webmdec.c

/*
 *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "./webmdec.h"

#include <stdarg.h>

#include "nestegg/include/nestegg/nestegg.h"

static int nestegg_read_cb(void *buffer, size_t length, void *userdata) {
  FILE *f = userdata;

  if (fread(buffer, 1, length, f) < length) {
    if (ferror(f))
      return -1;
    if (feof(f))
      return 0;
  }
  return 1;
}

static int nestegg_seek_cb(int64_t offset, int whence, void *userdata) {
  switch (whence) {
    case NESTEGG_SEEK_SET:
      whence = SEEK_SET;
      break;
    case NESTEGG_SEEK_CUR:
      whence = SEEK_CUR;
      break;
    case NESTEGG_SEEK_END:
      whence = SEEK_END;
      break;
  };
  return fseek(userdata, (int32_t)offset, whence) ? -1 : 0;
}

static int64_t nestegg_tell_cb(void *userdata) {
  return ftell(userdata);
}

static void nestegg_log_cb(nestegg *context,
                           unsigned int severity,
                           char const *format, ...) {
  va_list ap;
  va_start(ap, format);
  vfprintf(stderr, format, ap);
  fprintf(stderr, "\n");
  va_end(ap);
}

int file_is_webm(struct WebmInputContext *webm_ctx,
                 struct VpxInputContext *vpx_ctx) {
  uint32_t i, n;
  int track_type = -1;
  int codec_id;

  nestegg_io io = {nestegg_read_cb, nestegg_seek_cb, nestegg_tell_cb, 0};
  nestegg_video_params params;

  io.userdata = vpx_ctx->file;
  if (nestegg_init(&webm_ctx->nestegg_ctx, io, NULL))
    goto fail;