blob: 33f06d57e23a4e63182afe0b6c3768516766a589 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_SHIFT_LEFT_H
#define _LIBCPP___ALGORITHM_SHIFT_LEFT_H
#include <__algorithm/move.h>
#include <__config>
#include <__iterator/iterator_traits.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
template <class _ForwardIterator>
inline _LIBCPP_INLINE_VISIBILITY constexpr
_ForwardIterator
shift_left(_ForwardIterator __first, _ForwardIterator __last,
typename iterator_traits<_ForwardIterator>::difference_type __n)
{
if (__n == 0) {
return __last;
}
_ForwardIterator __m = __first;
if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
if (__n >= __last - __first) {
return __first;
}
__m += __n;
} else {
for (; __n > 0; --__n) {
if (__m == __last) {
return __first;
}
++__m;
}
}
return _VSTD::move(__m, __last, __first);
}
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_SHIFT_LEFT_H
|
