1 files changed, 58 insertions, 0 deletions
diff --git a/chromium/media/formats/mp4/cenc.cc b/chromium/media/formats/mp4/cenc.cc
new file mode 100644
index 00000000000..001b6d88161
--- /dev/null
+++ b/chromium/media/formats/mp4/cenc.cc
@@ -0,0 +1,58 @@
+// 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/cenc.h"
+
+#include <cstring>
+
+#include "media/formats/mp4/box_reader.h"
+#include "media/formats/mp4/rcheck.h"
+
+namespace media {
+namespace mp4 {
+
+FrameCENCInfo::FrameCENCInfo() {}
+FrameCENCInfo::~FrameCENCInfo() {}
+
+bool FrameCENCInfo::Parse(int iv_size, BufferReader* reader) {
+  const int kEntrySize = 6;
+  // Mandated by CENC spec
+  RCHECK(iv_size == 8 || iv_size == 16);
+
+  memset(iv, 0, sizeof(iv));
+  for (int i = 0; i < iv_size; i++)
+    RCHECK(reader->Read1(&iv[i]));
+
+  if (!reader->HasBytes(1)) return true;
+
+  uint16 subsample_count;
+  RCHECK(reader->Read2(&subsample_count) &&
+         reader->HasBytes(subsample_count * kEntrySize));
+
+  subsamples.resize(subsample_count);
+  for (int i = 0; i < subsample_count; i++) {
+    uint16 clear_bytes;
+    uint32 cypher_bytes;
+    RCHECK(reader->Read2(&clear_bytes) &&
+           reader->Read4(&cypher_bytes));
+    subsamples[i].clear_bytes = clear_bytes;
+    subsamples[i].cypher_bytes = cypher_bytes;
+  }
+  return true;
+}
+
+bool FrameCENCInfo::GetTotalSizeOfSubsamples(size_t* total_size) const {
+  size_t size = 0;
+  for (size_t i = 0; i < subsamples.size(); i++) {
+    size += subsamples[i].clear_bytes;
+    RCHECK(size >= subsamples[i].clear_bytes);  // overflow
+    size += subsamples[i].cypher_bytes;
+    RCHECK(size >= subsamples[i].cypher_bytes);  // overflow
+  }
+  *total_size = size;
+  return true;
+}
+
+}  // namespace mp4
+}  // namespace media