media/formats/mp4/sample_to_group_iterator.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/formats/mp4/sample_to_group_iterator.h"
   6
   7 #include "base/logging.h"
   8
   9 namespace media {
  10 namespace mp4 {
  11
  12 SampleToGroupIterator::SampleToGroupIterator(
  13     const SampleToGroup& sample_to_group)
  14     : remaining_samples_(0),
  15       sample_to_group_table_(sample_to_group.entries),
  16       iterator_(sample_to_group_table_.begin()) {
  17   // Handle the case that the table contains an entry with sample count 0.
  18   while (iterator_ != sample_to_group_table_.end()) {
  19     remaining_samples_ = iterator_->sample_count;
  20     if (remaining_samples_ > 0)
  21       break;
  22     ++iterator_;
  23   }
  24 }
  25
  26 SampleToGroupIterator::~SampleToGroupIterator() {}
  27
  28 bool SampleToGroupIterator::Advance() {
  29   DCHECK(IsValid());
  30
  31   --remaining_samples_;
  32   // Handle the case that the table contains an entry with sample count 0.
  33   while (remaining_samples_ == 0) {
  34     ++iterator_;
  35     if (iterator_ == sample_to_group_table_.end())
  36       return false;
  37     remaining_samples_ = iterator_->sample_count;
  38   }
  39   return true;
  40 }
  41
  42 bool SampleToGroupIterator::IsValid() const {
  43   return remaining_samples_ > 0;
  44 }
  45
  46 }  // namespace mp4
  47 }  // namespace media