1 files changed, 49 insertions, 0 deletions
diff --git a/chromium/media/formats/mp4/sample_to_group_iterator.h b/chromium/media/formats/mp4/sample_to_group_iterator.h
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+++ b/chromium/media/formats/mp4/sample_to_group_iterator.h
@@ -0,0 +1,49 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_
+#define MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_
+
+#include <vector>
+
+#include "media/formats/mp4/box_definitions.h"
+
+namespace media {
+namespace mp4 {
+
+// Sample To Group Box ('sbgp') can be used to find the group that a sample
+// belongs to and the associated description of that sample group. It is
+// compactly coded though. This class implements the iterator to iterate
+// through the compressed table to get the associated sample group description
+// index.
+class MEDIA_EXPORT SampleToGroupIterator {
+ public:
+  explicit SampleToGroupIterator(const SampleToGroup& sample_to_group);
+  ~SampleToGroupIterator();
+
+  // Advances the iterator to refer to the next sample. Return status
+  // indicating whether the sample is still valid.
+  bool Advance();
+
+  // Returns whether the current sample is valid.
+  bool IsValid() const;
+
+  // Returns group description index for current sample.
+  uint32 group_description_index() const {
+    return iterator_->group_description_index;
+  }
+
+ private:
+  // Track how many samples remaining for current table entry.
+  uint32 remaining_samples_;
+  const std::vector<SampleToGroupEntry>& sample_to_group_table_;
+  std::vector<SampleToGroupEntry>::const_iterator iterator_;
+
+  DISALLOW_COPY_AND_ASSIGN(SampleToGroupIterator);
+};
+
+}  // namespace mp4
+}  // namespace media
+
+#endif  // MEDIA_FORMATS_MP4_SAMPLE_TO_GROUP_ITERATOR_H_