{
    $Id$
    This file is part of the Free Pascal run time library.
    Copyright (c) 1993,97 by Michael Van Canneyt,
    member of the Free Pascal development team.

    Getopt implementation for Free Pascal, modeled after GNU getopt.

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}
unit getopts;

{ --------------------------------------------------------------------
  *NOTE*
  The routines are a more or less straightforward conversion

  of the GNU C implementation of getopt. One day they should be

  replaced by some 'real pascal code'.
  -------------------------------------------------------------------- }

Interface

Const No_Argument       = 0;
      Required_Argument = 1;
      Optional_Argument = 2;
      EndOfOptions      = #255;

Type TOption = Record
       Name    : String;
       Has_arg : Integer;
       Flag    : PChar;
       Value   : Char;
     end;
     POption  = ^TOption;
     Orderings = (require_order,permute,return_in_order);

Var OptArg : String;
    OptInd : Longint;
    OptErr : Boolean;
    OptOpt : Char;

Function GetOpt (ShortOpts : String) : char;
Function GetLongOpts (ShortOpts : String;LongOpts : POption;var Longind : Integer) : char;

Implementation

Var
  NextChar,
  Nrargs,
  first_nonopt,
  last_nonopt   : Longint;
  Ordering      : Orderings;

Procedure Exchange;
var
  bottom,
  middle,
  top,i,len : longint;
  temp      : pchar;
begin
  bottom:=first_nonopt;
  middle:=last_nonopt;
  top:=optind;
  while (top>middle) and (middle>bottom) do
    begin
    if (top-middle>middle-bottom) then
      begin
      len:=middle-bottom;
      for i:=1 to len-1 do
        begin
        temp:=argv[bottom+i];
        argv[bottom+i]:=argv[top-(middle-bottom)+i];
        argv[top-(middle-bottom)+i]:=temp;
        end;
      top:=top-len;
      end
    else
      begin
      len:=top-middle;
      for i:=0 to len-1 do
        begin
        temp:=argv[bottom+i];
        argv[bottom+i]:=argv[middle+i];
        argv[middle+i]:=temp;
        end;
      bottom:=bottom+len;
      end;
    end;
  first_nonopt:=first_nonopt + optind-last_nonopt;
  last_nonopt:=optind;
end; { exchange }


procedure getopt_init (var opts : string);
begin
{ Initialize some defaults. }
  Optarg:='';
  Optind:=1;
  First_nonopt:=1;
  Last_nonopt:=1;
  OptOpt:='?';
  Nextchar:=0;
  if opts[1]='-' then
   begin
     ordering:=return_in_order;
     delete(opts,1,1);
   end
  else
   if opts[1]='+' then
    begin
      ordering:=require_order;
      delete(opts,1,1);
    end
  else
   ordering:=permute;
end;



Function Internal_getopt (Var Optstring : string;LongOpts : POption;
                          LongInd : pointer;Long_only : boolean ) : char;
type
  pinteger=^integer;
var
  temp,endopt,option_index : byte;
  indfound: integer;
  currentarg,optname : string;
  p,pfound : POption;
  exact,ambig : boolean;
  c : char;
begin
  optarg:='';
  if optind=0 then
    getopt_init(optstring);
{ Check if We need the next argument. }
  if optind<nrargs then currentarg:=strpas(argv[optind]) else currentarg:='';
  if (nextchar=0) then
   begin
     if ordering=permute then
      begin
      { If we processed options following non-options : exchange }
        if (first_nonopt<>last_nonopt) and (last_nonopt<>optind) then
         exchange
        else
         if last_nonopt<>optind then
          first_nonopt:=optind;
        while (optind<nrargs) and ((argv[optind][0]<>'-') or
              (length(strpas(argv[optind]))=1)) do
          inc(optind);
        last_nonopt:=optind;
      end;
   { Check for '--' argument }
     if optind<nrargs then
      currentarg:=strpas(argv[optind])
     else
      currentarg:='';
     if (optind<>nrargs) and (currentarg='--') then
      begin
        inc(optind);
        if (first_nonopt<>last_nonopt) and (last_nonopt<>optind) then
         exchange
        else
         if first_nonopt=last_nonopt then
          first_nonopt:=optind;
        last_nonopt:=nrargs;
        optind:=nrargs;
      end;
   { Are we at the end of all arguments ? }
     if optind>=nrargs then
      begin
        if first_nonopt<>last_nonopt then
         optind:=first_nonopt;
        Internal_getopt:=EndOfOptions;
        exit;
      end;
     if optind<nrargs then
      currentarg:=strpas(argv[optind])
     else
      currentarg:='';
   { Are we at a non-option ? }
     if (currentarg[1]<>'-') or (currentarg='-') then
      begin
        if ordering=require_order then
         begin
           Internal_getopt:=EndOfOptions;
           exit;
         end
        else
         begin
           optarg:=strpas(argv[optind]);
           inc(optind);
           Internal_getopt:=#1;
           exit;
         end;
      end;
   { At this point we're at an option ...}
     nextchar:=2;
     if (longopts<>nil) and (currentarg[2]='-') then
      inc(nextchar);
   { So, now nextchar points at the first character of an option }
   end;
{ Check if we have a long option }
  if longopts<>nil then
   if length(currentarg)>1 then
    if (currentarg[2]='-') or
       ((not long_only) and (pos(currentarg[2],optstring)<>0)) then
     begin
     { Get option name }
       endopt:=pos('=',currentarg);
       if endopt=0 then
        endopt:=length(currentarg)+1;
       optname:=copy(currentarg,nextchar,endopt-nextchar);
     { Match partial or full }
       p:=longopts;
       pfound:=nil;
       exact:=false;
       ambig:=false;
       option_index:=0;
       indfound:=0;
       while (p^.name<>'') and (not exact) do
        begin
          if pos(optname,p^.name)<>0 then
           begin
             if length(optname)=length(p^.name) then
              begin
                exact:=true;
                pfound:=p;
                indfound:=option_index;
              end
             else
              if pfound=nil then
               begin
                 indfound:=option_index;
                 pfound:=p
               end
              else
               ambig:=true;
           end;
          inc (longint(p),sizeof(toption));
          inc (option_index);
        end;
       if ambig and not exact then
        begin
          if opterr then
           writeln (paramstr(0),': option "',optname,'" is ambiguous');
          nextchar:=0;
          inc(optind);
          Internal_getopt:='?';
        end;
       if pfound<>nil then
        begin
          inc(optind);
          if endopt<=length(currentarg) then
           begin
             if pfound^.has_arg>0 then
              optarg:=copy(currentarg,endopt+1,length(currentarg)-endopt)
             else
              begin
                if opterr then
                 if currentarg[2]='-' then
                  writeln (paramstr(0),': option "--',pfound^.name,'" doesn''t allow an argument')
                 else
                  writeln (paramstr(0),': option "',currentarg[1],pfound^.name,'" doesn''t allow an argument');
                nextchar:=0;
                internal_getopt:='?';
                exit;
              end;
           end
          else { argument in next paramstr...  }
           begin
             if pfound^.has_arg=1 then
              begin
                if optind<nrargs then
                 begin
                   optarg:=strpas(argv[optind]);
                   inc(optind);
                 end { required argument }
                else
                 begin { no req argument}
                   if opterr then
                    writeln (paramstr(0),': option ',pfound^.name,' requires an argument');
                   nextchar:=0;
                   if optstring[1]=':' then
                    Internal_getopt:=':'
                   else
                    Internal_getopt:='?';
                   exit;
                 end;
              end;
          end; { argument in next parameter end;}
         nextchar:=0;
         if longind<>nil then
          pinteger(longind)^:=indfound+1;
            if pfound^.flag<>nil then
            begin
              pfound^.flag^:=pfound^.value;
              internal_getopt:=#0;
              exit;
            end;
           internal_getopt:=pfound^.value;
           exit;
         end; { pfound<>nil }
      { We didn't find it as an option }
        if (not long_only) or
           ((currentarg[2]='-') or (pos(CurrentArg[nextchar],optstring)=0)) then
         begin
           if opterr then
            if currentarg[2]='-' then
             writeln (paramstr(0),' unrecognized option "--',optname,'"')
            else
             writeln (paramstr(0),' unrecognized option "',currentarg[1],optname,'"');
           nextchar:=0;
           inc(optind);
           Internal_getopt:='?';
           exit;
        end;
     end; { Of long options.}
{ We check for a short option. }
  temp:=pos(currentarg[nextchar],optstring);
  c:=currentarg[nextchar];
  inc(nextchar);
  if nextchar>length(currentarg) then
   begin
     inc(optind);
     nextchar:=0;
   end;
  if (temp=0) or (c=':') then
   begin
     if opterr then
      writeln (paramstr(0),': illegal option -- ',c);
     optopt:=currentarg[nextchar-1];
     internal_getopt:='?';
     exit;
   end;
  Internal_getopt:=optstring[temp];
  if optstring[temp+1]=':' then
   if currentarg[temp+2]=':' then
    begin { optional argument }
      optarg:=copy (currentarg,nextchar,length(currentarg)-nextchar+1);
      nextchar:=0;
    end
   else
    begin { required argument }
      if nextchar>0 then
       begin
         optarg:=copy (currentarg,nextchar,length(currentarg)-nextchar+1);
         inc(optind)
       end
      else
       if (optind=nrargs) then
        begin
          if opterr then
           writeln (paramstr(0),': option requires an argument -- ',optstring[temp]);
          optopt:=optstring[temp];
          if optstring[1]=':' then
           Internal_getopt:=':'
          else
           Internal_Getopt:='?'
        end
       else
        begin
          optarg:=strpas(argv[optind]);
          inc(optind)
        end;
       nextchar:=0;
    end; { End of required argument}
end; { End of internal getopt...}


Function GetOpt(ShortOpts : String) : char;
begin
  getopt:=internal_getopt (shortopts,nil,nil,false);
end;


Function GetLongOpts (ShortOpts : String;LongOpts : POption;var Longind : Integer) : char;
begin
  getlongopts:=internal_getopt ( shortopts,longopts,@longind,true);
end;


begin
{ Needed to detect startup }
  Opterr:=true;
  Optind:=0;
  nrargs:=paramcount+1;
end.

{
  $Log$
  Revision 1.2  1998-05-21 19:30:57  peter
    * objects compiles for linux
    + assign(pchar), assign(char), rename(pchar), rename(char)
    * fixed read_text_as_array
    + read_text_as_pchar which was not yet in the rtl

  Revision 1.1  1998/05/12 10:42:45  peter
    * moved getopts to inc/, all supported OS's need argc,argv exported
    + strpas, strlen are now exported in the systemunit
    * removed logs
    * removed $ifdef ver_above

}