JezK
Edit File: normalize.rb
# coding: utf-8 # frozen_string_literal: false # Copyright Ayumu Nojima (野島 歩) and Martin J. Dürst (duerst@it.aoyama.ac.jp) require 'unicode_normalize/tables.rb' module UnicodeNormalize ## Constant for max hash capacity to avoid DoS attack MAX_HASH_LENGTH = 18000 # enough for all test cases, otherwise tests get slow ## Regular Expressions and Hash Constants REGEXP_D = Regexp.compile(REGEXP_D_STRING, Regexp::EXTENDED) REGEXP_C = Regexp.compile(REGEXP_C_STRING, Regexp::EXTENDED) REGEXP_K = Regexp.compile(REGEXP_K_STRING, Regexp::EXTENDED) NF_HASH_D = Hash.new do |hash, key| hash.shift if hash.length>MAX_HASH_LENGTH # prevent DoS attack hash[key] = nfd_one(key) end NF_HASH_C = Hash.new do |hash, key| hash.shift if hash.length>MAX_HASH_LENGTH # prevent DoS attack hash[key] = nfc_one(key) end ## Constants For Hangul # for details such as the meaning of the identifiers below, please see # http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf, pp. 144/145 SBASE = 0xAC00 LBASE = 0x1100 VBASE = 0x1161 TBASE = 0x11A7 LCOUNT = 19 VCOUNT = 21 TCOUNT = 28 NCOUNT = VCOUNT * TCOUNT SCOUNT = LCOUNT * NCOUNT # Unicode-based encodings (except UTF-8) UNICODE_ENCODINGS = [Encoding::UTF_16BE, Encoding::UTF_16LE, Encoding::UTF_32BE, Encoding::UTF_32LE, Encoding::GB18030, Encoding::UCS_2BE, Encoding::UCS_4BE] ## Hangul Algorithm def self.hangul_decomp_one(target) syllable_index = target.ord - SBASE return target if syllable_index < 0 || syllable_index >= SCOUNT l = LBASE + syllable_index / NCOUNT v = VBASE + (syllable_index % NCOUNT) / TCOUNT t = TBASE + syllable_index % TCOUNT (t==TBASE ? [l, v] : [l, v, t]).pack('U*') + target[1..-1] end def self.hangul_comp_one(string) length = string.length if length>1 and 0 <= (lead =string[0].ord-LBASE) and lead < LCOUNT and 0 <= (vowel=string[1].ord-VBASE) and vowel < VCOUNT lead_vowel = SBASE + (lead * VCOUNT + vowel) * TCOUNT if length>2 and 0 <= (trail=string[2].ord-TBASE) and trail < TCOUNT (lead_vowel + trail).chr(Encoding::UTF_8) + string[3..-1] else lead_vowel.chr(Encoding::UTF_8) + string[2..-1] end else string end end ## Canonical Ordering def self.canonical_ordering_one(string) sorting = string.each_char.collect { |c| [c, CLASS_TABLE[c]] } (sorting.length-2).downto(0) do |i| # almost, but not exactly bubble sort (0..i).each do |j| later_class = sorting[j+1].last if 0<later_class and later_class<sorting[j].last sorting[j], sorting[j+1] = sorting[j+1], sorting[j] end end end return sorting.collect(&:first).join('') end ## Normalization Forms for Patterns (not whole Strings) def self.nfd_one(string) string = string.chars.map! {|c| DECOMPOSITION_TABLE[c] || c}.join('') canonical_ordering_one(hangul_decomp_one(string)) end def self.nfc_one(string) nfd_string = nfd_one string start = nfd_string[0] last_class = CLASS_TABLE[start]-1 accents = '' nfd_string[1..-1].each_char do |accent| accent_class = CLASS_TABLE[accent] if last_class<accent_class and composite = COMPOSITION_TABLE[start+accent] start = composite else accents << accent last_class = accent_class end end hangul_comp_one(start+accents) end def self.normalize(string, form = :nfc) encoding = string.encoding case encoding when Encoding::UTF_8 case form when :nfc then string.gsub REGEXP_C, NF_HASH_C when :nfd then string.gsub REGEXP_D, NF_HASH_D when :nfkc then string.gsub(REGEXP_K, KOMPATIBLE_TABLE).gsub(REGEXP_C, NF_HASH_C) when :nfkd then string.gsub(REGEXP_K, KOMPATIBLE_TABLE).gsub(REGEXP_D, NF_HASH_D) else raise ArgumentError, "Invalid normalization form #{form}." end when Encoding::US_ASCII string when *UNICODE_ENCODINGS normalize(string.encode(Encoding::UTF_8), form).encode(encoding) else raise Encoding::CompatibilityError, "Unicode Normalization not appropriate for #{encoding}" end end def self.normalized?(string, form = :nfc) encoding = string.encoding case encoding when Encoding::UTF_8 case form when :nfc then string.scan REGEXP_C do |match| return false if NF_HASH_C[match] != match end true when :nfd then string.scan REGEXP_D do |match| return false if NF_HASH_D[match] != match end true when :nfkc then normalized?(string, :nfc) and string !~ REGEXP_K when :nfkd then normalized?(string, :nfd) and string !~ REGEXP_K else raise ArgumentError, "Invalid normalization form #{form}." end when Encoding::US_ASCII true when *UNICODE_ENCODINGS normalized? string.encode(Encoding::UTF_8), form else raise Encoding::CompatibilityError, "Unicode Normalization not appropriate for #{encoding}" end end end # module