mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
82 lines
2.8 KiB
C++
82 lines
2.8 KiB
C++
#ifndef SPROUT_CSTRING_STRSPN_HPP
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#define SPROUT_CSTRING_STRSPN_HPP
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#include <cstddef>
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#include <iterator>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/iterator/operation.hpp>
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#include <sprout/tuple/tuple.hpp>
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#include <sprout/type_traits/is_char_type.hpp>
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#include <sprout/cstring/strchr.hpp>
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namespace sprout {
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namespace detail {
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template<typename InputIterator1, typename ForwardIterator2>
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inline SPROUT_CONSTEXPR sprout::tuples::tuple<InputIterator1, std::size_t, bool>
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strspn_impl_1(
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sprout::tuples::tuple<InputIterator1, std::size_t, bool> const& current,
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ForwardIterator2 first2, typename std::iterator_traits<InputIterator1>::difference_type n
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)
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{
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typedef sprout::tuples::tuple<InputIterator1, std::size_t, bool> type;
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return sprout::tuples::get<2>(current) || !*sprout::tuples::get<0>(current) ? current
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: n == 1 ? *sprout::detail::strchr(first2, *sprout::tuples::get<0>(current))
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? type(sprout::next(sprout::tuples::get<0>(current)), sprout::tuples::get<1>(current) + 1, false)
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: type(sprout::tuples::get<0>(current), sprout::tuples::get<1>(current), true)
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: sprout::detail::strspn_impl_1(
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sprout::detail::strspn_impl_1(
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current,
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first2, n / 2
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),
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first2, n - n / 2
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)
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;
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}
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template<typename InputIterator1, typename ForwardIterator2>
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inline SPROUT_CONSTEXPR sprout::tuples::tuple<InputIterator1, std::size_t, bool>
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strspn_impl(
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sprout::tuples::tuple<InputIterator1, std::size_t, bool> const& current,
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ForwardIterator2 first2, typename std::iterator_traits<InputIterator1>::difference_type n
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)
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{
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typedef sprout::tuples::tuple<InputIterator1, std::size_t, bool> type;
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return sprout::tuples::get<2>(current) || !*sprout::tuples::get<0>(current) ? current
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: sprout::detail::strspn_impl(
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sprout::detail::strspn_impl_1(
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current,
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first2, n
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),
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first2, n * 2
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)
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;
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}
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template<typename InputIterator1, typename ForwardIterator2>
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inline SPROUT_CONSTEXPR std::size_t
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strspn(InputIterator1 first1, ForwardIterator2 first2) {
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typedef sprout::tuples::tuple<InputIterator1, std::size_t, bool> type;
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return sprout::tuples::get<1>(sprout::detail::strspn_impl(type(first1, 0, false), first2, 1));
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}
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} // namespace detail
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// 7.21.5.6 strspn <20><EFBFBD>
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//
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// recursion depth:
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// O(log(N1+N2))
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//
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inline SPROUT_CONSTEXPR std::size_t
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strspn(char const* s1, char const* s2) {
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return sprout::detail::strspn(s1, s2);
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}
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template<typename Elem>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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sprout::is_char_type<Elem>::value,
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std::size_t
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>::type
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strspn(Elem* s1, Elem* s2) {
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return sprout::detail::strspn(s1, s2);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_CSTRING_STRSPN_HPP
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