stl_algobase.h

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

// Copyright (C) 2001, 2002, 2003, 2004 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// 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 <new>
//#include <iosfwd>
#include <bits/stl_pair.h>
#include <bits/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 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
#ifndef NO__GLIBCXX_FUNCTION_REQUIRES
            __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
                    _ForwardIterator1>)
                __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
                        _ForwardIterator2>)
                __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
                        _ValueType2>)
                __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
                        _ValueType1>)
#endif

                const _ValueType1 __tmp = *__a;
            *__a = *__b;
            *__b = __tmp;
        }

    /**
     *  @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
#ifndef NO__GLIBCXX_FUNCTION_REQUIRES
            __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
#endif

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

#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
#ifndef NO__GLIBCXX_FUNCTION_REQUIRES
            __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
#endif
                //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
#ifndef NO__GLIBCXX_FUNCTION_REQUIRES
            __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
#endif
                //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 functions 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<typename _InputIterator, typename _OutputIterator>
        inline _OutputIterator
        __copy(_InputIterator __first, _InputIterator __last,
                _OutputIterator __result, input_iterator_tag)
        {
            for (; __first != __last; ++__result, ++__first)
                *__result = *__first;
            return __result;
        }

    template<typename _RandomAccessIterator, typename _OutputIterator>
        inline _OutputIterator
        __copy(_RandomAccessIterator __first, _RandomAccessIterator __last,
                _OutputIterator __result, random_access_iterator_tag)
        {
            typedef typename iterator_traits<_RandomAccessIterator>::difference_type
                _Distance;
            for (_Distance __n = __last - __first; __n > 0; --__n)
            {
                *__result = *__first;
                ++__first;
                ++__result;
            }
            return __result;
        }

    template<typename _Tp>
        inline _Tp*
        __copy_trivial(const _Tp* __first, const _Tp* __last, _Tp* __result)
        {
            std::memmove(__result, __first, sizeof(_Tp) * (__last - __first));
            return __result + (__last - __first);
        }

    template<typename _InputIterator, typename _OutputIterator>
        inline _OutputIterator
        __copy_aux2(_InputIterator __first, _InputIterator __last,
                _OutputIterator __result, __false_type)
        { return std::__copy(__first, __last, __result,
                std::__iterator_category(__first)); }

    template<typename _InputIterator, typename _OutputIterator>
        inline _OutputIterator
        __copy_aux2(_InputIterator __first, _InputIterator __last,
                _OutputIterator __result, __true_type)
        { return std::__copy(__first, __last, __result,
                std::__iterator_category(__first)); }

    template<typename _Tp>
        inline _Tp*
        __copy_aux2(_Tp* __first, _Tp* __last, _Tp* __result, __true_type)
        { return std::__copy_trivial(__first, __last, __result); }

    template<typename _Tp>
        inline _Tp*