/* ----------------------------------------------------------------------------- The copyright in this software is being made available under the Clear BSD License, included below. No patent rights, trademark rights and/or other Intellectual Property Rights other than the copyrights concerning the Software are granted under this license. The Clear BSD License Copyright (c) 2018-2023, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. & The VVdeC Authors. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted (subject to the limitations in the disclaimer below) provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ------------------------------------------------------------------------------------------- */ /** \file BitStream.h \brief class for handling bitstream (header) */ #pragma once #include #include #include #include "CommonDef.h" namespace vvdec { // ==================================================================================================================== // Class definition // ==================================================================================================================== /** * Model of a writable bitstream that accumulates bits to produce a * bytestream. */ class OutputBitstream { /** * FIFO for storage of bytes. Use: * - fifo.push_back(x) to append words * - fifo.clear() to empty the FIFO * - &fifo.front() to get a pointer to the data array. * NB, this pointer is only valid until the next push_back()/clear() */ std::vector m_fifo; uint32_t m_num_held_bits; /// number of bits not flushed to bytestream. uint8_t m_held_bits; /// the bits held and not flushed to bytestream. /// this value is always msb-aligned, bigendian. public: // create / destroy OutputBitstream(); ~OutputBitstream(); // interface for encoding /** * append uiNumberOfBits least significant bits of uiBits to * the current bitstream */ void write ( uint32_t uiBits, uint32_t uiNumberOfBits ); /** insert one bits until the bitstream is byte-aligned */ void writeAlignOne (); /** insert zero bits until the bitstream is byte-aligned */ void writeAlignZero (); // utility functions /** * Return a pointer to the start of the byte-stream buffer. * Pointer is valid until the next write/flush/reset call. * NB, data is arranged such that subsequent bytes in the * bytestream are stored in ascending addresses. */ uint8_t* getByteStream() const; /** * Return the number of valid bytes available from getByteStream() */ uint32_t getByteStreamLength(); /** * Reset all internal state. */ void clear(); /** * returns the number of bits that need to be written to * achieve byte alignment. */ int getNumBitsUntilByteAligned() const { return (8 - m_num_held_bits) & 0x7; } /** * Return the number of bits that have been written since the last clear() */ uint32_t getNumberOfWrittenBits() const { return uint32_t(m_fifo.size()) * 8 + m_num_held_bits; } void insertAt(const OutputBitstream& src, uint32_t pos); /** * Return a reference to the internal fifo */ std::vector& getFIFO() { return m_fifo; } uint8_t getHeldBits () { return m_held_bits; } //OutputBitstream& operator= (const OutputBitstream& src); /** Return a reference to the internal fifo */ const std::vector& getFIFO() const { return m_fifo; } void addSubstream ( OutputBitstream* pcSubstream ); void writeByteAlignment(); //! returns the number of start code emulations contained in the current buffer int countStartCodeEmulations(); }; /** * Model of an input bitstream that extracts bits from a predefined * bytestream. */ class InputBitstream { protected: std::vector m_fifo; /// FIFO for storage of complete bytes std::vector m_emulationPreventionByteLocation; uint32_t m_fifo_idx = 0; /// Read index into m_fifo uint32_t m_num_held_bits = 0; uint8_t m_held_bits = 0; uint32_t m_numBitsRead = 0; public: /** * Create a new bitstream reader object that reads from buf. */ InputBitstream() = default; ~InputBitstream() = default; InputBitstream( const InputBitstream& src ) = default; InputBitstream( InputBitstream&& src ) = default; void resetToStart(); void inputZeroByte() { m_fifo.push_back(0); }; // interface for decoding void pseudoRead( uint32_t uiNumberOfBits, uint32_t& ruiBits ); void read ( uint32_t uiNumberOfBits, uint32_t& ruiBits ); void readByte ( uint32_t& ruiBits ) { ruiBits = m_fifo[m_fifo_idx++]; #if ENABLE_TRACING m_numBitsRead += 8; #endif } // In the function initBitstream, add a Byte at the end of m_fifo // In the past, readByteFlag judged whether to read data according to the flag, so it would not cross the boundary // Now, in order to speed up, readByteFlag will definitely read data, so it may cross the boundary void readByteFlag(uint32_t& ruiBits, int flag) { ruiBits = flag & m_fifo[m_fifo_idx]; m_fifo_idx += flag & 1; #if ENABLE_TRACING m_numBitsRead += flag & 8; #endif } void peekPreviousByte( uint32_t& byte ) { byte = m_fifo[m_fifo_idx - 1]; } uint32_t readOutTrailingBits(); uint8_t getHeldBits() { return m_held_bits; } OutputBitstream& operator=( const OutputBitstream& src ); uint32_t getByteLocation() { return m_fifo_idx; } // Peek at bits in word-storage. Used in determining if we have completed reading of current bitstream and therefore // slice in LCEC. uint32_t peekBits( uint32_t uiBits ) { uint32_t tmp; pseudoRead( uiBits, tmp ); return tmp; } // utility functions uint32_t read( uint32_t numberOfBits ) { uint32_t tmp; read( numberOfBits, tmp ); return tmp; } uint32_t readByte() { uint32_t tmp; readByte( tmp ); return tmp; } uint32_t readByteFlag(int flag) { uint32_t tmp; readByteFlag(tmp, flag); return tmp; } uint32_t getNumBitsUntilByteAligned() { return m_num_held_bits & ( 0x7 ); } uint32_t getNumBitsLeft() { return 8 * ( (uint32_t) m_fifo.size() - m_fifo_idx ) + m_num_held_bits; } uint32_t getNumBitsRead() { return m_numBitsRead; } uint32_t readByteAlignment(); InputBitstream* extractSubstream( uint32_t uiNumBits ); // Read the nominated number of bits, and return as a bitstream. void pushEmulationPreventionByteLocation( uint32_t pos ) { m_emulationPreventionByteLocation.push_back( pos ); } uint32_t numEmulationPreventionBytesRead() { return (uint32_t) m_emulationPreventionByteLocation.size(); } uint32_t getEmulationPreventionByteLocation( uint32_t idx ) { return m_emulationPreventionByteLocation[idx]; } const std::vector& getEmulationPreventionByteLocation() const { return m_emulationPreventionByteLocation; } void setEmulationPreventionByteLocation( const std::vector& vec ) { m_emulationPreventionByteLocation = vec; } void clearEmulationPreventionByteLocation() { m_emulationPreventionByteLocation.clear(); } const std::vector& getFifo() const { return m_fifo; } std::vector& getFifo() { return m_fifo; } void clearFifo() { m_fifo.clear(); } }; }