Sprout/sprout/cstring/memchr.hpp
2015-01-10 19:13:57 +09:00

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/*=============================================================================
Copyright (c) 2011-2015 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_CSTRING_MEMCHR_HPP
#define SPROUT_CSTRING_MEMCHR_HPP
#include <type_traits>
#include <utility>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/type_traits/enabler_if.hpp>
#include <sprout/iterator/ptr_index_iterator.hpp>
#include <sprout/algorithm/find.hpp>
namespace sprout {
namespace detail {
template<typename T>
struct memchr_result {
private:
static void const* test(void const*);
static void* test(void*);
static void test(...);
public:
typedef decltype(test(std::declval<T>())) type;
};
template<typename PtrIterator>
inline SPROUT_CONSTEXPR PtrIterator
memchr_impl(PtrIterator found, PtrIterator last) {
return found == last ? nullptr
: found
;
}
template<typename PtrIterator, typename T>
inline SPROUT_CONSTEXPR PtrIterator
memchr(PtrIterator s, T c, std::size_t n) {
return sprout::detail::memchr_impl(
sprout::ptr_unindex(
sprout::find(
sprout::ptr_index(s), sprout::ptr_index(s, n),
c
)
),
s + n
);
}
} // namespace detail
// 7.21.5.1 memchr ŠÖ<C5A0>
//
// recursion depth:
// O(log N)
//
#if 0
inline SPROUT_CONSTEXPR void const*
memchr(void const* s, int c, std::size_t n) {
return sprout::detail::memchr(static_cast<unsigned char const*>(s), static_cast<unsigned char>(c), n);
}
inline SPROUT_CONSTEXPR void*
memchr(void* s, int c, std::size_t n) {
return sprout::detail::memchr(static_cast<unsigned char*>(s), static_cast<unsigned char>(c), n);
}
#endif
template<
typename T,
typename sprout::enabler_if<std::is_same<typename sprout::detail::memchr_result<T>::type, void const*>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR void const*
memchr(T s, int c, std::size_t n) {
return sprout::detail::memchr(static_cast<unsigned char const*>(s), static_cast<unsigned char>(c), n);
}
template<
typename T,
typename sprout::enabler_if<std::is_same<typename sprout::detail::memchr_result<T>::type, void*>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR void*
memchr(T s, int c, std::size_t n) {
return sprout::detail::memchr(static_cast<unsigned char*>(s), static_cast<unsigned char>(c), n);
}
} // namespace sprout
#endif // #ifndef SPROUT_CSTRING_MEMCHR_HPP