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[libcxx] Properly convert the count arguments to the *_n algorithms before use.

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Summary:
The requirement on the `Size` type passed to *_n algorithms is that it is convertible to an integral type. This means we can't use a variable of type `Size` directly. Instead we need to convert it to an integral type first.  The problem is finding out what integral type to convert it to.  `__convert_to_integral` figures out what integral type to convert it to and performs the conversion, It also promotes the resulting integral type so that it is at least as big as an integer. `__convert_to_integral` also has a special case for converting enums. This should only work on non-scoped enumerations because it does not apply an explicit conversion from the enum to its underlying type.



Reviewers: chandlerc, mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D7449

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@228704 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2015-02-10 16:46:42 +00:00
parent f17cecb13f
commit 31cb7fe75e
9 changed files with 219 additions and 17 deletions
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20
include/algorithm
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@@ -1672,7 +1672,8 @@ search_n(_ForwardIterator __first, _ForwardIterator __last,
_Size __count, const _Tp& __value_, _BinaryPredicate __pred)
{
return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
(__first, __last, __count, __value_, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
(__first, __last, __convert_to_integral(__count), __value_, __pred,
typename iterator_traits<_ForwardIterator>::iterator_category());
}
template <class _ForwardIterator, class _Size, class _Tp>
@@ -1681,7 +1682,8 @@ _ForwardIterator
search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
{
typedef typename iterator_traits<_ForwardIterator>::value_type __v;
return _VSTD::search_n(__first, __last, __count, __value_, __equal_to<__v, _Tp>());
return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
__value_, __equal_to<__v, _Tp>());
}
// copy
@@ -1839,8 +1841,10 @@ typename enable_if
!__is_random_access_iterator<_InputIterator>::value,
_OutputIterator
>::type
copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
{
typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
_IntegralSize __n = __orig_n;
if (__n > 0)
{
*__result = *__first;
@@ -1862,8 +1866,10 @@ typename enable_if
__is_random_access_iterator<_InputIterator>::value,
_OutputIterator
>::type
copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
{
typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
_IntegralSize __n = __orig_n;
return _VSTD::copy(__first, __first + __n, __result);
}
@@ -2055,7 +2061,7 @@ inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
{
return _VSTD::__fill_n(__first, __n, __value_);
return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
}
// fill
@@ -2101,8 +2107,10 @@ generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
template <class _OutputIterator, class _Size, class _Generator>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
{
typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
_IntegralSize __n = __orig_n;
for (; __n > 0; ++__first, (void) --__n)
*__first = __gen();
return __first;

42
include/type_traits
View File

@@ -3646,6 +3646,48 @@ struct underlying_type
#endif // _LIBCPP_UNDERLYING_TYPE
template <class _Tp, bool = std::is_enum<_Tp>::value>
struct __sfinae_underlying_type
{
typedef typename underlying_type<_Tp>::type type;
typedef decltype(((type)1) + 0) __promoted_type;
};
template <class _Tp>
struct __sfinae_underlying_type<_Tp, false> {};
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
int __convert_to_integral(int __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
unsigned __convert_to_integral(unsigned __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
long __convert_to_integral(long __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
unsigned long __convert_to_integral(unsigned long __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
long long __convert_to_integral(long long __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
#ifndef _LIBCPP_HAS_NO_INT128
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
__int128_t __convert_to_integral(__int128_t __val) { return __val; }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
#endif
template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
typename __sfinae_underlying_type<_Tp>::__promoted_type
__convert_to_integral(_Tp __val) { return __val; }
#ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
template <class _Tp>