/*
  * Format register and lookup
  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "avformat.h"
 #include "internal.h"

 #include "libavutil/atomic.h"

 #include "libavutil/avstring.h"
 
 /**
  * @file
  * Format register and lookup
  */
 /** head of registered input format linked list */
 static AVInputFormat *first_iformat = NULL;
 /** head of registered output format linked list */
 static AVOutputFormat *first_oformat = NULL;
 

 static AVInputFormat **last_iformat = &first_iformat;
 static AVOutputFormat **last_oformat = &first_oformat;
 

 AVInputFormat *av_iformat_next(AVInputFormat *f)
 {
     if (f)
         return f->next;
     else
         return first_iformat;
 }
 
 AVOutputFormat *av_oformat_next(AVOutputFormat *f)
 {
     if (f)
         return f->next;
     else
         return first_oformat;
 }
 
 void av_register_input_format(AVInputFormat *format)
 {

     AVInputFormat **p = last_iformat;

 
     format->next = NULL;

     while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))

         p = &(*p)->next;

     last_iformat = &format->next;

 }
 
 void av_register_output_format(AVOutputFormat *format)
 {

     AVOutputFormat **p = last_oformat;

 
     format->next = NULL;

     while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))

         p = &(*p)->next;

     last_oformat = &format->next;

 }
 
 int av_match_ext(const char *filename, const char *extensions)
 {
     const char *ext, *p;
     char ext1[32], *q;
 
     if (!filename)
         return 0;
 
     ext = strrchr(filename, '.');
     if (ext) {
         ext++;
         p = extensions;
         for (;;) {
             q = ext1;
             while (*p != '\0' && *p != ','  && q - ext1 < sizeof(ext1) - 1)
                 *q++ = *p++;
             *q = '\0';
             if (!av_strcasecmp(ext1, ext))
                 return 1;
             if (*p == '\0')
                 break;
             p++;
         }
     }
     return 0;
 }
 
 static int match_format(const char *name, const char *names)
 {
     const char *p;
     int len, namelen;
 
     if (!name || !names)
         return 0;
 
     namelen = strlen(name);
     while ((p = strchr(names, ','))) {
         len = FFMAX(p - names, namelen);
         if (!av_strncasecmp(name, names, len))
             return 1;
         names = p + 1;
     }
     return !av_strcasecmp(name, names);
 }
 
 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
                                 const char *mime_type)
 {
     AVOutputFormat *fmt = NULL, *fmt_found;
     int score_max, score;
 
     /* specific test for image sequences */
 #if CONFIG_IMAGE2_MUXER
     if (!short_name && filename &&
         av_filename_number_test(filename) &&
         ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
         return av_guess_format("image2", NULL, NULL);
     }
 #endif
     /* Find the proper file type. */
     fmt_found = NULL;
     score_max = 0;
     while ((fmt = av_oformat_next(fmt))) {
         score = 0;

         if (fmt->name && short_name && match_format(short_name, fmt->name))

             score += 100;
         if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
             score += 10;
         if (filename && fmt->extensions &&
             av_match_ext(filename, fmt->extensions)) {
             score += 5;
         }
         if (score > score_max) {
             score_max = score;
             fmt_found = fmt;
         }
     }
     return fmt_found;
 }
 
 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
                               const char *filename, const char *mime_type,
                               enum AVMediaType type)
 {

     if (!strcmp(fmt->name, "segment") || !strcmp(fmt->name, "ssegment")) {
         fmt = av_guess_format(NULL, filename, NULL);
     }
 

     if (type == AVMEDIA_TYPE_VIDEO) {
         enum AVCodecID codec_id = AV_CODEC_ID_NONE;
 
 #if CONFIG_IMAGE2_MUXER
         if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
             codec_id = ff_guess_image2_codec(filename);
         }
 #endif
         if (codec_id == AV_CODEC_ID_NONE)
             codec_id = fmt->video_codec;
         return codec_id;
     } else if (type == AVMEDIA_TYPE_AUDIO)
         return fmt->audio_codec;
     else if (type == AVMEDIA_TYPE_SUBTITLE)
         return fmt->subtitle_codec;
     else
         return AV_CODEC_ID_NONE;
 }
 
 AVInputFormat *av_find_input_format(const char *short_name)
 {
     AVInputFormat *fmt = NULL;
     while ((fmt = av_iformat_next(fmt)))
         if (match_format(short_name, fmt->name))
             return fmt;
     return NULL;
 }