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Diffstat (limited to 'activesupport/lib/active_support/multibyte/unicode.rb')
| -rw-r--r-- | activesupport/lib/active_support/multibyte/unicode.rb | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb new file mode 100644 index 0000000000..f91e50c755 --- /dev/null +++ b/activesupport/lib/active_support/multibyte/unicode.rb @@ -0,0 +1,393 @@ +module ActiveSupport + module Multibyte + module Unicode + + extend self + + # A list of all available normalization forms. See http://www.unicode.org/reports/tr15/tr15-29.html for more + # information about normalization. + NORMALIZATION_FORMS = [:c, :kc, :d, :kd] + + # The Unicode version that is supported by the implementation + UNICODE_VERSION = '5.1.0' + + # The default normalization used for operations that require normalization. It can be set to any of the + # normalizations in NORMALIZATION_FORMS. + # + # Example: + # ActiveSupport::Multibyte::Unicode.default_normalization_form = :c + attr_accessor :default_normalization_form + @default_normalization_form = :kc + + # Hangul character boundaries and properties + HANGUL_SBASE = 0xAC00 + HANGUL_LBASE = 0x1100 + HANGUL_VBASE = 0x1161 + HANGUL_TBASE = 0x11A7 + HANGUL_LCOUNT = 19 + HANGUL_VCOUNT = 21 + HANGUL_TCOUNT = 28 + HANGUL_NCOUNT = HANGUL_VCOUNT * HANGUL_TCOUNT + HANGUL_SCOUNT = 11172 + HANGUL_SLAST = HANGUL_SBASE + HANGUL_SCOUNT + HANGUL_JAMO_FIRST = 0x1100 + HANGUL_JAMO_LAST = 0x11FF + + # All the unicode whitespace + WHITESPACE = [ + (0x0009..0x000D).to_a, # White_Space # Cc [5] <control-0009>..<control-000D> + 0x0020, # White_Space # Zs SPACE + 0x0085, # White_Space # Cc <control-0085> + 0x00A0, # White_Space # Zs NO-BREAK SPACE + 0x1680, # White_Space # Zs OGHAM SPACE MARK + 0x180E, # White_Space # Zs MONGOLIAN VOWEL SEPARATOR + (0x2000..0x200A).to_a, # White_Space # Zs [11] EN QUAD..HAIR SPACE + 0x2028, # White_Space # Zl LINE SEPARATOR + 0x2029, # White_Space # Zp PARAGRAPH SEPARATOR + 0x202F, # White_Space # Zs NARROW NO-BREAK SPACE + 0x205F, # White_Space # Zs MEDIUM MATHEMATICAL SPACE + 0x3000, # White_Space # Zs IDEOGRAPHIC SPACE + ].flatten.freeze + + # BOM (byte order mark) can also be seen as whitespace, it's a non-rendering character used to distinguish + # between little and big endian. This is not an issue in utf-8, so it must be ignored. + LEADERS_AND_TRAILERS = WHITESPACE + [65279] # ZERO-WIDTH NO-BREAK SPACE aka BOM + + # Returns a regular expression pattern that matches the passed Unicode codepoints + def self.codepoints_to_pattern(array_of_codepoints) #:nodoc: + array_of_codepoints.collect{ |e| [e].pack 'U*' }.join('|') + end + TRAILERS_PAT = /(#{codepoints_to_pattern(LEADERS_AND_TRAILERS)})+\Z/u + LEADERS_PAT = /\A(#{codepoints_to_pattern(LEADERS_AND_TRAILERS)})+/u + + # Unpack the string at codepoints boundaries. Raises an EncodingError when the encoding of the string isn't + # valid UTF-8. + # + # Example: + # Unicode.u_unpack('Café') #=> [67, 97, 102, 233] + def u_unpack(string) + begin + string.unpack 'U*' + rescue ArgumentError + raise EncodingError, 'malformed UTF-8 character' + end + end + + # Detect whether the codepoint is in a certain character class. Returns +true+ when it's in the specified + # character class and +false+ otherwise. Valid character classes are: <tt>:cr</tt>, <tt>:lf</tt>, <tt>:l</tt>, + # <tt>:v</tt>, <tt>:lv</tt>, <tt>:lvt</tt> and <tt>:t</tt>. + # + # Primarily used by the grapheme cluster support. + def in_char_class?(codepoint, classes) + classes.detect { |c| database.boundary[c] === codepoint } ? true : false + end + + # Unpack the string at grapheme boundaries. Returns a list of character lists. + # + # Example: + # Unicode.g_unpack('क्षि') #=> [[2325, 2381], [2359], [2367]] + # Unicode.g_unpack('Café') #=> [[67], [97], [102], [233]] + def g_unpack(string) + codepoints = u_unpack(string) + unpacked = [] + pos = 0 + marker = 0 + eoc = codepoints.length + while(pos < eoc) + pos += 1 + previous = codepoints[pos-1] + current = codepoints[pos] + if ( + # CR X LF + one = ( previous == database.boundary[:cr] and current == database.boundary[:lf] ) or + # L X (L|V|LV|LVT) + two = ( database.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or + # (LV|V) X (V|T) + three = ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or + # (LVT|T) X (T) + four = ( in_char_class?(previous, [:lvt,:t]) and database.boundary[:t] === current ) or + # X Extend + five = (database.boundary[:extend] === current) + ) + else + unpacked << codepoints[marker..pos-1] + marker = pos + end + end + unpacked + end + + # Reverse operation of g_unpack. + # + # Example: + # Unicode.g_pack(Unicode.g_unpack('क्षि')) #=> 'क्षि' + def g_pack(unpacked) + (unpacked.flatten).pack('U*') + end + + # Re-order codepoints so the string becomes canonical. + def reorder_characters(codepoints) + length = codepoints.length- 1 + pos = 0 + while pos < length do + cp1, cp2 = database.codepoints[codepoints[pos]], database.codepoints[codepoints[pos+1]] + if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0) + codepoints[pos..pos+1] = cp2.code, cp1.code + pos += (pos > 0 ? -1 : 1) + else + pos += 1 + end + end + codepoints + end + + # Decompose composed characters to the decomposed form. + def decompose_codepoints(type, codepoints) + codepoints.inject([]) do |decomposed, cp| + # if it's a hangul syllable starter character + if HANGUL_SBASE <= cp and cp < HANGUL_SLAST + sindex = cp - HANGUL_SBASE + ncp = [] # new codepoints + ncp << HANGUL_LBASE + sindex / HANGUL_NCOUNT + ncp << HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT + tindex = sindex % HANGUL_TCOUNT + ncp << (HANGUL_TBASE + tindex) unless tindex == 0 + decomposed.concat ncp + # if the codepoint is decomposable in with the current decomposition type + elsif (ncp = database.codepoints[cp].decomp_mapping) and (!database.codepoints[cp].decomp_type || type == :compatability) + decomposed.concat decompose_codepoints(type, ncp.dup) + else + decomposed << cp + end + end + end + + # Compose decomposed characters to the composed form. + def compose_codepoints(codepoints) + pos = 0 + eoa = codepoints.length - 1 + starter_pos = 0 + starter_char = codepoints[0] + previous_combining_class = -1 + while pos < eoa + pos += 1 + lindex = starter_char - HANGUL_LBASE + # -- Hangul + if 0 <= lindex and lindex < HANGUL_LCOUNT + vindex = codepoints[starter_pos+1] - HANGUL_VBASE rescue vindex = -1 + if 0 <= vindex and vindex < HANGUL_VCOUNT + tindex = codepoints[starter_pos+2] - HANGUL_TBASE rescue tindex = -1 + if 0 <= tindex and tindex < HANGUL_TCOUNT + j = starter_pos + 2 + eoa -= 2 + else + tindex = 0 + j = starter_pos + 1 + eoa -= 1 + end + codepoints[starter_pos..j] = (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT + tindex + HANGUL_SBASE + end + starter_pos += 1 + starter_char = codepoints[starter_pos] + # -- Other characters + else + current_char = codepoints[pos] + current = database.codepoints[current_char] + if current.combining_class > previous_combining_class + if ref = database.composition_map[starter_char] + composition = ref[current_char] + else + composition = nil + end + unless composition.nil? + codepoints[starter_pos] = composition + starter_char = composition + codepoints.delete_at pos + eoa -= 1 + pos -= 1 + previous_combining_class = -1 + else + previous_combining_class = current.combining_class + end + else + previous_combining_class = current.combining_class + end + if current.combining_class == 0 + starter_pos = pos + starter_char = codepoints[pos] + end + end + end + codepoints + end + + # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent resulting in a valid UTF-8 string. + # + # Passing +true+ will forcibly tidy all bytes, assuming that the string's encoding is entirely CP1252 or ISO-8859-1. + def tidy_bytes(string, force = false) + if force + return string.unpack("C*").map do |b| + tidy_byte(b) + end.flatten.compact.pack("C*").unpack("U*").pack("U*") + end + + bytes = string.unpack("C*") + conts_expected = 0 + last_lead = 0 + + bytes.each_index do |i| + + byte = bytes[i] + is_ascii = byte < 128 + is_cont = byte > 127 && byte < 192 + is_lead = byte > 191 && byte < 245 + is_unused = byte > 240 + is_restricted = byte > 244 + + # Impossible or highly unlikely byte? Clean it. + if is_unused || is_restricted + bytes[i] = tidy_byte(byte) + elsif is_cont + # Not expecting contination byte? Clean up. Otherwise, now expect one less. + conts_expected == 0 ? bytes[i] = tidy_byte(byte) : conts_expected -= 1 + else + if conts_expected > 0 + # Expected continuation, but got ASCII or leading? Clean backwards up to + # the leading byte. + (1..(i - last_lead)).each {|j| bytes[i - j] = tidy_byte(bytes[i - j])} + conts_expected = 0 + end + if is_lead + # Final byte is leading? Clean it. + if i == bytes.length - 1 + bytes[i] = tidy_byte(bytes.last) + else + # Valid leading byte? Expect continuations determined by position of + # first zero bit, with max of 3. + conts_expected = byte < 224 ? 1 : byte < 240 ? 2 : 3 + last_lead = i + end + end + end + end + bytes.empty? ? "" : bytes.flatten.compact.pack("C*").unpack("U*").pack("U*") + end + + # Returns the KC normalization of the string by default. NFKC is considered the best normalization form for + # passing strings to databases and validations. + # + # * <tt>string</tt> - The string to perform normalization on. + # * <tt>form</tt> - The form you want to normalize in. Should be one of the following: + # <tt>:c</tt>, <tt>:kc</tt>, <tt>:d</tt>, or <tt>:kd</tt>. Default is + # ActiveSupport::Multibyte.default_normalization_form + def normalize(string, form=nil) + form ||= @default_normalization_form + # See http://www.unicode.org/reports/tr15, Table 1 + codepoints = u_unpack(string) + case form + when :d + reorder_characters(decompose_codepoints(:canonical, codepoints)) + when :c + compose_codepoints(reorder_characters(decompose_codepoints(:canonical, codepoints))) + when :kd + reorder_characters(decompose_codepoints(:compatability, codepoints)) + when :kc + compose_codepoints(reorder_characters(decompose_codepoints(:compatability, codepoints))) + else + raise ArgumentError, "#{form} is not a valid normalization variant", caller + end.pack('U*') + end + + def apply_mapping(string, mapping) #:nodoc: + u_unpack(string).map do |codepoint| + cp = database.codepoints[codepoint] + if cp and (ncp = cp.send(mapping)) and ncp > 0 + ncp + else + codepoint + end + end.pack('U*') + end + + # Holds data about a codepoint in the Unicode database + class Codepoint + attr_accessor :code, :combining_class, :decomp_type, :decomp_mapping, :uppercase_mapping, :lowercase_mapping + end + + # Holds static data from the Unicode database + class UnicodeDatabase + ATTRIBUTES = :codepoints, :composition_exclusion, :composition_map, :boundary, :cp1252 + + attr_writer(*ATTRIBUTES) + + def initialize + @codepoints = Hash.new(Codepoint.new) + @composition_exclusion = [] + @composition_map = {} + @boundary = {} + @cp1252 = {} + end + + # Lazy load the Unicode database so it's only loaded when it's actually used + ATTRIBUTES.each do |attr_name| + class_eval(<<-EOS, __FILE__, __LINE__ + 1) + def #{attr_name} # def codepoints + load # load + @#{attr_name} # @codepoints + end # end + EOS + end + + # Loads the Unicode database and returns all the internal objects of UnicodeDatabase. + def load + begin + @codepoints, @composition_exclusion, @composition_map, @boundary, @cp1252 = File.open(self.class.filename, 'rb') { |f| Marshal.load f.read } + rescue Exception => e + raise IOError.new("Couldn't load the Unicode tables for UTF8Handler (#{e.message}), ActiveSupport::Multibyte is unusable") + end + + # Redefine the === method so we can write shorter rules for grapheme cluster breaks + @boundary.each do |k,_| + @boundary[k].instance_eval do + def ===(other) + detect { |i| i === other } ? true : false + end + end if @boundary[k].kind_of?(Array) + end + + # define attr_reader methods for the instance variables + class << self + attr_reader(*ATTRIBUTES) + end + end + + # Returns the directory in which the data files are stored + def self.dirname + File.dirname(__FILE__) + '/../values/' + end + + # Returns the filename for the data file for this version + def self.filename + File.expand_path File.join(dirname, "unicode_tables.dat") + end + end + + private + + def tidy_byte(byte) + if byte < 160 + [database.cp1252[byte] || byte].pack("U").unpack("C*") + elsif byte < 192 + [194, byte] + else + [195, byte - 64] + end + end + + def database + @database ||= UnicodeDatabase.new + end + + end + end +end |