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 // Note: ported from Chromium commit head: 2de6929 5 6 #include "vp9_raw_bits_reader.h" 7 8 #include <limits.h> 9 10 #include "base/logging.h" 11 #include "bit_reader.h" 12 13 namespace media { 14 15 Vp9RawBitsReader::Vp9RawBitsReader() : valid_(true) {} 16 17 Vp9RawBitsReader::~Vp9RawBitsReader() = default; 18 19 void Vp9RawBitsReader::Initialize(const uint8_t* data, size_t size) { 20 DCHECK(data); 21 reader_.reset(new BitReader(data, size)); 22 valid_ = true; 23 } 24 25 bool Vp9RawBitsReader::ReadBool() { 26 DCHECK(reader_); 27 if (!valid_) 28 return false; 29 30 int value = 0; 31 valid_ = reader_->ReadBits(1, &value); 32 return valid_ ? value == 1 : false; 33 } 34 35 int Vp9RawBitsReader::ReadLiteral(int bits) { 36 DCHECK(reader_); 37 if (!valid_) 38 return 0; 39 40 int value = 0; 41 DCHECK_LT(static_cast<size_t>(bits), sizeof(value) * 8); 42 valid_ = reader_->ReadBits(bits, &value); 43 return valid_ ? value : 0; 44 } 45 46 int Vp9RawBitsReader::ReadSignedLiteral(int bits) { 47 int value = ReadLiteral(bits); 48 return ReadBool() ? -value : value; 49 } 50 51 size_t Vp9RawBitsReader::GetBytesRead() const { 52 DCHECK(reader_); 53 return (reader_->bits_read() + 7) / 8; 54 } 55 56 bool Vp9RawBitsReader::ConsumeTrailingBits() { 57 DCHECK(reader_); 58 int bits_left = GetBytesRead() * 8 - reader_->bits_read(); 59 return ReadLiteral(bits_left) == 0; 60 } 61 62 } // namespace media 63
