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Diffstat (limited to 'src/third-party/scnlib/include/scn/unicode/unicode.h')
| -rw-r--r-- | src/third-party/scnlib/include/scn/unicode/unicode.h | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/third-party/scnlib/include/scn/unicode/unicode.h b/src/third-party/scnlib/include/scn/unicode/unicode.h new file mode 100644 index 0000000..011b0b9 --- /dev/null +++ b/src/third-party/scnlib/include/scn/unicode/unicode.h @@ -0,0 +1,243 @@ +// 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 +// +// The contents of this file are based on utfcpp: +// https://github.com/nemtrif/utfcpp +// Copyright (c) 2006 Nemanja Trifunovic +// Distributed under the Boost Software License, version 1.0 + +#ifndef SCN_UNICODE_UNICODE_H +#define SCN_UNICODE_UNICODE_H + +#include "utf16.h" +#include "utf8.h" + +namespace scn { + SCN_BEGIN_NAMESPACE + + namespace detail { + inline constexpr bool is_wide_multichar() + { + return sizeof(wchar_t) == 2; + } + + inline constexpr bool is_multichar_type(char) + { + return true; + } + inline constexpr bool is_multichar_type(wchar_t) + { + return is_wide_multichar(); + } + + using utf8_tag = std::integral_constant<size_t, 1>; + using utf16_tag = std::integral_constant<size_t, 2>; + using utf32_tag = std::integral_constant<size_t, 4>; + +#define SCN_MAKE_UTF_TAG(CharT) \ + std::integral_constant<size_t, sizeof(CharT)> {} + + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> parse_code_point(I begin, + S end, + code_point& cp, + utf8_tag) + { + return utf8::parse_code_point(begin, end, cp); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> parse_code_point(I begin, + S end, + code_point& cp, + utf16_tag) + { + return utf16::parse_code_point(begin, end, cp); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> parse_code_point(I begin, + S end, + code_point& cp, + utf32_tag) + { + SCN_EXPECT(begin != end); + cp = make_code_point(*begin); + return {++begin}; + } + } // namespace detail + + /** + * Parses a Unicode code point from the range at `[begin, end)`, and writes + * it into `cp`. + * + * The encoding is determined by the size of the value type of the range. + * Let `n = sizeof(typename std::iterator_traits<I>::value_type)`. + * If `n == 1` -> UTF-8. If `n == 2` -> UTF-16. If `n == 4` -> UTF-32. + * + * `begin != end` must be `true`. + * + * On error, `cp` is not written into. + * + * \return On success, returns an iterator one-past the last code unit used + * to parse `cp`. If the code point is encoded incorrectly, returns + * `error::invalid_encoding`. + */ + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> parse_code_point(I begin, S end, code_point& cp) + { + return detail::parse_code_point( + begin, end, cp, + SCN_MAKE_UTF_TAG(typename std::iterator_traits<I>::value_type)); + } + + namespace detail { + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> encode_code_point(I begin, + S end, + code_point cp, + utf8_tag) + { + return utf8::encode_code_point(begin, end, cp); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> encode_code_point(I begin, + S end, + code_point cp, + utf16_tag) + { + return utf16::encode_code_point(begin, end, cp); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> encode_code_point(I begin, + S end, + code_point cp, + utf32_tag) + { + SCN_EXPECT(begin + 1 >= end); + *begin++ = static_cast<uint32_t>(cp); + return {begin}; + } + } // namespace detail + + /** + * Writes the code point `cp` into `begin`, using the encoding determined by + * the type of `begin`. + * + * For more information on how the encoding is determined, see \ref + * parse_code_point(). + * + * `end` must be reachable from `begin`, and must have enough room to encode + * the code point (4 code units for UTF-8, 2 for UTF-16, and 1 for UTF-32). + * + * \param begin Beginning of the range to write the result to + * \param end End of the range to write the result to + * \param cp Code point to encode + * \return On success, one-past the last code unit written. + * If `cp` was not a valid code point, returns `error::invalid_encoding`. + */ + template <typename I, typename S> + SCN_CONSTEXPR14 expected<I> encode_code_point(I begin, S end, code_point cp) + { + return detail::encode_code_point( + begin, end, cp, + SCN_MAKE_UTF_TAG(typename std::iterator_traits<I>::value_type)); + } + + namespace detail { + template <typename T> + SCN_CONSTEXPR14 int get_sequence_length(T a, utf8_tag) + { + return utf8::get_sequence_length(a); + } + template <typename T> + SCN_CONSTEXPR14 int get_sequence_length(T a, utf16_tag) + { + return utf16::get_sequence_length(a); + } + template <typename T> + SCN_CONSTEXPR14 int get_sequence_length(T, utf32_tag) + { + return 1; + } + } // namespace detail + + /** + * Returns the length of the code point starting from code unit `a` in code + * units. + * + * For information on how the encoding is determined, see \ref + * parse_code_point(). + * + * \param a The first code unit in a code point. + * + * \return Length of the code point starting from `a`, in code units + * If the code point is encoded incorrectly, or this code unit is not the + * first code unit in a code point, returns 0. + */ + template <typename T> + SCN_CONSTEXPR14 int get_sequence_length(T a) + { + return detail::get_sequence_length(a, SCN_MAKE_UTF_TAG(T)); + } + + namespace detail { + template <typename I, typename S> + SCN_CONSTEXPR14 expected<std::ptrdiff_t> code_point_distance(I begin, + S end, + utf8_tag) + { + return utf8::code_point_distance(begin, end); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<std::ptrdiff_t> code_point_distance(I begin, + S end, + utf16_tag) + { + return utf16::code_point_distance(begin, end); + } + template <typename I, typename S> + SCN_CONSTEXPR14 expected<std::ptrdiff_t> code_point_distance(I begin, + S end, + utf32_tag) + { + return {end - begin}; + } + } // namespace detail + + /** + * Get the distance between two code points, in code points. + * + * `end >= begin` must be `true`. + * `begin` and `end` must both point to the first code units in a code + * point. + * + * \return The distance between `begin` and `end`, in code points. If the + * string was encoded incorrectly, returns `error::invalid_encoding`. + */ + template <typename I, typename S> + SCN_CONSTEXPR14 expected<std::ptrdiff_t> code_point_distance(I begin, S end) + { + return detail::code_point_distance( + begin, end, + SCN_MAKE_UTF_TAG(typename std::iterator_traits<I>::value_type)); + } + +#undef SCN_MAKE_UTF_TAG + + SCN_END_NAMESPACE +} // namespace scn + +#endif |