1 files changed, 54 insertions, 0 deletions
diff --git a/dom/media/BitReader.h b/dom/media/BitReader.h
new file mode 100644
index 0000000000..21c28f2c8c
--- /dev/null
+++ b/dom/media/BitReader.h
@@ -0,0 +1,54 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BIT_READER_H_
+#define BIT_READER_H_
+
+#include "MediaData.h"
+
+namespace mozilla {
+
+class BitReader {
+ public:
+  explicit BitReader(const MediaByteBuffer* aBuffer);
+  BitReader(const MediaByteBuffer* aBuffer, size_t aBits);
+  BitReader(const uint8_t* aBuffer, size_t aBits);
+  ~BitReader();
+  uint32_t ReadBits(size_t aNum);
+  bool ReadBit() { return ReadBits(1) != 0; }
+  uint32_t ReadU32() { return ReadBits(32); }
+  uint64_t ReadU64();
+
+  // Read the UTF-8 sequence and convert it to its 64-bit UCS-4 encoded form.
+  // Return 0xfffffffffffffff if sequence was invalid.
+  uint64_t ReadUTF8();
+  // Read unsigned integer Exp-Golomb-coded.
+  uint32_t ReadUE();
+  // Read signed integer Exp-Golomb-coded.
+  int32_t ReadSE();
+  // Read unsigned integer Little Endian Base 128 coded.
+  // Limited to unsigned 64 bits.
+  CheckedUint64 ReadULEB128();
+
+  // Return the number of bits parsed so far;
+  size_t BitCount() const;
+  // Return the number of bits left.
+  size_t BitsLeft() const;
+
+  // Return RBSP bit length.
+  static uint32_t GetBitLength(const MediaByteBuffer* aNAL);
+
+ private:
+  void FillReservoir();
+  const uint8_t* mData;
+  const size_t mOriginalBitSize;
+  size_t mTotalBitsLeft;
+  size_t mSize;         // Size left in bytes
+  uint32_t mReservoir;  // Left-aligned bits
+  size_t mNumBitsLeft;  // Number of bits left in reservoir.
+};
+
+}  // namespace mozilla
+
+#endif  // BIT_READER_H_