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Diffstat (limited to 'src/openvic-dataloader/detail/Detect.hpp')
-rw-r--r-- | src/openvic-dataloader/detail/Detect.hpp | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/src/openvic-dataloader/detail/Detect.hpp b/src/openvic-dataloader/detail/Detect.hpp new file mode 100644 index 0000000..ad36d04 --- /dev/null +++ b/src/openvic-dataloader/detail/Detect.hpp @@ -0,0 +1,627 @@ +/// Based heavily on https://github.com/hsivonen/chardetng/tree/143dadde20e283a46ef33ba960b517a3283a3d22 + +#pragma once + +#include <array> +#include <cassert> +#include <cstdint> +#include <optional> +#include <span> +#include <type_traits> +#include <variant> +#include <vector> + +#include <openvic-dataloader/detail/Encoding.hpp> + +#include <lexy/action/match.hpp> +#include <lexy/callback/constant.hpp> +#include <lexy/dsl.hpp> +#include <lexy/dsl/ascii.hpp> +#include <lexy/dsl/newline.hpp> +#include <lexy/encoding.hpp> +#include <lexy/input/buffer.hpp> + +#include "detail/dsl.hpp" + +namespace ovdl::encoding_detect { + using cbyte = char; + using ubyte = unsigned char; + + using Encoding = detail::Encoding; + + struct DetectAscii { + // & 0b10000000 == 0b00000000 + static constexpr auto rule = lexy::dsl::while_(lexy::dsl::ascii::character) + lexy::dsl::eol; + static constexpr auto value = lexy::constant(true); + }; + + template<bool IncludeAscii> + struct DetectUtf8 { + struct not_utf8 { + static constexpr auto name = "not utf8"; + }; + + static constexpr auto rule = [] { + constexpr auto is_not_ascii_flag = lexy::dsl::context_flag<DetectUtf8>; + + // & 0b10000000 == 0b00000000 + constexpr auto ascii_values = lexy::dsl::ascii::character; + // & 0b11100000 == 0b11000000 + constexpr auto two_byte = dsl::lit_b_range<0b11000000, 0b11011111>; + // & 0b11110000 == 0b11100000 + constexpr auto three_byte = dsl::lit_b_range<0b11100000, 0b11101111>; + // & 0b11111000 == 0b11110000 + constexpr auto four_byte = dsl::lit_b_range<0b11110000, 0b11110111>; + // & 0b11000000 == 0b10000000 + constexpr auto check_bytes = dsl::lit_b_range<0b10000000, 0b10111111>; + + constexpr auto utf8_check = + ((four_byte >> lexy::dsl::times<3>(check_bytes)) | + (three_byte >> lexy::dsl::times<2>(check_bytes)) | + (two_byte >> lexy::dsl::times<1>(check_bytes))) >> + is_not_ascii_flag.set(); + + return is_not_ascii_flag.template create<IncludeAscii>() + + lexy::dsl::while_(utf8_check | ascii_values) + + lexy::dsl::must(is_not_ascii_flag.is_set()).template error<not_utf8> + lexy::dsl::eof; + }(); + + static constexpr auto value = lexy::constant(true); + }; + + extern template struct DetectUtf8<true>; + extern template struct DetectUtf8<false>; + + template<typename Input> + constexpr bool is_ascii(const Input& input) { + return lexy::match<DetectAscii>(input); + } + + template<typename Input> + constexpr bool is_utf8_no_ascii(const Input& input) { + return lexy::match<DetectUtf8<false>>(input); + } + + template<typename Input> + constexpr bool is_utf8(const Input& input) { + return lexy::match<DetectUtf8<true>>(input); + } + + struct DetectorData { + static constexpr std::array latin_ascii = std::to_array<ubyte>({ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 0, 0, 0, 0, 0, 0, // + 0, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, // + 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 0, 0, 0, 0, 0, // + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, // + 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 0, 0, 0, 0, 0, // + }); + + static constexpr std::array non_latin_ascii = std::to_array<ubyte>({ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // + 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 0, 0, 0, 0, 0, 0, // + 0, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, // + 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 0, 0, 0, 0, 0, // + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, // + }); + + static constexpr std::array windows_1251 = std::to_array<ubyte>({ + 131, 130, 0, 2, 0, 0, 0, 0, 0, 0, 132, 0, 133, 130, 134, 135, // + 3, 0, 0, 0, 0, 0, 0, 0, 255, 0, 4, 0, 5, 2, 6, 7, // + 0, 136, 8, 140, 47, 130, 46, 47, 138, 49, 139, 49, 50, 46, 48, 141, // + 49, 50, 137, 9, 2, 49, 48, 46, 10, 47, 11, 48, 12, 130, 2, 13, // + 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, // + 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, // + 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, // + 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, // + }); + + static constexpr std::array windows_1252 = std::to_array<ubyte>({ + 0, 255, 0, 60, 0, 0, 0, 0, 0, 0, 156, 0, 157, 255, 185, 255, // + 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 28, 0, 29, 255, 57, 186, // + 0, 62, 60, 60, 60, 60, 59, 60, 60, 62, 60, 59, 63, 59, 61, 60, // + 62, 63, 61, 61, 60, 62, 61, 59, 60, 61, 60, 59, 62, 62, 62, 62, // + 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, // + 188, 174, 175, 176, 177, 178, 179, 63, 180, 181, 182, 183, 184, 188, 188, 27, // + 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, // + 60, 46, 47, 48, 49, 50, 51, 63, 52, 53, 54, 55, 56, 60, 60, 58, // + }); + + // clang-format off + static constexpr std::array cyrillic = std::to_array<ubyte>({ + 0, 0, 0, 0, 1, 0, 16, 38, 0, 2, 5, 10,121, 4, 20, 25, 26, 53, 9, 5, 61, 23, 20, 26, 15, 95, 60, 2, 26, 15, 25, 29, 0, 14, 6, 6, 25, 1, 0, 27, 25, 8, 5, 39, // , + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // a, + 0, 0, 0,255, 0, 0,255, 0,255, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255, 0, 0,255, 0, 0, // ѓ, + 0, 0,255, 0, 0, 0, 0, 0,255,255,255,255, 0,255, 2, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255,255,255,255, // ђ, + 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255, 0,255, 0, 0, 0, 0, 0, 4, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255,255,255,255, // љ, + 0, 0, 0, 0, 0, 0, 0, 0,255,255,255, 0, 0,255, 5, 0, 0, 0, 0, 2, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255,255,255,255, // њ, + 0, 0,255, 0, 0, 0, 0, 0,255, 0,255,255, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 1,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255,255,255,255, // ћ, + 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255,255,255,255,255, // џ, + 7, 0, 0,255,255,255,255,255, 0, 1, 0,255,255,255, 15, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255, 1, 0, 0, 0, 1, // ў, + 12, 0, 0,255,255, 0,255,255, 0, 2, 0, 0, 0, 0, 2, 3, 15, 5, 5, 0, 0, 4, 0, 0, 21, 15, 10, 17, 0, 6, 14, 4, 6, 0, 3, 1, 8, 1, 0, 0, 0, 2, 0, 0, 0, 0, // і, + 0, 0,255,255,255,255,255,255, 0, 0, 0,255,255, 0, 4, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // ё, + 6, 0, 0,255,255,255,255,255, 0, 0,255, 5,255, 0, 1, 7, 0, 3, 2, 0, 0, 0, 0, 0, 0, 2, 2, 2, 0, 0, 2, 2, 5, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // є, + 12, 0, 0, 0, 0, 0, 0, 0,255, 0,255, 0, 0, 0, 5, 1, 0, 0, 0, 2, 0, 0, 20,255, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255, 0,255,255,255,255, // ј, + 9, 0, 0,255,255,255,255,255,255, 5,255, 0, 0, 13, 3, 3, 0, 4, 1, 0, 1, 2, 0, 0, 0, 1, 0, 0, 4, 0, 0, 1, 3, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // ї, + 32, 0, 0, 2, 2, 2, 0, 0, 0, 1, 0, 0, 28, 0, 23, 22, 26, 22, 19, 0, 3, 12, 5, 0, 44, 38, 18, 58, 1, 21, 44, 17, 54, 1, 2, 28, 5, 8, 3, 1, 9, 0, 12, 0, 0, 0, // а, + 40, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 7, 0, 0, 0, 1, 7, 0, 1, 1, 0, 0, 7, 4, 1, 9, 0, 1, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, // б, + 31, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 3, 0, 0, 19, 0, 0, 1, 1, 6, 0, 2, 6, 0, 1, 0, 1, 0, 32, 0, 2, 2, 23, 9, 0, 0, 0, 1, 0, 0, 1, 1, 0, 3, 0, 2, // в, + 23, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 7, 0, 1, 20, 0, 0, 1, 0, 9, 0, 0, 9, 7, 0, 5, 2, 18, 11, 0, 8, 3, 2, 3, 0, 0, 0, 0, 0, 0, 0, 3, 0, 13, 0, 3, // г, + 26, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 2, 0, 2, 19, 0, 1, 5, 0, 13, 2, 2, 3, 2, 0, 6, 1, 12, 30, 0, 4, 0, 0, 7, 0, 0, 0, 0, 0, 0, 1, 0, 0, 5, 0, 1, // д, + 12, 0, 0, 1, 4, 5, 0, 0, 0, 0, 0, 0, 24, 1, 5, 7, 11, 3, 12, 1, 6, 6, 11, 0, 3, 15, 14, 14, 4, 8, 25, 14, 29, 0, 1, 1, 4, 8, 8, 2, 0, 3, 1, 0, 0, 0, // е, + 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 1, 2, 2, 0, 0, 0, 0, 0, 3, 2, 1, 2, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, // ж, + 19, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 1, 6, 0, 0, 0, 11, 8, 0, 0, 8, 0, 0, 0, 0, 0, 4, 0, 1, 0, 0, 3, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, // з, + 24, 0, 0, 0, 0, 1, 5, 0, 0, 0, 0, 0, 1, 0, 1, 10, 16, 21, 22, 0, 6, 5, 6, 1, 15, 15, 8, 38, 2, 4, 27, 9, 15, 0, 3, 8, 12, 7, 6, 1, 0, 0, 0, 0, 0, 0, // и, + 6, 0, 0, 0,255,255,255,255, 0, 7, 0, 0,255, 4, 21, 0, 0, 0, 0, 5, 0, 0, 39, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 5, 0, 3, 0, 0, // й, + 54, 0, 0, 0, 0, 0, 0, 0, 1, 8, 0, 0, 0, 0, 10, 0, 1, 0, 1, 11, 0, 0, 12, 0, 1, 2, 0, 4, 8, 0, 2, 23, 2, 4, 0, 2, 3, 3, 8, 0, 0, 3, 16, 1, 4, 3, // к, + 12, 0, 0, 0, 0, 0, 0, 0, 2, 6, 0, 6, 0, 4, 29, 12, 4, 5, 2, 18, 0, 0, 17, 4, 5, 11, 0, 0, 21, 2, 3, 4, 1, 15, 1, 0, 0, 0, 0, 0, 4, 3, 2, 12, 0, 2, // л, + 23, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 4, 0, 0, 17, 1, 0, 0, 0, 7, 0, 1, 13, 2, 0, 0, 0, 0, 13, 0, 2, 4, 0, 2, 0, 0, 0, 0, 0, 0, 1, 4, 2, 4, 1, 1, // м, + 42, 0, 0, 0, 0, 0, 0, 0, 4, 12, 6, 7, 1, 7, 76, 0, 22, 1, 4, 27, 1, 3, 34, 30, 0, 7, 1, 13, 24, 1, 3, 5, 3, 4, 0, 1, 0, 4, 1, 0, 2, 18, 7, 16, 0, 4, // н, + 37, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 1, 0, 1, 10, 27, 22, 15, 1, 2, 3, 7, 5, 32, 11, 7, 38, 8, 21, 24, 11, 23, 0, 2, 10, 2, 2, 3, 2, 0, 0, 1, 0, 0, 0, // о, + 47, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 1, 0, 0, 2, 0, 1, 2, 4, 0, 0, 2, 0, 6, 0, 0, 5, 0, 2, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, // п, + 19, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 8, 0, 5, 47, 4, 6, 6, 5, 23, 0, 0, 5, 2, 6, 0, 0, 0, 23, 22, 0, 1, 14, 9, 1, 0, 1, 0, 0, 0, 7, 2, 8, 16, 0, 3, // р, + 53, 0, 0, 0, 0, 0, 0, 0, 4, 9, 2, 0, 1, 2, 21, 1, 4, 1, 2, 11, 0, 0, 12, 2, 4, 7, 1, 13, 15, 1, 4, 6, 3, 6, 0, 0, 0, 0, 0, 0, 1, 2, 3, 5, 0, 1, // с, + 28, 0, 0, 0, 0, 0, 0, 0, 1, 6, 0, 1, 0, 1, 32, 0, 1, 3, 0, 12, 0, 1, 22, 1, 4, 7, 1, 6, 23, 0, 14, 41, 14, 3, 0, 1, 1, 1, 21, 0, 2, 2, 6, 2, 1, 4, // т, + 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 2, 4, 2, 4, 6, 3, 0, 2, 0, 0, 6, 5, 6, 3, 0, 3, 7, 4, 7, 18, 1, 6, 0, 2, 0, 0, 0, 0, 0, 0, 1, 0, // у, + 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // ф, + 41, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 1, 0, 2, 30, 0, 2, 0, 0, 11, 0, 0, 5, 1, 14, 3, 0, 3, 6, 0, 7, 0, 0, 1, 0, 1, 0, 2, 0, 0, 0, 4, 3, 5, 0, 0, // х, + 8, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 7, 0, 0, 0, 0, 4, 0, 0, 7, 1, 0, 1, 0, 2, 1, 0, 0, 9, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 1, 1, // ц, + 6, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 5, 0, 1, 5, 0, 2, 0, 0, 6, 0, 0, 1, 0, 0, 3, 0, 2, 0, 0, 2, 0, 1, 0, 0, 3, 0, 0, 2, 0, 0, 0, 0, // ч, + 12, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 17, 0, 0, 1, 0, 2, 0, 0, 26, 0, 0, 0, 0, 0, 22, 2, 6, 0, 0, 5, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, // ш, + 2, 0,255, 0,255,255,255,255,255, 0, 0, 0,255, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, // щ, + 0, 0,255,255,255,255, 0,255, 0, 0, 0,255,255,255, 0, 3, 4, 0, 2, 0, 0, 0, 0, 0, 11, 0, 1, 0, 0, 2, 2, 5, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // ъ, + 1, 0, 0,255,255,255,255,255, 0, 0, 0, 0, 0,255, 0, 3, 11, 0, 4, 0, 2, 1, 0, 0, 0, 3, 1, 16, 0, 0, 22, 2, 10, 0, 0, 0, 8, 6, 3, 0, 0, 0, 0, 0, 0, 0, // ы, + 0, 0, 0,255,255, 0, 0, 0,255, 0, 0, 0, 0, 0, 5, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 15, 0, 7, 3, 0, 1, 13, 7, 7, 0, 35, 6, 0, 0, 0, 0, 0, 0, 0, 6, 0, // ь, + 10, 0, 0,255,255,255,255,255, 0, 0, 0, 0,255, 0, 0, 1, 1, 10, 11, 0, 2, 2, 0, 0, 0, 9, 3, 9, 0, 0, 7, 6, 9, 0, 0, 8, 3, 2, 1, 0, 0, 0, 0, 17, 0, 0, // э, + 14, 0, 0, 0,255,255,255,255, 0, 0, 0, 0,255, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // ю, + 5, 0, 0,255,255,255,255,255, 0, 9, 0, 0,255, 0, 11, 0, 3, 0, 0, 0, 0, 2, 24, 0, 0, 5, 2, 14, 1, 0, 2, 3, 1, 0, 0, 1, 3, 0, 0, 0, 0, 16, 1, 0, 0, 0, // я, + // , a, ѓ, ђ, љ, њ, ћ, џ, ў, і, ё, є, ј, ї, а, б, в, г, д, е, ж, з, и, й, к, л, м, н, о, п, р, с, т, у, ф, х, ц, ч, ш, щ, ъ, ы, ь, э, ю, я, + }); + // clang-format on + + // clang-format off + static constexpr std::array western = std::to_array<ubyte>({ + 18, 3, 0,254, 74, 0, 5,254,254, 2, 25,254,149, 4,254, 66,148,254, 0,254,122,238, 8, 1, 20, 13,254, 35, 20, 3, 1, 0, // , + 0, 3, 0, 0, 0, 0, 0, 5, 2, 0, 86, 9, 76, 0, 0, 0,241, 0, 0, 49, 0, 0, 0, 0, 11, 2, 0, 34, 0, 1, 2, 0, // a, + 19, 0, 0, 5, 5, 0, 0, 8, 13, 5, 0, 34, 22, 0, 0, 0, 4, 0, 0, 0, 6, 1, 3, 3, 42, 37, 8, 8, 0, 67, 0, 0, // b, + 0, 0, 0, 9, 6, 1, 0, 22, 10, 1, 0, 19, 54, 1, 0, 1, 18, 3, 1, 2, 40, 7, 0, 0, 6, 0, 3, 5, 1, 34, 0, 0, // c, + 0, 0, 0, 5, 5, 0, 0, 12, 45, 16, 1, 6, 42, 0, 13, 3, 10, 0, 2, 0, 66, 11, 5, 8, 33,104, 3, 4, 0, 19, 0, 0, // d, + 63, 5, 0, 0, 0, 0, 2, 33, 15, 1, 3, 0, 87, 0, 0, 0, 0, 0, 1, 21, 0, 0, 0, 49, 1, 11, 0, 3, 0, 9, 1, 0, // e, + 0, 0, 0, 8, 8, 0, 0, 10, 2, 7, 0,162, 23, 0, 13, 0, 4, 0, 0, 0, 1, 3, 0, 0, 15, 4, 0, 0, 0, 4, 0, 0, // f, + 1, 0, 0, 14, 16, 24, 0, 29, 11, 41, 0, 13, 86, 0, 14, 9, 3, 0, 0, 0, 20, 8, 7, 7, 13, 37, 14, 0, 0, 12, 0, 0, // g, + 1, 0, 0, 0, 0, 0, 0, 47, 2, 0, 0, 0, 1, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 29, 20, 0, 0, 0, 0, 45, 0, 0, // h, + 5, 4, 0,166,120, 0, 0,144, 0, 2, 3, 88,254, 0, 0, 0, 0, 0, 0, 3, 28,107, 0,112, 8, 2, 44, 32, 0, 3, 3, 0, // i, + 0, 0, 0, 0, 0, 0, 0, 39, 9, 0, 0, 2, 1, 0, 2, 0, 0, 0, 0, 4, 0, 0, 0, 16, 18, 44, 0, 0, 0, 0, 0,255, // j, + 0, 2, 0, 0, 1, 0, 0, 48, 31, 32, 1, 60, 1, 0, 4, 0, 1, 0, 0, 0, 1, 3, 0, 2, 20, 47, 0, 0, 0, 20, 0, 0, // k, + 4, 0, 0, 12, 16, 0, 0, 54, 40, 48, 0, 64, 36, 0, 39, 6, 12, 3, 0, 0, 27, 9, 3, 24, 42, 33, 2, 9, 7, 77, 0, 0, // l, + 0, 0, 0, 14, 5, 4, 0, 60, 11, 4, 3, 48, 30, 7, 28, 1, 10, 1, 0, 0, 24, 41, 3, 3, 19, 24, 1, 8, 2, 36, 0, 0, // m, + 1, 1, 0, 24, 91, 16, 0,132, 62, 73, 1, 56, 71, 33, 78, 7, 35, 2, 3, 0, 94,254, 10, 21, 33, 38, 24, 21, 1, 61, 0, 0, // n, + 0, 1, 0, 0, 0, 0,254, 6, 0, 1, 27, 0, 13, 0, 0, 84,127, 0, 0, 62, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, // o, + 0, 0, 0, 5, 2, 0, 0, 9, 15, 0, 0, 4, 34, 0, 6, 0, 6, 0, 0, 0, 20, 12, 9, 28, 10, 22, 0, 3, 0, 7, 0, 0, // p, + 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 33, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,255,255, // q, + 0, 0, 0, 83, 62, 1, 0,198,139,125, 0,229, 94, 54,190, 38, 18, 1, 0, 0,176, 24, 16, 29,193,181, 13, 13, 2,131, 0, 0, // r, + 1, 0, 0, 41, 34, 0, 0, 41, 24, 42, 0, 68,113, 15,159, 6, 43, 19, 4, 58, 14, 18, 1, 4, 48, 42, 4, 12, 9, 20, 0, 0, // s, + 7, 1, 0, 14, 20, 8, 0, 56, 37, 31, 0,104, 67, 14,113, 3, 50, 9, 5, 0, 89, 7, 19, 22, 13, 14, 40, 12, 15, 18, 0, 0, // t, + 0, 1, 5, 1, 2, 0, 0, 30, 0, 0, 1, 15, 2, 0, 1, 0, 1, 0, 0, 2, 4, 0, 0, 36, 0, 0, 0, 0, 0, 0, 0, 0, // u, + 0, 2, 0, 1, 6, 0, 0, 29, 33, 13, 0, 19, 46, 0, 15, 0, 7, 0, 1, 31, 2, 2, 3, 1, 32, 27, 0, 0, 1, 1, 0, 0, // v, + 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 3, 0, 0, 4, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0,255, // w, + 0, 0, 0, 1, 16, 0, 0, 23, 0, 0, 0, 3, 14, 0, 0, 0, 2, 3, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, // x, + 0, 0, 0, 0, 0, 0, 0, 58, 8, 0, 0, 1, 1, 62, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 6, 82, 0, 0, 0, 0, 0,255, // y, + 0, 0, 0, 0, 2, 0, 0, 0, 14, 0, 0, 7, 3, 0, 6, 0, 3, 5, 0, 0, 0, 0, 4, 0, 1, 0, 0, 0, 0, 0, 0, 0, // z, + 0, 29, 0, 0, 0, 15, 0, 0, 0, 11, 0, 0, 0, 0, 0, 20, 0, 0, 0, 0, 0, 37, 0, 0, 0, 0, 0, 0,255,255, 0, 0,255,255, 4, 0, 0,255,255, 0,255, 0,255, 0, 0,255,255,255, 0, 0, 0, 8, 0,255, 0, 0, 2, 0, 0, // ß, + 6, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 10, 1, 0, 0, 0, 0, 0, 0, 0,255, 0, 1, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0,255,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // š, + 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0,255,255,255, 0, 0, 0,255,255,255, 0,255,255,255,255, 0, 0,255,255,255,255,255,255, 0,255,255,255, 0,255,255, // œ, + 107, 0, 22, 16, 18, 14, 6, 24, 46, 15, 2, 0, 42, 18, 17, 0, 36, 0, 34, 4,254, 1, 2, 0, 0, 1, 0, 0, 0,255, 0, 0, 0, 0, 0,255,255, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0,255,255,255,255,255, 0, 0,255, 0, 0, 0, // à, + 41, 0, 10, 8, 21, 34, 5, 5, 60, 18, 5, 1, 29, 42, 26, 2, 16, 0, 27, 9, 43, 28, 7, 0, 0, 1, 4, 0, 0,255, 0, 0,255,255,255, 0,255, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255, 0, 0, 0, 0, 0,255, // á, + 24, 0, 1, 2, 0, 0, 0, 0, 7, 0, 0, 0, 3, 1, 0, 0, 0, 0, 2, 0, 5, 0, 1, 0, 0, 0, 0,255, 0,255, 0, 0, 0,255, 0,255, 0, 0, 0, 2, 0,255, 0,255, 0, 0, 0, 0,255, 0,255,255,255,255,255, 0,255, 0,255, // â, + 0, 0, 0, 1, 2, 3, 0, 1, 2, 12, 0, 0, 1, 7, 29, 4, 1,255, 11, 66, 11, 0, 1, 0, 0, 0, 0,255, 0,255,255,255, 0, 0, 0,255,255,127,255,255,255,255,255, 0, 0,255, 0, 0,255,255, 0,255,255,255,255,255,255,255,255, // ã, + 134, 1, 11, 0, 25, 6, 15, 11, 61, 24,123, 95,114, 68, 53, 1, 49, 0, 60, 98,198, 0, 88, 29, 0, 6, 12, 0, 0,255, 0,255, 0, 0,118, 0,255, 0,255, 0,255, 0,255, 0,255,255, 0,255,255, 0,255, 2,255,255,255, 0, 0, 0,255, // ä, + 156, 0, 12, 14, 19, 3, 12, 47, 17, 3, 12, 5, 30, 47, 22, 0,205, 0,184, 70, 19, 0, 22, 8, 0, 6, 1,255, 0,255,255, 0,255, 0, 0, 0, 0, 0,255, 0,255, 0,255, 0, 0,255,255,255,255,255,255, 0, 0,255,255,255,255,255,255, // å, + 26, 0, 7, 0, 4, 0, 23, 8, 15, 0, 18, 19, 56, 23, 24, 0, 9, 0, 82, 37, 24, 0, 71, 0, 0, 0, 0,255, 0,255,255, 0,255,255, 0, 0, 0, 0,255, 0,255,255,255, 0,255,255, 0,255,255,255,255, 0, 0,255,255,255,255, 0,255, // æ, + 17,112, 0, 2, 0, 15, 0, 0, 0, 35, 0, 0, 2, 0, 59, 9, 1, 0, 36, 0, 0, 8, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255,255, // ç, + 254, 0, 9, 14, 20, 0, 15, 6, 70,144, 14, 45, 47, 92, 16, 3,123, 0, 38, 23,115, 52, 22, 42, 2, 80, 19,255, 0,255, 0, 0,255,255, 0,255,255, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0,255,255,255, 0, 0, 0, 1,255,255, // è, + 152, 2, 19, 24, 85, 0, 29, 23, 26, 25, 2, 9, 43, 60, 62, 1, 32, 0,122, 45,169, 15, 13, 30, 7, 4, 8, 0, 0,255, 0, 0, 0, 0, 0,255, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 1,255, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, // é, + 5, 0, 0, 3, 7, 0, 0, 10, 2, 3, 0, 26, 6, 6, 20, 1, 2, 0, 20, 1, 11, 5, 5, 2, 0, 0, 1,255, 0,255,255,255, 0,255,255,255,255, 0, 0, 0, 0, 0,255, 0, 0, 0, 0,255, 0, 0,255,255,255, 0,255, 0, 0, 0,255, // ê, + 36, 2, 23, 15, 36,143, 5, 23, 52, 52, 66, 48, 92, 57,216, 10,125, 35, 89, 58,254, 9, 24, 14, 0, 0, 8,255, 0,255, 0,255,255,255, 0, 0,255, 1, 0, 0, 0, 0, 0,255, 0, 0, 0,255,255,255, 0, 0, 0, 0,255, 0, 0, 0,255, // ë, + 12, 0, 1, 4, 6, 0, 3, 21, 10, 0, 0, 0, 18, 8, 4, 0, 1, 0, 65, 35, 8, 3, 0, 0, 0, 0, 0,255, 0,255, 0, 0,255,255,255,255,255,255, 0, 0, 0,255, 0, 0, 0,255, 0, 0,255, 0,255,255,255, 0,255,255, 0, 0,255, // ì, + 40, 72, 7, 10, 16, 2, 23, 10, 34, 0, 0, 1, 34, 15, 21, 1, 3, 0,203, 28, 58, 23, 11, 0, 10, 0, 2, 0, 0, 0, 0, 0, 0,255, 0,255,255, 0, 0, 0, 0,255, 0, 0,255,255, 1,255, 0,255,255, 0,255,255, 0,255, 2, 0,255, // í, + 6, 5, 1, 9, 5, 0, 0, 0, 22, 0, 9, 8, 8, 6, 9, 1, 10, 0, 20, 6,182, 0, 13, 0, 0, 24, 1,255, 0,255,255,255, 0, 0,255, 0,255, 0,255, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0,255,255,255,255,255, 0,255,255,255, // î, + 0, 6, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0,255,255, 0, 0, 0, 0,255, 0,255, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0,255, 0, 0, 0, 0,255,255, 0, 0, 0,255,255, // ï, + 0,254, 0, 0, 0, 26, 0, 0, 0, 61, 0, 0, 0, 0, 0, 14, 0, 0, 0, 0, 0, 25, 0, 0, 0, 0, 0,255,255,255, 0, 0, 0, 0, 0, 0,255,255, 0, 0, 0,255, 0, 1, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0,255, 0,255,255, // ñ, + 20, 0, 56, 43, 8,162, 14, 3, 23, 19, 2,118, 31, 26, 46, 0, 20, 0, 23, 6, 24, 19, 6, 21, 5, 27, 63,255, 0,255, 0, 0,255,255,255,255,255, 3, 0,255,255,255, 0, 0,255, 0, 0, 0, 0,255, 0,255,255, 0,255,255, 0,255,255, // ò, + 67, 0, 12, 15, 9, 7, 8, 66, 13,254, 3, 23, 14, 16, 16, 0, 8, 0, 29, 11, 26, 0, 5, 5, 1, 10, 13,255, 0,255,255, 0,255, 0, 0,255,255, 1,255, 0,255,255, 0, 0,255, 0, 1, 0, 0, 0, 0,255,255,255, 0,255,255, 0,255, // ó, + 18, 3, 3, 12, 1, 0, 2, 0, 7, 0, 1, 0, 2, 2, 8, 0, 6, 0, 6, 7, 4, 0, 2, 0, 0, 0, 1,255, 0, 0,255, 0, 0,255,255,255, 0, 0, 0, 0, 0,255,255, 0, 0, 0, 0, 0, 0, 0,255,255,255,255, 0, 0,255,255,255, // ô, + 29, 2, 0, 0, 0, 0, 0, 0, 5, 2, 22, 30, 25, 38, 19, 0, 33,255, 4, 39, 24, 0, 88, 0, 0, 0, 0,255, 0,255,255, 0,255, 0,255,255,255, 36,255,255,255,255,255, 0,255,255, 0,255, 0, 0, 6, 0,255,255,255, 0, 0, 0,255, // õ, + 44, 0, 33, 0, 25, 0,142, 5, 46, 10, 25, 32, 26, 13, 6, 0, 3, 0, 30, 8, 35, 0, 25, 5, 0, 44, 7, 0, 0,255,255, 0,255,255, 73, 0,255, 0, 0, 0,255,255,255,255,255, 0, 0,255, 0, 0, 0, 39, 0,255,255,255, 0, 0, 0, // ö, + 52, 0, 21, 0, 57, 0,119, 12, 47, 3, 59, 33, 45, 15, 12, 0, 3, 0, 52, 82, 49, 1, 11, 0, 0, 0, 0, 0,255, 0,255,255,255,255,255, 0, 0, 0,255, 0,255,255,255, 0,255,255, 0,255,255,255,255, 0, 0,255,255,255,255,255, 0, // ø, + 25, 0, 4, 3, 53, 0, 0, 2, 12, 72, 0, 0, 30, 0, 0,254, 0, 0, 6, 3, 3, 0, 0, 0, 0, 0, 0,255, 0,255, 0,255, 0,255,255,255,255, 0, 0, 0, 0,255, 0,255,255,255,255, 0,255, 0, 0,255,255, 0, 0, 0, 0, 0, 0, // ù, + 19, 2, 1, 7, 9, 1, 12, 5, 9, 41, 1, 0, 10, 7, 9, 0, 8, 0, 12, 28, 8, 0, 0, 0, 0, 1, 0,255, 0,255,255, 0,255,255,255,255, 0, 0,255, 0,255,255,255, 0,255,255, 0, 0, 0,255, 0,255,255, 0, 0,255,255, 0,255, // ú, + 0, 0, 0, 0, 1, 5, 0, 0, 1, 0, 0, 0, 0, 0, 0, 45, 0, 0, 3, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,255,255,255, 0,255,255,255,255, 0,255, 0,255,255,255, 0, 0,255,255,255,255, 0,255,255,255, 0,255, 0, 0,255, 0, // û, + 95, 2, 19, 0, 6, 2,121, 9, 15, 1, 5, 44, 18, 26, 7, 0, 11, 2, 68, 49, 20, 0, 2, 17, 0, 0, 6, 0, 0,255, 0,255,255,255, 0,255,255, 0,255, 0,255, 0,255,255,255, 0, 0,255,255,255, 0, 0,255, 0, 0, 0, 31, 0, 0, // ü, + 1, 1, 0, 0, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0, 0, 0,255, 0, 0,255,255, 0, 0,255, 0,255, 0,255,255,255,255, 0, 0, 0, 0,255, 0, 0, 0, 0, 0,255, // ž, + 0, 0, 0, 0, 0, 0,255, 0, 0,255, 0, 0, 0, 0, 0, 0, 0,255, 0, 0, 0, 0, 0, 0,255,255, 0,255,255,255,255,255,255, 0,255, 0,255,255,255,255,255,255,255,255,255,255,255,255,255, 0, 0,255, 0,255,255,255, 0, 0, 0, // ÿ, + // , a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, ß, š, œ, à, á, â, ã, ä, å, æ, ç, è, é, ê, ë, ì, í, î, ï, ñ, ò, ó, ô, õ, ö, ø, ù, ú, û, ü, ž, ÿ, + + }); + // clang-format on + }; + + namespace class_size { + constexpr std::size_t cyrillic_ascii = 2; + constexpr std::size_t cyrillic_non_ascii = 44; + constexpr std::size_t western_ascii = 27; + constexpr std::size_t western_non_ascii = 32; + } + + constexpr std::size_t ASCII_DIGIT = 100; + + struct ByteScore { + const Encoding encoding; + const std::array<ubyte, 128>& lower; + const std::array<ubyte, 128>& upper; + const std::span<const ubyte> probabilities; + const std::size_t ascii; + const std::size_t non_ascii; + + static inline constexpr std::optional<std::size_t> compute_index(std::size_t x, std::size_t y, std::size_t ascii_classes, std::size_t non_ascii_classes) { + if (x == 0 && y == 0) { + return std::nullopt; + } + + if (x < ascii_classes && y < ascii_classes) { + return std::nullopt; + } + + if (y >= ascii_classes) { + return (ascii_classes * non_ascii_classes) + (ascii_classes + non_ascii_classes) * (y - ascii_classes) + x; + } + + return y * non_ascii_classes + x - ascii_classes; + } + + inline constexpr cbyte classify(cbyte byte) const { + cbyte high = byte >> 7; + cbyte low = byte & 0x7F; + if (high == 0) { + return lower[low]; + } + + return upper[low]; + } + + inline constexpr bool is_latin_alphabetic(cbyte caseless_class) const { + return caseless_class > 0 && caseless_class < (ascii + non_ascii); + } + + inline constexpr bool is_non_latin_alphabetic(cbyte caseless_class) const { + return caseless_class > 1 && caseless_class < (ascii + non_ascii); + } + + inline constexpr int64_t score(cbyte current_class, cbyte previous_class) const { + constexpr std::size_t IMPLAUSABILITY_PENALTY = -220; + + constexpr std::size_t PLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE = 0; + constexpr std::size_t IMPLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE = 1; + constexpr std::size_t IMPLAUSIBLE_BEFORE_ALPHABETIC = 2; + constexpr std::size_t IMPLAUSIBLE_AFTER_ALPHABETIC = 3; + constexpr std::size_t PLAUSIBLE_NEXT_TO_NON_ASCII_ALPHABETIC_ON_EITHER_SIDE = 4; + constexpr std::size_t PLAUSIBLE_NEXT_TO_ASCII_ALPHABETIC_ON_EITHER_SIDE = 5; + + std::size_t stored_boundary = ascii + non_ascii; + if (current_class < stored_boundary) { + if (previous_class < stored_boundary) { + if (auto index = compute_index(previous_class, current_class, ascii, non_ascii); index) { + ubyte b = probabilities[index.value()]; + if (b == 255) { + return IMPLAUSABILITY_PENALTY; + } + return b; + } + return 0; + } + + if (current_class == 0 || current_class == ASCII_DIGIT) { + return 0; + } + + std::size_t previous_unstored = previous_class - stored_boundary; + switch (previous_unstored) { + case PLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE: + case IMPLAUSIBLE_AFTER_ALPHABETIC: + return 0; + case IMPLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE: + case IMPLAUSIBLE_BEFORE_ALPHABETIC: + return IMPLAUSABILITY_PENALTY; + case PLAUSIBLE_NEXT_TO_NON_ASCII_ALPHABETIC_ON_EITHER_SIDE: + if (current_class < ascii) { + return IMPLAUSABILITY_PENALTY; + } + return 0; + case PLAUSIBLE_NEXT_TO_ASCII_ALPHABETIC_ON_EITHER_SIDE: + if (current_class < ascii) { + return 0; + } + return IMPLAUSABILITY_PENALTY; + default: + assert(previous_class == ASCII_DIGIT); + return 0; + } + } + + if (previous_class < stored_boundary) { + if (previous_class == 0 || previous_class == ASCII_DIGIT) { + return 0; + } + + std::size_t current_unstored = current_class - stored_boundary; + switch (current_unstored) { + case PLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE: + case IMPLAUSIBLE_BEFORE_ALPHABETIC: + return 0; + case IMPLAUSIBLE_NEXT_TO_ALPHABETIC_ON_EITHER_SIDE: + case IMPLAUSIBLE_AFTER_ALPHABETIC: + return IMPLAUSABILITY_PENALTY; + case PLAUSIBLE_NEXT_TO_NON_ASCII_ALPHABETIC_ON_EITHER_SIDE: + if (previous_class < ascii) { + return IMPLAUSABILITY_PENALTY; + } + return 0; + case PLAUSIBLE_NEXT_TO_ASCII_ALPHABETIC_ON_EITHER_SIDE: + if (previous_class < ascii) { + return 0; + } + return IMPLAUSABILITY_PENALTY; + default: + assert(current_class == ASCII_DIGIT); + return 0; + } + } + + if (current_class == ASCII_DIGIT || previous_class == ASCII_DIGIT) { + return 0; + } + + return IMPLAUSABILITY_PENALTY; + } + }; + + enum class ScoreIndex { + Windows1251, + Windows1252 + }; + + static constexpr std::array byte_scores { + ByteScore { + .encoding = Encoding::Windows1251, + .lower = DetectorData::non_latin_ascii, + .upper = DetectorData::windows_1251, + .probabilities = DetectorData::cyrillic, + .ascii = class_size::cyrillic_ascii, + .non_ascii = class_size::cyrillic_non_ascii }, + ByteScore { + .encoding = Encoding::Windows1252, + .lower = DetectorData::latin_ascii, + .upper = DetectorData::windows_1252, + .probabilities = DetectorData::western, + .ascii = class_size::western_ascii, + .non_ascii = class_size::western_non_ascii } + }; + + constexpr const ByteScore& get_byte_score(ScoreIndex index) { + return byte_scores[static_cast<std::underlying_type_t<ScoreIndex>>(index)]; + } + + struct Utf8Canidate { + std::optional<int64_t> read(const std::span<const cbyte>& buffer); + }; + + struct AsciiCanidate { + std::optional<int64_t> read(const std::span<const cbyte>& buffer); + }; + + struct NonLatinCasedCanidate { + enum class CaseState { + Space, + Upper, + Lower, + UpperLower, + AllCaps, + Mix, + }; + + const ByteScore& score_data; + cbyte prev {}; + CaseState case_state = CaseState::Space; + bool prev_ascii = true; + uint64_t current_word_len {}; + uint64_t longest_word {}; + bool ibm866 = false; + bool prev_was_a0 = false; + + std::optional<int64_t> read(const std::span<const cbyte>& buffer); + }; + + struct LatinCanidate { + enum class CaseState { + Space, + Upper, + Lower, + AllCaps, + }; + + enum class OrdinalState { + Other, + Space, + PeriodAfterN, + OrdinalExpectingSpace, + OrdinalExpectingSpaceUndoImplausibility, + OrdinalExpectingSpaceOrDigit, + OrdinalExpectingSpaceOrDigitUndoImplausibily, + UpperN, + LowerN, + FeminineAbbreviationStartLetter, + Digit, + Roman, + Copyright, + }; + + const ByteScore& score_data; + cbyte prev {}; + CaseState case_state = CaseState::Space; + uint32_t prev_non_ascii {}; + OrdinalState ordinal_state = OrdinalState::Space; // Used only when `windows1252 == true` + bool windows1252; + + constexpr LatinCanidate(const ByteScore& data) : score_data(data) { + windows1252 = data.encoding == Encoding::Windows1252; + } + + std::optional<int64_t> read(const std::span<const cbyte>& buffer); + }; + + using InnerCanidate = std::variant<NonLatinCasedCanidate, LatinCanidate, Utf8Canidate, AsciiCanidate>; + + template<class... Ts> + struct overloaded : Ts... { + using Ts::operator()...; + }; + + template<class... Ts> + overloaded(Ts...) -> overloaded<Ts...>; + + struct Canidate { + InnerCanidate inner; + std::optional<int64_t> score_value; + + template<typename CanidateT> + static constexpr Canidate create_canidate() { + return { + .inner = CanidateT(), + .score_value = 0 + }; + } + + template<typename CanidateT> + static constexpr Canidate create_canidate(const ByteScore& score) { + return { + .inner = CanidateT { score }, + .score_value = 0 + }; + } + + static constexpr Canidate new_utf8() { + return create_canidate<Utf8Canidate>(); + } + + static constexpr Canidate new_ascii() { + return create_canidate<AsciiCanidate>(); + } + + static constexpr Canidate new_latin(ScoreIndex index) { + return create_canidate<LatinCanidate>(get_byte_score(index)); + } + + static constexpr Canidate new_non_latin_cased(ScoreIndex index) { + return create_canidate<NonLatinCasedCanidate>(get_byte_score(index)); + } + + constexpr std::optional<int64_t> score(const std::span<const cbyte>& buffer, std::size_t encoding, bool expectation_is_valid) { + if (auto old_score = score_value) { + auto new_score = std::visit([&](auto& inner) { + return inner.read(buffer); + }, + inner); + if (new_score) { + score_value = old_score.value() + new_score.value(); + } else { + score_value = std::nullopt; + } + } + + if (auto nlcc = std::get_if<NonLatinCasedCanidate>(&inner)) { + if (nlcc->longest_word < 2) { + return std::nullopt; + } + } + return score_value; + } + + constexpr Encoding encoding() const { + return std::visit( + overloaded { + [](const Utf8Canidate& canidate) { + return Encoding::Utf8; + }, + [](const AsciiCanidate& canidate) { + return Encoding::Ascii; + }, + [](const LatinCanidate& canidate) { + return canidate.score_data.encoding; + }, + [](const NonLatinCasedCanidate& canidate) { + return canidate.score_data.encoding; + } }, + inner); + } + }; + + struct Detector { + std::vector<Canidate> canidates { + Canidate::new_ascii(), + Canidate::new_utf8(), + Canidate::new_latin(ScoreIndex::Windows1252), + Canidate::new_non_latin_cased(ScoreIndex::Windows1251), + }; + + Encoding default_fallback = Encoding::Unknown; + + constexpr std::pair<Encoding, bool> detect_assess(std::span<const cbyte> buffer, bool allow_utf8 = true) { + int64_t max = 0; + Encoding encoding = default_fallback; // Presumes fallback, defaults to Unknown encoding if unknown (which skips conversion) + std::size_t i = 0; + for (Canidate& canidate : canidates) { + if (!allow_utf8 && canidate.encoding() == Encoding::Utf8) { + continue; + } + + if (auto score = canidate.score(buffer, i, false)) { + switch (canidate.encoding()) { + using enum Encoding; + case Ascii: + case Utf8: + return { canidate.encoding(), true }; + default: break; + } + + auto value = score.value(); + if (value > max) { + max = value; + encoding = canidate.encoding(); + } + } + i++; + } + return { encoding, max >= 0 }; + } + + constexpr Encoding detect(std::span<const cbyte> buffer, bool allow_utf8 = true) { + return detect_assess(buffer, allow_utf8).first; + } + + template<typename BufferEncoding> + std::pair<Encoding, bool> detect_assess(const lexy::buffer<BufferEncoding, void>& buffer, bool allow_utf8 = true) { + auto span = std::span<const cbyte>(buffer.data(), buffer.size()); + return detect_assess(span); + } + + template<typename BufferEncoding> + constexpr Encoding detect(const lexy::buffer<BufferEncoding, void>& buffer, bool allow_utf8 = true) { + return detect_assess(buffer, allow_utf8).first; + } + }; +}
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