 }
  32
  33 int url_open(URLContext **puc, const char *filename, int flags)
  34 {
  35     URLContext *uc;
  36     URLProtocol *up;
  37     const char *p;
  38     char proto_str[128], *q;
  39     int err;
  40
  41     p = filename;
  42     q = proto_str;
  43     while (*p != '\0' && *p != ':') {
  44         if ((q - proto_str) < sizeof(proto_str) - 1)
  45             *q++ = *p;
  46         p++;
  47     }
  48     /* if the protocol has length 1, we consider it is a dos drive */
  49     if (*p == '\0' || (q - proto_str) <= 1) {
  50         strcpy(proto_str, "file");
  51     } else {
  52         *q = '\0';
  53     }
  54
  55     up = first_protocol;
  56     while (up != NULL) {
  57         if (!strcmp(proto_str, up->name))
  58             goto found;
  59         up = up->next;
  60     }
  61     return -ENOENT;
  62  found:
  63     uc = av_malloc(sizeof(URLContext));
  64     if (!uc)
  65         return -ENOMEM;
  66     uc->prot = up;
  67     uc->flags = flags;
  68     uc->is_streamed = 0; /* default = not streamed */
  69     uc->packet_size = 1; /* default packet size */
  70     err = up->url_open(uc, filename, flags);
  71     if (err < 0) {
  72         av_free(uc);
  73         *puc = NULL;
  74         return err;
  75     }
  76     *puc = uc;
  77     return 0;
  78 }
  79
  80 int url_read(URLContext *h, unsigned char *buf, int size)
  81 {
  82     int ret;
  83     if (h->flags & URL_WRONLY)
  84         return -EIO;
  85     ret = h->prot->url_read(h, buf, size);
  86     return ret;
  87 }
  88
  89 int url_write(URLContext *h, unsigned char *buf, int size)
  90 {
  91     int ret;
  92     if (!(h->flags & URL_WRONLY))
  93         return -EIO;
  94     ret = h->prot->url_write(h, buf, size);
  95     return ret;
  96 }
  97
  98 offset_t url_seek(URLContext *h, offset_t pos, int whence)
  99 {
 100     offset_t ret;
 101
 102     if (!h->prot->url_seek)
 103         return -EPIPE;
 104     ret = h->prot->url_seek(h, pos, whence);
 105     return ret;
 106 }
 107
 108 int url_close(URLContext *h)
 109 {
 110     int ret;
 111
 112     ret = h->prot->url_close(h);
 113     av_free(h);
 114     return ret;
 115 }
 116
 117 int url_exist(const char *filename)
 118 {
 119     URLContext *h;
 120     if (url_open(&h, filename, URL_RDONLY) < 0)
 121         return 0;
 122     url_close(h);
 123     return 1;
 124 }
 125
 126 offset_t url_filesize(URLContext *h)
 127 {
 128     offset_t pos, size;
 129
 130     pos = url_seek(h, 0, SEEK_CUR);
 131     size = url_seek(h, 0, SEEK_END);
 132     url_seek(h, pos, SEEK_SET);
 133     return size;
 134 }