📄 stl_algo.h
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template<typename _ForwardIterator, typename _BinaryPredicate>
_ForwardIterator
adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
_BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
__glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
typename iterator_traits<_ForwardIterator>::value_type,
typename iterator_traits<_ForwardIterator>::value_type>)
__glibcxx_requires_valid_range(__first, __last);
if (__first == __last)
return __last;
_ForwardIterator __next = __first;
while(++__next != __last)
{
if (__binary_pred(*__first, *__next))
return __first;
__first = __next;
}
return __last;
}
/**
* @brief Count the number of copies of a value in a sequence.
* @param first An input iterator.
* @param last An input iterator.
* @param value The value to be counted.
* @return The number of iterators @c i in the range @p [first,last)
* for which @c *i == @p value
*/
template<typename _InputIterator, typename _Tp>
typename iterator_traits<_InputIterator>::difference_type
count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
__glibcxx_function_requires(_EqualityComparableConcept<
typename iterator_traits<_InputIterator>::value_type >)
__glibcxx_function_requires(_EqualityComparableConcept<_Tp>)
__glibcxx_requires_valid_range(__first, __last);
typename iterator_traits<_InputIterator>::difference_type __n = 0;
for ( ; __first != __last; ++__first)
if (*__first == __value)
++__n;
return __n;
}
/**
* @brief Count the elements of a sequence for which a predicate is true.
* @param first An input iterator.
* @param last An input iterator.
* @param pred A predicate.
* @return The number of iterators @c i in the range @p [first,last)
* for which @p pred(*i) is true.
*/
template<typename _InputIterator, typename _Predicate>
typename iterator_traits<_InputIterator>::difference_type
count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
__glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
typename iterator_traits<_InputIterator>::value_type>)
__glibcxx_requires_valid_range(__first, __last);
typename iterator_traits<_InputIterator>::difference_type __n = 0;
for ( ; __first != __last; ++__first)
if (__pred(*__first))
++__n;
return __n;
}
/**
* @brief Search a sequence for a matching sub-sequence.
* @param first1 A forward iterator.
* @param last1 A forward iterator.
* @param first2 A forward iterator.
* @param last2 A forward iterator.
* @return The first iterator @c i in the range
* @p [first1,last1-(last2-first2)) such that @c *(i+N) == @p *(first2+N)
* for each @c N in the range @p [0,last2-first2), or @p last1 if no
* such iterator exists.
*
* Searches the range @p [first1,last1) for a sub-sequence that compares
* equal value-by-value with the sequence given by @p [first2,last2) and
* returns an iterator to the first element of the sub-sequence, or
* @p last1 if the sub-sequence is not found.
*
* Because the sub-sequence must lie completely within the range
* @p [first1,last1) it must start at a position less than
* @p last1-(last2-first2) where @p last2-first2 is the length of the
* sub-sequence.
* This means that the returned iterator @c i will be in the range
* @p [first1,last1-(last2-first2))
*/
template<typename _ForwardIterator1, typename _ForwardIterator2>
_ForwardIterator1
search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2, _ForwardIterator2 __last2)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_ForwardIterator1>::value_type,
typename iterator_traits<_ForwardIterator2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
// Test for empty ranges
if (__first1 == __last1 || __first2 == __last2)
return __first1;
// Test for a pattern of length 1.
_ForwardIterator2 __tmp(__first2);
++__tmp;
if (__tmp == __last2)
return std::find(__first1, __last1, *__first2);
// General case.
_ForwardIterator2 __p1, __p;
__p1 = __first2; ++__p1;
_ForwardIterator1 __current = __first1;
while (__first1 != __last1)
{
__first1 = std::find(__first1, __last1, *__first2);
if (__first1 == __last1)
return __last1;
__p = __p1;
__current = __first1;
if (++__current == __last1)
return __last1;
while (*__current == *__p)
{
if (++__p == __last2)
return __first1;
if (++__current == __last1)
return __last1;
}
++__first1;
}
return __first1;
}
/**
* @brief Search a sequence for a matching sub-sequence using a predicate.
* @param first1 A forward iterator.
* @param last1 A forward iterator.
* @param first2 A forward iterator.
* @param last2 A forward iterator.
* @param predicate A binary predicate.
* @return The first iterator @c i in the range
* @p [first1,last1-(last2-first2)) such that
* @p predicate(*(i+N),*(first2+N)) is true for each @c N in the range
* @p [0,last2-first2), or @p last1 if no such iterator exists.
*
* Searches the range @p [first1,last1) for a sub-sequence that compares
* equal value-by-value with the sequence given by @p [first2,last2),
* using @p predicate to determine equality, and returns an iterator
* to the first element of the sub-sequence, or @p last1 if no such
* iterator exists.
*
* @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
*/
template<typename _ForwardIterator1, typename _ForwardIterator2,
typename _BinaryPredicate>
_ForwardIterator1
search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2, _ForwardIterator2 __last2,
_BinaryPredicate __predicate)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
__glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
typename iterator_traits<_ForwardIterator1>::value_type,
typename iterator_traits<_ForwardIterator2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
// Test for empty ranges
if (__first1 == __last1 || __first2 == __last2)
return __first1;
// Test for a pattern of length 1.
_ForwardIterator2 __tmp(__first2);
++__tmp;
if (__tmp == __last2)
{
while (__first1 != __last1 && !__predicate(*__first1, *__first2))
++__first1;
return __first1;
}
// General case.
_ForwardIterator2 __p1, __p;
__p1 = __first2; ++__p1;
_ForwardIterator1 __current = __first1;
while (__first1 != __last1)
{
while (__first1 != __last1)
{
if (__predicate(*__first1, *__first2))
break;
++__first1;
}
while (__first1 != __last1 && !__predicate(*__first1, *__first2))
++__first1;
if (__first1 == __last1)
return __last1;
__p = __p1;
__current = __first1;
if (++__current == __last1)
return __last1;
while (__predicate(*__current, *__p))
{
if (++__p == __last2)
return __first1;
if (++__current == __last1)
return __last1;
}
++__first1;
}
return __first1;
}
/**
* @brief Search a sequence for a number of consecutive values.
* @param first A forward iterator.
* @param last A forward iterator.
* @param count The number of consecutive values.
* @param val The value to find.
* @return The first iterator @c i in the range @p [first,last-count)
* such that @c *(i+N) == @p val for each @c N in the range @p [0,count),
* or @p last if no such iterator exists.
*
* Searches the range @p [first,last) for @p count consecutive elements
* equal to @p val.
*/
template<typename _ForwardIterator, typename _Integer, typename _Tp>
_ForwardIterator
search_n(_ForwardIterator __first, _ForwardIterator __last,
_Integer __count, const _Tp& __val)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
__glibcxx_function_requires(_EqualityComparableConcept<
typename iterator_traits<_ForwardIterator>::value_type>)
__glibcxx_function_requires(_EqualityComparableConcept<_Tp>)
__glibcxx_requires_valid_range(__first, __last);
if (__count <= 0)
return __first;
else
{
__first = std::find(__first, __last, __val);
while (__first != __last)
{
typename iterator_traits<_ForwardIterator>::difference_type
__n = __count;
_ForwardIterator __i = __first;
++__i;
while (__i != __last && __n != 1 && *__i == __val)
{
++__i;
--__n;
}
if (__n == 1)
return __first;
else
__first = std::find(__i, __last, __val);
}
return __last;
}
}
/**
* @brief Search a sequence for a number of consecutive values using a
* predicate.
* @param first A forward iterator.
* @param last A forward iterator.
* @param count The number of consecutive values.
* @param val The value to find.
* @param binary_pred A binary predicate.
* @return The first iterator @c i in the range @p [first,last-count)
* such that @p binary_pred(*(i+N),val) is true for each @c N in the
* range @p [0,count), or @p last if no such iterator exists.
*
* Searches the range @p [first,last) for @p count consecutive elements
* for which the predicate returns true.
*/
template<typename _ForwardIterator, typename _Integer, typename _Tp,
typename _BinaryPredicate>
_ForwardIterator
search_n(_ForwardIterator __first, _ForwardIterator __last,
_Integer __count, const _Tp& __val,
_BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
__glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
__glibcxx_requires_valid_range(__first, __last);
if (__count <= 0)
return __first;
else
{
while (__first != __last)
{
if (__binary_pred(*__first, __val))
break;
++__first;
}
while (__first != __last)
{
typename iterator_traits<_ForwardIterator>::difference_type
__n = __count;
_ForwardIterator __i = __first;
++__i;
while (__i != __last && __n != 1 && __binary_pred(*__i, __val))
{
++__i;
--__n;
}
if (__n == 1)
return __first;
else
{
while (__i != __last)
{
if (__binary_pred(*__i, __val))
break;
++__i;
}
__first = __i;
}
}
return __last;
}
}
/**
* @brief Swap the elements of two sequences.
* @param first1 A forward iterator.
* @param last1 A forward iterator.
* @param first2 A forward iterator.
* @return An iterator equal to @p first2+(last1-first1).
*
* Swaps each element in the range @p [first1,last1) with the
* corresponding element in the range @p [first2,(last1-first1)).
* The ranges must not overlap.
*/
template<typename _ForwardIterator1, typename _ForwardIterator2>
_ForwardIterator2
swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2)
{
// concept requirements
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator1>)
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator2>)
__glibcxx_function_requires(_ConvertibleConcept<
typename iterator_traits<_ForwardIterator1>::value_type,
typename iterator_traits<_ForwardIterator2>::value_type>)
__glibcxx_function_requires(_ConvertibleConcept<
typename iterator_traits<_ForwardIterator2>::value_type,
typename iterator_traits<_ForwardIterator1>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
for ( ; __first1 != __last1; ++__first1, ++__first2)
std::iter_swap(__first1, __first2);
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