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// Bits and pieces used in algorithms -*- C++ -*-
// Copyright (C) 2001 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 __GLIBCPP_INTERNAL_ALGOBASE_H
#define __GLIBCPP_INTERNAL_ALGOBASE_H
#include <bits/c++config.h>
#include <bits/stl_pair.h>
#include <bits/type_traits.h>
#include <bits/std_cstring.h>
#include <bits/std_climits.h>
#include <bits/std_cstdlib.h>
#include <bits/std_cstddef.h>
#include <new>
#include <bits/std_iosfwd.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>
namespace std
{
// swap and iter_swap
/**
* @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 _ForwardIter1, typename _ForwardIter2>
inline void
iter_swap(_ForwardIter1 __a, _ForwardIter2 __b)
{
typedef typename iterator_traits<_ForwardIter1>::value_type _ValueType1;
typedef typename iterator_traits<_ForwardIter2>::value_type _ValueType2;
// concept requirements
__glibcpp_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter1>)
__glibcpp_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter2>)
__glibcpp_function_requires(_ConvertibleConcept<_ValueType1, _ValueType2>)
__glibcpp_function_requires(_ConvertibleConcept<_ValueType2, _ValueType1>)
_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
__glibcpp_function_requires(_SGIAssignableConcept<_Tp>)
_Tp __tmp = __a;
__a = __b;
__b = __tmp;
}
//--------------------------------------------------
// min and max
#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
__glibcpp_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
__glibcpp_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;
}
//--------------------------------------------------
// copy
// 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 _InputIter, typename _OutputIter>
inline _OutputIter
__copy(_InputIter __first, _InputIter __last,
_OutputIter __result,
input_iterator_tag)
{
for ( ; __first != __last; ++__result, ++__first)
*__result = *__first;
return __result;
}
template<typename _RandomAccessIter, typename _OutputIter>
inline _OutputIter
__copy(_RandomAccessIter __first, _RandomAccessIter __last,
_OutputIter __result,
random_access_iterator_tag)
{
typedef typename iterator_traits<_RandomAccessIter>::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)
{
memmove(__result, __first, sizeof(_Tp) * (__last - __first));
return __result + (__last - __first);
}
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_aux2(_InputIter __first, _InputIter __last,
_OutputIter __result, __false_type)
{ return __copy(__first, __last, __result, __iterator_category(__first)); }
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_aux2(_InputIter __first, _InputIter __last,
_OutputIter __result, __true_type)
{ return __copy(__first, __last, __result, __iterator_category(__first)); }
template<typename _Tp>
inline _Tp*
__copy_aux2(_Tp* __first, _Tp* __last,
_Tp* __result, __true_type)
{ return __copy_trivial(__first, __last, __result); }
template<typename _Tp>
inline _Tp*
__copy_aux2(const _Tp* __first, const _Tp* __last,
_Tp* __result, __true_type)
{ return __copy_trivial(__first, __last, __result); }
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_ni2(_InputIter __first, _InputIter __last,
_OutputIter __result, __true_type)
{
typedef typename iterator_traits<_InputIter>::value_type
_ValueType;
typedef typename __type_traits<_ValueType>::has_trivial_assignment_operator
_Trivial;
return _OutputIter(__copy_aux2(__first, __last,
__result.base(),
_Trivial()));
}
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_ni2(_InputIter __first, _InputIter __last,
_OutputIter __result, __false_type)
{
typedef typename iterator_traits<_InputIter>::value_type
_ValueType;
typedef typename __type_traits<_ValueType>::has_trivial_assignment_operator
_Trivial;
return __copy_aux2(__first, __last,
__result,
_Trivial());
}
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_ni1(_InputIter __first, _InputIter __last,
_OutputIter __result, __true_type)
{
typedef typename _Is_normal_iterator<_OutputIter>::_Normal __Normal;
return __copy_ni2(__first.base(), __last.base(), __result, __Normal());
}
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
__copy_ni1(_InputIter __first, _InputIter __last,
_OutputIter __result, __false_type)
{
typedef typename _Is_normal_iterator<_OutputIter>::_Normal __Normal;
return __copy_ni2(__first, __last, __result, __Normal());
}
/**
* @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). If the input range and the output
* range overlap, then the copy_backward function should be used instead.
*/
template<typename _InputIter, typename _OutputIter>
inline _OutputIter
copy(_InputIter __first, _InputIter __last, _OutputIter __result)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
typename iterator_traits<_InputIter>::value_type>)
typedef typename _Is_normal_iterator<_InputIter>::_Normal __Normal;
return __copy_ni1(__first, __last, __result, __Normal());
}
//--------------------------------------------------
// copy_backward
template<typename _BidirectionalIter1, typename _BidirectionalIter2>
inline _BidirectionalIter2
__copy_backward(_BidirectionalIter1 __first, _BidirectionalIter1 __last,
_BidirectionalIter2 __result,
bidirectional_iterator_tag)
{
while (__first != __last)
*--__result = *--__last;
return __result;
}
template<typename _RandomAccessIter, typename _BidirectionalIter>
inline _BidirectionalIter
__copy_backward(_RandomAccessIter __first, _RandomAccessIter __last,
_BidirectionalIter __result,
random_access_iterator_tag)
{
typename iterator_traits<_RandomAccessIter>::difference_type __n;
for (__n = __last - __first; __n > 0; --__n)
*--__result = *--__last;
return __result;
}
// This dispatch class is a workaround for compilers that do not
// have partial ordering of function templates. All we're doing is
// creating a specialization so that we can turn a call to copy_backward
// into a memmove whenever possible.
template<typename _BidirectionalIter1, typename _BidirectionalIter2,
typename _BoolType>
struct __copy_backward_dispatch
{
static _BidirectionalIter2
copy(_BidirectionalIter1 __first, _BidirectionalIter1 __last,
_BidirectionalIter2 __result)
{
return __copy_backward(__first, __last,
__result,
__iterator_category(__first));
}
};
template<typename _Tp>
struct __copy_backward_dispatch<_Tp*, _Tp*, __true_type>
{
static _Tp*
copy(const _Tp* __first, const _Tp* __last, _Tp* __result)
{
const ptrdiff_t _Num = __last - __first;
memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
return __result - _Num;
}
};
template<typename _Tp>
struct __copy_backward_dispatch<const _Tp*, _Tp*, __true_type>
{
static _Tp*
copy(const _Tp* __first, const _Tp* __last, _Tp* __result)
{
return __copy_backward_dispatch<_Tp*, _Tp*, __true_type>
::copy(__first, __last, __result);
}
};
template<typename _BI1, typename _BI2>
inline _BI2
__copy_backward_aux(_BI1 __first, _BI1 __last, _BI2 __result)
{
typedef typename __type_traits<typename iterator_traits<_BI2>::value_type>
::has_trivial_assignment_operator _Trivial;
return __copy_backward_dispatch<_BI1, _BI2, _Trivial>
::copy(__first, __last, __result);
}
template <typename _BI1, typename _BI2>
inline _BI2
__copy_backward_output_normal_iterator(_BI1 __first, _BI1 __last,
_BI2 __result, __true_type)
{ return _BI2(__copy_backward_aux(__first, __last, __result.base())); }
template <typename _BI1, typename _BI2>
inline _BI2
__copy_backward_output_normal_iterator(_BI1 __first, _BI1 __last,
_BI2 __result, __false_type)
{ return __copy_backward_aux(__first, __last, __result); }
template <typename _BI1, typename _BI2>
inline _BI2
__copy_backward_input_normal_iterator(_BI1 __first, _BI1 __last,
_BI2 __result, __true_type)
{
typedef typename _Is_normal_iterator<_BI2>::_Normal __Normal;
return __copy_backward_output_normal_iterator(__first.base(), __last.base(),
__result, __Normal());
}
template <typename _BI1, typename _BI2>
inline _BI2
__copy_backward_input_normal_iterator(_BI1 __first, _BI1 __last,
_BI2 __result, __false_type)
{
typedef typename _Is_normal_iterator<_BI2>::_Normal __Normal;
return __copy_backward_output_normal_iterator(__first, __last, __result,
__Normal());
}
/**
* @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)
*
* 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).
*/
template <typename _BI1, typename _BI2>
inline _BI2
copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
{
// concept requirements
__glibcpp_function_requires(_BidirectionalIteratorConcept<_BI1>)
__glibcpp_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
__glibcpp_function_requires(_ConvertibleConcept<
typename iterator_traits<_BI1>::value_type,
typename iterator_traits<_BI2>::value_type>)
typedef typename _Is_normal_iterator<_BI1>::_Normal __Normal;
return __copy_backward_input_normal_iterator(__first, __last, __result,
__Normal());
}
//--------------------------------------------------
// copy_n (not part of the C++ standard)
template<typename _InputIter, typename _Size, typename _OutputIter>
pair<_InputIter, _OutputIter>
__copy_n(_InputIter __first, _Size __count,
_OutputIter __result,
input_iterator_tag)
{
for ( ; __count > 0; --__count) {
*__result = *__first;
++__first;
++__result;
}
return pair<_InputIter, _OutputIter>(__first, __result);
}
template<typename _RAIter, typename _Size, typename _OutputIter>
inline pair<_RAIter, _OutputIter>
__copy_n(_RAIter __first, _Size __count,
_OutputIter __result,
random_access_iterator_tag)
{
_RAIter __last = __first + __count;
return pair<_RAIter, _OutputIter>(__last, copy(__first, __last, __result));
}
/**
* @brief Copies the range [first,first+count) into [result,result+count).
* @param first An input iterator.
* @param count The number of elements to copy.
* @param result An output iterator.
* @return A std::pair composed of first+count and result+count.
*
* This is an SGI extension.
* 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).
* @ingroup SGIextensions
*/
template<typename _InputIter, typename _Size, typename _OutputIter>
inline pair<_InputIter, _OutputIter>
copy_n(_InputIter __first, _Size __count, _OutputIter __result)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
typename iterator_traits<_InputIter>::value_type>)
return __copy_n(__first, __count, __result, __iterator_category(__first));
}
//--------------------------------------------------
// fill and fill_n
/**
* @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 _ForwardIter, typename _Tp>
void
fill(_ForwardIter __first, _ForwardIter __last, const _Tp& __value)
{
// concept requirements
__glibcpp_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter>)
for ( ; __first != __last; ++__first)
*__first = __value;
}
/**
* @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 _OutputIter, typename _Size, typename _Tp>
_OutputIter
fill_n(_OutputIter __first, _Size __n, const _Tp& __value)
{
// concept requirements
__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,_Tp>)
for ( ; __n > 0; --__n, ++__first)
*__first = __value;
return __first;
}
// Specialization: for one-byte types we can use memset.
inline void
fill(unsigned char* __first, unsigned char* __last, const unsigned char& __c)
{
unsigned char __tmp = __c;
memset(__first, __tmp, __last - __first);
}
inline void
fill(signed char* __first, signed char* __last, const signed char& __c)
{
signed char __tmp = __c;
memset(__first, static_cast<unsigned char>(__tmp), __last - __first);
}
inline void
fill(char* __first, char* __last, const char& __c)
{
char __tmp = __c;
memset(__first, static_cast<unsigned char>(__tmp), __last - __first);
}
template<typename _Size>
inline unsigned char*
fill_n(unsigned char* __first, _Size __n, const unsigned char& __c)
{
fill(__first, __first + __n, __c);
return __first + __n;
}
template<typename _Size>
inline signed char*
fill_n(char* __first, _Size __n, const signed char& __c)
{
fill(__first, __first + __n, __c);
return __first + __n;
}
template<typename _Size>
inline char*
fill_n(char* __first, _Size __n, const char& __c)
{
fill(__first, __first + __n, __c);
return __first + __n;
}
//--------------------------------------------------
// equal and mismatch
/**
* @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 _InputIter1, typename _InputIter2>
pair<_InputIter1, _InputIter2>
mismatch(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
__glibcpp_function_requires(_EqualityComparableConcept<
typename iterator_traits<_InputIter1>::value_type>)
__glibcpp_function_requires(_EqualityComparableConcept<
typename iterator_traits<_InputIter2>::value_type>)
while (__first1 != __last1 && *__first1 == *__first2) {
++__first1;
++__first2;
}
return pair<_InputIter1, _InputIter2>(__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 _InputIter1, typename _InputIter2, typename _BinaryPredicate>
pair<_InputIter1, _InputIter2>
mismatch(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2,
_BinaryPredicate __binary_pred)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
while (__first1 != __last1 && __binary_pred(*__first1, *__first2)) {
++__first1;
++__first2;
}
return pair<_InputIter1, _InputIter2>(__first1, __first2);
}
/**
* @brief Tests a range for element-wise equality.
* @param first1 An input iterator.
* @param last1 An input iterator.
* @param first2 An input iterator.
* @return A boolean true or false.
*
* This compares the elements of two ranges using @c == and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _InputIter1, typename _InputIter2>
inline bool
equal(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
__glibcpp_function_requires(_EqualOpConcept<
typename iterator_traits<_InputIter1>::value_type,
typename iterator_traits<_InputIter2>::value_type>)
for ( ; __first1 != __last1; ++__first1, ++__first2)
if (!(*__first1 == *__first2))
return false;
return true;
}
/**
* @brief Tests a range for element-wise equality.
* @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 boolean true or false.
*
* This compares the elements of two ranges using the binary_pred
* parameter, and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _InputIter1, typename _InputIter2, typename _BinaryPredicate>
inline bool
equal(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2,
_BinaryPredicate __binary_pred)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
for ( ; __first1 != __last1; ++__first1, ++__first2)
if (!__binary_pred(*__first1, *__first2))
return false;
return true;
}
//--------------------------------------------------
// lexicographical_compare and lexicographical_compare_3way.
// (the latter is not part of the C++ standard.)
/**
* @brief Performs "dictionary" comparison on ranges.
* @param first1 An input iterator.
* @param last1 An input iterator.
* @param first2 An input iterator.
* @param last2 An input iterator.
* @return A boolean true or false.
*
* "Returns true if the sequence of elements defined by the range
* [first1,last1) is lexicographically less than the sequence of elements
* defined by the range [first2,last2). Returns false otherwise."
* (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
* then this is an inline call to @c memcmp.
*/
template<typename _InputIter1, typename _InputIter2>
bool
lexicographical_compare(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2, _InputIter2 __last2)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
__glibcpp_function_requires(_LessThanComparableConcept<
typename iterator_traits<_InputIter1>::value_type>)
__glibcpp_function_requires(_LessThanComparableConcept<
typename iterator_traits<_InputIter2>::value_type>)
for ( ; __first1 != __last1 && __first2 != __last2
; ++__first1, ++__first2) {
if (*__first1 < *__first2)
return true;
if (*__first2 < *__first1)
return false;
}
return __first1 == __last1 && __first2 != __last2;
}
/**
* @brief Performs "dictionary" comparison on ranges.
* @param first1 An input iterator.
* @param last1 An input iterator.
* @param first2 An input iterator.
* @param last2 An input iterator.
* @param comp A @link s20_3_3_comparisons comparison functor@endlink.
* @return A boolean true or false.
*
* The same as the four-parameter @c lexigraphical_compare, but uses the
* comp parameter instead of @c <.
*/
template<typename _InputIter1, typename _InputIter2, typename _Compare>
bool
lexicographical_compare(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2, _InputIter2 __last2,
_Compare __comp)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
for ( ; __first1 != __last1 && __first2 != __last2
; ++__first1, ++__first2) {
if (__comp(*__first1, *__first2))
return true;
if (__comp(*__first2, *__first1))
return false;
}
return __first1 == __last1 && __first2 != __last2;
}
inline bool
lexicographical_compare(const unsigned char* __first1, const unsigned char* __last1,
const unsigned char* __first2, const unsigned char* __last2)
{
const size_t __len1 = __last1 - __first1;
const size_t __len2 = __last2 - __first2;
const int __result = memcmp(__first1, __first2, min(__len1, __len2));
return __result != 0 ? __result < 0 : __len1 < __len2;
}
inline bool
lexicographical_compare(const char* __first1, const char* __last1,
const char* __first2, const char* __last2)
{
#if CHAR_MAX == SCHAR_MAX
return lexicographical_compare((const signed char*) __first1,
(const signed char*) __last1,
(const signed char*) __first2,
(const signed char*) __last2);
#else /* CHAR_MAX == SCHAR_MAX */
return lexicographical_compare((const unsigned char*) __first1,
(const unsigned char*) __last1,
(const unsigned char*) __first2,
(const unsigned char*) __last2);
#endif /* CHAR_MAX == SCHAR_MAX */
}
template<typename _InputIter1, typename _InputIter2>
int
__lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2, _InputIter2 __last2)
{
while (__first1 != __last1 && __first2 != __last2) {
if (*__first1 < *__first2)
return -1;
if (*__first2 < *__first1)
return 1;
++__first1;
++__first2;
}
if (__first2 == __last2) {
return !(__first1 == __last1);
}
else {
return -1;
}
}
inline int
__lexicographical_compare_3way(const unsigned char* __first1,
const unsigned char* __last1,
const unsigned char* __first2,
const unsigned char* __last2)
{
const ptrdiff_t __len1 = __last1 - __first1;
const ptrdiff_t __len2 = __last2 - __first2;
const int __result = memcmp(__first1, __first2, min(__len1, __len2));
return __result != 0 ? __result
: (__len1 == __len2 ? 0 : (__len1 < __len2 ? -1 : 1));
}
inline int
__lexicographical_compare_3way(const char* __first1, const char* __last1,
const char* __first2, const char* __last2)
{
#if CHAR_MAX == SCHAR_MAX
return __lexicographical_compare_3way(
(const signed char*) __first1,
(const signed char*) __last1,
(const signed char*) __first2,
(const signed char*) __last2);
#else
return __lexicographical_compare_3way((const unsigned char*) __first1,
(const unsigned char*) __last1,
(const unsigned char*) __first2,
(const unsigned char*) __last2);
#endif
}
/**
* @brief @c memcmp on steroids.
* @param first1 An input iterator.
* @param last1 An input iterator.
* @param first2 An input iterator.
* @param last2 An input iterator.
* @return An int, as with @c memcmp.
*
* The return value will be less than zero if the first range is
* "lexigraphically less than" the second, greater than zero if the second
* range is "lexigraphically less than" the first, and zero otherwise.
* This is an SGI extension.
* @ingroup SGIextensions
*/
template<typename _InputIter1, typename _InputIter2>
int
lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
_InputIter2 __first2, _InputIter2 __last2)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
__glibcpp_function_requires(_LessThanComparableConcept<
typename iterator_traits<_InputIter1>::value_type>)
__glibcpp_function_requires(_LessThanComparableConcept<
typename iterator_traits<_InputIter2>::value_type>)
return __lexicographical_compare_3way(__first1, __last1, __first2, __last2);
}
} // namespace std
#endif /* __GLIBCPP_INTERNAL_ALGOBASE_H */
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