1 files changed, 47 insertions, 0 deletions
diff --git a/chromium/media/formats/mp4/sample_to_group_iterator.cc b/chromium/media/formats/mp4/sample_to_group_iterator.cc
new file mode 100644
index 00000000000..01c707292d7
--- /dev/null
+++ b/chromium/media/formats/mp4/sample_to_group_iterator.cc
@@ -0,0 +1,47 @@
+// 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.
+
+#include "media/formats/mp4/sample_to_group_iterator.h"
+
+#include "base/logging.h"
+
+namespace media {
+namespace mp4 {
+
+SampleToGroupIterator::SampleToGroupIterator(
+    const SampleToGroup& sample_to_group)
+    : remaining_samples_(0),
+      sample_to_group_table_(sample_to_group.entries),
+      iterator_(sample_to_group_table_.begin()) {
+  // Handle the case that the table contains an entry with sample count 0.
+  while (iterator_ != sample_to_group_table_.end()) {
+    remaining_samples_ = iterator_->sample_count;
+    if (remaining_samples_ > 0)
+      break;
+    ++iterator_;
+  }
+}
+
+SampleToGroupIterator::~SampleToGroupIterator() {}
+
+bool SampleToGroupIterator::Advance() {
+  DCHECK(IsValid());
+
+  --remaining_samples_;
+  // Handle the case that the table contains an entry with sample count 0.
+  while (remaining_samples_ == 0) {
+    ++iterator_;
+    if (iterator_ == sample_to_group_table_.end())
+      return false;
+    remaining_samples_ = iterator_->sample_count;
+  }
+  return true;
+}
+
+bool SampleToGroupIterator::IsValid() const {
+  return remaining_samples_ > 0;
+}
+
+}  // namespace mp4
+}  // namespace media