Split the bit reader functionalities from the byte stream provider.

media/base/bit_reader_h264.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.

[acolwell GONE FROM CHROMIUM, 2014/01/11 00:24:37]

s/2013/2014

[damienv1, 2014/01/13 22:41:06]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_BIT_READER_H264_H_
+#define MEDIA_BASE_BIT_READER_H264_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/bit_reader_core.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT BitReaderH264

[acolwell GONE FROM CHROMIUM, 2014/01/11 00:24:37]

I'm assuming you're removing this before landing since it isn't used by
production code yet.

[damienv1, 2014/01/13 22:41:06]

Correct. Will fix the nits and remove it after that (will be part of a different
CL).

+    : NON_EXPORTED_BASE(private BitReaderCore::ByteStreamProvider)  {
+ public:
+  // Initialize the reader to start reading at |data|, |size| being size
+  // of |data| in bytes.
+  BitReaderH264(const uint8* data, int size);
+  virtual ~BitReaderH264();
+
+  template<typename T> bool ReadBits(int num_bits, T* out) {
+    return bit_reader_core_.ReadBits(num_bits, out);
+  }
+
+  bool ReadFlag(bool* flag) {
+    return bit_reader_core_.ReadFlag(flag);
+  }
+
+  bool SkipBits(int num_bits) {
+    return bit_reader_core_.SkipBits(num_bits);
+  }
+
+  int bits_read() const {
+    return bit_reader_core_.bits_read();
+  }
+
+  // Read an unsigned exp-golomb value and optionaly return the Exp-Golomb
+  // code size in |*code_size|.
+  // Return false if not successful, that can be the case:
+  // - if the end of stream has been reached, the code size is set to -1,
+  // - if the Exp-Glomb code size is too long,
+  //   i.e greater than |kMaxExpGolombCodeSize|.
+  bool ReadUE(uint32* out, int* code_size = NULL);
+
+  // See the definition of more_rbsp_data() in spec.
+  bool HasMoreRBSPData();
+
+  static const int kMaxExpGolombCodeSize;
+
+ private:
+  // BitReaderCore::ByteStreamProvider implementation.
+  virtual int GetBytes(int max_n, const uint8** out) OVERRIDE;
+
+  int ReadUEInternal(uint32* out);
+
+  // Pointer to the next unread byte in the stream.
+  const uint8* data_;
+
+  // Bytes left in the stream.
+  int bytes_left_;
+
+  // Array used to return some bytes when some start code emulation prevention
+  // bytes are detected.
+  uint8 data_window_[8];
+
+  // Last two bytes read from the stream.
+  uint32 prev_two_bytes_;
+
+  BitReaderCore bit_reader_core_;
+
+  DISALLOW_COPY_AND_ASSIGN(BitReaderH264);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_BIT_READER_H264_H_