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Diffstat (limited to 'src/third-party/scnlib/include/scn/tuple_return/tuple_return.h')
| -rw-r--r-- | src/third-party/scnlib/include/scn/tuple_return/tuple_return.h | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/src/third-party/scnlib/include/scn/tuple_return/tuple_return.h b/src/third-party/scnlib/include/scn/tuple_return/tuple_return.h new file mode 100644 index 0000000..91d6254 --- /dev/null +++ b/src/third-party/scnlib/include/scn/tuple_return/tuple_return.h @@ -0,0 +1,123 @@ +// 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_TUPLE_RETURN_TUPLE_RETURN_H +#define SCN_TUPLE_RETURN_TUPLE_RETURN_H + +#include "../scan/vscan.h" +#include "util.h" + +namespace scn { + SCN_BEGIN_NAMESPACE + + namespace dummy { + } + +/** + * Alternative interface for scanning, returning values as a tuple, instead + * of taking them by reference. + * + * It's highly recommended to use this interface only with C++17 or later, + * as structured bindings make it way more ergonomic. + * + * Compared to the regular scan interface, the performance of this interface + * is the same (generated code is virtually identical with optimizations + * enabled), but the compile time is slower. + * + * Values scanned by this function still need to be default-constructible. + * To scan a non-default-constructible value, use \c scn::optional + * + * \param r Input range + * \param f Format string to use + * + * \return Tuple, where the first element is the scan result, and the + * remaining elements are the scanned values. + */ +#if SCN_DOXYGEN + template <typename... Args, typename Range, typename Format> + auto scan_tuple(Range&& r, Format f) + -> std::tuple<detail::scan_result_for_range<Range>, Args...>; +#else + template <typename... Args, typename Range, typename Format> + SCN_NODISCARD auto scan_tuple(Range&& r, Format f) + -> std::tuple<detail::scan_result_for_range<Range>, Args...> + { + using result = detail::scan_result_for_range<Range>; + using range_type = typename result::wrapped_range_type; + + using context_type = basic_context<range_type>; + using parse_context_type = + basic_parse_context<typename context_type::locale_type>; + using char_type = typename range_type::char_type; + + auto range = wrap(SCN_FWD(r)); + auto scanfn = [&range, &f](Args&... a) { + auto args = make_args<context_type, parse_context_type>(a...); + return vscan(SCN_MOVE(range), basic_string_view<char_type>(f), + {args}); + }; + + std::tuple<Args...> values{Args{}...}; + auto ret = detail::apply(scanfn, values); + return std::tuple_cat( + std::tuple<result>{detail::wrap_result(wrapped_error{ret.err}, + detail::range_tag<Range>{}, + SCN_MOVE(ret.range))}, + SCN_MOVE(values)); + } +#endif + + /** + * Equivalent to `scan_tuple`, except uses `vscan_default` under the hood. + */ +#if SCN_DOXYGEN + template <typename... Args, typename Range> + auto scan_tuple_default(Range&& r) + -> std::tuple<detail::scan_result_for_range<Range>, Args...>; +#else + template <typename... Args, typename Range> + SCN_NODISCARD auto scan_tuple_default(Range&& r) + -> std::tuple<detail::scan_result_for_range<Range>, Args...> + { + using result = detail::scan_result_for_range<Range>; + using range_type = typename result::wrapped_range_type; + + using context_type = basic_context<range_type>; + using parse_context_type = + basic_empty_parse_context<typename context_type::locale_type>; + + auto range = wrap(SCN_FWD(r)); + auto scanfn = [&range](Args&... a) { + auto args = make_args<context_type, parse_context_type>(a...); + return vscan_default(SCN_MOVE(range), + static_cast<int>(sizeof...(Args)), {args}); + }; + + std::tuple<Args...> values{Args{}...}; + auto ret = detail::apply(scanfn, values); + return std::tuple_cat( + std::tuple<result>{detail::wrap_result(wrapped_error{ret.err}, + detail::range_tag<Range>{}, + SCN_MOVE(ret.range))}, + SCN_MOVE(values)); + } +#endif + + SCN_END_NAMESPACE +} // namespace scn + +#endif |