// TCP/IP stack for DOS
// ftp://ftp.delorie.com/pub/djgpp/current/v2tk/wat3222br6.zip
// ftp://ftp.delorie.com/pub/djgpp/current/v2tk/wat3222sr6.zip

{$MODE OBJFPC}
{$PACKRECORDS C}

{$MODESWITCH OUT}
{$LONGSTRINGS ON}
{$MACRO ON}

{$IF DEFINED(GO32V2)}
  {$LINKLIB libwatt.a}
  {$DEFINE LibraryLibWattDecl := cdecl}
  {$DEFINE LibraryLibWattImp := cdecl; external}
  {$DEFINE LibraryLibWattVar := cvar; external}
{$ELSE}
  {$ERROR what?}
{$ENDIF}

unit watt32;

interface

  uses ctypes;

  const
    (* socket size have another size on 64-bit systems *)
    W32_UNDOC_TCP_SOCKET_SIZE = 4470;
    W32_UNDOC_UDP_SOCKET_SIZE = 4470;
    FD_MAXFDSET = 512; (* FD_SETSIZE *)

  type
    (* Watt32 -> sys/wtypes.h -> fd_set *)
    TFDSet = record
      fd_bits: array [0..63] of cuchar;
    end;

    tcp_Socket = record
      undoc: array [0..W32_UNDOC_TCP_SOCKET_SIZE - 1] of cuchar;
    end;

    udp_Socket = record
      undoc: array [0..W32_UNDOC_UDP_SOCKET_SIZE - 1] of cuchar;
    end;

    Psock_type = Pointer;

  var
    wattcpCopyrigh: PChar; LibraryLibWattVar;
    my_ip_addr: culong; external name '__w32_my_ip_addr';

  function wattcpVersion: PChar; LibraryLibWattImp;
  function wattcpCapabilities: PChar; LibraryLibWattImp;
  function wattcpBuildCC: PChar; LibraryLibWattImp;
  function wattcpBuildCCexe: PChar; LibraryLibWattImp;
  function wattcpBuildCflags: PChar; LibraryLibWattImp;

  function sock_init: cint; inline; (* MACRO *)
  function watt_sock_init (tcp_Sock_size, udp_Sock_size, time_t_size: csize_t): cint; LibraryLibWattImp;

  function sock_init_err (rc: cint): PChar; LibraryLibWattImp name '_w32_sock_init_err';
  procedure sock_exit; LibraryLibWattImp;
  procedure dbug_init; LibraryLibWattImp;
  procedure init_misc; LibraryLibWattImp;
  procedure sock_sig_exit (const msg: PChar; sigint: cint); LibraryLibWattImp;

  function hires_timer (on: cint): cint; LibraryLibWattImp name '_w32_hires_timer';

  procedure init_userSuppliedTimerTick; LibraryLibWattImp name '_w32_init_userSuppliedTimerTick';
  procedure userTimerTick (elapsed_time_msec: culong); LibraryLibWattImp name '_w32_userTimerTick';
  procedure init_timer_isr; LibraryLibWattImp;
  procedure exit_timer_isr; LibraryLibWattImp;

  function tcp_tick (s: Psock_type): culong; LibraryLibWattImp name '_w32_tcp_tick';

  function htons (hostshort: cuint16): cuint16; LibraryLibWattImp;
  function htonl (hostlong: cuint32): cuint32; LibraryLibWattImp;
  function ntohs (netshort: cuint16): cuint16; LibraryLibWattImp;
  function ntohl (netlong: cuint32): cuint32; LibraryLibWattImp;

  (* MACRO *)
  function fpFD_SET (fdno: cint; var nset: TFDSet): cint;
  function fpFD_CLR (fdno:cint; var nset: TFDSet): cint;
  function fpFD_ZERO (out nset: TFDSet): cint;
  function fpFD_ISSET (fdno: cint;const nset: TFDSet): cint;

implementation

  function sock_init: cint; inline;
  begin
    sock_init := watt_sock_init(sizeof(tcp_Socket), sizeof(udp_Socket), sizeof(cuint)) (* !!! DJGPP *)
  end;

  function fpFD_SET (fdno: cint; var nset: TFDSet): cint;
  begin
    if (fdno < 0) or (fdno > FD_MAXFDSET) then
      exit(-1);
    nset.fd_bits[fdno div 8] := nset.fd_bits[fdno div 8] OR (culong(1) shl (fdno and 7));
    fpFD_SET := 0
  end;

  function fpFD_CLR (fdno: cint; var nset: TFDSet): cint;
  begin
    if (fdno < 0) or (fdno > FD_MAXFDSET) Then
      exit(-1);
    nset.fd_bits[fdno div 8] := nset.fd_bits[fdno div 8] AND Cardinal(NOT (culong(1) shl (fdno and 7)));
    fpFD_CLR := 0
  end;

  function fpFD_ZERO (out nset: TFDSet): cint;
    var i :longint;
  begin
    for i := 0 to (512 + 7) div 8 DO
      nset.fd_bits[i] := 0;
    fpFD_ZERO := 0
  end;

  function fpFD_ISSET (fdno: cint; const nset: TFDSet): cint;
  begin
    if (fdno < 0) or (fdno > FD_MAXFDSET) Then
      exit(-1);
    if ((nset.fd_bits[fdno div 8]) and (culong(1) shl (fdno and 7))) > 0 then
      fpFD_ISSET := 1
    else
      fpFD_ISSET := 0
  end;

end.