1 | #ifndef _DATE_TIME_INT_ADAPTER_HPP__ |
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2 | #define _DATE_TIME_INT_ADAPTER_HPP__ |
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3 | |
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4 | /* Copyright (c) 2002,2003 CrystalClear Software, Inc. |
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5 | * Use, modification and distribution is subject to the |
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6 | * Boost Software License, Version 1.0. (See accompanying |
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7 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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8 | * Author: Jeff Garland, Bart Garst |
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9 | * $Date: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $ |
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10 | */ |
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11 | |
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12 | |
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13 | #include "boost/config.hpp" |
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14 | #include "boost/limits.hpp" //work around compilers without limits |
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15 | #include "boost/date_time/special_defs.hpp" |
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16 | #include "boost/date_time/locale_config.hpp" |
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17 | #ifndef BOOST_DATE_TIME_NO_LOCALE |
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18 | # include <ostream> |
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19 | #endif |
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20 | |
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21 | namespace boost { |
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22 | namespace date_time { |
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23 | |
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24 | |
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25 | //! Adapter to create integer types with +-infinity, and not a value |
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26 | /*! This class is used internally in counted date/time representations. |
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27 | * It adds the floating point like features of infinities and |
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28 | * not a number. It also provides mathmatical operations with |
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29 | * consideration to special values following these rules: |
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30 | *@code |
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31 | * +infinity - infinity == Not A Number (NAN) |
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32 | * infinity * non-zero == infinity |
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33 | * infinity * zero == NAN |
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34 | * +infinity * -integer == -infinity |
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35 | * infinity / infinity == NAN |
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36 | * infinity * infinity == infinity |
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37 | *@endcode |
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38 | */ |
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39 | template<typename int_type_> |
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40 | class int_adapter { |
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41 | public: |
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42 | typedef int_type_ int_type; |
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43 | int_adapter(int_type v) : |
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44 | value_(v) |
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45 | {} |
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46 | static bool has_infinity() |
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47 | { |
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48 | return true; |
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49 | } |
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50 | static const int_adapter pos_infinity() |
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51 | { |
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52 | return (::std::numeric_limits<int_type>::max)(); |
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53 | } |
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54 | static const int_adapter neg_infinity() |
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55 | { |
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56 | return (::std::numeric_limits<int_type>::min)(); |
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57 | } |
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58 | static const int_adapter not_a_number() |
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59 | { |
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60 | return (::std::numeric_limits<int_type>::max)()-1; |
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61 | } |
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62 | static int_adapter max BOOST_PREVENT_MACRO_SUBSTITUTION () |
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63 | { |
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64 | return (::std::numeric_limits<int_type>::max)()-2; |
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65 | } |
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66 | static int_adapter min BOOST_PREVENT_MACRO_SUBSTITUTION () |
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67 | { |
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68 | return (::std::numeric_limits<int_type>::min)()+1; |
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69 | } |
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70 | static int_adapter from_special(special_values sv) |
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71 | { |
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72 | switch (sv) { |
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73 | case not_a_date_time: return not_a_number(); |
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74 | case neg_infin: return neg_infinity(); |
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75 | case pos_infin: return pos_infinity(); |
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76 | case max_date_time: return (max)(); |
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77 | case min_date_time: return (min)(); |
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78 | default: return not_a_number(); |
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79 | } |
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80 | } |
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81 | static bool is_inf(int_type v) |
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82 | { |
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83 | return (v == neg_infinity().as_number() || |
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84 | v == pos_infinity().as_number()); |
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85 | } |
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86 | static bool is_neg_inf(int_type v) |
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87 | { |
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88 | return (v == neg_infinity().as_number()); |
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89 | } |
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90 | static bool is_pos_inf(int_type v) |
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91 | { |
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92 | return (v == pos_infinity().as_number()); |
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93 | } |
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94 | static bool is_not_a_number(int_type v) |
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95 | { |
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96 | return (v == not_a_number().as_number()); |
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97 | } |
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98 | //! Returns either special value type or is_not_special |
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99 | static special_values to_special(int_type v) |
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100 | { |
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101 | if (is_not_a_number(v)) return not_a_date_time; |
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102 | if (is_neg_inf(v)) return neg_infin; |
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103 | if (is_pos_inf(v)) return pos_infin; |
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104 | return not_special; |
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105 | } |
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106 | |
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107 | //-3 leaves room for representations of infinity and not a date |
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108 | static int_type maxcount() |
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109 | { |
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110 | return (::std::numeric_limits<int_type>::max)()-3; |
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111 | } |
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112 | bool is_infinity() const |
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113 | { |
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114 | return (value_ == neg_infinity().as_number() || |
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115 | value_ == pos_infinity().as_number()); |
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116 | } |
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117 | bool is_pos_infinity()const |
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118 | { |
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119 | return(value_ == pos_infinity().as_number()); |
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120 | } |
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121 | bool is_neg_infinity()const |
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122 | { |
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123 | return(value_ == neg_infinity().as_number()); |
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124 | } |
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125 | bool is_nan() const |
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126 | { |
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127 | return (value_ == not_a_number().as_number()); |
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128 | } |
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129 | bool is_special() const |
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130 | { |
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131 | return(is_infinity() || is_nan()); |
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132 | } |
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133 | bool operator==(const int_adapter& rhs) const |
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134 | { |
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135 | return (compare(rhs) == 0); |
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136 | } |
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137 | bool operator==(const int& rhs) const |
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138 | { |
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139 | // quiets compiler warnings |
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140 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
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141 | if(!is_signed) |
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142 | { |
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143 | if(is_neg_inf(value_) && rhs == 0) |
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144 | { |
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145 | return false; |
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146 | } |
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147 | } |
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148 | return (compare(rhs) == 0); |
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149 | } |
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150 | bool operator!=(const int_adapter& rhs) const |
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151 | { |
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152 | return (compare(rhs) != 0); |
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153 | } |
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154 | bool operator!=(const int& rhs) const |
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155 | { |
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156 | // quiets compiler warnings |
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157 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
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158 | if(!is_signed) |
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159 | { |
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160 | if(is_neg_inf(value_) && rhs == 0) |
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161 | { |
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162 | return true; |
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163 | } |
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164 | } |
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165 | return (compare(rhs) != 0); |
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166 | } |
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167 | bool operator<(const int_adapter& rhs) const |
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168 | { |
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169 | return (compare(rhs) == -1); |
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170 | } |
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171 | bool operator<(const int& rhs) const |
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172 | { |
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173 | // quiets compiler warnings |
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174 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
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175 | if(!is_signed) |
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176 | { |
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177 | if(is_neg_inf(value_) && rhs == 0) |
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178 | { |
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179 | return true; |
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180 | } |
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181 | } |
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182 | return (compare(rhs) == -1); |
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183 | } |
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184 | bool operator>(const int_adapter& rhs) const |
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185 | { |
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186 | return (compare(rhs) == 1); |
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187 | } |
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188 | int_type as_number() const |
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189 | { |
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190 | return value_; |
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191 | } |
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192 | //! Returns either special value type or is_not_special |
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193 | special_values as_special() const |
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194 | { |
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195 | return int_adapter::to_special(value_); |
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196 | } |
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197 | //creates nasty ambiguities |
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198 | // operator int_type() const |
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199 | // { |
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200 | // return value_; |
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201 | // } |
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202 | |
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203 | /*! Operator allows for adding dissimilar int_adapter types. |
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204 | * The return type will match that of the the calling object's type */ |
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205 | template<class rhs_type> |
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206 | inline |
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207 | int_adapter operator+(const int_adapter<rhs_type>& rhs) const |
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208 | { |
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209 | if(is_special() || rhs.is_special()) |
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210 | { |
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211 | if (is_nan() || rhs.is_nan()) |
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212 | { |
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213 | return int_adapter::not_a_number(); |
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214 | } |
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215 | if((is_pos_inf(value_) && rhs.is_neg_inf(rhs.as_number())) || |
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216 | (is_neg_inf(value_) && rhs.is_pos_inf(rhs.as_number())) ) |
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217 | { |
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218 | return int_adapter::not_a_number(); |
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219 | } |
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220 | if (is_infinity()) |
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221 | { |
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222 | return *this; |
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223 | } |
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224 | if (rhs.is_pos_inf(rhs.as_number())) |
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225 | { |
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226 | return int_adapter::pos_infinity(); |
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227 | } |
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228 | if (rhs.is_neg_inf(rhs.as_number())) |
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229 | { |
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230 | return int_adapter::neg_infinity(); |
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231 | } |
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232 | } |
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233 | return int_adapter<int_type>(value_ + rhs.as_number()); |
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234 | } |
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235 | |
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236 | int_adapter operator+(const int_type rhs) const |
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237 | { |
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238 | if(is_special()) |
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239 | { |
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240 | if (is_nan()) |
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241 | { |
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242 | return int_adapter<int_type>(not_a_number()); |
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243 | } |
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244 | if (is_infinity()) |
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245 | { |
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246 | return *this; |
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247 | } |
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248 | } |
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249 | return int_adapter<int_type>(value_ + rhs); |
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250 | } |
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251 | |
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252 | /*! Operator allows for subtracting dissimilar int_adapter types. |
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253 | * The return type will match that of the the calling object's type */ |
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254 | template<class rhs_type> |
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255 | inline |
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256 | int_adapter operator-(const int_adapter<rhs_type>& rhs)const |
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257 | { |
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258 | if(is_special() || rhs.is_special()) |
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259 | { |
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260 | if (is_nan() || rhs.is_nan()) |
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261 | { |
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262 | return int_adapter::not_a_number(); |
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263 | } |
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264 | if((is_pos_inf(value_) && rhs.is_pos_inf(rhs.as_number())) || |
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265 | (is_neg_inf(value_) && rhs.is_neg_inf(rhs.as_number())) ) |
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266 | { |
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267 | return int_adapter::not_a_number(); |
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268 | } |
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269 | if (is_infinity()) |
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270 | { |
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271 | return *this; |
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272 | } |
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273 | if (rhs.is_pos_inf(rhs.as_number())) |
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274 | { |
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275 | return int_adapter::neg_infinity(); |
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276 | } |
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277 | if (rhs.is_neg_inf(rhs.as_number())) |
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278 | { |
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279 | return int_adapter::pos_infinity(); |
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280 | } |
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281 | } |
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282 | return int_adapter<int_type>(value_ - rhs.as_number()); |
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283 | } |
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284 | int_adapter operator-(const int_type rhs) const |
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285 | { |
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286 | if(is_special()) |
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287 | { |
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288 | if (is_nan()) |
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289 | { |
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290 | return int_adapter<int_type>(not_a_number()); |
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291 | } |
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292 | if (is_infinity()) |
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293 | { |
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294 | return *this; |
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295 | } |
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296 | } |
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297 | return int_adapter<int_type>(value_ - rhs); |
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298 | } |
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299 | |
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300 | // should templatize this to be consistant with op +- |
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301 | int_adapter operator*(const int_adapter& rhs)const |
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302 | { |
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303 | if(this->is_special() || rhs.is_special()) |
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304 | { |
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305 | return mult_div_specials(rhs); |
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306 | } |
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307 | return int_adapter<int_type>(value_ * rhs.value_); |
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308 | } |
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309 | /*! Provided for cases when automatic conversion from |
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310 | * 'int' to 'int_adapter' causes incorrect results. */ |
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311 | int_adapter operator*(const int rhs) const |
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312 | { |
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313 | if(is_special()) |
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314 | { |
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315 | return mult_div_specials(rhs); |
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316 | } |
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317 | return int_adapter<int_type>(value_ * rhs); |
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318 | } |
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319 | |
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320 | // should templatize this to be consistant with op +- |
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321 | int_adapter operator/(const int_adapter& rhs)const |
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322 | { |
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323 | if(this->is_special() || rhs.is_special()) |
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324 | { |
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325 | if(is_infinity() && rhs.is_infinity()) |
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326 | { |
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327 | return int_adapter<int_type>(not_a_number()); |
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328 | } |
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329 | if(rhs != 0) |
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330 | { |
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331 | return mult_div_specials(rhs); |
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332 | } |
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333 | else { // let divide by zero blow itself up |
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334 | return int_adapter<int_type>(value_ / rhs.value_); |
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335 | } |
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336 | } |
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337 | return int_adapter<int_type>(value_ / rhs.value_); |
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338 | } |
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339 | /*! Provided for cases when automatic conversion from |
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340 | * 'int' to 'int_adapter' causes incorrect results. */ |
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341 | int_adapter operator/(const int rhs) const |
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342 | { |
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343 | if(is_special() && rhs != 0) |
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344 | { |
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345 | return mult_div_specials(rhs); |
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346 | } |
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347 | return int_adapter<int_type>(value_ / rhs); |
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348 | } |
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349 | |
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350 | // should templatize this to be consistant with op +- |
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351 | int_adapter operator%(const int_adapter& rhs)const |
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352 | { |
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353 | if(this->is_special() || rhs.is_special()) |
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354 | { |
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355 | if(is_infinity() && rhs.is_infinity()) |
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356 | { |
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357 | return int_adapter<int_type>(not_a_number()); |
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358 | } |
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359 | if(rhs != 0) |
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360 | { |
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361 | return mult_div_specials(rhs); |
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362 | } |
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363 | else { // let divide by zero blow itself up |
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364 | return int_adapter<int_type>(value_ % rhs.value_); |
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365 | } |
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366 | } |
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367 | return int_adapter<int_type>(value_ % rhs.value_); |
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368 | } |
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369 | /*! Provided for cases when automatic conversion from |
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370 | * 'int' to 'int_adapter' causes incorrect results. */ |
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371 | int_adapter operator%(const int rhs) const |
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372 | { |
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373 | if(is_special() && rhs != 0) |
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374 | { |
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375 | return mult_div_specials(rhs); |
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376 | } |
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377 | return int_adapter<int_type>(value_ % rhs); |
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378 | } |
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379 | private: |
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380 | int_type value_; |
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381 | |
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382 | //! returns -1, 0, 1, or 2 if 'this' is <, ==, >, or 'nan comparison' rhs |
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383 | int compare(const int_adapter& rhs)const |
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384 | { |
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385 | if(this->is_special() || rhs.is_special()) |
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386 | { |
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387 | if(this->is_nan() || rhs.is_nan()) { |
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388 | if(this->is_nan() && rhs.is_nan()) { |
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389 | return 0; // equal |
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390 | } |
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391 | else { |
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392 | return 2; // nan |
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393 | } |
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394 | } |
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395 | if((is_neg_inf(value_) && !is_neg_inf(rhs.value_)) || |
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396 | (is_pos_inf(rhs.value_) && !is_pos_inf(value_)) ) |
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397 | { |
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398 | return -1; // less than |
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399 | } |
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400 | if((is_pos_inf(value_) && !is_pos_inf(rhs.value_)) || |
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401 | (is_neg_inf(rhs.value_) && !is_neg_inf(value_)) ) { |
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402 | return 1; // greater than |
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403 | } |
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404 | } |
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405 | if(value_ < rhs.value_) return -1; |
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406 | if(value_ > rhs.value_) return 1; |
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407 | // implied-> if(value_ == rhs.value_) |
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408 | return 0; |
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409 | } |
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410 | /* When multiplying and dividing with at least 1 special value |
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411 | * very simmilar rules apply. In those cases where the rules |
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412 | * are different, they are handled in the respective operator |
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413 | * function. */ |
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414 | //! Assumes at least 'this' or 'rhs' is a special value |
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415 | int_adapter mult_div_specials(const int_adapter& rhs)const |
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416 | { |
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417 | int min_value; |
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418 | // quiets compiler warnings |
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419 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
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420 | if(is_signed) { |
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421 | min_value = 0; |
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422 | } |
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423 | else { |
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424 | min_value = 1;// there is no zero with unsigned |
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425 | } |
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426 | if(this->is_nan() || rhs.is_nan()) { |
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427 | return int_adapter<int_type>(not_a_number()); |
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428 | } |
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429 | if((*this > 0 && rhs > 0) || (*this < min_value && rhs < min_value)) { |
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430 | return int_adapter<int_type>(pos_infinity()); |
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431 | } |
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432 | if((*this > 0 && rhs < min_value) || (*this < min_value && rhs > 0)) { |
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433 | return int_adapter<int_type>(neg_infinity()); |
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434 | } |
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435 | //implied -> if(this->value_ == 0 || rhs.value_ == 0) |
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436 | return int_adapter<int_type>(not_a_number()); |
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437 | } |
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438 | /* Overloaded function necessary because of special |
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439 | * situation where int_adapter is instantiated with |
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440 | * 'unsigned' and func is called with negative int. |
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441 | * It would produce incorrect results since 'unsigned' |
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442 | * wraps around when initialized with a negative value */ |
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443 | //! Assumes 'this' is a special value |
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444 | int_adapter mult_div_specials(const int& rhs) const |
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445 | { |
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446 | int min_value; |
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447 | // quiets compiler warnings |
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448 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
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449 | if(is_signed) { |
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450 | min_value = 0; |
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451 | } |
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452 | else { |
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453 | min_value = 1;// there is no zero with unsigned |
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454 | } |
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455 | if(this->is_nan()) { |
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456 | return int_adapter<int_type>(not_a_number()); |
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457 | } |
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458 | if((*this > 0 && rhs > 0) || (*this < min_value && rhs < 0)) { |
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459 | return int_adapter<int_type>(pos_infinity()); |
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460 | } |
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461 | if((*this > 0 && rhs < 0) || (*this < min_value && rhs > 0)) { |
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462 | return int_adapter<int_type>(neg_infinity()); |
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463 | } |
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464 | //implied -> if(this->value_ == 0 || rhs.value_ == 0) |
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465 | return int_adapter<int_type>(not_a_number()); |
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466 | } |
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467 | |
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468 | }; |
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469 | |
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470 | #ifndef BOOST_DATE_TIME_NO_LOCALE |
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471 | /*! Expected output is either a numeric representation |
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472 | * or a special values representation.<BR> |
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473 | * Ex. "12", "+infinity", "not-a-number", etc. */ |
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474 | //template<class charT = char, class traits = std::traits<charT>, typename int_type> |
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475 | template<class charT, class traits, typename int_type> |
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476 | inline |
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477 | std::basic_ostream<charT, traits>& |
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478 | operator<<(std::basic_ostream<charT, traits>& os, const int_adapter<int_type>& ia) |
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479 | { |
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480 | if(ia.is_special()) { |
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481 | // switch copied from date_names_put.hpp |
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482 | switch(ia.as_special()) |
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483 | { |
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484 | case not_a_date_time: |
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485 | os << "not-a-number"; |
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486 | break; |
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487 | case pos_infin: |
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488 | os << "+infinity"; |
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489 | break; |
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490 | case neg_infin: |
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491 | os << "-infinity"; |
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492 | break; |
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493 | default: |
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494 | os << ""; |
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495 | } |
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496 | } |
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497 | else { |
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498 | os << ia.as_number(); |
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499 | } |
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500 | return os; |
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501 | } |
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502 | #endif |
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503 | |
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504 | |
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505 | } } //namespace date_time |
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506 | |
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507 | |
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508 | |
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509 | #endif |
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