include/cpair.h

   1 //
   2 //  Copyright (C) 2008 by Martin Moracek
   3 //
   4 //  This program is free software; you can redistribute it and/or modify
   5 //  it under the terms of the GNU General Public License as published by
   6 //  the Free Software Foundation; either version 2 of the License, or
   7 //  (at your option) any later version.
   8 //
   9 //  This program is distributed in the hope that it will be useful,
  10 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 //  GNU General Public License for more details.
  13 //
  14 //  You should have received a copy of the GNU General Public License
  15 //  along with this program; if not, write to the Free Software
  16 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 //
  18
  19 /**
  20  *  @file cpair.h
  21  *
  22  *  Comparable pair classes, based on SGI implementation of std::pair class.
  23  */
  24
  25 #pragma once
  26
  27 #include <utility>
  28
  29 template <typename T, typename U>
  30 class cpair {
  31   public:
  32     typedef T first_type;
  33     typedef U second_type;
  34
  35   public:
  36     T first;
  37     U second;
  38
  39   public:
  40     // constructors
  41     cpair() : first(), second() {}
  42     cpair(const T & a, const U & b) : first(a), second(b) {}
  43
  44     template <typename V1, typename V2>
  45     cpair(const cpair<V1, V2> & p) : first(p.first), second(p.second) {}
  46
  47     // also include copy constructors for equivalent std::pair
  48     template <typename V1, typename V2>
  49     cpair(const std::pair<V1, V2> & p) : first(p.first), second(p.second) {}
  50 };
  51
  52 // operator ==
  53 template <typename T, typename U>
  54 inline bool operator == (const cpair<T, U> & l, const cpair<T, U> & r)
  55 {
  56   return l.first == r.first && l.second == r.second;
  57 }
  58
  59 template <typename T, typename U>
  60 inline bool operator == (const cpair<T, U> & l, const std::pair<T, U> & r)
  61 {
  62   return l.first == r.first && l.second == r.second;
  63 }
  64
  65 template <typename T, typename U>
  66 inline bool operator == (const std::pair<T, U> & l, const cpair<T, U> & r)
  67 {
  68   return l.first == r.first && l.second == r.second;
  69 }
  70
  71 // operator !=
  72 template <typename T, typename U>
  73 inline bool operator != (const cpair<T, U> & l, const cpair<T, U> & r)
  74 {
  75   return !(l == r);
  76 }
  77
  78 template <typename T, typename U>
  79 inline bool operator != (const cpair<T, U> & l, const std::pair<T, U> & r)
  80 {
  81   return !(l == r);
  82 }
  83
  84 template <typename T, typename U>
  85 inline bool operator != (const std::pair<T, U> & l, const cpair<T, U> & r)
  86 {
  87   return !(l == r);
  88 }
  89
  90 // operator <
  91 template <typename T, typename U>
  92 inline bool operator < (const cpair<T, U> & l, const cpair<T, U> & r)
  93 {
  94   return l.first < r.first;
  95 }
  96
  97 template <typename T, typename U>
  98 inline bool operator < (const T & l, const cpair<T, U> & r)
  99 {
 100   return l < r.first;
 101 }
 102
 103 template <typename T, typename U>
 104 inline bool operator < (const cpair<T, U> & l, const T & r)
 105 {
 106   return l.first < r;
 107 }
 108
 109 // A convenience wrapper for creating a pair from two objects.
 110 // template <typename T, typename U>
 111 // inline cpair<T, U> make_cpair(T l, U r)
 112 // {
 113 //   return cpair<T, U>(l, r);
 114 // }