1 | #ifndef LOCAL_TIME_LOCAL_DATE_TIME_HPP__ |
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2 | #define LOCAL_TIME_LOCAL_DATE_TIME_HPP__ |
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3 | |
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4 | /* Copyright (c) 2003-2005 CrystalClear Software, Inc. |
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5 | * Subject to the Boost Software License, Version 1.0. |
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6 | * (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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7 | * Author: Jeff Garland, Bart Garst |
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8 | * $Date: 2010-01-10 14:17:23 -0500 (Sun, 10 Jan 2010) $ |
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9 | */ |
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10 | |
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11 | #include <string> |
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12 | #include <iomanip> |
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13 | #include <sstream> |
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14 | #include <stdexcept> |
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15 | #include <boost/shared_ptr.hpp> |
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16 | #include <boost/throw_exception.hpp> |
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17 | #include <boost/date_time/time.hpp> |
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18 | #include <boost/date_time/posix_time/posix_time.hpp> //todo remove? |
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19 | #include <boost/date_time/dst_rules.hpp> |
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20 | #include <boost/date_time/time_zone_base.hpp> |
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21 | #include <boost/date_time/special_defs.hpp> |
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22 | #include <boost/date_time/time_resolution_traits.hpp> // absolute_value |
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23 | |
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24 | namespace boost { |
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25 | namespace local_time { |
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26 | |
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27 | //! simple exception for reporting when STD or DST cannot be determined |
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28 | struct ambiguous_result : public std::logic_error |
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29 | { |
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30 | ambiguous_result (std::string const& msg = std::string()) : |
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31 | std::logic_error(std::string("Daylight Savings Results are ambiguous: " + msg)) {} |
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32 | }; |
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33 | //! simple exception for when time label given cannot exist |
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34 | struct time_label_invalid : public std::logic_error |
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35 | { |
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36 | time_label_invalid (std::string const& msg = std::string()) : |
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37 | std::logic_error(std::string("Time label given is invalid: " + msg)) {} |
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38 | }; |
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39 | struct dst_not_valid: public std::logic_error |
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40 | { |
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41 | dst_not_valid(std::string const& msg = std::string()) : |
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42 | std::logic_error(std::string("is_dst flag does not match resulting dst for time label given: " + msg)) {} |
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43 | }; |
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44 | |
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45 | //TODO: I think these should be in local_date_time_base and not |
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46 | // necessarily brought into the namespace |
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47 | using date_time::time_is_dst_result; |
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48 | using date_time::is_in_dst; |
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49 | using date_time::is_not_in_dst; |
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50 | using date_time::ambiguous; |
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51 | using date_time::invalid_time_label; |
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52 | |
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53 | //! Representation of "wall-clock" time in a particular time zone |
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54 | /*! Representation of "wall-clock" time in a particular time zone |
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55 | * Local_date_time_base holds a time value (date and time offset from 00:00) |
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56 | * along with a time zone. The time value is stored as UTC and conversions |
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57 | * to wall clock time are made as needed. This approach allows for |
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58 | * operations between wall-clock times in different time zones, and |
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59 | * daylight savings time considerations, to be made. Time zones are |
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60 | * required to be in the form of a boost::shared_ptr<time_zone_base>. |
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61 | */ |
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62 | template<class utc_time_=posix_time::ptime, |
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63 | class tz_type=date_time::time_zone_base<utc_time_,char> > |
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64 | class local_date_time_base : public date_time::base_time<utc_time_, |
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65 | boost::posix_time::posix_time_system> { |
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66 | public: |
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67 | typedef utc_time_ utc_time_type; |
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68 | typedef typename utc_time_type::time_duration_type time_duration_type; |
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69 | typedef typename utc_time_type::date_type date_type; |
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70 | typedef typename date_type::duration_type date_duration_type; |
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71 | typedef typename utc_time_type::time_system_type time_system_type; |
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72 | /*! This constructor interprets the passed time as a UTC time. |
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73 | * So, for example, if the passed timezone is UTC-5 then the |
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74 | * time will be adjusted back 5 hours. The time zone allows for |
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75 | * automatic calculation of whether the particular time is adjusted for |
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76 | * daylight savings, etc. |
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77 | * If the time zone shared pointer is null then time stays unadjusted. |
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78 | *@param t A UTC time |
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79 | *@param tz Timezone for to adjust the UTC time to. |
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80 | */ |
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81 | local_date_time_base(utc_time_type t, |
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82 | boost::shared_ptr<tz_type> tz) : |
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83 | date_time::base_time<utc_time_type, time_system_type>(t), |
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84 | zone_(tz) |
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85 | { |
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86 | // param was already utc so nothing more to do |
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87 | } |
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88 | |
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89 | /*! This constructs a local time -- the passed time information |
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90 | * understood to be in the passed tz. The DST flag must be passed |
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91 | * to indicate whether the time is in daylight savings or not. |
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92 | * @throws -- time_label_invalid if the time passed does not exist in |
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93 | * the given locale. The non-existent case occurs typically |
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94 | * during the shift-back from daylight savings time. When |
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95 | * the clock is shifted forward a range of times |
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96 | * (2 am to 3 am in the US) is skipped and hence is invalid. |
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97 | * @throws -- dst_not_valid if the DST flag is passed for a period |
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98 | * where DST is not active. |
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99 | */ |
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100 | local_date_time_base(date_type d, |
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101 | time_duration_type td, |
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102 | boost::shared_ptr<tz_type> tz, |
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103 | bool dst_flag) : //necessary for constr_adj() |
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104 | date_time::base_time<utc_time_type,time_system_type>(construction_adjustment(utc_time_type(d, td), tz, dst_flag)), |
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105 | zone_(tz) |
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106 | { |
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107 | if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()){ |
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108 | |
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109 | // d & td are already local so we use them |
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110 | time_is_dst_result result = check_dst(d, td, tz); |
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111 | bool in_dst = (result == is_in_dst); // less processing than is_dst() |
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112 | |
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113 | // ambig occurs at end, invalid at start |
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114 | if(result == invalid_time_label){ |
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115 | // Ex: 2:15am local on trans-in day in nyc, dst_flag irrelevant |
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116 | std::ostringstream ss; |
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117 | ss << "time given: " << d << ' ' << td; |
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118 | boost::throw_exception(time_label_invalid(ss.str())); |
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119 | } |
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120 | else if(result != ambiguous && in_dst != dst_flag){ |
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121 | // is dst_flag accurate? |
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122 | // Ex: false flag in NYC in June |
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123 | std::ostringstream ss; |
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124 | ss.setf(std::ios_base::boolalpha); |
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125 | ss << "flag given: dst=" << dst_flag << ", dst calculated: dst=" << in_dst; |
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126 | boost::throw_exception(dst_not_valid(ss.str())); |
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127 | } |
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128 | |
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129 | // everything checks out and conversion to utc already done |
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130 | } |
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131 | } |
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132 | |
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133 | //TODO maybe not the right set...Ignore the last 2 for now... |
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134 | enum DST_CALC_OPTIONS { EXCEPTION_ON_ERROR, NOT_DATE_TIME_ON_ERROR }; |
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135 | //ASSUME_DST_ON_ERROR, ASSUME_NOT_DST_ON_ERROR }; |
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136 | |
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137 | /*! This constructs a local time -- the passed time information |
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138 | * understood to be in the passed tz. The DST flag is calculated |
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139 | * according to the specified rule. |
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140 | */ |
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141 | local_date_time_base(date_type d, |
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142 | time_duration_type td, |
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143 | boost::shared_ptr<tz_type> tz, |
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144 | DST_CALC_OPTIONS calc_option) : |
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145 | // dummy value - time_ is set in constructor code |
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146 | date_time::base_time<utc_time_type,time_system_type>(utc_time_type(d,td)), |
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147 | zone_(tz) |
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148 | { |
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149 | time_is_dst_result result = check_dst(d, td, tz); |
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150 | if(result == ambiguous) { |
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151 | if(calc_option == EXCEPTION_ON_ERROR){ |
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152 | std::ostringstream ss; |
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153 | ss << "time given: " << d << ' ' << td; |
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154 | boost::throw_exception(ambiguous_result(ss.str())); |
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155 | } |
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156 | else{ // NADT on error |
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157 | this->time_ = posix_time::posix_time_system::get_time_rep(date_type(date_time::not_a_date_time), time_duration_type(date_time::not_a_date_time)); |
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158 | } |
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159 | } |
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160 | else if(result == invalid_time_label){ |
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161 | if(calc_option == EXCEPTION_ON_ERROR){ |
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162 | std::ostringstream ss; |
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163 | ss << "time given: " << d << ' ' << td; |
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164 | boost::throw_exception(time_label_invalid(ss.str())); |
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165 | } |
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166 | else{ // NADT on error |
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167 | this->time_ = posix_time::posix_time_system::get_time_rep(date_type(date_time::not_a_date_time), time_duration_type(date_time::not_a_date_time)); |
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168 | } |
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169 | } |
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170 | else if(result == is_in_dst){ |
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171 | utc_time_type t = |
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172 | construction_adjustment(utc_time_type(d, td), tz, true); |
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173 | this->time_ = posix_time::posix_time_system::get_time_rep(t.date(), |
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174 | t.time_of_day()); |
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175 | } |
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176 | else{ |
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177 | utc_time_type t = |
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178 | construction_adjustment(utc_time_type(d, td), tz, false); |
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179 | this->time_ = posix_time::posix_time_system::get_time_rep(t.date(), |
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180 | t.time_of_day()); |
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181 | } |
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182 | } |
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183 | |
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184 | |
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185 | //! Determines if given time label is in daylight savings for given zone |
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186 | /*! Determines if given time label is in daylight savings for given zone. |
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187 | * Takes a date and time_duration representing a local time, along |
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188 | * with time zone, and returns a time_is_dst_result object as result. |
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189 | */ |
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190 | static time_is_dst_result check_dst(date_type d, |
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191 | time_duration_type td, |
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192 | boost::shared_ptr<tz_type> tz) |
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193 | { |
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194 | if(tz != boost::shared_ptr<tz_type>() && tz->has_dst()) { |
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195 | typedef typename date_time::dst_calculator<date_type, time_duration_type> dst_calculator; |
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196 | return dst_calculator::local_is_dst( |
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197 | d, td, |
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198 | tz->dst_local_start_time(d.year()).date(), |
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199 | tz->dst_local_start_time(d.year()).time_of_day(), |
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200 | tz->dst_local_end_time(d.year()).date(), |
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201 | tz->dst_local_end_time(d.year()).time_of_day(), |
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202 | tz->dst_offset() |
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203 | ); |
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204 | } |
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205 | else{ |
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206 | return is_not_in_dst; |
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207 | } |
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208 | } |
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209 | |
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210 | //! Simple destructor, releases time zone if last referrer |
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211 | ~local_date_time_base() {}; |
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212 | |
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213 | //! Copy constructor |
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214 | local_date_time_base(const local_date_time_base& rhs) : |
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215 | date_time::base_time<utc_time_type, time_system_type>(rhs), |
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216 | zone_(rhs.zone_) |
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217 | {} |
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218 | |
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219 | //! Special values constructor |
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220 | explicit local_date_time_base(const boost::date_time::special_values sv, |
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221 | boost::shared_ptr<tz_type> tz = boost::shared_ptr<tz_type>()) : |
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222 | date_time::base_time<utc_time_type, time_system_type>(utc_time_type(sv)), |
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223 | zone_(tz) |
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224 | {} |
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225 | |
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226 | //! returns time zone associated with calling instance |
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227 | boost::shared_ptr<tz_type> zone() const |
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228 | { |
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229 | return zone_; |
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230 | } |
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231 | //! returns false is time_zone is NULL and if time value is a special_value |
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232 | bool is_dst() const |
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233 | { |
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234 | if(zone_ != boost::shared_ptr<tz_type>() && zone_->has_dst() && !this->is_special()) { |
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235 | // check_dst takes a local time, *this is utc |
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236 | utc_time_type lt(this->time_); |
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237 | lt += zone_->base_utc_offset(); |
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238 | // dst_offset only needs to be considered with ambiguous time labels |
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239 | // make that adjustment there |
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240 | |
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241 | switch(check_dst(lt.date(), lt.time_of_day(), zone_)){ |
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242 | case is_not_in_dst: |
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243 | return false; |
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244 | case is_in_dst: |
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245 | return true; |
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246 | case ambiguous: |
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247 | if(lt + zone_->dst_offset() < zone_->dst_local_end_time(lt.date().year())) { |
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248 | return true; |
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249 | } |
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250 | break; |
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251 | case invalid_time_label: |
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252 | if(lt >= zone_->dst_local_start_time(lt.date().year())) { |
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253 | return true; |
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254 | } |
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255 | break; |
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256 | } |
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257 | } |
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258 | return false; |
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259 | } |
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260 | //! Returns object's time value as a utc representation |
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261 | utc_time_type utc_time() const |
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262 | { |
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263 | return utc_time_type(this->time_); |
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264 | } |
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265 | //! Returns object's time value as a local representation |
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266 | utc_time_type local_time() const |
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267 | { |
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268 | if(zone_ != boost::shared_ptr<tz_type>()){ |
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269 | utc_time_type lt = this->utc_time() + zone_->base_utc_offset(); |
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270 | if (is_dst()) { |
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271 | lt += zone_->dst_offset(); |
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272 | } |
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273 | return lt; |
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274 | } |
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275 | return utc_time_type(this->time_); |
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276 | } |
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277 | //! Returns string in the form "2003-Aug-20 05:00:00 EDT" |
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278 | /*! Returns string in the form "2003-Aug-20 05:00:00 EDT". If |
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279 | * time_zone is NULL the time zone abbreviation will be "UTC". The time |
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280 | * zone abbrev will not be included if calling object is a special_value*/ |
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281 | std::string to_string() const |
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282 | { |
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283 | //TODO is this a temporary function ??? |
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284 | std::ostringstream ss; |
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285 | if(this->is_special()){ |
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286 | ss << utc_time(); |
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287 | return ss.str(); |
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288 | } |
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289 | if(zone_ == boost::shared_ptr<tz_type>()) { |
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290 | ss << utc_time() << " UTC"; |
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291 | return ss.str(); |
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292 | } |
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293 | bool is_dst_ = is_dst(); |
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294 | utc_time_type lt = this->utc_time() + zone_->base_utc_offset(); |
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295 | if (is_dst_) { |
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296 | lt += zone_->dst_offset(); |
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297 | } |
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298 | ss << local_time() << " "; |
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299 | if (is_dst()) { |
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300 | ss << zone_->dst_zone_abbrev(); |
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301 | } |
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302 | else { |
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303 | ss << zone_->std_zone_abbrev(); |
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304 | } |
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305 | return ss.str(); |
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306 | } |
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307 | /*! returns a local_date_time_base in the given time zone with the |
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308 | * optional time_duration added. */ |
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309 | local_date_time_base local_time_in(boost::shared_ptr<tz_type> new_tz, |
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310 | time_duration_type td=time_duration_type(0,0,0)) const |
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311 | { |
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312 | return local_date_time_base(utc_time_type(this->time_) + td, new_tz); |
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313 | } |
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314 | |
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315 | //! Returns name of associated time zone or "Coordinated Universal Time". |
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316 | /*! Optional bool parameter will return time zone as an offset |
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317 | * (ie "+07:00" extended iso format). Empty string is returned for |
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318 | * classes that do not use a time_zone */ |
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319 | std::string zone_name(bool as_offset=false) const |
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320 | { |
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321 | if(zone_ == boost::shared_ptr<tz_type>()) { |
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322 | if(as_offset) { |
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323 | return std::string("Z"); |
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324 | } |
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325 | else { |
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326 | return std::string("Coordinated Universal Time"); |
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327 | } |
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328 | } |
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329 | if (is_dst()) { |
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330 | if(as_offset) { |
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331 | time_duration_type td = zone_->base_utc_offset(); |
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332 | td += zone_->dst_offset(); |
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333 | return zone_as_offset(td, ":"); |
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334 | } |
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335 | else { |
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336 | return zone_->dst_zone_name(); |
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337 | } |
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338 | } |
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339 | else { |
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340 | if(as_offset) { |
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341 | time_duration_type td = zone_->base_utc_offset(); |
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342 | return zone_as_offset(td, ":"); |
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343 | } |
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344 | else { |
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345 | return zone_->std_zone_name(); |
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346 | } |
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347 | } |
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348 | } |
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349 | //! Returns abbreviation of associated time zone or "UTC". |
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350 | /*! Optional bool parameter will return time zone as an offset |
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351 | * (ie "+0700" iso format). Empty string is returned for classes |
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352 | * that do not use a time_zone */ |
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353 | std::string zone_abbrev(bool as_offset=false) const |
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354 | { |
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355 | if(zone_ == boost::shared_ptr<tz_type>()) { |
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356 | if(as_offset) { |
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357 | return std::string("Z"); |
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358 | } |
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359 | else { |
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360 | return std::string("UTC"); |
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361 | } |
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362 | } |
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363 | if (is_dst()) { |
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364 | if(as_offset) { |
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365 | time_duration_type td = zone_->base_utc_offset(); |
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366 | td += zone_->dst_offset(); |
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367 | return zone_as_offset(td, ""); |
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368 | } |
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369 | else { |
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370 | return zone_->dst_zone_abbrev(); |
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371 | } |
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372 | } |
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373 | else { |
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374 | if(as_offset) { |
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375 | time_duration_type td = zone_->base_utc_offset(); |
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376 | return zone_as_offset(td, ""); |
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377 | } |
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378 | else { |
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379 | return zone_->std_zone_abbrev(); |
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380 | } |
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381 | } |
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382 | } |
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383 | |
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384 | //! returns a posix_time_zone string for the associated time_zone. If no time_zone, "UTC+00" is returned. |
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385 | std::string zone_as_posix_string() const |
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386 | { |
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387 | if(zone_ == shared_ptr<tz_type>()) { |
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388 | return std::string("UTC+00"); |
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389 | } |
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390 | return zone_->to_posix_string(); |
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391 | } |
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392 | |
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393 | //! Equality comparison operator |
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394 | /*bool operator==(const date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>& rhs) const |
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395 | { // fails due to rhs.time_ being protected |
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396 | return date_time::base_time<boost::posix_time::ptime,boost::posix_time::posix_time_system>::operator==(rhs); |
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397 | //return this->time_ == rhs.time_; |
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398 | }*/ |
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399 | //! Equality comparison operator |
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400 | bool operator==(const local_date_time_base& rhs) const |
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401 | { |
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402 | return time_system_type::is_equal(this->time_, rhs.time_); |
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403 | } |
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404 | //! Non-Equality comparison operator |
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405 | bool operator!=(const local_date_time_base& rhs) const |
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406 | { |
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407 | return !(*this == rhs); |
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408 | } |
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409 | //! Less than comparison operator |
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410 | bool operator<(const local_date_time_base& rhs) const |
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411 | { |
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412 | return time_system_type::is_less(this->time_, rhs.time_); |
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413 | } |
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414 | //! Less than or equal to comparison operator |
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415 | bool operator<=(const local_date_time_base& rhs) const |
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416 | { |
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417 | return (*this < rhs || *this == rhs); |
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418 | } |
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419 | //! Greater than comparison operator |
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420 | bool operator>(const local_date_time_base& rhs) const |
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421 | { |
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422 | return !(*this <= rhs); |
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423 | } |
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424 | //! Greater than or equal to comparison operator |
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425 | bool operator>=(const local_date_time_base& rhs) const |
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426 | { |
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427 | return (*this > rhs || *this == rhs); |
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428 | } |
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429 | |
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430 | //! Local_date_time + date_duration |
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431 | local_date_time_base operator+(const date_duration_type& dd) const |
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432 | { |
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433 | return local_date_time_base(time_system_type::add_days(this->time_,dd), zone_); |
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434 | } |
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435 | //! Local_date_time += date_duration |
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436 | local_date_time_base operator+=(const date_duration_type& dd) |
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437 | { |
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438 | this->time_ = time_system_type::add_days(this->time_,dd); |
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439 | return *this; |
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440 | } |
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441 | //! Local_date_time - date_duration |
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442 | local_date_time_base operator-(const date_duration_type& dd) const |
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443 | { |
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444 | return local_date_time_base(time_system_type::subtract_days(this->time_,dd), zone_); |
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445 | } |
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446 | //! Local_date_time -= date_duration |
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447 | local_date_time_base operator-=(const date_duration_type& dd) |
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448 | { |
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449 | this->time_ = time_system_type::subtract_days(this->time_,dd); |
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450 | return *this; |
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451 | } |
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452 | //! Local_date_time + time_duration |
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453 | local_date_time_base operator+(const time_duration_type& td) const |
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454 | { |
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455 | return local_date_time_base(time_system_type::add_time_duration(this->time_,td), zone_); |
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456 | } |
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457 | //! Local_date_time += time_duration |
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458 | local_date_time_base operator+=(const time_duration_type& td) |
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459 | { |
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460 | this->time_ = time_system_type::add_time_duration(this->time_,td); |
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461 | return *this; |
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462 | } |
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463 | //! Local_date_time - time_duration |
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464 | local_date_time_base operator-(const time_duration_type& td) const |
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465 | { |
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466 | return local_date_time_base(time_system_type::subtract_time_duration(this->time_,td), zone_); |
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467 | } |
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468 | //! Local_date_time -= time_duration |
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469 | local_date_time_base operator-=(const time_duration_type& td) |
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470 | { |
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471 | this->time_ = time_system_type::subtract_time_duration(this->time_,td); |
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472 | return *this; |
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473 | } |
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474 | //! local_date_time -= local_date_time --> time_duration_type |
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475 | time_duration_type operator-(const local_date_time_base& rhs) const |
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476 | { |
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477 | return utc_time_type(this->time_) - utc_time_type(rhs.time_); |
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478 | } |
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479 | private: |
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480 | boost::shared_ptr<tz_type> zone_; |
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481 | //bool is_dst_; |
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482 | |
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483 | /*! Adjust the passed in time to UTC? |
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484 | */ |
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485 | utc_time_type construction_adjustment(utc_time_type t, |
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486 | boost::shared_ptr<tz_type> z, |
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487 | bool dst_flag) |
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488 | { |
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489 | if(z != boost::shared_ptr<tz_type>()) { |
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490 | if(dst_flag && z->has_dst()) { |
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491 | t -= z->dst_offset(); |
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492 | } // else no adjust |
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493 | t -= z->base_utc_offset(); |
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494 | } |
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495 | return t; |
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496 | } |
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497 | |
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498 | /*! Simple formatting code -- todo remove this? |
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499 | */ |
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500 | std::string zone_as_offset(const time_duration_type& td, |
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501 | const std::string& separator) const |
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502 | { |
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503 | std::ostringstream ss; |
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504 | if(td.is_negative()) { |
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505 | // a negative duration is represented as "-[h]h:mm" |
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506 | // we require two digits for the hour. A positive duration |
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507 | // with the %H flag will always give two digits |
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508 | ss << "-"; |
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509 | } |
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510 | else { |
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511 | ss << "+"; |
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512 | } |
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513 | ss << std::setw(2) << std::setfill('0') |
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514 | << date_time::absolute_value(td.hours()) |
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515 | << separator |
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516 | << std::setw(2) << std::setfill('0') |
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517 | << date_time::absolute_value(td.minutes()); |
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518 | return ss.str(); |
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519 | } |
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520 | }; |
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521 | |
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522 | //!Use the default parameters to define local_date_time |
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523 | typedef local_date_time_base<> local_date_time; |
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524 | |
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525 | } } |
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526 | |
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527 | |
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528 | #endif |
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