1 | /* The copyright in this software is being made available under the BSD |
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2 | * License, included below. This software may be subject to other third party |
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3 | * and contributor rights, including patent rights, and no such rights are |
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4 | * granted under this license. |
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5 | * |
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6 | * Copyright (c) 2010-2014, ITU/ISO/IEC |
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7 | * All rights reserved. |
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8 | * |
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9 | * Redistribution and use in source and binary forms, with or without |
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10 | * modification, are permitted provided that the following conditions are met: |
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11 | * |
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12 | * * Redistributions of source code must retain the above copyright notice, |
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13 | * this list of conditions and the following disclaimer. |
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14 | * * Redistributions in binary form must reproduce the above copyright notice, |
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15 | * this list of conditions and the following disclaimer in the documentation |
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16 | * and/or other materials provided with the distribution. |
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17 | * * Neither the name of the ITU/ISO/IEC nor the names of its contributors may |
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18 | * be used to endorse or promote products derived from this software without |
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19 | * specific prior written permission. |
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20 | * |
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21 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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22 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS |
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25 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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27 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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30 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
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31 | * THE POSSIBILITY OF SUCH DAMAGE. |
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32 | */ |
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33 | |
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34 | /** \file TComBitStream.h |
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35 | \brief class for handling bitstream (header) |
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36 | */ |
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37 | |
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38 | #ifndef __TCOMBITSTREAM__ |
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39 | #define __TCOMBITSTREAM__ |
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40 | |
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41 | #if _MSC_VER > 1000 |
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42 | #pragma once |
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43 | #endif // _MSC_VER > 1000 |
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44 | |
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45 | #include <stdint.h> |
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46 | #include <vector> |
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47 | #include <stdio.h> |
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48 | #include <assert.h> |
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49 | #include "CommonDef.h" |
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50 | |
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51 | //! \ingroup TLibCommon |
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52 | //! \{ |
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53 | |
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54 | // ==================================================================================================================== |
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55 | // Class definition |
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56 | // ==================================================================================================================== |
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57 | |
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58 | /// pure virtual class for basic bit handling |
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59 | class TComBitIf |
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60 | { |
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61 | public: |
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62 | virtual Void writeAlignOne () {}; |
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63 | virtual Void writeAlignZero () {}; |
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64 | virtual Void write ( UInt uiBits, UInt uiNumberOfBits ) = 0; |
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65 | virtual Void resetBits () = 0; |
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66 | virtual UInt getNumberOfWrittenBits() const = 0; |
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67 | virtual ~TComBitIf() {} |
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68 | }; |
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69 | |
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70 | /** |
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71 | * Model of a writable bitstream that accumulates bits to produce a |
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72 | * bytestream. |
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73 | */ |
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74 | class TComOutputBitstream : public TComBitIf |
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75 | { |
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76 | /** |
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77 | * FIFO for storage of bytes. Use: |
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78 | * - fifo.push_back(x) to append words |
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79 | * - fifo.clear() to empty the FIFO |
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80 | * - &fifo.front() to get a pointer to the data array. |
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81 | * NB, this pointer is only valid until the next push_back()/clear() |
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82 | */ |
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83 | std::vector<uint8_t> m_fifo; |
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84 | |
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85 | UInt m_num_held_bits; /// number of bits not flushed to bytestream. |
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86 | UChar m_held_bits; /// the bits held and not flushed to bytestream. |
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87 | /// this value is always msb-aligned, bigendian. |
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88 | public: |
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89 | // create / destroy |
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90 | TComOutputBitstream(); |
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91 | ~TComOutputBitstream(); |
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92 | |
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93 | // interface for encoding |
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94 | /** |
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95 | * append uiNumberOfBits least significant bits of uiBits to |
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96 | * the current bitstream |
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97 | */ |
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98 | Void write ( UInt uiBits, UInt uiNumberOfBits ); |
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99 | |
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100 | /** insert one bits until the bitstream is byte-aligned */ |
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101 | Void writeAlignOne (); |
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102 | |
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103 | /** insert zero bits until the bitstream is byte-aligned */ |
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104 | Void writeAlignZero (); |
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105 | |
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106 | /** this function should never be called */ |
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107 | Void resetBits() { assert(0); } |
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108 | |
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109 | // utility functions |
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110 | |
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111 | /** |
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112 | * Return a pointer to the start of the byte-stream buffer. |
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113 | * Pointer is valid until the next write/flush/reset call. |
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114 | * NB, data is arranged such that subsequent bytes in the |
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115 | * bytestream are stored in ascending addresses. |
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116 | */ |
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117 | Char* getByteStream() const; |
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118 | |
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119 | /** |
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120 | * Return the number of valid bytes available from getByteStream() |
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121 | */ |
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122 | UInt getByteStreamLength(); |
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123 | |
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124 | /** |
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125 | * Reset all internal state. |
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126 | */ |
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127 | Void clear(); |
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128 | |
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129 | /** |
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130 | * returns the number of bits that need to be written to |
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131 | * achieve byte alignment. |
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132 | */ |
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133 | Int getNumBitsUntilByteAligned() { return (8 - m_num_held_bits) & 0x7; } |
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134 | |
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135 | /** |
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136 | * Return the number of bits that have been written since the last clear() |
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137 | */ |
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138 | UInt getNumberOfWrittenBits() const { return UInt(m_fifo.size()) * 8 + m_num_held_bits; } |
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139 | |
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140 | Void insertAt(const TComOutputBitstream& src, UInt pos); |
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141 | |
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142 | /** |
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143 | * Return a reference to the internal fifo |
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144 | */ |
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145 | std::vector<uint8_t>& getFIFO() { return m_fifo; } |
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146 | |
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147 | UChar getHeldBits () { return m_held_bits; } |
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148 | |
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149 | //TComOutputBitstream& operator= (const TComOutputBitstream& src); |
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150 | /** Return a reference to the internal fifo */ |
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151 | const std::vector<uint8_t>& getFIFO() const { return m_fifo; } |
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152 | |
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153 | Void addSubstream ( TComOutputBitstream* pcSubstream ); |
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154 | Void writeByteAlignment(); |
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155 | |
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156 | //! returns the number of start code emulations contained in the current buffer |
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157 | Int countStartCodeEmulations(); |
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158 | }; |
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159 | |
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160 | /** |
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161 | * Model of an input bitstream that extracts bits from a predefined |
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162 | * bytestream. |
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163 | */ |
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164 | class TComInputBitstream |
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165 | { |
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166 | std::vector<uint8_t> *m_fifo; /// FIFO for storage of complete bytes |
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167 | std::vector<UInt> m_emulationPreventionByteLocation; |
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168 | |
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169 | protected: |
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170 | UInt m_fifo_idx; /// Read index into m_fifo |
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171 | |
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172 | UInt m_num_held_bits; |
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173 | UChar m_held_bits; |
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174 | UInt m_numBitsRead; |
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175 | |
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176 | public: |
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177 | /** |
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178 | * Create a new bitstream reader object that reads from #buf#. Ownership |
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179 | * of #buf# remains with the callee, although the constructed object |
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180 | * will hold a reference to #buf# |
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181 | */ |
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182 | TComInputBitstream(std::vector<uint8_t>* buf); |
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183 | ~TComInputBitstream(); |
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184 | |
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185 | // interface for decoding |
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186 | Void pseudoRead ( UInt uiNumberOfBits, UInt& ruiBits ); |
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187 | Void read ( UInt uiNumberOfBits, UInt& ruiBits ); |
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188 | Void readByte ( UInt &ruiBits ) |
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189 | { |
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190 | assert(m_fifo_idx < m_fifo->size()); |
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191 | ruiBits = (*m_fifo)[m_fifo_idx++]; |
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192 | } |
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193 | |
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194 | Void peekPreviousByte( UInt &byte ) |
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195 | { |
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196 | assert(m_fifo_idx > 0); |
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197 | byte = (*m_fifo)[m_fifo_idx - 1]; |
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198 | } |
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199 | |
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200 | UInt readOutTrailingBits (); |
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201 | UChar getHeldBits () { return m_held_bits; } |
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202 | TComOutputBitstream& operator= (const TComOutputBitstream& src); |
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203 | UInt getByteLocation ( ) { return m_fifo_idx ; } |
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204 | |
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205 | // Peek at bits in word-storage. Used in determining if we have completed reading of current bitstream and therefore slice in LCEC. |
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206 | UInt peekBits (UInt uiBits) { UInt tmp; pseudoRead(uiBits, tmp); return tmp; } |
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207 | |
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208 | // utility functions |
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209 | UInt read(UInt numberOfBits) { UInt tmp; read(numberOfBits, tmp); return tmp; } |
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210 | UInt readByte() { UInt tmp; readByte( tmp ); return tmp; } |
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211 | UInt getNumBitsUntilByteAligned() { return m_num_held_bits & (0x7); } |
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212 | UInt getNumBitsLeft() { return 8*((UInt)m_fifo->size() - m_fifo_idx) + m_num_held_bits; } |
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213 | TComInputBitstream *extractSubstream( UInt uiNumBits ); // Read the nominated number of bits, and return as a bitstream. |
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214 | Void deleteFifo(); // Delete internal fifo of bitstream. |
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215 | UInt getNumBitsRead() { return m_numBitsRead; } |
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216 | UInt readByteAlignment(); |
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217 | |
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218 | Void pushEmulationPreventionByteLocation ( UInt pos ) { m_emulationPreventionByteLocation.push_back( pos ); } |
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219 | UInt numEmulationPreventionBytesRead () { return (UInt) m_emulationPreventionByteLocation.size(); } |
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220 | std::vector<UInt> getEmulationPreventionByteLocation () { return m_emulationPreventionByteLocation; } |
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221 | UInt getEmulationPreventionByteLocation ( UInt idx ) { return m_emulationPreventionByteLocation[ idx ]; } |
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222 | Void clearEmulationPreventionByteLocation() { m_emulationPreventionByteLocation.clear(); } |
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223 | Void setEmulationPreventionByteLocation ( std::vector<UInt> vec ) { m_emulationPreventionByteLocation = vec; } |
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224 | |
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225 | const std::vector<uint8_t> *getFifo() const { return m_fifo; } |
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226 | }; |
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227 | |
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228 | //! \} |
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229 | |
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230 | #endif |
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