Move H264Parser and H264BitReader to media/filters.

content/common/gpu/media/h264_bit_reader.cc

-// Copyright (c) 2012 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 "content/common/gpu/media/h264_bit_reader.h"
-#include "base/logging.h"
-
-namespace content {
-
-H264BitReader::H264BitReader()
-    : data_(NULL), bytes_left_(0), curr_byte_(0),
-      num_remaining_bits_in_curr_byte_(0), prev_two_bytes_(0),
-      emulation_prevention_bytes_(0) {
-}
-
-H264BitReader::~H264BitReader() {}
-
-bool H264BitReader::Initialize(const uint8* data, off_t size) {
-  DCHECK(data);
-
-  if (size < 1)
-    return false;
-
-  data_ = data;
-  bytes_left_ = size;
-  num_remaining_bits_in_curr_byte_ = 0;
-  // Initially set to 0xffff to accept all initial two-byte sequences.
-  prev_two_bytes_ = 0xffff;
-  emulation_prevention_bytes_ = 0;
-
-  return true;
-}
-
-bool H264BitReader::UpdateCurrByte() {
-  if (bytes_left_ < 1)
-    return false;
-
-  // Emulation prevention three-byte detection.
-  // If a sequence of 0x000003 is found, skip (ignore) the last byte (0x03).
-  if (*data_ == 0x03 && (prev_two_bytes_ & 0xffff) == 0) {
-    // Detected 0x000003, skip last byte.
-    ++data_;
-    --bytes_left_;
-    ++emulation_prevention_bytes_;
-    // Need another full three bytes before we can detect the sequence again.
-    prev_two_bytes_ = 0xffff;
-
-    if (bytes_left_ < 1)
-      return false;
-  }
-
-  // Load a new byte and advance pointers.
-  curr_byte_ = *data_++ & 0xff;
-  --bytes_left_;
-  num_remaining_bits_in_curr_byte_ = 8;
-
-  prev_two_bytes_ = (prev_two_bytes_ << 8) | curr_byte_;
-
-  return true;
-}
-
-// Read |num_bits| (1 to 31 inclusive) from the stream and return them
-// in |out|, with first bit in the stream as MSB in |out| at position
-// (|num_bits| - 1).
-bool H264BitReader::ReadBits(int num_bits, int *out) {
-  int bits_left = num_bits;
-  *out = 0;
-  DCHECK(num_bits <= 31);
-
-  while (num_remaining_bits_in_curr_byte_ < bits_left) {
-    // Take all that's left in current byte, shift to make space for the rest.
-    *out |= (curr_byte_ << (bits_left - num_remaining_bits_in_curr_byte_));
-    bits_left -= num_remaining_bits_in_curr_byte_;
-
-    if (!UpdateCurrByte())
-      return false;
-  }
-
-  *out |= (curr_byte_ >> (num_remaining_bits_in_curr_byte_ - bits_left));
-  *out &= ((1 << num_bits) - 1);
-  num_remaining_bits_in_curr_byte_ -= bits_left;
-
-  return true;
-}
-
-off_t H264BitReader::NumBitsLeft() {
-  return (num_remaining_bits_in_curr_byte_ + bytes_left_ * 8);
-}
-
-bool H264BitReader::HasMoreRBSPData() {
-  // Make sure we have more bits, if we are at 0 bits in current byte
-  // and updating current byte fails, we don't have more data anyway.
-  if (num_remaining_bits_in_curr_byte_ == 0 && !UpdateCurrByte())
-      return false;
-
-  // On last byte?
-  if (bytes_left_)
-    return true;
-
-  // Last byte, look for stop bit;
-  // We have more RBSP data if the last non-zero bit we find is not the
-  // first available bit.
-  return (curr_byte_ &
-          ((1 << (num_remaining_bits_in_curr_byte_ - 1)) - 1)) != 0;
-}
-
-size_t H264BitReader::NumEmulationPreventionBytesRead()
-{
-  return emulation_prevention_bytes_;
-}
-
-}  // namespace content