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eedf4d7699
Additionally, BitReader and BitWriter now support ULEB128 values which are used in AV1 sequence headers. Differential Revision: https://phabricator.services.mozilla.com/D141072
55 lines
1.6 KiB
C++
55 lines
1.6 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef BIT_READER_H_
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#define BIT_READER_H_
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#include "MediaData.h"
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namespace mozilla {
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class BitReader {
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public:
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explicit BitReader(const MediaByteBuffer* aBuffer);
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BitReader(const MediaByteBuffer* aBuffer, size_t aBits);
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BitReader(const uint8_t* aBuffer, size_t aBits);
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~BitReader();
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uint32_t ReadBits(size_t aNum);
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bool ReadBit() { return ReadBits(1) != 0; }
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uint32_t ReadU32() { return ReadBits(32); }
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uint64_t ReadU64();
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// Read the UTF-8 sequence and convert it to its 64-bit UCS-4 encoded form.
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// Return 0xfffffffffffffff if sequence was invalid.
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uint64_t ReadUTF8();
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// Read unsigned integer Exp-Golomb-coded.
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uint32_t ReadUE();
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// Read signed integer Exp-Golomb-coded.
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int32_t ReadSE();
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// Read unsigned integer Little Endian Base 128 coded.
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// Limited to unsigned 64 bits.
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CheckedUint64 ReadULEB128();
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// Return the number of bits parsed so far;
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size_t BitCount() const;
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// Return the number of bits left.
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size_t BitsLeft() const;
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// Return RBSP bit length.
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static uint32_t GetBitLength(const MediaByteBuffer* aNAL);
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private:
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void FillReservoir();
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const uint8_t* mData;
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const size_t mOriginalBitSize;
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size_t mTotalBitsLeft;
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size_t mSize; // Size left in bytes
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uint32_t mReservoir; // Left-aligned bits
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size_t mNumBitsLeft; // Number of bits left in reservoir.
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};
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} // namespace mozilla
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#endif // BIT_READER_H_
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