| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <iterator> |
| |
| // template <InputIterator Iter> |
| // Iter prev(Iter x, Iter::difference_type n = 1); |
| |
| #include <iterator> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| #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(int, char**) |
| { |
| { |
| const char* s = "1234567890"; |
| test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)); |
| test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s)); |
| test(bidirectional_iterator<const char*>(s), -10, bidirectional_iterator<const char*>(s+10)); |
| test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s)); |
| test(random_access_iterator<const char*>(s), -10, random_access_iterator<const char*>(s+10)); |
| 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(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" ); |
| static_assert( constexpr_test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s)), "" ); |
| static_assert( constexpr_test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" ); |
| static_assert( constexpr_test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s)), "" ); |
| static_assert( constexpr_test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" ); |
| 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 |
| |
| |
| return 0; |
| } |