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 "os_support.h"
  25 #include "avformat.h"
  26
  27 #if LIBAVFORMAT_VERSION_MAJOR >= 53
  28 /** @name Logging context. */
  29 /*@{*/
  30 static const char *urlcontext_to_name(void *ptr)
  31 {
  32     URLContext *h = (URLContext *)ptr;
  33     if(h->prot) return h->prot->name;
  34     else        return "NULL";
  35 }
  36 static const AVOption options[] = {{NULL}};
  37 static const AVClass urlcontext_class =
  38         { "URLContext", urlcontext_to_name, options };
  39 /*@}*/
  40 #endif
  41
  42 static int default_interrupt_cb(void);
  43
  44 URLProtocol *first_protocol = NULL;
  45 URLInterruptCB *url_interrupt_cb = default_interrupt_cb;
  46
  47 URLProtocol *av_protocol_next(URLProtocol *p)
  48 {
  49     if(p) return p->next;
  50     else  return first_protocol;
  51 }
  52
  53 int register_protocol(URLProtocol *protocol)
  54 {
  55     URLProtocol **p;
  56     p = &first_protocol;
  57     while (*p != NULL) p = &(*p)->next;
  58     *p = protocol;
  59     protocol->next = NULL;
  60     return 0;
  61 }
  62
  63 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
  64                        const char *filename, int flags)
  65 {
  66     URLContext *uc;
  67     int err;
  68
  69     uc = av_malloc(sizeof(URLContext) + strlen(filename) + 1);
  70     if (!uc) {
  71         err = AVERROR(ENOMEM);
  72         goto fail;
  73     }
  74 #if LIBAVFORMAT_VERSION_MAJOR >= 53
  75     uc->av_class = &urlcontext_class;
  76 #endif
  77     uc->filename = (char *) &uc[1];
  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
  90     //We must be carefull here as url_seek() could be slow, for example for http
  91     if(   (flags & (URL_WRONLY | URL_RDWR))
  92        || !strcmp(up->name, "file"))
  93         if(!uc->is_streamed && url_seek(uc, 0, SEEK_SET) < 0)
  94             uc->is_streamed= 1;
  95     *puc = uc;
  96     return 0;
  97  fail:
  98     *puc = NULL;
  99     return err;
 100 }
 101
 102 int url_open(URLContext **puc, const char *filename, int flags)
 103 {
 104     URLProtocol *up;
 105     const char *p;
 106     char proto_str[128], *q;
 107
 108     p = filename;
 109     q = proto_str;
 110     while (*p != '\0' && *p != ':') {
 111         /* protocols can only contain alphabetic chars */
 112         if (!isalpha(*p))
 113             goto file_proto;
 114         if ((q - proto_str) < sizeof(proto_str) - 1)
 115             *q++ = *p;
 116         p++;
 117     }
 118     /* if the protocol has length 1, we consider it is a dos drive */
 119     if (*p == '\0' || is_dos_path(filename)) {
 120     file_proto:
 121         strcpy(proto_str, "file");
 122     } else {
 123         *q = '\0';
 124     }
 125
 126     up = first_protocol;
 127     while (up != NULL) {
 128         if (!strcmp(proto_str, up->name))
 129             return url_open_protocol (puc, up, filename, flags);
 130         up = up->next;
 131     }
 132     *puc = NULL;
 133     return AVERROR(ENOENT);
 134 }
 135
 136 int url_read(URLContext *h, unsigned char *buf, int size)
 137 {
 138     int ret;
 139     if (h->flags & URL_WRONLY)
 140         return AVERROR(EIO);
 141     ret = h->prot->url_read(h, buf, size);
 142     return ret;
 143 }
 144
 145 int url_write(URLContext *h, unsigned char *buf, int size)
 146 {
 147     int ret;
 148     if (!(h->flags & (URL_WRONLY | URL_RDWR)))
 149         return AVERROR(EIO);
 150     /* avoid sending too big packets */
 151     if (h->max_packet_size && size > h->max_packet_size)
 152         return AVERROR(EIO);
 153     ret = h->prot->url_write(h, buf, size);
 154     return ret;
 155 }
 156
 157 int64_t url_seek(URLContext *h, int64_t pos, int whence)
 158 {
 159     int64_t ret;
 160
 161     if (!h->prot->url_seek)
 162         return AVERROR(EPIPE);
 163     ret = h->prot->url_seek(h, pos, whence);
 164     return ret;
 165 }
 166
 167 int url_close(URLContext *h)
 168 {
 169     int ret = 0;
 170     if (!h) return 0; /* can happen when url_open fails */
 171
 172     if (h->prot->url_close)
 173         ret = h->prot->url_close(h);
 174     av_free(h);
 175     return ret;
 176 }
 177
 178 int url_exist(const char *filename)
 179 {
 180     URLContext *h;
 181     if (url_open(&h, filename, URL_RDONLY) < 0)
 182         return 0;
 183     url_close(h);
 184     return 1;
 185 }
 186
 187 int64_t url_filesize(URLContext *h)
 188 {
 189     int64_t pos, size;
 190
 191     size= url_seek(h, 0, AVSEEK_SIZE);
 192     if(size<0){
 193         pos = url_seek(h, 0, SEEK_CUR);
 194         if ((size = url_seek(h, -1, SEEK_END)) < 0)
 195             return size;
 196         size++;
 197         url_seek(h, pos, SEEK_SET);
 198     }
 199     return size;
 200 }
 201
 202 int url_get_max_packet_size(URLContext *h)
 203 {
 204     return h->max_packet_size;
 205 }
 206
 207 void url_get_filename(URLContext *h, char *buf, int buf_size)
 208 {
 209     av_strlcpy(buf, h->filename, buf_size);
 210 }
 211
 212
 213 static int default_interrupt_cb(void)
 214 {
 215     return 0;
 216 }
 217
 218 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
 219 {
 220     if (!interrupt_cb)
 221         interrupt_cb = default_interrupt_cb;
 222     url_interrupt_cb = interrupt_cb;
 223 }
 224
 225 int av_url_read_pause(URLContext *h, int pause)
 226 {
 227     if (!h->prot->url_read_pause)
 228         return AVERROR(ENOSYS);
 229     return h->prot->url_read_pause(h, pause);
 230 }
 231
 232 int64_t av_url_read_seek(URLContext *h,
 233         int stream_index, int64_t timestamp, int flags)
 234 {
 235     if (!h->prot->url_read_seek)
 236         return AVERROR(ENOSYS);
 237     return h->prot->url_read_seek(h, stream_index, timestamp, flags);
 238 }