# The grammars in this file conform to the ABNF given in Appendix A of RFC 3986
# Uniform Resource Identifier (URI): Generic Syntax.
#
# See http://tools.ietf.org/html/rfc3986#appendix-A for more information.

grammar IPv4Address
  # A host identified by an IPv4 literal address is represented in
  # dotted-decimal notation (a sequence of four decimal numbers in the
  # range 0 to 255, separated by "."), as described in [RFC1123] by
  # reference to [RFC0952].  Note that other forms of dotted notation may
  # be interpreted on some platforms, as described in Section 7.4, but
  # only the dotted-decimal form of four octets is allowed by this
  # grammar.
  rule IPv4address
    (dec-octet '.' dec-octet '.' dec-octet '.' dec-octet) {
      def version; 4 end
    }
  end

  rule dec-octet
      '25' [0-5]        # 250-255
    | '2' [0-4] DIGIT   # 200-249
    | '1' DIGIT DIGIT   # 100-199
    | [1-9] DIGIT       # 10-99
    | DIGIT             # 0-9
  end

  rule DIGIT
    [0-9]
  end
end

grammar IPv6Address
  include IPv4Address

  # A 128-bit IPv6 address is divided into eight 16-bit pieces. Each
  # piece is represented numerically in case-insensitive hexadecimal,
  # using one to four hexadecimal digits (leading zeroes are permitted).
  # The eight encoded pieces are given most-significant first, separated
  # by colon characters. Optionally, the least-significant two pieces
  # may instead be represented in IPv4 address textual format. A
  # sequence of one or more consecutive zero-valued 16-bit pieces within
  # the address may be elided, omitting all their digits and leaving
  # exactly two consecutive colons in their place to mark the elision.
  rule IPv6address
    (                         (h16 ":")6*6 ls32
    |                    "::" (h16 ":")5*5 ls32
    |  h16             ? "::" (h16 ":")4*4 ls32
    | (h16 (":" h16)*1)? "::" (h16 ":")3*3 ls32
    | (h16 (":" h16)*2)? "::" (h16 ":")2*2 ls32
    | (h16 (":" h16)*3)? "::"  h16 ":"     ls32
    | (h16 (":" h16)*4)? "::"              ls32
    | (h16 (":" h16)*5)? "::"              h16
    | (h16 (":" h16)*6)? "::"
    ) {
      def version; 6 end
    }
  end

  # 16-bit address represented in hexadecimal.
  rule h16
    HEXDIG 1*4
  end

  # Least-significant 32 bits of address.
  rule ls32
    (h16 ":" h16) | IPv4address
  end

  rule HEXDIG
    DIGIT | [a-fA-F] # Hexadecimal should be case-insensitive.
  end
end

grammar IPAddress
  include IPv4Address
  include IPv6Address

  rule IPaddress
    IPv4address | IPv6address
  end
end