68 lines
1.9 KiB
C++
68 lines
1.9 KiB
C++
// 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: e5a9a62
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#ifndef VP9_RAW_BITS_READER_H_
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#define VP9_RAW_BITS_READER_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <memory>
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#include "base/macros.h"
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namespace media {
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class BitReader;
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// A class to read raw bits stream. See VP9 spec, "RAW-BITS DECODING" section
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// for detail.
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class Vp9RawBitsReader {
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public:
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Vp9RawBitsReader();
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~Vp9RawBitsReader();
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// |data| is the input buffer with |size| bytes.
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void Initialize(const uint8_t* data, size_t size);
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// Returns true if none of the reads since the last Initialize() call has
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// gone beyond the end of available data.
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bool IsValid() const { return valid_; }
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// Returns how many bytes were read since the last Initialize() call.
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// Partial bytes will be counted as one byte. For example, it will return 1
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// if 3 bits were read.
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size_t GetBytesRead() const;
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// Reads one bit.
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// If the read goes beyond the end of buffer, the return value is undefined.
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bool ReadBool();
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// Reads a literal with |bits| bits.
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// If the read goes beyond the end of buffer, the return value is undefined.
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int ReadLiteral(int bits);
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// Reads a signed literal with |bits| bits (not including the sign bit).
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// If the read goes beyond the end of buffer, the return value is undefined.
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int ReadSignedLiteral(int bits);
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// Consumes trailing bits up to next byte boundary. Returns true if no
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// trailing bits or they are all zero.
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bool ConsumeTrailingBits();
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private:
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std::unique_ptr<BitReader> reader_;
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// Indicates if none of the reads since the last Initialize() call has gone
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// beyond the end of available data.
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bool valid_;
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DISALLOW_COPY_AND_ASSIGN(Vp9RawBitsReader);
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};
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} // namespace media
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#endif // VP9_RAW_BITS_READER_H_
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