media/formats/mp4/sample_to_group_iterator.h

   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 #ifndef MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_
   6 #define MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_
   7
   8 #include <vector>
   9
  10 #include "media/formats/mp4/box_definitions.h"
  11
  12 namespace media {
  13 namespace mp4 {
  14
  15 // Sample To Group Box ('sbgp') can be used to find the group that a sample
  16 // belongs to and the associated description of that sample group. It is
  17 // compactly coded though. This class implements the iterator to iterate
  18 // through the compressed table to get the associated sample group description
  19 // index.
  20 class MEDIA_EXPORT SampleToGroupIterator {
  21  public:
  22   explicit SampleToGroupIterator(const SampleToGroup& sample_to_group);
  23   ~SampleToGroupIterator();
  24
  25   // Advances the iterator to refer to the next sample. Return status
  26   // indicating whether the sample is still valid.
  27   bool Advance();
  28
  29   // Returns whether the current sample is valid.
  30   bool IsValid() const;
  31
  32   // Returns group description index for current sample.
  33   uint32 group_description_index() const {
  34     return iterator_->group_description_index;
  35   }
  36
  37  private:
  38   // Track how many samples remaining for current table entry.
  39   uint32 remaining_samples_;
  40   const std::vector<SampleToGroupEntry>& sample_to_group_table_;
  41   std::vector<SampleToGroupEntry>::const_iterator iterator_;
  42
  43   DISALLOW_COPY_AND_ASSIGN(SampleToGroupIterator);
  44 };
  45
  46 }  // namespace mp4
  47 }  // namespace media
  48
  49 #endif  // MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_