Subversion Repositories Kolibri OS

Rev

Go to most recent revision | Blame | Last modification | View Log | RSS feed

  1. // Functor implementations -*- C++ -*-
  2.  
  3. // Copyright (C) 2001-2013 Free Software Foundation, Inc.
  4. //
  5. // This file is part of the GNU ISO C++ Library.  This library is free
  6. // software; you can redistribute it and/or modify it under the
  7. // terms of the GNU General Public License as published by the
  8. // Free Software Foundation; either version 3, or (at your option)
  9. // any later version.
  10.  
  11. // This library is distributed in the hope that it will be useful,
  12. // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14. // GNU General Public License for more details.
  15.  
  16. // Under Section 7 of GPL version 3, you are granted additional
  17. // permissions described in the GCC Runtime Library Exception, version
  18. // 3.1, as published by the Free Software Foundation.
  19.  
  20. // You should have received a copy of the GNU General Public License and
  21. // a copy of the GCC Runtime Library Exception along with this program;
  22. // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23. // <http://www.gnu.org/licenses/>.
  24.  
  25. /*
  26.  *
  27.  * Copyright (c) 1994
  28.  * Hewlett-Packard Company
  29.  *
  30.  * Permission to use, copy, modify, distribute and sell this software
  31.  * and its documentation for any purpose is hereby granted without fee,
  32.  * provided that the above copyright notice appear in all copies and
  33.  * that both that copyright notice and this permission notice appear
  34.  * in supporting documentation.  Hewlett-Packard Company makes no
  35.  * representations about the suitability of this software for any
  36.  * purpose.  It is provided "as is" without express or implied warranty.
  37.  *
  38.  *
  39.  * Copyright (c) 1996-1998
  40.  * Silicon Graphics Computer Systems, Inc.
  41.  *
  42.  * Permission to use, copy, modify, distribute and sell this software
  43.  * and its documentation for any purpose is hereby granted without fee,
  44.  * provided that the above copyright notice appear in all copies and
  45.  * that both that copyright notice and this permission notice appear
  46.  * in supporting documentation.  Silicon Graphics makes no
  47.  * representations about the suitability of this software for any
  48.  * purpose.  It is provided "as is" without express or implied warranty.
  49.  */
  50.  
  51. /** @file backward/binders.h
  52.  *  This is an internal header file, included by other library headers.
  53.  *  Do not attempt to use it directly. @headername{functional}
  54.  */
  55.  
  56. #ifndef _BACKWARD_BINDERS_H
  57. #define _BACKWARD_BINDERS_H 1
  58.  
  59. namespace std _GLIBCXX_VISIBILITY(default)
  60. {
  61. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  62.  
  63.   // 20.3.6 binders
  64.   /** @defgroup binders Binder Classes
  65.    * @ingroup functors
  66.    *
  67.    *  Binders turn functions/functors with two arguments into functors
  68.    *  with a single argument, storing an argument to be applied later.
  69.    *  For example, a variable @c B of type @c binder1st is constructed
  70.    *  from a functor @c f and an argument @c x. Later, B's @c
  71.    *  operator() is called with a single argument @c y. The return
  72.    *  value is the value of @c f(x,y). @c B can be @a called with
  73.    *  various arguments (y1, y2, ...) and will in turn call @c
  74.    *  f(x,y1), @c f(x,y2), ...
  75.    *
  76.    *  The function @c bind1st is provided to save some typing. It takes the
  77.    *  function and an argument as parameters, and returns an instance of
  78.    *  @c binder1st.
  79.    *
  80.    *  The type @c binder2nd and its creator function @c bind2nd do the same
  81.    *  thing, but the stored argument is passed as the second parameter instead
  82.    *  of the first, e.g., @c bind2nd(std::minus<float>(),1.3) will create a
  83.    *  functor whose @c operator() accepts a floating-point number, subtracts
  84.    *  1.3 from it, and returns the result. (If @c bind1st had been used,
  85.    *  the functor would perform <em>1.3 - x</em> instead.
  86.    *
  87.    *  Creator-wrapper functions like @c bind1st are intended to be used in
  88.    *  calling algorithms. Their return values will be temporary objects.
  89.    *  (The goal is to not require you to type names like
  90.    *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
  91.    *  return value from @c bind1st(std::plus<int>(),5).
  92.    *
  93.    *  These become more useful when combined with the composition functions.
  94.    *
  95.    *  These functions are deprecated in C++11 and can be replaced by
  96.    *  @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
  97.    *  supporting functions with any number of arguments.  Uses of @c bind1st
  98.    *  can be replaced by @c std::bind(f, x, std::placeholders::_1) and
  99.    *  @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
  100.    *  @{
  101.    */
  102.   /// One of the @link binders binder functors@endlink.
  103.   template<typename _Operation>
  104.     class binder1st
  105.     : public unary_function<typename _Operation::second_argument_type,
  106.                             typename _Operation::result_type>
  107.     {
  108.     protected:
  109.       _Operation op;
  110.       typename _Operation::first_argument_type value;
  111.  
  112.     public:
  113.       binder1st(const _Operation& __x,
  114.                 const typename _Operation::first_argument_type& __y)
  115.       : op(__x), value(__y) { }
  116.  
  117.       typename _Operation::result_type
  118.       operator()(const typename _Operation::second_argument_type& __x) const
  119.       { return op(value, __x); }
  120.  
  121.       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  122.       // 109.  Missing binders for non-const sequence elements
  123.       typename _Operation::result_type
  124.       operator()(typename _Operation::second_argument_type& __x) const
  125.       { return op(value, __x); }
  126.     } _GLIBCXX_DEPRECATED;
  127.  
  128.   /// One of the @link binders binder functors@endlink.
  129.   template<typename _Operation, typename _Tp>
  130.     inline binder1st<_Operation>
  131.     bind1st(const _Operation& __fn, const _Tp& __x)
  132.     {
  133.       typedef typename _Operation::first_argument_type _Arg1_type;
  134.       return binder1st<_Operation>(__fn, _Arg1_type(__x));
  135.     }
  136.  
  137.   /// One of the @link binders binder functors@endlink.
  138.   template<typename _Operation>
  139.     class binder2nd
  140.     : public unary_function<typename _Operation::first_argument_type,
  141.                             typename _Operation::result_type>
  142.     {
  143.     protected:
  144.       _Operation op;
  145.       typename _Operation::second_argument_type value;
  146.  
  147.     public:
  148.       binder2nd(const _Operation& __x,
  149.                 const typename _Operation::second_argument_type& __y)
  150.       : op(__x), value(__y) { }
  151.  
  152.       typename _Operation::result_type
  153.       operator()(const typename _Operation::first_argument_type& __x) const
  154.       { return op(__x, value); }
  155.  
  156.       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  157.       // 109.  Missing binders for non-const sequence elements
  158.       typename _Operation::result_type
  159.       operator()(typename _Operation::first_argument_type& __x) const
  160.       { return op(__x, value); }
  161.     } _GLIBCXX_DEPRECATED;
  162.  
  163.   /// One of the @link binders binder functors@endlink.
  164.   template<typename _Operation, typename _Tp>
  165.     inline binder2nd<_Operation>
  166.     bind2nd(const _Operation& __fn, const _Tp& __x)
  167.     {
  168.       typedef typename _Operation::second_argument_type _Arg2_type;
  169.       return binder2nd<_Operation>(__fn, _Arg2_type(__x));
  170.     }
  171.   /** @}  */
  172.  
  173. _GLIBCXX_END_NAMESPACE_VERSION
  174. } // namespace
  175.  
  176. #endif /* _BACKWARD_BINDERS_H */
  177.