unescapeHTML

# File lib/cgi/util.rb, line 65
  def unescapeHTML(string)
    enc = string.encoding
    unless enc.ascii_compatible?
      if enc.dummy?
        origenc = enc
        enc = Encoding::Converter.asciicompat_encoding(enc)
        string = enc ? string.encode(enc) : string.b
      end
      string = string.gsub(Regexp.new('&(apos|amp|quot|gt|lt|#[0-9]+|#x[0-9A-Fa-f]+);'.encode(enc))) do
        case $1.encode(Encoding::US_ASCII)
        when 'apos'                then "'".encode(enc)
        when 'amp'                 then '&'.encode(enc)
        when 'quot'                then '"'.encode(enc)
        when 'gt'                  then '>'.encode(enc)
        when 'lt'                  then '<'.encode(enc)
        when /\A#0*(\d+)\z/        then $1.to_i.chr(enc)
        when /\A#x([0-9a-f]+)\z/  then $1.hex.chr(enc)
        end
      end
      string.encode!(origenc) if origenc
      return string
    end
    return string unless string.include? '&'
    charlimit = case enc
                when Encoding::UTF_8; 0x10ffff
                when Encoding::ISO_8859_1; 256
                else 128
                end
    string.gsub(/&(apos|amp|quot|gt|lt|\#[0-9]+|\#[xX][0-9A-Fa-f]+);/) do
      match = $1.dup
      case match
      when 'apos'                then "'"
      when 'amp'                 then '&'
      when 'quot'                then '"'
      when 'gt'                  then '>'
      when 'lt'                  then '<'
      when /\A#0*(\d+)\z/
        n = $1.to_i
        if n < charlimit
          n.chr(enc)
        else
          "&##{$1};"
        end
      when /\A#x([0-9a-f]+)\z/
        n = $1.hex
        if n < charlimit
          n.chr(enc)
        else
          "&#x#{$1};"
        end
      else
        "&#{match};"
      end
    end
  end