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- /*
- * Copyright (c) 2022, mat
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <AK/Find.h>
- #include <AK/QuickSort.h>
- #include <AK/Utf8View.h>
- #include <AK/Vector.h>
- #include <LibUnicode/CharacterTypes.h>
- #include <LibUnicode/Normalize.h>
- #if ENABLE_UNICODE_DATA
- # include <LibUnicode/UnicodeData.h>
- #else
- struct Unicode::CodePointDecomposition { };
- #endif
- namespace Unicode {
- Optional<CodePointDecomposition const> __attribute__((weak)) code_point_decomposition(u32) { return {}; }
- Optional<CodePointDecomposition const> __attribute__((weak)) code_point_decomposition_by_index(size_t) { return {}; }
- NormalizationForm normalization_form_from_string(StringView form)
- {
- if (form == "NFD"sv)
- return NormalizationForm::NFD;
- if (form == "NFC"sv)
- return NormalizationForm::NFC;
- if (form == "NFKD"sv)
- return NormalizationForm::NFKD;
- if (form == "NFKC"sv)
- return NormalizationForm::NFKC;
- VERIFY_NOT_REACHED();
- }
- StringView normalization_form_to_string(NormalizationForm form)
- {
- switch (form) {
- case NormalizationForm::NFD:
- return "NFD"sv;
- case NormalizationForm::NFC:
- return "NFC"sv;
- case NormalizationForm::NFKD:
- return "NFKD"sv;
- case NormalizationForm::NFKC:
- return "NFKC"sv;
- }
- VERIFY_NOT_REACHED();
- }
- ALWAYS_INLINE static bool is_starter(u32 code_point)
- {
- return Unicode::canonical_combining_class(code_point) == 0;
- }
- // From https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G56669
- static constexpr u32 HANGUL_SYLLABLE_BASE = 0xAC00;
- static constexpr u32 HANGUL_LEADING_BASE = 0x1100;
- static constexpr u32 HANGUL_VOWEL_BASE = 0x1161;
- static constexpr u32 HANGUL_TRAILING_BASE = 0x11A7;
- static constexpr u32 HANGUL_LEADING_COUNT = 19;
- static constexpr u32 HANGUL_VOWEL_COUNT = 21;
- static constexpr u32 HANGUL_TRAILING_COUNT = 28;
- // NCount in the standard.
- static constexpr u32 HANGUL_BLOCK_COUNT = HANGUL_VOWEL_COUNT * HANGUL_TRAILING_COUNT;
- static constexpr u32 HANGUL_SYLLABLE_COUNT = HANGUL_LEADING_COUNT * HANGUL_BLOCK_COUNT;
- ALWAYS_INLINE static bool is_hangul_code_point(u32 code_point)
- {
- return code_point >= HANGUL_SYLLABLE_BASE && code_point < HANGUL_SYLLABLE_BASE + HANGUL_SYLLABLE_COUNT;
- }
- ALWAYS_INLINE static bool is_hangul_leading(u32 code_point)
- {
- return code_point >= HANGUL_LEADING_BASE && code_point < HANGUL_LEADING_BASE + HANGUL_LEADING_COUNT;
- }
- ALWAYS_INLINE static bool is_hangul_vowel(u32 code_point)
- {
- return code_point >= HANGUL_VOWEL_BASE && code_point < HANGUL_VOWEL_BASE + HANGUL_VOWEL_COUNT;
- }
- ALWAYS_INLINE static bool is_hangul_trailing(u32 code_point)
- {
- return code_point >= HANGUL_TRAILING_BASE && code_point < HANGUL_TRAILING_BASE + HANGUL_TRAILING_COUNT;
- }
- // https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G56669
- static ErrorOr<void> decompose_hangul_code_point(u32 code_point, Vector<u32>& code_points_output)
- {
- auto const index = code_point - HANGUL_SYLLABLE_BASE;
- auto const leading_index = index / HANGUL_BLOCK_COUNT;
- auto const vowel_index = (index % HANGUL_BLOCK_COUNT) / HANGUL_TRAILING_COUNT;
- auto const trailing_index = index % HANGUL_TRAILING_COUNT;
- auto const leading_part = HANGUL_LEADING_BASE + leading_index;
- auto const vowel_part = HANGUL_VOWEL_BASE + vowel_index;
- auto const trailing_part = HANGUL_TRAILING_BASE + trailing_index;
- TRY(code_points_output.try_append(leading_part));
- TRY(code_points_output.try_append(vowel_part));
- if (trailing_index != 0)
- TRY(code_points_output.try_append(trailing_part));
- return {};
- }
- // L, V and LV, T Hangul Syllable Composition
- // https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G59688
- static u32 combine_hangul_code_points(u32 a, u32 b)
- {
- if (is_hangul_leading(a) && is_hangul_vowel(b)) {
- auto const leading_index = a - HANGUL_LEADING_BASE;
- auto const vowel_index = b - HANGUL_VOWEL_BASE;
- auto const leading_vowel_index = leading_index * HANGUL_BLOCK_COUNT + vowel_index * HANGUL_TRAILING_COUNT;
- return HANGUL_SYLLABLE_BASE + leading_vowel_index;
- }
- // LV characters are the first in each "T block", so use this check to avoid combining LVT with T.
- if (is_hangul_code_point(a) && (a - HANGUL_SYLLABLE_BASE) % HANGUL_TRAILING_COUNT == 0 && is_hangul_trailing(b)) {
- return a + b - HANGUL_TRAILING_BASE;
- }
- return 0;
- }
- static u32 combine_code_points([[maybe_unused]] u32 a, [[maybe_unused]] u32 b)
- {
- #if ENABLE_UNICODE_DATA
- Array<u32, 2> const points { a, b };
- // FIXME: Do something better than linear search to find reverse mappings.
- for (size_t index = 0;; ++index) {
- auto mapping_maybe = Unicode::code_point_decomposition_by_index(index);
- if (!mapping_maybe.has_value())
- break;
- auto& mapping = mapping_maybe.value();
- if (mapping.tag == CompatibilityFormattingTag::Canonical && mapping.decomposition == points) {
- if (code_point_has_property(mapping.code_point, Property::Full_Composition_Exclusion))
- continue;
- return mapping.code_point;
- }
- }
- #endif
- return 0;
- }
- enum class UseCompatibility {
- Yes,
- No
- };
- static ErrorOr<void> decompose_code_point(u32 code_point, Vector<u32>& code_points_output, [[maybe_unused]] UseCompatibility use_compatibility)
- {
- if (is_hangul_code_point(code_point))
- return decompose_hangul_code_point(code_point, code_points_output);
- #if ENABLE_UNICODE_DATA
- auto const mapping = Unicode::code_point_decomposition(code_point);
- if (mapping.has_value() && (mapping->tag == CompatibilityFormattingTag::Canonical || use_compatibility == UseCompatibility::Yes)) {
- for (auto code_point : mapping->decomposition) {
- TRY(decompose_code_point(code_point, code_points_output, use_compatibility));
- }
- } else {
- TRY(code_points_output.try_append(code_point));
- }
- #endif
- return {};
- }
- // This can be any sorting algorithm that maintains order (like std::stable_sort),
- // however bubble sort is easier to implement, so go with it (for now).
- template<typename T, typename LessThan>
- void bubble_sort(Span<T> span, LessThan less_than)
- {
- for (size_t i = 0; i < span.size() - 1; ++i) {
- for (size_t j = 0; j < span.size() - 1 - i; ++j) {
- if (!less_than(span[j], span[j + 1]))
- swap(span[j], span[j + 1]);
- }
- }
- }
- // The Canonical Ordering Algorithm, as specified in Version 15.0.0 of the Unicode Standard.
- // See Section 3.11, D109; and UAX #15 https://unicode.org/reports/tr15
- // https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G49591
- static void canonical_ordering_algorithm(Span<u32> code_points)
- {
- for (size_t i = 0; i < code_points.size(); ++i) {
- if (!is_starter(code_points[i])) {
- auto starter = find_if(code_points.begin() + i, code_points.end(), is_starter);
- auto const span_size = static_cast<size_t>(starter - (code_points.begin() + i));
- // Nothing to reorder, so continue.
- if (span_size <= 1)
- continue;
- Span<u32> const span { code_points.data() + i, span_size };
- bubble_sort(span, [](u32 a, u32 b) {
- // Use <= to keep ordering.
- return Unicode::canonical_combining_class(a) <= Unicode::canonical_combining_class(b);
- });
- // Skip over span we just sorted.
- i += span_size - 1;
- }
- }
- }
- // See Section 3.11, D115 of Version 15.0.0 of the Unicode Standard.
- static bool is_blocked(Span<u32> code_points, size_t a, size_t c)
- {
- if (!is_starter(code_points[a]) || a == c - 1)
- return false;
- auto const c_combining_class = Unicode::canonical_combining_class(code_points[c]);
- auto const b_combining_class = Unicode::canonical_combining_class(code_points[c - 1]);
- return b_combining_class == 0 || b_combining_class >= c_combining_class;
- }
- // The Canonical Composition Algorithm, as specified in Version 15.0.0 of the Unicode Standard.
- // See Section 3.11, D117; and UAX #15 https://unicode.org/reports/tr15
- // https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G50628
- static void canonical_composition_algorithm(Vector<u32>& code_points)
- {
- for (size_t i = 1; i < code_points.size(); ++i) {
- auto const current_character = code_points[i];
- // R1. Seek back (left) to find the last Starter L preceding C in the character sequence
- for (ssize_t j = i - 1; j >= 0; --j) {
- if (!is_starter(code_points[j]))
- continue;
- // R2. If there is such an L, and C is not blocked from L,
- // and there exists a Primary Composite P which is canonically equivalent to <L, C>,
- // then replace L by P in the sequence and delete C from the sequence.
- if (is_blocked(code_points.span(), j, i))
- continue;
- auto composite = combine_hangul_code_points(code_points[j], current_character);
- if (composite == 0)
- composite = combine_code_points(code_points[j], current_character);
- if (composite != 0) {
- code_points[j] = composite;
- code_points.remove(i);
- --i;
- break;
- }
- }
- }
- }
- static ErrorOr<Vector<u32>> normalize_nfd(Utf8View string)
- {
- Vector<u32> result;
- for (auto const code_point : string)
- TRY(decompose_code_point(code_point, result, UseCompatibility::No));
- canonical_ordering_algorithm(result);
- return result;
- }
- static ErrorOr<Vector<u32>> normalize_nfc(Utf8View string)
- {
- auto result = TRY(normalize_nfd(string));
- canonical_composition_algorithm(result);
- return result;
- }
- static ErrorOr<Vector<u32>> normalize_nfkd(Utf8View string)
- {
- Vector<u32> result;
- for (auto const code_point : string)
- TRY(decompose_code_point(code_point, result, UseCompatibility::Yes));
- canonical_ordering_algorithm(result);
- return result;
- }
- static ErrorOr<Vector<u32>> normalize_nfkc(Utf8View string)
- {
- auto result = TRY(normalize_nfkd(string));
- canonical_composition_algorithm(result);
- return result;
- }
- static ErrorOr<Vector<u32>> normalize_implementation(Utf8View string, NormalizationForm form)
- {
- switch (form) {
- case NormalizationForm::NFD:
- return normalize_nfd(string);
- case NormalizationForm::NFC:
- return normalize_nfc(string);
- case NormalizationForm::NFKD:
- return normalize_nfkd(string);
- case NormalizationForm::NFKC:
- return normalize_nfkc(string);
- }
- VERIFY_NOT_REACHED();
- }
- ErrorOr<DeprecatedString> normalize(StringView string, NormalizationForm form)
- {
- auto const code_points = TRY(normalize_implementation(Utf8View { string }, form));
- StringBuilder builder;
- for (auto code_point : code_points)
- TRY(builder.try_append_code_point(code_point));
- return builder.to_deprecated_string();
- }
- }
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