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libavformat/avio.c

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00001 /*
00002  * Unbuffered io for ffmpeg system
00003  * Copyright (c) 2001 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/avstring.h"
00023 #include "libavcodec/opt.h"
00024 #include "os_support.h"
00025 #include "avformat.h"
00026 
00027 #if LIBAVFORMAT_VERSION_MAJOR >= 53
00028 
00030 static const char *urlcontext_to_name(void *ptr)
00031 {
00032     URLContext *h = (URLContext *)ptr;
00033     if(h->prot) return h->prot->name;
00034     else        return "NULL";
00035 }
00036 static const AVOption options[] = {{NULL}};
00037 static const AVClass urlcontext_class =
00038         { "URLContext", urlcontext_to_name, options };
00040 #endif
00041 
00042 static int default_interrupt_cb(void);
00043 
00044 URLProtocol *first_protocol = NULL;
00045 URLInterruptCB *url_interrupt_cb = default_interrupt_cb;
00046 
00047 URLProtocol *av_protocol_next(URLProtocol *p)
00048 {
00049     if(p) return p->next;
00050     else  return first_protocol;
00051 }
00052 
00053 int av_register_protocol(URLProtocol *protocol)
00054 {
00055     URLProtocol **p;
00056     p = &first_protocol;
00057     while (*p != NULL) p = &(*p)->next;
00058     *p = protocol;
00059     protocol->next = NULL;
00060     return 0;
00061 }
00062 
00063 #if LIBAVFORMAT_VERSION_MAJOR < 53
00064 int register_protocol(URLProtocol *protocol)
00065 {
00066     return av_register_protocol(protocol);
00067 }
00068 #endif
00069 
00070 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
00071                        const char *filename, int flags)
00072 {
00073     URLContext *uc;
00074     int err;
00075 
00076     uc = av_malloc(sizeof(URLContext) + strlen(filename) + 1);
00077     if (!uc) {
00078         err = AVERROR(ENOMEM);
00079         goto fail;
00080     }
00081 #if LIBAVFORMAT_VERSION_MAJOR >= 53
00082     uc->av_class = &urlcontext_class;
00083 #endif
00084     uc->filename = (char *) &uc[1];
00085     strcpy(uc->filename, filename);
00086     uc->prot = up;
00087     uc->flags = flags;
00088     uc->is_streamed = 0; /* default = not streamed */
00089     uc->max_packet_size = 0; /* default: stream file */
00090     err = up->url_open(uc, filename, flags);
00091     if (err < 0) {
00092         av_free(uc);
00093         *puc = NULL;
00094         return err;
00095     }
00096 
00097     //We must be carefull here as url_seek() could be slow, for example for http
00098     if(   (flags & (URL_WRONLY | URL_RDWR))
00099        || !strcmp(up->name, "file"))
00100         if(!uc->is_streamed && url_seek(uc, 0, SEEK_SET) < 0)
00101             uc->is_streamed= 1;
00102     *puc = uc;
00103     return 0;
00104  fail:
00105     *puc = NULL;
00106     return err;
00107 }
00108 
00109 int url_open(URLContext **puc, const char *filename, int flags)
00110 {
00111     URLProtocol *up;
00112     const char *p;
00113     char proto_str[128], *q;
00114 
00115     p = filename;
00116     q = proto_str;
00117     while (*p != '\0' && *p != ':') {
00118         /* protocols can only contain alphabetic chars */
00119         if (!isalpha(*p))
00120             goto file_proto;
00121         if ((q - proto_str) < sizeof(proto_str) - 1)
00122             *q++ = *p;
00123         p++;
00124     }
00125     /* if the protocol has length 1, we consider it is a dos drive */
00126     if (*p == '\0' || is_dos_path(filename)) {
00127     file_proto:
00128         strcpy(proto_str, "file");
00129     } else {
00130         *q = '\0';
00131     }
00132 
00133     up = first_protocol;
00134     while (up != NULL) {
00135         if (!strcmp(proto_str, up->name))
00136             return url_open_protocol (puc, up, filename, flags);
00137         up = up->next;
00138     }
00139     *puc = NULL;
00140     return AVERROR(ENOENT);
00141 }
00142 
00143 int url_read(URLContext *h, unsigned char *buf, int size)
00144 {
00145     int ret;
00146     if (h->flags & URL_WRONLY)
00147         return AVERROR(EIO);
00148     ret = h->prot->url_read(h, buf, size);
00149     return ret;
00150 }
00151 
00152 int url_write(URLContext *h, unsigned char *buf, int size)
00153 {
00154     int ret;
00155     if (!(h->flags & (URL_WRONLY | URL_RDWR)))
00156         return AVERROR(EIO);
00157     /* avoid sending too big packets */
00158     if (h->max_packet_size && size > h->max_packet_size)
00159         return AVERROR(EIO);
00160     ret = h->prot->url_write(h, buf, size);
00161     return ret;
00162 }
00163 
00164 int64_t url_seek(URLContext *h, int64_t pos, int whence)
00165 {
00166     int64_t ret;
00167 
00168     if (!h->prot->url_seek)
00169         return AVERROR(EPIPE);
00170     ret = h->prot->url_seek(h, pos, whence);
00171     return ret;
00172 }
00173 
00174 int url_close(URLContext *h)
00175 {
00176     int ret = 0;
00177     if (!h) return 0; /* can happen when url_open fails */
00178 
00179     if (h->prot->url_close)
00180         ret = h->prot->url_close(h);
00181     av_free(h);
00182     return ret;
00183 }
00184 
00185 int url_exist(const char *filename)
00186 {
00187     URLContext *h;
00188     if (url_open(&h, filename, URL_RDONLY) < 0)
00189         return 0;
00190     url_close(h);
00191     return 1;
00192 }
00193 
00194 int64_t url_filesize(URLContext *h)
00195 {
00196     int64_t pos, size;
00197 
00198     size= url_seek(h, 0, AVSEEK_SIZE);
00199     if(size<0){
00200         pos = url_seek(h, 0, SEEK_CUR);
00201         if ((size = url_seek(h, -1, SEEK_END)) < 0)
00202             return size;
00203         size++;
00204         url_seek(h, pos, SEEK_SET);
00205     }
00206     return size;
00207 }
00208 
00209 int url_get_max_packet_size(URLContext *h)
00210 {
00211     return h->max_packet_size;
00212 }
00213 
00214 void url_get_filename(URLContext *h, char *buf, int buf_size)
00215 {
00216     av_strlcpy(buf, h->filename, buf_size);
00217 }
00218 
00219 
00220 static int default_interrupt_cb(void)
00221 {
00222     return 0;
00223 }
00224 
00225 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
00226 {
00227     if (!interrupt_cb)
00228         interrupt_cb = default_interrupt_cb;
00229     url_interrupt_cb = interrupt_cb;
00230 }
00231 
00232 int av_url_read_pause(URLContext *h, int pause)
00233 {
00234     if (!h->prot->url_read_pause)
00235         return AVERROR(ENOSYS);
00236     return h->prot->url_read_pause(h, pause);
00237 }
00238 
00239 int64_t av_url_read_seek(URLContext *h,
00240         int stream_index, int64_t timestamp, int flags)
00241 {
00242     if (!h->prot->url_read_seek)
00243         return AVERROR(ENOSYS);
00244     return h->prot->url_read_seek(h, stream_index, timestamp, flags);
00245 }

Generated on Sat Feb 16 2013 09:23:14 for ffmpeg by  doxygen 1.7.1