# File activesupport/lib/active_support/multibyte/unicode.rb, line 155
def compose(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

# File activesupport/lib/active_support/multibyte/unicode.rb, line 134
def decompose(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 == :compatibility)
      decomposed.concat decompose(type, ncp.dup)
    else
      decomposed << cp
    end
  end
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 278
def downcase(string)
  apply_mapping string, :lowercase_mapping
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 71
def in_char_class?(codepoint, classes)
  classes.detect { |c| database.boundary[c] === codepoint } ? true : false
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 260
def normalize(string, form=nil)
  form ||= @default_normalization_form
  # See http://www.unicode.org/reports/tr15, Table 1
  codepoints = string.codepoints.to_a
  case form
    when :d
      reorder_characters(decompose(:canonical, codepoints))
    when :c
      compose(reorder_characters(decompose(:canonical, codepoints)))
    when :kd
      reorder_characters(decompose(:compatibility, codepoints))
    when :kc
      compose(reorder_characters(decompose(:compatibility, codepoints)))
    else
      raise ArgumentError, "#{form} is not a valid normalization variant", caller
  end.pack('U*')
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 113
def pack_graphemes(unpacked)
  unpacked.flatten.pack('U*')
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 118
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

# File activesupport/lib/active_support/multibyte/unicode.rb, line 286
def swapcase(string)
  apply_mapping string, :swapcase_mapping
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 220
def tidy_bytes(string, force = false)
  return string if string.empty?
  return recode_windows1252_chars(string) if force
  string.scrub { |bad| recode_windows1252_chars(bad) }
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 80
def unpack_graphemes(string)
  codepoints = string.codepoints.to_a
  unpacked = []
  pos = 0
  marker = 0
  eoc = codepoints.length
  while(pos < eoc)
    pos += 1
    previous = codepoints[pos-1]
    current = codepoints[pos]
    if (
        # CR X LF
        ( previous == database.boundary[:cr] and current == database.boundary[:lf] ) or
        # L X (L|V|LV|LVT)
        ( database.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or
        # (LV|V) X (V|T)
        ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or
        # (LVT|T) X (T)
        ( in_char_class?(previous, [:lvt,:t]) and database.boundary[:t] === current ) or
        # X Extend
        (database.boundary[:extend] === current)
      )
    else
      unpacked << codepoints[marker..pos-1]
      marker = pos
    end
  end
  unpacked
end

# File activesupport/lib/active_support/multibyte/unicode.rb, line 282
def upcase(string)
  apply_mapping string, :uppercase_mapping
end