forked from mirror/libcxx
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// <iterator>
|
|
|
|
// template <BidirectionalIterator Iter>
|
|
// Iter prev(Iter x, Iter::difference_type n = 1);
|
|
|
|
#include <iterator>
|
|
#include <cassert>
|
|
|
|
#include "test_iterators.h"
|
|
|
|
template <class It>
|
|
void
|
|
test(It i, typename std::iterator_traits<It>::difference_type n, It x)
|
|
{
|
|
assert(std::prev(i, n) == x);
|
|
|
|
It (*prev)(It, typename std::iterator_traits<It>::difference_type) = std::prev;
|
|
assert(prev(i, n) == x);
|
|
}
|
|
|
|
template <class It>
|
|
void
|
|
test(It i, It x)
|
|
{
|
|
assert(std::prev(i) == x);
|
|
}
|
|
|
|
#if TEST_STD_VER > 14
|
|
template <class It>
|
|
constexpr bool
|
|
constexpr_test(It i, typename std::iterator_traits<It>::difference_type n, It x)
|
|
{
|
|
return std::prev(i, n) == x;
|
|
}
|
|
|
|
template <class It>
|
|
constexpr bool
|
|
constexpr_test(It i, It x)
|
|
{
|
|
return std::prev(i) == x;
|
|
}
|
|
#endif
|
|
|
|
int main()
|
|
{
|
|
{
|
|
const char* s = "1234567890";
|
|
test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s));
|
|
test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s));
|
|
test(s+10, 10, s);
|
|
|
|
test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
|
|
test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s));
|
|
test(s+1, s);
|
|
}
|
|
#if TEST_STD_VER > 14
|
|
{
|
|
constexpr const char* s = "1234567890";
|
|
static_assert( constexpr_test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s)), "" );
|
|
static_assert( constexpr_test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s)), "" );
|
|
static_assert( constexpr_test(s+10, 10, s), "" );
|
|
|
|
static_assert( constexpr_test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s)), "" );
|
|
static_assert( constexpr_test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s)), "" );
|
|
static_assert( constexpr_test(s+1, s), "" );
|
|
}
|
|
#endif
|
|
|
|
}
|