media/filters/vp9_raw_bits_reader.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/filters/vp9_raw_bits_reader.h"
   6
   7 #include <limits.h>
   8
   9 #include "base/logging.h"
  10 #include "media/base/bit_reader.h"
  11
  12 namespace media {
  13
  14 Vp9RawBitsReader::Vp9RawBitsReader() : valid_(true) {}
  15
  16 Vp9RawBitsReader::~Vp9RawBitsReader() {}
  17
  18 void Vp9RawBitsReader::Initialize(const uint8_t* data, size_t size) {
  19   DCHECK(data);
  20   reader_.reset(new BitReader(data, size));
  21   valid_ = true;
  22 }
  23
  24 bool Vp9RawBitsReader::ReadBool() {
  25   DCHECK(reader_);
  26   if (!valid_)
  27     return false;
  28
  29   int value = 0;
  30   valid_ = reader_->ReadBits(1, &value);
  31   return valid_ ? value == 1 : false;
  32 }
  33
  34 int Vp9RawBitsReader::ReadLiteral(int bits) {
  35   DCHECK(reader_);
  36   if (!valid_)
  37     return 0;
  38
  39   int value = 0;
  40   DCHECK_LT(static_cast<size_t>(bits), sizeof(value) * 8);
  41   valid_ = reader_->ReadBits(bits, &value);
  42   return valid_ ? value : 0;
  43 }
  44
  45 int Vp9RawBitsReader::ReadSignedLiteral(int bits) {
  46   int value = ReadLiteral(bits);
  47   return ReadBool() ? -value : value;
  48 }
  49
  50 size_t Vp9RawBitsReader::GetBytesRead() const {
  51   DCHECK(reader_);
  52   return (reader_->bits_read() + 7) / 8;
  53 }
  54
  55 }  // namespace media