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b6e011b18b
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@362252 91177308-0d34-0410-b5e6-96231b3b80d8
87 lines
3.0 KiB
C++
87 lines
3.0 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <iterator>
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// template <InputIterator Iter>
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// Iter prev(Iter x, Iter::difference_type n = 1);
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#include <iterator>
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#include <cassert>
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#include "test_macros.h"
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#include "test_iterators.h"
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template <class It>
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void
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test(It i, typename std::iterator_traits<It>::difference_type n, It x)
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{
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assert(std::prev(i, n) == x);
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It (*prev)(It, typename std::iterator_traits<It>::difference_type) = std::prev;
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assert(prev(i, n) == x);
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}
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template <class It>
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void
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test(It i, It x)
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{
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assert(std::prev(i) == x);
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}
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#if TEST_STD_VER > 14
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template <class It>
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constexpr bool
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constexpr_test(It i, typename std::iterator_traits<It>::difference_type n, It x)
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{
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return std::prev(i, n) == x;
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}
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template <class It>
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constexpr bool
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constexpr_test(It i, It x)
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{
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return std::prev(i) == x;
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}
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#endif
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int main(int, char**)
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{
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{
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const char* s = "1234567890";
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test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10));
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test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s));
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test(bidirectional_iterator<const char*>(s), -10, bidirectional_iterator<const char*>(s+10));
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test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s));
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test(random_access_iterator<const char*>(s), -10, random_access_iterator<const char*>(s+10));
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test(s+10, 10, s);
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test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
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test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s));
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test(s+1, s);
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}
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#if TEST_STD_VER > 14
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{
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constexpr const char* s = "1234567890";
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static_assert( constexpr_test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" );
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static_assert( constexpr_test(bidirectional_iterator<const char*>(s+10), 10, bidirectional_iterator<const char*>(s)), "" );
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static_assert( constexpr_test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" );
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static_assert( constexpr_test(random_access_iterator<const char*>(s+10), 10, random_access_iterator<const char*>(s)), "" );
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static_assert( constexpr_test(forward_iterator <const char*>(s), -10, forward_iterator <const char*>(s+10)), "" );
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static_assert( constexpr_test(s+10, 10, s), "" );
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static_assert( constexpr_test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s)), "" );
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static_assert( constexpr_test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s)), "" );
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static_assert( constexpr_test(s+1, s), "" );
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}
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#endif
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return 0;
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}
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