1 | #ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_MIPS_HPP_INCLUDED |
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2 | #define BOOST_DETAIL_SP_COUNTED_BASE_GCC_MIPS_HPP_INCLUDED |
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3 | |
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4 | // MS compatible compilers support #pragma once |
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5 | |
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6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
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7 | # pragma once |
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8 | #endif |
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9 | |
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10 | // |
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11 | // detail/sp_counted_base_gcc_mips.hpp - g++ on MIPS |
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12 | // |
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13 | // Copyright (c) 2009, Spirent Communications, Inc. |
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14 | // |
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15 | // Distributed under the Boost Software License, Version 1.0. (See |
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16 | // accompanying file LICENSE_1_0.txt or copy at |
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17 | // http://www.boost.org/LICENSE_1_0.txt) |
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18 | // |
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19 | // |
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20 | // Lock-free algorithm by Alexander Terekhov |
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21 | // |
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22 | |
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23 | #include <boost/detail/sp_typeinfo.hpp> |
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24 | |
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25 | namespace boost |
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26 | { |
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27 | |
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28 | namespace detail |
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29 | { |
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30 | |
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31 | inline void atomic_increment( int * pw ) |
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32 | { |
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33 | // ++*pw; |
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34 | |
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35 | int tmp; |
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36 | |
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37 | __asm__ __volatile__ |
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38 | ( |
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39 | "0:\n\t" |
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40 | "ll %0, %1\n\t" |
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41 | "addiu %0, 1\n\t" |
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42 | "sc %0, %1\n\t" |
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43 | "beqz %0, 0b": |
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44 | "=&r"( tmp ), "=m"( *pw ): |
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45 | "m"( *pw ) |
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46 | ); |
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47 | } |
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48 | |
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49 | inline int atomic_decrement( int * pw ) |
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50 | { |
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51 | // return --*pw; |
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52 | |
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53 | int rv, tmp; |
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54 | |
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55 | __asm__ __volatile__ |
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56 | ( |
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57 | "0:\n\t" |
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58 | "ll %1, %2\n\t" |
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59 | "addiu %0, %1, -1\n\t" |
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60 | "sc %0, %2\n\t" |
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61 | "beqz %0, 0b\n\t" |
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62 | "addiu %0, %1, -1": |
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63 | "=&r"( rv ), "=&r"( tmp ), "=m"( *pw ): |
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64 | "m"( *pw ): |
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65 | "memory" |
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66 | ); |
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67 | |
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68 | return rv; |
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69 | } |
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70 | |
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71 | inline int atomic_conditional_increment( int * pw ) |
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72 | { |
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73 | // if( *pw != 0 ) ++*pw; |
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74 | // return *pw; |
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75 | |
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76 | int rv, tmp; |
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77 | |
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78 | __asm__ __volatile__ |
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79 | ( |
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80 | "0:\n\t" |
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81 | "ll %0, %2\n\t" |
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82 | "beqz %0, 1f\n\t" |
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83 | "addiu %1, %0, 1\n\t" |
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84 | "sc %1, %2\n\t" |
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85 | "beqz %1, 0b\n\t" |
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86 | "addiu %0, %0, 1\n\t" |
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87 | "1:": |
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88 | "=&r"( rv ), "=&r"( tmp ), "=m"( *pw ): |
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89 | "m"( *pw ): |
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90 | "memory" |
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91 | ); |
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92 | |
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93 | return rv; |
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94 | } |
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95 | |
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96 | class sp_counted_base |
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97 | { |
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98 | private: |
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99 | |
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100 | sp_counted_base( sp_counted_base const & ); |
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101 | sp_counted_base & operator= ( sp_counted_base const & ); |
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102 | |
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103 | int use_count_; // #shared |
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104 | int weak_count_; // #weak + (#shared != 0) |
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105 | |
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106 | public: |
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107 | |
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108 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) |
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109 | { |
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110 | } |
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111 | |
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112 | virtual ~sp_counted_base() // nothrow |
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113 | { |
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114 | } |
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115 | |
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116 | // dispose() is called when use_count_ drops to zero, to release |
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117 | // the resources managed by *this. |
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118 | |
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119 | virtual void dispose() = 0; // nothrow |
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120 | |
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121 | // destroy() is called when weak_count_ drops to zero. |
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122 | |
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123 | virtual void destroy() // nothrow |
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124 | { |
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125 | delete this; |
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126 | } |
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127 | |
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128 | virtual void * get_deleter( sp_typeinfo const & ti ) = 0; |
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129 | |
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130 | void add_ref_copy() |
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131 | { |
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132 | atomic_increment( &use_count_ ); |
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133 | } |
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134 | |
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135 | bool add_ref_lock() // true on success |
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136 | { |
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137 | return atomic_conditional_increment( &use_count_ ) != 0; |
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138 | } |
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139 | |
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140 | void release() // nothrow |
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141 | { |
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142 | if( atomic_decrement( &use_count_ ) == 0 ) |
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143 | { |
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144 | dispose(); |
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145 | weak_release(); |
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146 | } |
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147 | } |
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148 | |
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149 | void weak_add_ref() // nothrow |
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150 | { |
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151 | atomic_increment( &weak_count_ ); |
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152 | } |
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153 | |
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154 | void weak_release() // nothrow |
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155 | { |
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156 | if( atomic_decrement( &weak_count_ ) == 0 ) |
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157 | { |
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158 | destroy(); |
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159 | } |
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160 | } |
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161 | |
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162 | long use_count() const // nothrow |
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163 | { |
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164 | return static_cast<int const volatile &>( use_count_ ); |
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165 | } |
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166 | }; |
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167 | |
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168 | } // namespace detail |
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169 | |
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170 | } // namespace boost |
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171 | |
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172 | #endif // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_MIPS_HPP_INCLUDED |
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