| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| |
| } |