// Copyright 2015 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Note: ported from Chromium commit head: 2de6929
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#include "vp9_raw_bits_reader.h"
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#include <limits.h>
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#include "base/logging.h"
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#include "bit_reader.h"
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namespace media {
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Vp9RawBitsReader::Vp9RawBitsReader() : valid_(true) {}
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Vp9RawBitsReader::~Vp9RawBitsReader() = default;
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void Vp9RawBitsReader::Initialize(const uint8_t* data, size_t size) {
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DCHECK(data);
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reader_.reset(new BitReader(data, size));
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valid_ = true;
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}
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bool Vp9RawBitsReader::ReadBool() {
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DCHECK(reader_);
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if (!valid_)
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return false;
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int value = 0;
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valid_ = reader_->ReadBits(1, &value);
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return valid_ ? value == 1 : false;
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}
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int Vp9RawBitsReader::ReadLiteral(int bits) {
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DCHECK(reader_);
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if (!valid_)
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return 0;
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int value = 0;
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DCHECK_LT(static_cast<size_t>(bits), sizeof(value) * 8);
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valid_ = reader_->ReadBits(bits, &value);
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return valid_ ? value : 0;
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}
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int Vp9RawBitsReader::ReadSignedLiteral(int bits) {
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int value = ReadLiteral(bits);
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return ReadBool() ? -value : value;
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}
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size_t Vp9RawBitsReader::GetBytesRead() const {
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DCHECK(reader_);
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return (reader_->bits_read() + 7) / 8;
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}
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bool Vp9RawBitsReader::ConsumeTrailingBits() {
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DCHECK(reader_);
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int bits_left = GetBytesRead() * 8 - reader_->bits_read();
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return ReadLiteral(bits_left) == 0;
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}
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} // namespace media
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