510 lines
14 KiB
C++
510 lines
14 KiB
C++
#ifndef _DATE_TIME_INT_ADAPTER_HPP__
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#define _DATE_TIME_INT_ADAPTER_HPP__
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/* Copyright (c) 2002,2003 CrystalClear Software, Inc.
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* Use, modification and distribution is subject to the
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* Boost Software License, Version 1.0. (See accompanying
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* file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
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* Author: Jeff Garland, Bart Garst
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* $Date$
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*/
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#include "boost/config.hpp"
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#include "boost/limits.hpp" //work around compilers without limits
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#include "boost/date_time/special_defs.hpp"
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#include "boost/date_time/locale_config.hpp"
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#ifndef BOOST_DATE_TIME_NO_LOCALE
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# include <ostream>
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#endif
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namespace boost {
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namespace date_time {
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//! Adapter to create integer types with +-infinity, and not a value
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/*! This class is used internally in counted date/time representations.
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* It adds the floating point like features of infinities and
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* not a number. It also provides mathmatical operations with
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* consideration to special values following these rules:
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*@code
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* +infinity - infinity == Not A Number (NAN)
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* infinity * non-zero == infinity
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* infinity * zero == NAN
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* +infinity * -integer == -infinity
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* infinity / infinity == NAN
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* infinity * infinity == infinity
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*@endcode
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*/
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template<typename int_type_>
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class int_adapter {
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public:
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typedef int_type_ int_type;
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int_adapter(int_type v) :
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value_(v)
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{}
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static bool has_infinity()
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{
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return true;
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}
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static const int_adapter pos_infinity()
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{
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return (::std::numeric_limits<int_type>::max)();
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}
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static const int_adapter neg_infinity()
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{
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return (::std::numeric_limits<int_type>::min)();
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}
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static const int_adapter not_a_number()
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{
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return (::std::numeric_limits<int_type>::max)()-1;
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}
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static int_adapter max BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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return (::std::numeric_limits<int_type>::max)()-2;
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}
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static int_adapter min BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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return (::std::numeric_limits<int_type>::min)()+1;
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}
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static int_adapter from_special(special_values sv)
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{
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switch (sv) {
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case not_a_date_time: return not_a_number();
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case neg_infin: return neg_infinity();
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case pos_infin: return pos_infinity();
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case max_date_time: return (max)();
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case min_date_time: return (min)();
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default: return not_a_number();
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}
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}
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static bool is_inf(int_type v)
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{
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return (v == neg_infinity().as_number() ||
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v == pos_infinity().as_number());
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}
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static bool is_neg_inf(int_type v)
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{
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return (v == neg_infinity().as_number());
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}
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static bool is_pos_inf(int_type v)
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{
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return (v == pos_infinity().as_number());
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}
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static bool is_not_a_number(int_type v)
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{
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return (v == not_a_number().as_number());
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}
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//! Returns either special value type or is_not_special
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static special_values to_special(int_type v)
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{
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if (is_not_a_number(v)) return not_a_date_time;
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if (is_neg_inf(v)) return neg_infin;
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if (is_pos_inf(v)) return pos_infin;
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return not_special;
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}
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//-3 leaves room for representations of infinity and not a date
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static int_type maxcount()
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{
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return (::std::numeric_limits<int_type>::max)()-3;
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}
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bool is_infinity() const
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{
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return (value_ == neg_infinity().as_number() ||
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value_ == pos_infinity().as_number());
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}
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bool is_pos_infinity()const
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{
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return(value_ == pos_infinity().as_number());
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}
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bool is_neg_infinity()const
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{
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return(value_ == neg_infinity().as_number());
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}
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bool is_nan() const
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{
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return (value_ == not_a_number().as_number());
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}
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bool is_special() const
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{
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return(is_infinity() || is_nan());
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}
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bool operator==(const int_adapter& rhs) const
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{
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return (compare(rhs) == 0);
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}
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bool operator==(const int& rhs) const
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{
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// quiets compiler warnings
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bool is_signed = std::numeric_limits<int_type>::is_signed;
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if(!is_signed)
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{
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if(is_neg_inf(value_) && rhs == 0)
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{
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return false;
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}
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}
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return (compare(rhs) == 0);
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}
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bool operator!=(const int_adapter& rhs) const
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{
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return (compare(rhs) != 0);
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}
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bool operator!=(const int& rhs) const
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{
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// quiets compiler warnings
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bool is_signed = std::numeric_limits<int_type>::is_signed;
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if(!is_signed)
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{
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if(is_neg_inf(value_) && rhs == 0)
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{
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return true;
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}
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}
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return (compare(rhs) != 0);
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}
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bool operator<(const int_adapter& rhs) const
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{
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return (compare(rhs) == -1);
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}
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bool operator<(const int& rhs) const
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{
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// quiets compiler warnings
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bool is_signed = std::numeric_limits<int_type>::is_signed;
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if(!is_signed)
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{
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if(is_neg_inf(value_) && rhs == 0)
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{
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return true;
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}
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}
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return (compare(rhs) == -1);
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}
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bool operator>(const int_adapter& rhs) const
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{
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return (compare(rhs) == 1);
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}
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int_type as_number() const
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{
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return value_;
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}
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//! Returns either special value type or is_not_special
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special_values as_special() const
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{
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return int_adapter::to_special(value_);
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}
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//creates nasty ambiguities
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// operator int_type() const
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// {
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// return value_;
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// }
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/*! Operator allows for adding dissimilar int_adapter types.
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* The return type will match that of the the calling object's type */
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template<class rhs_type>
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inline
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int_adapter operator+(const int_adapter<rhs_type>& rhs) const
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{
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if(is_special() || rhs.is_special())
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{
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if (is_nan() || rhs.is_nan())
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{
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return int_adapter::not_a_number();
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}
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if((is_pos_inf(value_) && rhs.is_neg_inf(rhs.as_number())) ||
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(is_neg_inf(value_) && rhs.is_pos_inf(rhs.as_number())) )
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{
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return int_adapter::not_a_number();
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}
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if (is_infinity())
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{
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return *this;
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}
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if (rhs.is_pos_inf(rhs.as_number()))
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{
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return int_adapter::pos_infinity();
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}
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if (rhs.is_neg_inf(rhs.as_number()))
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{
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return int_adapter::neg_infinity();
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}
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}
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return int_adapter<int_type>(value_ + static_cast<int_type>(rhs.as_number()));
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}
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int_adapter operator+(const int_type rhs) const
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{
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if(is_special())
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{
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if (is_nan())
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{
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return int_adapter<int_type>(not_a_number());
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}
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if (is_infinity())
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{
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return *this;
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}
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}
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return int_adapter<int_type>(value_ + rhs);
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}
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/*! Operator allows for subtracting dissimilar int_adapter types.
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* The return type will match that of the the calling object's type */
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template<class rhs_type>
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inline
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int_adapter operator-(const int_adapter<rhs_type>& rhs)const
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{
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if(is_special() || rhs.is_special())
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{
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if (is_nan() || rhs.is_nan())
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{
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return int_adapter::not_a_number();
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}
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if((is_pos_inf(value_) && rhs.is_pos_inf(rhs.as_number())) ||
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(is_neg_inf(value_) && rhs.is_neg_inf(rhs.as_number())) )
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{
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return int_adapter::not_a_number();
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}
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if (is_infinity())
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{
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return *this;
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}
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if (rhs.is_pos_inf(rhs.as_number()))
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{
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return int_adapter::neg_infinity();
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}
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if (rhs.is_neg_inf(rhs.as_number()))
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{
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return int_adapter::pos_infinity();
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}
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}
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return int_adapter<int_type>(value_ - static_cast<int_type>(rhs.as_number()));
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}
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int_adapter operator-(const int_type rhs) const
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{
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if(is_special())
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{
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if (is_nan())
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{
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return int_adapter<int_type>(not_a_number());
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}
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if (is_infinity())
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{
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return *this;
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}
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}
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return int_adapter<int_type>(value_ - rhs);
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}
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// should templatize this to be consistant with op +-
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int_adapter operator*(const int_adapter& rhs)const
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{
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if(this->is_special() || rhs.is_special())
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{
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return mult_div_specials(rhs);
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}
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return int_adapter<int_type>(value_ * rhs.value_);
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}
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/*! Provided for cases when automatic conversion from
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* 'int' to 'int_adapter' causes incorrect results. */
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int_adapter operator*(const int rhs) const
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{
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if(is_special())
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{
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return mult_div_specials(rhs);
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}
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return int_adapter<int_type>(value_ * rhs);
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}
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// should templatize this to be consistant with op +-
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int_adapter operator/(const int_adapter& rhs)const
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{
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if(this->is_special() || rhs.is_special())
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{
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if(is_infinity() && rhs.is_infinity())
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{
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return int_adapter<int_type>(not_a_number());
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}
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if(rhs != 0)
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{
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return mult_div_specials(rhs);
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}
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else { // let divide by zero blow itself up
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return int_adapter<int_type>(value_ / rhs.value_);
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}
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}
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return int_adapter<int_type>(value_ / rhs.value_);
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}
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/*! Provided for cases when automatic conversion from
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* 'int' to 'int_adapter' causes incorrect results. */
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int_adapter operator/(const int rhs) const
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{
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if(is_special() && rhs != 0)
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{
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return mult_div_specials(rhs);
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}
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return int_adapter<int_type>(value_ / rhs);
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}
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// should templatize this to be consistant with op +-
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int_adapter operator%(const int_adapter& rhs)const
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{
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if(this->is_special() || rhs.is_special())
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{
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if(is_infinity() && rhs.is_infinity())
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{
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return int_adapter<int_type>(not_a_number());
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}
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if(rhs != 0)
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{
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return mult_div_specials(rhs);
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}
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else { // let divide by zero blow itself up
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return int_adapter<int_type>(value_ % rhs.value_);
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}
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}
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return int_adapter<int_type>(value_ % rhs.value_);
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}
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/*! Provided for cases when automatic conversion from
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* 'int' to 'int_adapter' causes incorrect results. */
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int_adapter operator%(const int rhs) const
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{
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if(is_special() && rhs != 0)
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{
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return mult_div_specials(rhs);
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}
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return int_adapter<int_type>(value_ % rhs);
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}
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private:
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int_type value_;
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//! returns -1, 0, 1, or 2 if 'this' is <, ==, >, or 'nan comparison' rhs
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int compare(const int_adapter& rhs)const
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{
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if(this->is_special() || rhs.is_special())
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{
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if(this->is_nan() || rhs.is_nan()) {
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if(this->is_nan() && rhs.is_nan()) {
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return 0; // equal
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}
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else {
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return 2; // nan
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}
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}
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if((is_neg_inf(value_) && !is_neg_inf(rhs.value_)) ||
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(is_pos_inf(rhs.value_) && !is_pos_inf(value_)) )
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{
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return -1; // less than
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}
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if((is_pos_inf(value_) && !is_pos_inf(rhs.value_)) ||
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(is_neg_inf(rhs.value_) && !is_neg_inf(value_)) ) {
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return 1; // greater than
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}
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}
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if(value_ < rhs.value_) return -1;
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if(value_ > rhs.value_) return 1;
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// implied-> if(value_ == rhs.value_)
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return 0;
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}
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/* When multiplying and dividing with at least 1 special value
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* very simmilar rules apply. In those cases where the rules
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* are different, they are handled in the respective operator
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* function. */
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//! Assumes at least 'this' or 'rhs' is a special value
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int_adapter mult_div_specials(const int_adapter& rhs)const
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{
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int min_value;
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// quiets compiler warnings
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bool is_signed = std::numeric_limits<int_type>::is_signed;
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if(is_signed) {
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min_value = 0;
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}
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else {
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min_value = 1;// there is no zero with unsigned
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}
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if(this->is_nan() || rhs.is_nan()) {
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return int_adapter<int_type>(not_a_number());
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}
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if((*this > 0 && rhs > 0) || (*this < min_value && rhs < min_value)) {
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return int_adapter<int_type>(pos_infinity());
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}
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if((*this > 0 && rhs < min_value) || (*this < min_value && rhs > 0)) {
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return int_adapter<int_type>(neg_infinity());
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}
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//implied -> if(this->value_ == 0 || rhs.value_ == 0)
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return int_adapter<int_type>(not_a_number());
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}
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/* Overloaded function necessary because of special
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* situation where int_adapter is instantiated with
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* 'unsigned' and func is called with negative int.
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* It would produce incorrect results since 'unsigned'
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* wraps around when initialized with a negative value */
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//! Assumes 'this' is a special value
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int_adapter mult_div_specials(const int& rhs) const
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{
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int min_value;
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// quiets compiler warnings
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bool is_signed = std::numeric_limits<int_type>::is_signed;
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if(is_signed) {
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min_value = 0;
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}
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else {
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min_value = 1;// there is no zero with unsigned
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}
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if(this->is_nan()) {
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return int_adapter<int_type>(not_a_number());
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}
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if((*this > 0 && rhs > 0) || (*this < min_value && rhs < 0)) {
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return int_adapter<int_type>(pos_infinity());
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}
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if((*this > 0 && rhs < 0) || (*this < min_value && rhs > 0)) {
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return int_adapter<int_type>(neg_infinity());
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}
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//implied -> if(this->value_ == 0 || rhs.value_ == 0)
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return int_adapter<int_type>(not_a_number());
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}
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};
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#ifndef BOOST_DATE_TIME_NO_LOCALE
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/*! Expected output is either a numeric representation
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* or a special values representation.<BR>
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* Ex. "12", "+infinity", "not-a-number", etc. */
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//template<class charT = char, class traits = std::traits<charT>, typename int_type>
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template<class charT, class traits, typename int_type>
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inline
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std::basic_ostream<charT, traits>&
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operator<<(std::basic_ostream<charT, traits>& os, const int_adapter<int_type>& ia)
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{
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if(ia.is_special()) {
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// switch copied from date_names_put.hpp
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switch(ia.as_special())
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{
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case not_a_date_time:
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os << "not-a-number";
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break;
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case pos_infin:
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os << "+infinity";
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break;
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case neg_infin:
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os << "-infinity";
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break;
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default:
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os << "";
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}
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}
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else {
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os << ia.as_number();
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}
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return os;
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}
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#endif
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} } //namespace date_time
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#endif
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