mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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56 lines
1.8 KiB
C++
56 lines
1.8 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2014 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_ITERATOR_ADVANCE_HPP
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#define SPROUT_ITERATOR_ADVANCE_HPP
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#include <iterator>
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#include <sprout/config.hpp>
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#include <sprout/assert.hpp>
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#include <sprout/math/greater_equal.hpp>
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namespace sprout {
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namespace detail {
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template<typename InputIterator, typename Distance>
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inline SPROUT_CXX14_CONSTEXPR void
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advance_impl(InputIterator& it, Distance n, std::input_iterator_tag*) {
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SPROUT_ASSERT(sprout::math::greater_equal(n, 0));
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for (; 0 < n; --n) {
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++it;
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}
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}
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template<typename BidirectionalIterator, typename Distance>
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inline SPROUT_CXX14_CONSTEXPR void
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advance_impl(BidirectionalIterator& it, Distance n, std::bidirectional_iterator_tag*) {
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if (n > 0) {
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for (; 0 < n; --n) {
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++it;
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}
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} else {
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for (; n < 0; ++n) {
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--it;
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}
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}
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}
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template<typename RandomAccessIterator, typename Distance>
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inline SPROUT_CXX14_CONSTEXPR void
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advance_impl(RandomAccessIterator& it, Distance n, std::random_access_iterator_tag*) {
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it += n;
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}
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} // namespace detail
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//
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// advance
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//
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template<typename Iterator, typename Distance>
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inline SPROUT_CXX14_CONSTEXPR void
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advance(Iterator& it, Distance n) {
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typedef typename std::iterator_traits<Iterator>::iterator_category* category;
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sprout::detail::advance_impl(it, n, category());
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_ITERATOR_ADVANCE_HPP
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