Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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Class template wrapping_int

boost::date_time::wrapping_int — A wrapping integer used to support time durations (WARNING: only instantiate with a signed type).

Synopsis

// In header: <boost/date_time/wrapping_int.hpp>

template<typename int_type_, int_type_ wrap_val> 
class wrapping_int {
public:
  // types
  typedef int_type_ int_type;

  // construct/copy/destruct
  wrapping_int(int_type);

  // public static functions
  static int_type wrap_value() ;

  // public member functions
  int_type as_int() const;
  operator int_type() const;
  template<typename IntT> IntT add(IntT) ;
  template<typename IntT> IntT subtract(IntT) ;

  // private member functions
  template<typename IntT> IntT calculate_wrap(IntT) ;
};

Description

In composite date and time types this type is used to wrap at the day boundary. Ex: A wrapping_int<short, 10> will roll over after nine, and roll under below zero. This gives a range of [0,9]

NOTE: it is strongly recommended that wrapping_int2 be used instead of wrapping_int as wrapping_int is to be depricated at some point soon.

Also Note that warnings will occur if instantiated with an unsigned type. Only a signed type should be used!

wrapping_int public construct/copy/destruct

  1. wrapping_int(int_type v);

wrapping_int public static functions

  1. static int_type wrap_value() ;

wrapping_int public member functions

  1. int_type as_int() const;
  2. operator int_type() const;
  3. template<typename IntT> IntT add(IntT v) ;

    The sign of the returned value will indicate which direction the wraps went. Ex: add a negative number and wrapping under could occur, this would be indicated by a negative return value. If wrapping over took place, a positive value would be returned

  4. template<typename IntT> IntT subtract(IntT v) ;

    The sign of the returned value will indicate which direction the wraps went (positive indicates wrap under, negative indicates wrap over). Ex: subtract a negative number and wrapping over could occur, this would be indicated by a negative return value. If wrapping under took place, a positive value would be returned.

wrapping_int private member functions

  1. template<typename IntT> IntT calculate_wrap(IntT wrap) ;

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