mingw/lib/gcc/mingw32/4.3.3/include/c++/backward/binders.h

   1 // Functor implementations -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /*
  32  *
  33  * Copyright (c) 1994
  34  * Hewlett-Packard Company
  35  *
  36  * Permission to use, copy, modify, distribute and sell this software
  37  * and its documentation for any purpose is hereby granted without fee,
  38  * provided that the above copyright notice appear in all copies and
  39  * that both that copyright notice and this permission notice appear
  40  * in supporting documentation.  Hewlett-Packard Company makes no
  41  * representations about the suitability of this software for any
  42  * purpose.  It is provided "as is" without express or implied warranty.
  43  *
  44  *
  45  * Copyright (c) 1996-1998
  46  * Silicon Graphics Computer Systems, Inc.
  47  *
  48  * Permission to use, copy, modify, distribute and sell this software
  49  * and its documentation for any purpose is hereby granted without fee,
  50  * provided that the above copyright notice appear in all copies and
  51  * that both that copyright notice and this permission notice appear
  52  * in supporting documentation.  Silicon Graphics makes no
  53  * representations about the suitability of this software for any
  54  * purpose.  It is provided "as is" without express or implied warranty.
  55  */
  56
  57 /** @file backward/binders.h
  58  *  This is an internal header file, included by other library headers.
  59  *  You should not attempt to use it directly.
  60  */
  61
  62 #ifndef _GLIBCXX_BINDERS_H
  63 #define _GLIBCXX_BINDERS_H 1
  64
  65 _GLIBCXX_BEGIN_NAMESPACE(std)
  66
  67   // 20.3.6 binders
  68   /** @defgroup s20_3_6_binder Binder Classes
  69    *  Binders turn functions/functors with two arguments into functors with
  70    *  a single argument, storing an argument to be applied later.  For
  71    *  example, a variable @c B of type @c binder1st is constructed from a
  72    *  functor @c f and an argument @c x.  Later, B's @c operator() is called
  73    *  with a single argument @c y.  The return value is the value of @c f(x,y).
  74    *  @c B can be "called" with various arguments (y1, y2, ...) and will in
  75    *  turn call @c f(x,y1), @c f(x,y2), ...
  76    *
  77    *  The function @c bind1st is provided to save some typing.  It takes the
  78    *  function and an argument as parameters, and returns an instance of
  79    *  @c binder1st.
  80    *
  81    *  The type @c binder2nd and its creator function @c bind2nd do the same
  82    *  thing, but the stored argument is passed as the second parameter instead
  83    *  of the first, e.g., @c bind2nd(std::minus<float>,1.3) will create a
  84    *  functor whose @c operator() accepts a floating-point number, subtracts
  85    *  1.3 from it, and returns the result.  (If @c bind1st had been used,
  86    *  the functor would perform "1.3 - x" instead.
  87    *
  88    *  Creator-wrapper functions like @c bind1st are intended to be used in
  89    *  calling algorithms.  Their return values will be temporary objects.
  90    *  (The goal is to not require you to type names like
  91    *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
  92    *  return value from @c bind1st(std::plus<int>,5).
  93    *
  94    *  These become more useful when combined with the composition functions.
  95    *
  96    *  @{
  97    */
  98   /// One of the @link s20_3_6_binder binder functors@endlink.
  99   template<typename _Operation>
 100     class binder1st
 101     : public unary_function<typename _Operation::second_argument_type,
 102                             typename _Operation::result_type>
 103     {
 104     protected:
 105       _Operation op;
 106       typename _Operation::first_argument_type value;
 107
 108     public:
 109       binder1st(const _Operation& __x,
 110                 const typename _Operation::first_argument_type& __y)
 111       : op(__x), value(__y) { }
 112
 113       typename _Operation::result_type
 114       operator()(const typename _Operation::second_argument_type& __x) const
 115       { return op(value, __x); }
 116
 117       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 118       // 109.  Missing binders for non-const sequence elements
 119       typename _Operation::result_type
 120       operator()(typename _Operation::second_argument_type& __x) const
 121       { return op(value, __x); }
 122     } _GLIBCXX_DEPRECATED_ATTR;
 123
 124   /// One of the @link s20_3_6_binder binder functors@endlink.
 125   template<typename _Operation, typename _Tp>
 126     inline binder1st<_Operation>
 127     bind1st(const _Operation& __fn, const _Tp& __x)
 128     {
 129       typedef typename _Operation::first_argument_type _Arg1_type;
 130       return binder1st<_Operation>(__fn, _Arg1_type(__x));
 131     }
 132
 133   /// One of the @link s20_3_6_binder binder functors@endlink.
 134   template<typename _Operation>
 135     class binder2nd
 136     : public unary_function<typename _Operation::first_argument_type,
 137                             typename _Operation::result_type>
 138     {
 139     protected:
 140       _Operation op;
 141       typename _Operation::second_argument_type value;
 142
 143     public:
 144       binder2nd(const _Operation& __x,
 145                 const typename _Operation::second_argument_type& __y)
 146       : op(__x), value(__y) { }
 147
 148       typename _Operation::result_type
 149       operator()(const typename _Operation::first_argument_type& __x) const
 150       { return op(__x, value); }
 151
 152       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 153       // 109.  Missing binders for non-const sequence elements
 154       typename _Operation::result_type
 155       operator()(typename _Operation::first_argument_type& __x) const
 156       { return op(__x, value); }
 157     } _GLIBCXX_DEPRECATED_ATTR;
 158
 159   /// One of the @link s20_3_6_binder binder functors@endlink.
 160   template<typename _Operation, typename _Tp>
 161     inline binder2nd<_Operation>
 162     bind2nd(const _Operation& __fn, const _Tp& __x)
 163     {
 164       typedef typename _Operation::second_argument_type _Arg2_type;
 165       return binder2nd<_Operation>(__fn, _Arg2_type(__x));
 166     }
 167   /** @}  */
 168
 169 _GLIBCXX_END_NAMESPACE
 170
 171 #endif /* _GLIBCXX_BINDERS_H */