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-module(fp_mysql_greeting).

-define(TIMEOUT, 3000). % milli-seconds
-define(PORT, 3306). % mysql port
-define(MAXPKT, 1). % only greeting packet is needed
-define(DESCRIPTION, "TCP/3306: Mysql version identification").

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find_null(Bin, Pos) ->
  case Bin of
    <<Start:Pos/binary, 0, Rest/binary>> ->
      % found
      {Start, Rest};
    <<Bin:Pos/binary>> ->
      % not found
      error;
    <<_:Pos/binary, _/binary>>=B ->
      % go forward

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-define(PROTO, 16#0a). % only interested in protocol version 10

parse_content(_Args,
  <<
    ?PROTO:8,     % protocol version
    Rest/binary
  >>) ->
  case find_null(Rest, 1) of
    error ->
      {{error, up}, unexpected_data};

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parse_header(Args,
  <<
    Pldlen:24/little,  % 3 bytes payload length
    _:8,               % 1 byte sequence id or packet nb
    Pld/binary         % content
  >>) ->
  case byte_size(Pld) == Pldlen of
    true ->
      parse_content(Args, Pld);
    false ->

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callback_next_step(Args) when Args#args.moddata == undefined ->
  {continue, Args#args.maxpkt, "", true};
callback_next_step(Args) when Args#args.packetrcv < 1 ->
  {result, {{error,up}, timeout}};
callback_next_step(Args) ->
  {result, parse_header(Args, Args#args.datarcv)}.