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// 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>

    inline _OI

    __copy_aux(_II __first, _II __last, _OI __result)

    {

      typedef typename iterator_traits<_II>::value_type _ValueTypeI;

      typedef typename iterator_traits<_OI>::value_type _ValueTypeO;

      typedef typename iterator_traits<_II>::iterator_category _Category;

      const bool __simple = (__is_scalar<_ValueTypeI>::__value

                             && __is_pointer<_II>::__value

                             && __is_pointer<_OI>::__value

                             && __are_same<_ValueTypeI, _ValueTypeO>::__value);

      return std::__copy<__simple, _Category>::copy(__first, __last, __result);

    }

  template<bool, bool>

    struct __copy_normal

    {

      template<typename _II, typename _OI>

        static _OI

        copy_n(_II __first, _II __last, _OI __result)

        { return std::__copy_aux(__first, __last, __result); }

    };

  template<>

    struct __copy_normal<true, false>

    {

      template<typename _II, typename _OI>

        static _OI

        copy_n(_II __first, _II __last, _OI __result)

        { return std::__copy_aux(__first.base(), __last.base(), __result); }

    };

  template<>

    struct __copy_normal<false, true>

    {

      template<typename _II, typename _OI>

        static _OI

        copy_n(_II __first, _II __last, _OI __result)

        { return _OI(std::__copy_aux(__first, __last, __result.base())); }

    };

  template<>

    struct __copy_normal<true, true>

    {

      template<typename _II, typename _OI>

        static _OI

        copy_n(_II __first, _II __last, _OI __result)

        { return _OI(std::__copy_aux(__first.base(), __last.base(),

                                     __result.base())); }

    };

  /**

   *  @brief Copies the range [first,last) into result.

   *  @param  first  An input iterator.

   *  @param  last   An input iterator.

   *  @param  result An output iterator.

   *  @return   result + (first - last)

   *

   *  This inline function will boil down to a call to @c memmove whenever

   *  possible.  Failing that, if random access iterators are passed, then the

   *  loop count will be known (and therefore a candidate for compiler

   *  optimizations such as unrolling).  Result may not be contained within

   *  [first,last); the copy_backward function should be used instead.

   *

   *  Note that the end of the output range is permitted to be contained

   *  within [first,last).

  */

  template<typename _InputIterator, typename _OutputIterator>

    inline _OutputIterator

    copy(_InputIterator __first, _InputIterator __last,

         _OutputIterator __result)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,

            typename iterator_traits<_InputIterator>::value_type>)

      __glibcxx_requires_valid_range(__first, __last);

       const bool __in = __is_normal_iterator<_InputIterator>::__value;

       const bool __out = __is_normal_iterator<_OutputIterator>::__value;

       return std::__copy_normal<__in, __out>::copy_n(__first, __last,

                                                      __result);

    }

  template<bool, typename>

    struct __copy_backward

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b(_BI1 __first, _BI1 __last, _BI2 __result)

        {

          while (__first != __last)

            *--__result = *--__last;

          return __result;

        }

    };

  template<bool _BoolType>

    struct __copy_backward<_BoolType, random_access_iterator_tag>

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b(_BI1 __first, _BI1 __last, _BI2 __result)

        {

          typename iterator_traits<_BI1>::difference_type __n;

          for (__n = __last - __first; __n > 0; --__n)

            *--__result = *--__last;

          return __result;

        }

    };

  template<>

    struct __copy_backward<true, random_access_iterator_tag>

    {

      template<typename _Tp>

        static _Tp*

        copy_b(const _Tp* __first, const _Tp* __last, _Tp* __result)

        {

          const ptrdiff_t _Num = __last - __first;

          std::memmove(__result - _Num, __first, sizeof(_Tp) * _Num);

          return __result - _Num;

        }

    };

  template<typename _BI1, typename _BI2>

    inline _BI2

    __copy_backward_aux(_BI1 __first, _BI1 __last, _BI2 __result)

    {

      typedef typename iterator_traits<_BI1>::value_type _ValueType1;

      typedef typename iterator_traits<_BI2>::value_type _ValueType2;

      typedef typename iterator_traits<_BI1>::iterator_category _Category;

      const bool __simple = (__is_scalar<_ValueType1>::__value

                             && __is_pointer<_BI1>::__value

                             && __is_pointer<_BI2>::__value

                             && __are_same<_ValueType1, _ValueType2>::__value);

      return std::__copy_backward<__simple, _Category>::copy_b(__first, __last,

                                                               __result);

    }

  template<bool, bool>

    struct __copy_backward_normal

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)

        { return std::__copy_backward_aux(__first, __last, __result); }

    };

  template<>

    struct __copy_backward_normal<true, false>

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)

        { return std::__copy_backward_aux(__first.base(), __last.base(),

                                          __result); }

    };

  template<>

    struct __copy_backward_normal<false, true>

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)

        { return _BI2(std::__copy_backward_aux(__first, __last,

                                               __result.base())); }

    };

  template<>

    struct __copy_backward_normal<true, true>

    {

      template<typename _BI1, typename _BI2>

        static _BI2

        copy_b_n(_BI1 __first, _BI1 __last, _BI2 __result)

        { return _BI2(std::__copy_backward_aux(__first.base(), __last.base(),

                                               __result.base())); }

    };

  /**

   *  @brief Copies the range [first,last) into result.

   *  @param  first  A bidirectional iterator.

   *  @param  last   A bidirectional iterator.

   *  @param  result A bidirectional iterator.

   *  @return   result - (first - last)

   *

   *  The function has the same effect as copy, but starts at the end of the

   *  range and works its way to the start, returning the start of the result.

   *  This inline function will boil down to a call to @c memmove whenever

   *  possible.  Failing that, if random access iterators are passed, then the

   *  loop count will be known (and therefore a candidate for compiler

   *  optimizations such as unrolling).

   *

   *  Result may not be in the range [first,last).  Use copy instead.  Note

   *  that the start of the output range may overlap [first,last).

  */

  template <typename _BI1, typename _BI2>

    inline _BI2

    copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)

    {

      // concept requirements

      __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)

      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)

      __glibcxx_function_requires(_ConvertibleConcept<

            typename iterator_traits<_BI1>::value_type,

            typename iterator_traits<_BI2>::value_type>)

      __glibcxx_requires_valid_range(__first, __last);

      const bool __bi1 = __is_normal_iterator<_BI1>::__value;

      const bool __bi2 = __is_normal_iterator<_BI2>::__value;

      return std::__copy_backward_normal<__bi1, __bi2>::copy_b_n(__first, __last,

                                                                 __result);

    }

  template<bool>

    struct __fill

    {

      template<typename _ForwardIterator, typename _Tp>

        static void

        fill(_ForwardIterator __first, _ForwardIterator __last,

             const _Tp& __value)

        {

          for (; __first != __last; ++__first)

            *__first = __value;

        }

    };

  template<>

    struct __fill<true>

    {

      template<typename _ForwardIterator, typename _Tp>

        static void

        fill(_ForwardIterator __first, _ForwardIterator __last,

             const _Tp& __value)

        {

          const _Tp __tmp = __value;

          for (; __first != __last; ++__first)

            *__first = __tmp;

        }

    };

  /**

   *  @brief Fills the range [first,last) with copies of value.

   *  @param  first  A forward iterator.

   *  @param  last   A forward iterator.

   *  @param  value  A reference-to-const of arbitrary type.

   *  @return   Nothing.

   *

   *  This function fills a range with copies of the same value.  For one-byte

   *  types filling contiguous areas of memory, this becomes an inline call to

   *  @c memset.

  */

  template<typename _ForwardIterator, typename _Tp>

    void

    fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)

    {

      // concept requirements

      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<

                                  _ForwardIterator>)

      __glibcxx_requires_valid_range(__first, __last);

      const bool __scalar = __is_scalar<_Tp>::__value;

      std::__fill<__scalar>::fill(__first, __last, __value);

    }

  // Specialization: for one-byte types we can use memset.

  inline void

  fill(unsigned char* __first, unsigned char* __last, const unsigned char& __c)

  {

    __glibcxx_requires_valid_range(__first, __last);

    const unsigned char __tmp = __c;

    std::memset(__first, __tmp, __last - __first);

  }

  inline void

  fill(signed char* __first, signed char* __last, const signed char& __c)

  {

    __glibcxx_requires_valid_range(__first, __last);

    const signed char __tmp = __c;

    std::memset(__first, static_cast<unsigned char>(__tmp), __last - __first);

  }

  inline void

  fill(char* __first, char* __last, const char& __c)

  {

    __glibcxx_requires_valid_range(__first, __last);

    const char __tmp = __c;

    std::memset(__first, static_cast<unsigned char>(__tmp), __last - __first);

  }

  template<bool>

    struct __fill_n

    {

      template<typename _OutputIterator, typename _Size, typename _Tp>

        static _OutputIterator

        fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)

        {

          for (; __n > 0; --__n, ++__first)

            *__first = __value;

          return __first;

        }

    };

  template<>

    struct __fill_n<true>

    {

      template<typename _OutputIterator, typename _Size, typename _Tp>

        static _OutputIterator

        fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)

        {

          const _Tp __tmp = __value;

          for (; __n > 0; --__n, ++__first)

            *__first = __tmp;

          return __first;

        }

    };

  /**

   *  @brief Fills the range [first,first+n) with copies of value.

   *  @param  first  An output iterator.

   *  @param  n      The count of copies to perform.

   *  @param  value  A reference-to-const of arbitrary type.

   *  @return   The iterator at first+n.

   *

   *  This function fills a range with copies of the same value.  For one-byte

   *  types filling contiguous areas of memory, this becomes an inline call to

   *  @c memset.

  */

  template<typename _OutputIterator, typename _Size, typename _Tp>

    _OutputIterator

    fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)

    {

      // concept requirements

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _Tp>)

      const bool __scalar = __is_scalar<_Tp>::__value;

      return std::__fill_n<__scalar>::fill_n(__first, __n, __value);

    }

  template<typename _Size>

    inline unsigned char*

    fill_n(unsigned char* __first, _Size __n, const unsigned char& __c)

    {

      std::fill(__first, __first + __n, __c);

      return __first + __n;

    }

  template<typename _Size>

    inline signed char*

    fill_n(char* __first, _Size __n, const signed char& __c)

    {

      std::fill(__first, __first + __n, __c);

      return __first + __n;

    }

  template<typename _Size>

    inline char*

    fill_n(char* __first, _Size __n, const char& __c)

    {

      std::fill(__first, __first + __n, __c);

      return __first + __n;

    }

  /**

   *  @brief Finds the places in ranges which don't match.

   *  @param  first1  An input iterator.

   *  @param  last1   An input iterator.

   *  @param  first2  An input iterator.

   *  @return   A pair of iterators pointing to the first mismatch.

   *

   *  This compares the elements of two ranges using @c == and returns a pair

   *  of iterators.  The first iterator points into the first range, the

   *  second iterator points into the second range, and the elements pointed

   *  to by the iterators are not equal.

  */

  template<typename _InputIterator1, typename _InputIterator2>

    pair<_InputIterator1, _InputIterator2>

    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,

             _InputIterator2 __first2)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)

      __glibcxx_function_requires(_EqualOpConcept<

            typename iterator_traits<_InputIterator1>::value_type,

            typename iterator_traits<_InputIterator2>::value_type>)

      __glibcxx_requires_valid_range(__first1, __last1);

      while (__first1 != __last1 && *__first1 == *__first2)

        {

          ++__first1;

          ++__first2;

        }

      return pair<_InputIterator1, _InputIterator2>(__first1, __first2);

    }

  /**

   *  @brief Finds the places in ranges which don't match.

   *  @param  first1  An input iterator.

   *  @param  last1   An input iterator.

   *  @param  first2  An input iterator.

   *  @param  binary_pred  A binary predicate @link s20_3_1_base functor@endlink.

   *  @return   A pair of iterators pointing to the first mismatch.

   *

   *  This compares the elements of two ranges using the binary_pred

   *  parameter, and returns a pair

   *  of iterators.  The first iterator points into the first range, the

   *  second iterator points into the second range, and the elements pointed

   *  to by the iterators are not equal.

  */

  template<typename _InputIterator1, typename _InputIterator2,

           typename _BinaryPredicate>

    pair<_InputIterator1, _InputIterator2>

    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,

             _InputIterator2 __first2, _BinaryPredicate __binary_pred)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)

      __glibcxx_requires_valid_range(__first1, __last1);

      while (__first1 != __last1 && __binary_pred(*__first1, *__first2))