
[;1m  decode_packet(Type, Bin, Options)[0m

  Decodes the binary [;;4mBin[0m according to the packet protocol
  specified by [;;4mType[0m. Similar to the packet handling done by
  sockets with option [;;4m{packet,Type}.[0m

  If an entire packet is contained in [;;4mBin[0m, it is returned together
  with the remainder of the binary as [;;4m{ok,Packet,Rest}[0m.

  If [;;4mBin[0m does not contain the entire packet, [;;4m{more,Length}[0m is
  returned. [;;4mLength[0m is either the expected total size of the
  packet, or [;;4mundefined[0m if the expected packet size is unknown. [;;4m[0m
  [;;4mdecode_packet[0m can then be called again with more data added.

  If the packet does not conform to the protocol format, [;;4m[0m
  [;;4m{error,Reason}[0m is returned.

  [;;4mType[0ms:

   • [;;4mraw | 0[0m - No packet handling is done. The entire binary is
     returned unless it is empty.

   • [;;4m1 | 2 | 4[0m - Packets consist of a header specifying the
     number of bytes in the packet, followed by that number of
     bytes. The length of the header can be one, two, or four
     bytes; the order of the bytes is big-endian. The header is
     stripped off when the packet is returned.

   • [;;4mline[0m - A packet is a line-terminated by a delimiter byte,
     default is the latin-1 newline character. The delimiter byte
     is included in the returned packet unless the line was
     truncated according to option [;;4mline_length[0m.

   • [;;4masn1 | cdr | sunrm | fcgi | tpkt[0m - The header is not
     stripped off.

     The meanings of the packet types are as follows:

      ￮ [;;4masn1[0m - ASN.1 BER

      ￮ [;;4msunrm[0m - Sun's RPC encoding

      ￮ [;;4mcdr[0m - CORBA (GIOP 1.1)

      ￮ [;;4mfcgi[0m - Fast CGI

      ￮ [;;4mtpkt[0m - TPKT format [RFC1006]

   • [;;4mhttp | httph | http_bin | httph_bin[0m - The Hypertext
     Transfer Protocol. The packets are returned with the format
     according to [;;4mHttpPacket[0m described earlier. A packet is
     either a request, a response, a header, or an end of header
     mark. Invalid lines are returned as [;;4mHttpError[0m.

     Recognized request methods and header fields are returned as
     atoms. Others are returned as strings. Strings of
     unrecognized header fields are formatted with only capital
     letters first and after hyphen characters, for example, [;;4m[0m
     [;;4m"Sec-Websocket-Key"[0m. Header field names are also returned
     in [;;4mUnmodifiedField[0m as strings, without any conversion or
     formatting.

     The protocol type [;;4mhttp[0m is only to be used for the first
     line when an [;;4mHttpRequest[0m or an [;;4mHttpResponse[0m is expected.
     The following calls are to use [;;4mhttph[0m to get [;;4mHttpHeader[0ms
     until [;;4mhttp_eoh[0m is returned, which marks the end of the
     headers and the beginning of any following message body.

     The variants [;;4mhttp_bin[0m and [;;4mhttph_bin[0m return strings ([;;4m[0m
     [;;4mHttpString[0m) as binaries instead of lists.

     Since OTP 26.0, [;;4mHost[0m may be an IPv6 address enclosed in [;;4m[0m
     [;;4m[][0m, as defined in RFC2732 .

  Options:

   • [;;4m{packet_size, integer() >= 0}[0m - Sets the maximum allowed
     size of the packet body. If the packet header indicates that
     the length of the packet is longer than the maximum allowed
     length, the packet is considered invalid. Defaults to 0,
     which means no size limit.

   • [;;4m{line_length, integer() >= 0}[0m - For packet type [;;4mline[0m,
     lines longer than the indicated length are truncated.

     Option [;;4mline_length[0m also applies to [;;4mhttp*[0m packet types as
     an alias for option [;;4mpacket_size[0m if [;;4mpacket_size[0m itself is
     not set. This use is only intended for backward
     compatibility.

   • [;;4m{line_delimiter, 0 =< byte() =< 255}[0m - For packet type [;;4m[0m
     [;;4mline[0m, sets the delimiting byte. Default is the latin-1
     character [;;4m$\n[0m.

  Examples:

    > erlang:decode_packet(1,<<3,"abcd">>,[]).
    {ok,<<"abc">>,<<"d">>}
    > erlang:decode_packet(1,<<5,"abcd">>,[]).
    {more,6}
