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Diffstat (limited to 'src/third-party/scnlib/include/scn/detail/vectored.h')
| -rw-r--r-- | src/third-party/scnlib/include/scn/detail/vectored.h | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/third-party/scnlib/include/scn/detail/vectored.h b/src/third-party/scnlib/include/scn/detail/vectored.h new file mode 100644 index 0000000..f5c3868 --- /dev/null +++ b/src/third-party/scnlib/include/scn/detail/vectored.h @@ -0,0 +1,166 @@ +// Copyright 2017 Elias Kosunen +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// This file is a part of scnlib: +// https://github.com/eliaskosunen/scnlib + +#ifndef SCN_DETAIL_VECTORED_H +#define SCN_DETAIL_VECTORED_H + +#include "../ranges/util.h" +#include "../util/math.h" + +namespace scn { + SCN_BEGIN_NAMESPACE + + namespace detail { + namespace _get_buffer { + struct fn { + private: + template <typename It> + static It _get_end(It begin, It end, size_t max_size) + { + return begin + + min(max_size, static_cast<std::size_t>( + ranges::distance(begin, end))); + } + + template <typename CharT> + static SCN_CONSTEXPR14 + span<typename std::add_const<CharT>::type> + impl(span<span<CharT>> s, + typename span<CharT>::iterator begin, + size_t max_size, + priority_tag<3>) noexcept + { + auto buf_it = s.begin(); + for (; buf_it != s.end(); ++buf_it) { + if (begin >= buf_it->begin() && begin < buf_it->end()) { + break; + } + if (begin == buf_it->end()) { + ++buf_it; + begin = buf_it->begin(); + break; + } + } + if (buf_it == s.end()) { + return {}; + } + return {begin, _get_end(begin, buf_it->end(), max_size)}; + } + + template < + typename Range, + typename std::enable_if<SCN_CHECK_CONCEPT( + ranges::contiguous_range<Range>)>::type* = nullptr> + static SCN_CONSTEXPR14 span<typename std::add_const< + ranges::range_value_t<const Range>>::type> + impl(const Range& s, + ranges::iterator_t<const Range> begin, + size_t max_size, + priority_tag<2>) noexcept + { + auto b = ranges::begin(s); + auto e = ranges::end(s); + return {to_address(begin), + _get_end(to_address(begin), + to_address_safe(e, b, e), max_size)}; + } + + template <typename Range, typename It> + static auto impl( + const Range& r, + It begin, + size_t max_size, + priority_tag<1>) noexcept(noexcept(r.get_buffer(begin, + max_size))) + -> decltype(r.get_buffer(begin, max_size)) + { + return r.get_buffer(begin, max_size); + } + + template <typename Range, typename It> + static auto impl( + const Range& r, + It begin, + size_t max_size, + priority_tag<0>) noexcept(noexcept(get_buffer(r, + begin, + max_size))) + -> decltype(get_buffer(r, begin, max_size)) + { + return get_buffer(r, begin, max_size); + } + + public: + template <typename Range, typename It> + SCN_CONSTEXPR14 auto operator()(const Range& r, + It begin, + size_t max_size) const + noexcept(noexcept( + fn::impl(r, begin, max_size, priority_tag<3>{}))) + -> decltype(fn::impl(r, + begin, + max_size, + priority_tag<3>{})) + { + return fn::impl(r, begin, max_size, priority_tag<3>{}); + } + + template <typename Range, typename It> + SCN_CONSTEXPR14 auto operator()(const Range& r, It begin) const + noexcept( + noexcept(fn::impl(r, + begin, + std::numeric_limits<size_t>::max(), + priority_tag<3>{}))) + -> decltype(fn::impl(r, + begin, + std::numeric_limits<size_t>::max(), + priority_tag<3>{})) + { + return fn::impl(r, begin, + std::numeric_limits<size_t>::max(), + priority_tag<3>{}); + } + }; + } // namespace _get_buffer + + namespace { + static constexpr auto& get_buffer = + detail::static_const<_get_buffer::fn>::value; + } // namespace + + struct provides_buffer_access_concept { + template <typename Range, typename Iterator> + auto _test_requires(const Range& r, Iterator begin) + -> decltype(scn::detail::valid_expr( + ::scn::detail::get_buffer(r, begin))); + }; + template <typename Range, typename = void> + struct provides_buffer_access_impl + : std::integral_constant< + bool, + ::scn::custom_ranges::detail::_requires< + provides_buffer_access_concept, + Range, + ::scn::ranges::iterator_t<const Range>>::value> { + }; + } // namespace detail + + SCN_END_NAMESPACE +} // namespace scn + +#endif |