Chris@16: #ifndef _DATE_TIME_WRAPPING_INT_HPP__
Chris@16: #define _DATE_TIME_WRAPPING_INT_HPP__
Chris@16: 
Chris@16: /* Copyright (c) 2002,2003,2005 CrystalClear Software, Inc.
Chris@16:  * Use, modification and distribution is subject to the
Chris@16:  * Boost Software License, Version 1.0. (See accompanying
Chris@16:  * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  * Author: Jeff Garland, Bart Garst
Chris@101:  * $Date$
Chris@16:  */
Chris@16: 
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace date_time {
Chris@16: 
Chris@16: //! A wrapping integer used to support time durations (WARNING: only instantiate with a signed type)
Chris@16: /*! In composite date and time types this type is used to
Chris@16:  *  wrap at the day boundary.
Chris@16:  *  Ex:
Chris@16:  *  A wrapping_int<short, 10> will roll over after nine, and
Chris@16:  *  roll under below zero. This gives a range of [0,9]
Chris@16:  *
Chris@16:  * NOTE: it is strongly recommended that wrapping_int2 be used
Chris@16:  * instead of wrapping_int as wrapping_int is to be depricated
Chris@16:  * at some point soon.
Chris@16:  *
Chris@16:  * Also Note that warnings will occur if instantiated with an
Chris@16:  * unsigned type. Only a signed type should be used!
Chris@16:  */
Chris@16: template<typename int_type_, int_type_ wrap_val>
Chris@16: class wrapping_int {
Chris@16: public:
Chris@16:   typedef int_type_ int_type;
Chris@16:   //typedef overflow_type_ overflow_type;
Chris@16:   static int_type wrap_value() {return wrap_val;}
Chris@16:   //!Add, return true if wrapped
Chris@16:   wrapping_int(int_type v) : value_(v) {}
Chris@16:   //! Explicit converion method
Chris@16:   int_type as_int()   const   {return value_;}
Chris@16:   operator int_type() const   {return value_;}
Chris@16:   //!Add, return number of wraps performed
Chris@16:   /*! The sign of the returned value will indicate which direction the
Chris@16:    * wraps went. Ex: add a negative number and wrapping under could occur,
Chris@16:    * this would be indicated by a negative return value. If wrapping over
Chris@16:    * took place, a positive value would be returned */
Chris@16:   template< typename IntT >
Chris@16:   IntT add(IntT v)
Chris@16:   {
Chris@16:     int_type remainder = static_cast<int_type>(v % (wrap_val));
Chris@16:     IntT overflow = static_cast<IntT>(v / (wrap_val));
Chris@16:     value_ = static_cast<int_type>(value_ + remainder);
Chris@16:     return calculate_wrap(overflow);
Chris@16:   }
Chris@16:   //! Subtract will return '+d' if wrapping under took place ('d' is the number of wraps)
Chris@16:   /*! The sign of the returned value will indicate which direction the
Chris@16:    * wraps went (positive indicates wrap under, negative indicates wrap over).
Chris@16:    * Ex: subtract a negative number and wrapping over could
Chris@16:    * occur, this would be indicated by a negative return value. If
Chris@16:    * wrapping under took place, a positive value would be returned. */
Chris@16:   template< typename IntT >
Chris@16:   IntT subtract(IntT v)
Chris@16:   {
Chris@16:     int_type remainder = static_cast<int_type>(v % (wrap_val));
Chris@16:     IntT underflow = static_cast<IntT>(-(v / (wrap_val)));
Chris@16:     value_ = static_cast<int_type>(value_ - remainder);
Chris@16:     return calculate_wrap(underflow) * -1;
Chris@16:   }
Chris@16: private:
Chris@16:   int_type value_;
Chris@16: 
Chris@16:   template< typename IntT >
Chris@16:   IntT calculate_wrap(IntT wrap)
Chris@16:   {
Chris@16:     if ((value_) >= wrap_val)
Chris@16:     {
Chris@16:       ++wrap;
Chris@16:       value_ -= (wrap_val);
Chris@16:     }
Chris@16:     else if(value_ < 0)
Chris@16:     {
Chris@16:       --wrap;
Chris@16:       value_ += (wrap_val);
Chris@16:     }
Chris@16:     return wrap;
Chris@16:   }
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: //! A wrapping integer used to wrap around at the top (WARNING: only instantiate with a signed type)
Chris@16: /*! Bad name, quick impl to fix a bug -- fix later!!
Chris@16:  *  This allows the wrap to restart at a value other than 0.
Chris@16:  */
Chris@16: template<typename int_type_, int_type_ wrap_min, int_type_ wrap_max>
Chris@16: class wrapping_int2 {
Chris@16: public:
Chris@16:   typedef int_type_ int_type;
Chris@16:   static int_type wrap_value() {return wrap_max;}
Chris@16:   static int_type min_value()  {return wrap_min;}
Chris@16:   /*! If initializing value is out of range of [wrap_min, wrap_max],
Chris@16:    * value will be initialized to closest of min or max */
Chris@16:   wrapping_int2(int_type v) : value_(v) {
Chris@16:     if(value_ < wrap_min)
Chris@16:     {
Chris@16:       value_ = wrap_min;
Chris@16:     }
Chris@16:     if(value_ > wrap_max)
Chris@16:     {
Chris@16:       value_ = wrap_max;
Chris@16:     }
Chris@16:   }
Chris@16:   //! Explicit converion method
Chris@16:   int_type as_int()   const   {return value_;}
Chris@16:   operator int_type() const {return value_;}
Chris@16:   //!Add, return number of wraps performed
Chris@16:   /*! The sign of the returned value will indicate which direction the
Chris@16:    * wraps went. Ex: add a negative number and wrapping under could occur,
Chris@16:    * this would be indicated by a negative return value. If wrapping over
Chris@16:    * took place, a positive value would be returned */
Chris@16:   template< typename IntT >
Chris@16:   IntT add(IntT v)
Chris@16:   {
Chris@16:     int_type remainder = static_cast<int_type>(v % (wrap_max - wrap_min + 1));
Chris@16:     IntT overflow = static_cast<IntT>(v / (wrap_max - wrap_min + 1));
Chris@16:     value_ = static_cast<int_type>(value_ + remainder);
Chris@16:     return calculate_wrap(overflow);
Chris@16:   }
Chris@16:   //! Subtract will return '-d' if wrapping under took place ('d' is the number of wraps)
Chris@16:   /*! The sign of the returned value will indicate which direction the
Chris@16:    * wraps went. Ex: subtract a negative number and wrapping over could
Chris@16:    * occur, this would be indicated by a positive return value. If
Chris@16:    * wrapping under took place, a negative value would be returned */
Chris@16:   template< typename IntT >
Chris@16:   IntT subtract(IntT v)
Chris@16:   {
Chris@16:     int_type remainder = static_cast<int_type>(v % (wrap_max - wrap_min + 1));
Chris@16:     IntT underflow = static_cast<IntT>(-(v / (wrap_max - wrap_min + 1)));
Chris@16:     value_ = static_cast<int_type>(value_ - remainder);
Chris@16:     return calculate_wrap(underflow);
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   int_type value_;
Chris@16: 
Chris@16:   template< typename IntT >
Chris@16:   IntT calculate_wrap(IntT wrap)
Chris@16:   {
Chris@16:     if ((value_) > wrap_max)
Chris@16:     {
Chris@16:       ++wrap;
Chris@16:       value_ -= (wrap_max - wrap_min + 1);
Chris@16:     }
Chris@16:     else if((value_) < wrap_min)
Chris@16:     {
Chris@16:       --wrap;
Chris@16:       value_ += (wrap_max - wrap_min + 1);
Chris@16:     }
Chris@16:     return wrap;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: } } //namespace date_time
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: #endif
Chris@16: