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1 #pragma once
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2
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3 namespace bitreader_helper {
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4
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5 inline static size_t extract_bit(const uint8_t * p_stream,size_t p_offset) {
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6 return (p_stream[p_offset>>3] >> (7-(p_offset&7)))&1;
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7 }
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8
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9 inline static size_t extract_int(const uint8_t * p_stream,size_t p_base,size_t p_width) {
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10 size_t ret = 0;
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11 size_t offset = p_base;
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12 for(size_t bit=0;bit<p_width;bit++) {
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13 ret <<= 1;
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14 ret |= extract_bit(p_stream,offset++);
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15 }
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16 return ret;
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17 }
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18 inline static void write_bit( uint8_t * p_stream, size_t p_offset, size_t bit ) {
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19 size_t bshift = 7 - (p_offset&7);
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20 size_t mask = (size_t)1 << bshift;
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21 uint8_t & b = p_stream[p_offset>>3];
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22 b = (b & ~mask) | ((bit&1) << bshift);
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23 }
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24 inline static void write_int( uint8_t * p_stream, size_t p_base, size_t p_width, size_t p_value) {
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25 size_t offset = p_base;
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26 size_t val = p_value;
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27 for( size_t bit = 0; bit < p_width; ++ bit ) {
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28 write_bit( p_stream, offset++, val >> (p_width - bit - 1));
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29 }
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30 }
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31
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32 class bitreader
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33 {
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34 public:
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35 inline bitreader(const t_uint8 * p_ptr,t_size p_base)
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36 : m_ptr(p_ptr), m_bitptr(p_base)
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37 {
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38 }
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39
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40 inline void skip(t_size p_bits)
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41 {
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42 m_bitptr += p_bits;
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43 }
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44
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45
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46 template<typename t_ret>
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47 t_ret peek_t(t_size p_bits) const {
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48 size_t ptr = m_bitptr;
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49 t_ret ret = 0;
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50 for(t_size bit=0;bit<p_bits;bit++)
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51 {
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52 ret <<= 1;
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53 ret |= (m_ptr[ptr >>3] >> (7-(ptr &7)))&1;
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54 ptr++;
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55 }
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56 return ret;
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57 }
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58
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59 template<typename t_ret>
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60 t_ret read_t(t_size p_bits) {
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61 t_ret ret = peek_t<t_ret>(p_bits);
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62 skip(p_bits);
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63 return ret;
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64 }
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65
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66 size_t peek(size_t bits) const {
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67 return peek_t<size_t>(bits);
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68 }
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69
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70 t_size read(t_size p_bits) {return read_t<t_size>(p_bits);}
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71
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72 inline t_size get_bitptr() const {return m_bitptr;}
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73
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74 inline bool read_bit() {
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75 bool state = ( (m_ptr[m_bitptr>>3] >> (7-(m_bitptr&7)))&1 ) != 0;
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76 m_bitptr++;
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77 return state;
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78 }
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79
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80 private:
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81
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82 const t_uint8 * m_ptr;
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83 t_size m_bitptr;
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84 };
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85
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86 class bitreader_fromfile
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87 {
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88 public:
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89 inline bitreader_fromfile(service_ptr_t<file> const& p_file) : m_file(p_file), m_buffer_ptr(0) {}
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90
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91 t_size read(t_size p_bits,abort_callback & p_abort) {
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92 t_size ret = 0;
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93 for(t_size bit=0;bit<p_bits;bit++) {
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94 if (m_buffer_ptr == 0)
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95 m_file->read_object(&m_buffer,1,p_abort);
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96
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97 ret <<= 1;
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98 ret |= (m_buffer >> (7-m_buffer_ptr))&1;
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99 m_buffer_ptr = (m_buffer_ptr+1) & 7;
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100 }
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101 return ret;
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102 }
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103
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104 void skip(t_size p_bits,abort_callback & p_abort) {
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105 for(t_size bit=0;bit<p_bits;bit++) {
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106 if (m_buffer_ptr == 0) m_file->read_object(&m_buffer,1,p_abort);
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107 m_buffer_ptr = (m_buffer_ptr+1) & 7;
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108 }
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109 }
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110
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111 inline void byte_align() {m_buffer_ptr = 0;}
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112
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113 private:
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114 service_ptr_t<file> m_file;
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115 t_size m_buffer_ptr;
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116 t_uint8 m_buffer;
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117 };
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118
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119 class bitreader_limited
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120 {
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121 public:
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122 inline bitreader_limited(const t_uint8 * p_ptr,t_size p_base,t_size p_remaining) : m_reader(p_ptr,p_base), m_remaining(p_remaining) {}
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123
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124 inline t_size get_bitptr() const {return m_reader.get_bitptr();}
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125
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126 inline t_size get_remaining() const {return m_remaining;}
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127
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128 inline void skip(t_size p_bits) {
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129 if (p_bits > m_remaining) throw exception_io_data_truncation();
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130 m_remaining -= p_bits;
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131 m_reader.skip(p_bits);
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132 }
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133
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134 size_t peek(size_t bits) {
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135 if (bits > m_remaining) throw exception_io_data_truncation();
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136 return m_reader.peek(bits);
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137 }
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138 t_size read(t_size p_bits)
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139 {
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140 if (p_bits > m_remaining) throw exception_io_data_truncation();
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141 m_remaining -= p_bits;
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142 return m_reader.read(p_bits);
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143 }
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144
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145 private:
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146 bitreader m_reader;
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147 t_size m_remaining;
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148 };
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149
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150 inline static t_size extract_bits(const t_uint8 * p_buffer,t_size p_base,t_size p_count) {
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151 return bitreader(p_buffer,p_base).read(p_count);
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152 }
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153
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154 }
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