stl_algobase.h

linux下编程用 编译软件

// Bits and pieces used in algorithms -*- C++ -*-

// Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996-1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file stl_algobase.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef _ALGOBASE_H
#define _ALGOBASE_H 1

#include <bits/c++config.h>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cstddef>
#include <iosfwd>
#include <bits/stl_pair.h>
#include <bits/cpp_type_traits.h>
#include <bits/stl_iterator_base_types.h>
#include <bits/stl_iterator_base_funcs.h>
#include <bits/stl_iterator.h>
#include <bits/concept_check.h>
#include <debug/debug.h>

namespace std
{

  /**
   *  @brief Swaps two values.
   *  @param  a  A thing of arbitrary type.
   *  @param  b  Another thing of arbitrary type.
   *  @return   Nothing.
   *
   *  This is the simple classic generic implementation.  It will work on
   *  any type which has a copy constructor and an assignment operator.
  */
  template<typename _Tp>
    inline void
    swap(_Tp& __a, _Tp& __b)
    {
      // concept requirements
      __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)

      _Tp __tmp = __a;
      __a = __b;
      __b = __tmp;
    }

  // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
  // nutshell, we are partially implementing the resolution of DR 187,
  // when it's safe, i.e., the value_types are equal.
  template<bool _BoolType>
    struct __iter_swap
    {
      template<typename _ForwardIterator1, typename _ForwardIterator2>
        static void
        iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
        {
          typedef typename iterator_traits<_ForwardIterator1>::value_type
            _ValueType1;
          _ValueType1 __tmp = *__a;
          *__a = *__b;
          *__b = __tmp; 
	}
    };

  template<>
    struct __iter_swap<true>
    {
      template<typename _ForwardIterator1, typename _ForwardIterator2>
        static void 
        iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
        {
          swap(*__a, *__b);
        }
    };

  /**
   *  @brief Swaps the contents of two iterators.
   *  @param  a  An iterator.
   *  @param  b  Another iterator.
   *  @return   Nothing.
   *
   *  This function swaps the values pointed to by two iterators, not the
   *  iterators themselves.
  */
  template<typename _ForwardIterator1, typename _ForwardIterator2>
    inline void
    iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
    {
      typedef typename iterator_traits<_ForwardIterator1>::value_type
	_ValueType1;
      typedef typename iterator_traits<_ForwardIterator2>::value_type
	_ValueType2;

      // concept requirements
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator1>)
      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
				  _ForwardIterator2>)
      __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
				  _ValueType2>)
      __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
				  _ValueType1>)

      typedef typename iterator_traits<_ForwardIterator1>::reference
	_ReferenceType1;
      typedef typename iterator_traits<_ForwardIterator2>::reference
	_ReferenceType2;
      std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value &&
	__are_same<_ValueType1 &, _ReferenceType1>::__value &&
	__are_same<_ValueType2 &, _ReferenceType2>::__value>::
	iter_swap(__a, __b);
    }

  #undef min
  #undef max

  /**
   *  @brief This does what you think it does.
   *  @param  a  A thing of arbitrary type.
   *  @param  b  Another thing of arbitrary type.
   *  @return   The lesser of the parameters.
   *
   *  This is the simple classic generic implementation.  It will work on
   *  temporary expressions, since they are only evaluated once, unlike a
   *  preprocessor macro.
  */
  template<typename _Tp>
    inline const _Tp&
    min(const _Tp& __a, const _Tp& __b)
    {
      // concept requirements
      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
      //return __b < __a ? __b : __a;
      if (__b < __a)
	return __b;
      return __a;
    }

  /**
   *  @brief This does what you think it does.
   *  @param  a  A thing of arbitrary type.
   *  @param  b  Another thing of arbitrary type.
   *  @return   The greater of the parameters.
   *
   *  This is the simple classic generic implementation.  It will work on
   *  temporary expressions, since they are only evaluated once, unlike a
   *  preprocessor macro.
  */
  template<typename _Tp>
    inline const _Tp&
    max(const _Tp& __a, const _Tp& __b)
    {
      // concept requirements
      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
      //return  __a < __b ? __b : __a;
      if (__a < __b)
	return __b;
      return __a;
    }

  /**
   *  @brief This does what you think it does.
   *  @param  a  A thing of arbitrary type.
   *  @param  b  Another thing of arbitrary type.
   *  @param  comp  A @link s20_3_3_comparisons comparison functor@endlink.
   *  @return   The lesser of the parameters.
   *
   *  This will work on temporary expressions, since they are only evaluated
   *  once, unlike a preprocessor macro.
  */
  template<typename _Tp, typename _Compare>
    inline const _Tp&
    min(const _Tp& __a, const _Tp& __b, _Compare __comp)
    {
      //return __comp(__b, __a) ? __b : __a;
      if (__comp(__b, __a))
	return __b;
      return __a;
    }

  /**
   *  @brief This does what you think it does.
   *  @param  a  A thing of arbitrary type.
   *  @param  b  Another thing of arbitrary type.
   *  @param  comp  A @link s20_3_3_comparisons comparison functor@endlink.
   *  @return   The greater of the parameters.
   *
   *  This will work on temporary expressions, since they are only evaluated
   *  once, unlike a preprocessor macro.
  */
  template<typename _Tp, typename _Compare>
    inline const _Tp&
    max(const _Tp& __a, const _Tp& __b, _Compare __comp)
    {
      //return __comp(__a, __b) ? __b : __a;
      if (__comp(__a, __b))
	return __b;
      return __a;
    }

  // All of these auxiliary structs serve two purposes.  (1) Replace
  // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
  // because the input and output ranges are permitted to overlap.)
  // (2) If we're using random access iterators, then write the loop as
  // a for loop with an explicit count.

  template<bool, typename>
    struct __copy
    {
      template<typename _II, typename _OI>
        static _OI
        copy(_II __first, _II __last, _OI __result)
        {
	  for (; __first != __last; ++__result, ++__first)
	    *__result = *__first;
	  return __result;
	}
    };

  template<bool _BoolType>
    struct __copy<_BoolType, random_access_iterator_tag>
    {
      template<typename _II, typename _OI>
        static _OI
        copy(_II __first, _II __last, _OI __result)
        { 
	  typedef typename iterator_traits<_II>::difference_type _Distance;
	  for(_Distance __n = __last - __first; __n > 0; --__n)
	    {
	      *__result = *__first;
	      ++__first;
	      ++__result;
	    }
	  return __result;
	}
    };

  template<>
    struct __copy<true, random_access_iterator_tag>
    {
      template<typename _Tp>
        static _Tp*
        copy(const _Tp* __first, const _Tp* __last, _Tp* __result)
        { 
	  std::memmove(__result, __first, sizeof(_Tp) * (__last - __first));
	  return __result + (__last - __first);
	}
    };

  template<typename _II, typename _OI>