module CGI::Escape

def escape(string)
  encoding = string.encoding
  buffer = string.b
  buffer.gsub!(/([^ a-zA-Z0-9_.\-~]+)/) do |m|
    '%' + m.unpack('H2' * m.bytesize).join('%').upcase
  end
  buffer.tr!(' ', '+')
  buffer.force_encoding(encoding)
end

def escapeElement(string, *elements)
  elements = elements[0] if elements[0].kind_of?(Array)
  unless elements.empty?
    string.gsub(/<\/?(?:#{elements.join("|")})\b[^<>]*+>?/im) do
      CGI.escapeHTML($&)
    end
  else
    string
  end
end

def escapeHTML(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
    table = Hash[TABLE_FOR_ESCAPE_HTML__.map {|pair|pair.map {|s|s.encode(enc)}}]
    string = string.gsub(/#{"['&\"<>]".encode(enc)}/, table)
    string.encode!(origenc) if origenc
    string
  else
    string = string.b
    string.gsub!(/['&\"<>]/, TABLE_FOR_ESCAPE_HTML__)
    string.force_encoding(enc)
  end
end

def escapeURIComponent(string)
  encoding = string.encoding
  buffer = string.b
  buffer.gsub!(/([^a-zA-Z0-9_.\-~]+)/) do |m|
    '%' + m.unpack('H2' * m.bytesize).join('%').upcase
  end
  buffer.force_encoding(encoding)
end

def unescape(string, encoding = @@accept_charset)
  str = string.tr('+', ' ')
  str = str.b
  str.gsub!(/((?:%[0-9a-fA-F]{2})+)/) do |m|
    [m.delete('%')].pack('H*')
  end
  str.force_encoding(encoding)
  str.valid_encoding? ? str : str.force_encoding(string.encoding)
end

def unescapeElement(string, *elements)
  elements = elements[0] if elements[0].kind_of?(Array)
  unless elements.empty?
    string.gsub(/<\/?(?:#{elements.join("|")})\b(?>[^&]+|&(?![gl]t;)\w+;)*(?:>)?/im) do
      unescapeHTML($&)
    end
  else
    string
  end
end

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/i  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 = string.b
  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/i
      n = $1.hex
      if n < charlimit
        n.chr(enc)
      else
        "&#x#{$1};"
      end
    else
      "&#{match};"
    end
  end
  string.force_encoding enc
end

def unescapeURIComponent(string, encoding = @@accept_charset)
  str = string.b
  str.gsub!(/((?:%[0-9a-fA-F]{2})+)/) do |m|
    [m.delete('%')].pack('H*')
  end
  str.force_encoding(encoding)
  str.valid_encoding? ? str : str.force_encoding(string.encoding)
end