FCL/interim/sftools/linux_build: comparison imgtools/imglib/boostlibrary/boost/date_time/local_time

equal deleted inserted replaced

-:820b22e13ff1
+:39c28ec933dd
+#ifndef DATE_TIME_LOCAL_TIME_ADJUSTOR_HPP__
+#define DATE_TIME_LOCAL_TIME_ADJUSTOR_HPP__
+/* Copyright (c) 2002,2003 CrystalClear Software, Inc.
+* Use, modification and distribution is subject to the
+* Boost Software License, Version 1.0. (See accompanying
+* file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+* Author: Jeff Garland
+* $Date: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $
+*/
+/*! @file local_time_adjustor.hpp
+Time adjustment calculations for local times
+*/
+#include <stdexcept>
+#include <boost/throw_exception.hpp>
+#include <boost/date_time/compiler_config.hpp>
+#include <boost/date_time/date_generators.hpp>
+#include <boost/date_time/dst_rules.hpp>
+#include <boost/date_time/time_defs.hpp> // boost::date_time::dst_flags
+#include <boost/date_time/special_defs.hpp> // not_a_date_time
+namespace boost {
+namespace date_time {
+//! Provides a base offset adjustment from utc
+template<class time_duration_type,
+short hours, unsigned short minutes = 0>
+class utc_adjustment
+{
+public:
+static time_duration_type local_to_utc_base_offset()
+{
+time_duration_type td(hours,minutes,0);
+return td.invert_sign();
+}
+static time_duration_type utc_to_local_base_offset()
+{
+return time_duration_type(hours,minutes,0);
+}
+};
+//! Allow sliding utc adjustment with fixed dst rules
+template<class time_type, class dst_rules>
+class dynamic_local_time_adjustor : public dst_rules
+{
+public:
+typedef typename time_type::time_duration_type time_duration_type;
+typedef typename time_type::date_type date_type;
+dynamic_local_time_adjustor(time_duration_type utc_offset) :
+utc_offset_(utc_offset)
+{}
+//! Presumes local time
+time_duration_type utc_offset(bool is_dst)
+{
+if (is_dst) {
+return utc_offset_ + this->dst_offset();
+}
+else {
+return utc_offset_;
+}
+}
+private:
+time_duration_type utc_offset_;
+};
+//! Embed the rules for local time adjustments at compile time
+template<class time_type, class dst_rules, class utc_offset_rules>
+class static_local_time_adjustor: public dst_rules, public utc_offset_rules
+{
+public:
+typedef typename time_type::time_duration_type time_duration_type;
+typedef typename time_type::date_type date_type;
+//! Calculates the offset from a utc time to local based on dst and utc offset
+/*! @param t UTC time to calculate offset to local time
+*  This adjustment depends on the following observations about the
+*  workings of the DST boundary offset.  Since UTC time labels are
+*  monotonically increasing we can determine if a given local time
+*  is in DST or not and therefore adjust the offset appropriately.
+*
+*  The logic is as follows.  Starting with UTC time use the offset to
+*  create a label for an non-dst adjusted local time.  Then call
+*  dst_rules::local_is_dst with the non adjust local time.  The
+*  results of this function will either unabiguously decide that
+*  the initial local time is in dst or return an illegal or
+*  ambiguous result.  An illegal result only occurs at the end
+*  of dst (where labels are skipped) and indicates that dst has
+*  ended.  An ambiguous result means that we need to recheck by
+*  making a dst adjustment and then rechecking.  If the dst offset
+*  is added to the utc time and the recheck proves non-ambiguous
+*  then we are past the boundary.  If it is still ambiguous then
+*  we are ahead of the boundary and dst is still in effect.
+*
+*  TODO -- check if all dst offsets are positive.  If not then
+*  the algorithm needs to check for this and reverse the
+*  illegal/ambiguous logic.
+*/
+static time_duration_type utc_to_local_offset(const time_type& t)
+{
+//get initial local time guess by applying utc offset
+time_type initial = t + utc_offset_rules::utc_to_local_base_offset();
+time_is_dst_result dst_flag =
+dst_rules::local_is_dst(initial.date(), initial.time_of_day());
+switch(dst_flag) {
+case is_in_dst:        return utc_offset_rules::utc_to_local_base_offset() + dst_rules::dst_offset();
+case is_not_in_dst:    return utc_offset_rules::utc_to_local_base_offset();
+case invalid_time_label:return utc_offset_rules::utc_to_local_base_offset() + dst_rules::dst_offset();
+case ambiguous: {
+time_type retry = initial + dst_rules::dst_offset();
+dst_flag = dst_rules::local_is_dst(retry.date(), retry.time_of_day());
+//if still ambibuous then the utc time still translates to a dst time
+if (dst_flag == ambiguous) {
+return utc_offset_rules::utc_to_local_base_offset() + dst_rules::dst_offset();
+}
+// we are past the dst boundary
+else {
+return utc_offset_rules::utc_to_local_base_offset();
+}
+}
+}//case
+//TODO  better exception type
+boost::throw_exception(std::out_of_range("Unreachable case"));
+BOOST_DATE_TIME_UNREACHABLE_EXPRESSION(return time_duration_type(not_a_date_time)); // should never reach
+}
+//! Get the offset to UTC given a local time
+static time_duration_type local_to_utc_offset(const time_type& t,
+date_time::dst_flags dst=date_time::calculate)
+{
+switch (dst) {
+case is_dst:
+return utc_offset_rules::local_to_utc_base_offset() - dst_rules::dst_offset();
+case not_dst:
+return utc_offset_rules::local_to_utc_base_offset();
+case calculate:
+time_is_dst_result res =
+dst_rules::local_is_dst(t.date(), t.time_of_day());
+switch(res) {
+case is_in_dst:      return utc_offset_rules::local_to_utc_base_offset() - dst_rules::dst_offset();
+case is_not_in_dst:      return utc_offset_rules::local_to_utc_base_offset();
+case ambiguous:          return utc_offset_rules::local_to_utc_base_offset();
+case invalid_time_label: break;
+}
+}
+boost::throw_exception(std::out_of_range("Time label invalid"));
+BOOST_DATE_TIME_UNREACHABLE_EXPRESSION(return time_duration_type(not_a_date_time)); // should never reach
+}
+private:
+};
+void dummy_to_prevent_msvc6_ice(); //why ask why?
+//! Template that simplifies the creation of local time calculator
+/*! Use this template to create the timezone to utc convertors as required.
+*
+*  This class will also work for other regions that don't use dst and
+*  have a utc offset which is an integral number of hours.
+*
+*  <b>Template Parameters</b>
+*  -time_type  -- Time class to use
+*  -utc_offset -- Number hours local time is adjust from utc
+*  -use_dst -- true (default) if region uses dst, false otherwise
+*  For example:
+*  @code
+*  //eastern timezone is utc-5
+typedef date_time::local_adjustor<ptime, -5, us_dst> us_eastern;
+typedef date_time::local_adjustor<ptime, -6, us_dst> us_central;
+typedef date_time::local_adjustor<ptime, -7, us_dst> us_mountain;
+typedef date_time::local_adjustor<ptime, -8, us_dst> us_pacific;
+typedef date_time::local_adjustor<ptime, -7, no_dst> us_arizona;
+@endcode
+*/
+template<class time_type, short utc_offset, class dst_rule>
+class local_adjustor
+{
+public:
+typedef typename time_type::time_duration_type time_duration_type;
+typedef typename time_type::date_type date_type;
+typedef static_local_time_adjustor<time_type,
+dst_rule,
+utc_adjustment<time_duration_type,
+utc_offset> > dst_adjustor;
+//! Convert a utc time to local time
+static time_type utc_to_local(const time_type& t)
+{
+time_duration_type td = dst_adjustor::utc_to_local_offset(t);
+return t + td;
+}
+//! Convert a local time to utc
+static time_type local_to_utc(const time_type& t,
+date_time::dst_flags dst=date_time::calculate)
+{
+time_duration_type td = dst_adjustor::local_to_utc_offset(t, dst);
+return t + td;
+}
+};
+} } //namespace date_time
+#endif