segment lpsrx(input,output);

   { Program to search for a voter name in a file in Database format}

   {Brian Gilmore September 1987}

   
TYPE
   pns = string[40];

   {$I lptype}

VAR
   xa: xaf;
   s, target: string[40];  
   tgt, tgt2: string[4];
   i,flag, max, last_address, indx, max_add: integer;

{$i lpexti}

PROCEDURE construct_index;
   VAR i: byte;
   BEGIN
     for i := 0 to 25 do begin
        seek(ndfile, i+1);
        xa[i] := ndfile^.r_no+27;
     end; 
     xa[26] := max_val+27;
   END;

FUNCTION try_match(x, y: s_integer): s_integer;
   VAR q: s_integer;
   BEGIN
      if y > (x+1) then q := (x+y) DIV 2 else q := x;
      seek(ndfile, q);
cursor(21, 0); write('Low, high, C:',x:5,y:5,q:5,' [',tgt,'][',ndfile^.sname,']');
      tgt2 := ndfile^.sname;

      if x<>q then begin 
         if tgt < tgt2 then q := try_match(x, q) else begin
            if tgt > tgt2 then q := try_match(q+1, y);
         end;
      end;
      if pos(tgt,tgt2) = 0 then q := 0;
      try_match := q;
   END; 

FUNCTION test_voter(x,y: s_integer): s_integer;
   VAR i,j,n: s_integer;
       k: byte;
   BEGIN       {target is incoming string}
      i := x;
      k := length(target); if k > 4 then k := 4;
      tgt := copy(target, 1, k);
      if y < x then i := 0 else i := try_match(x, y);
      n:= i;
      if i > 0 then begin
         seek(ndfile, i);
         if ndfile^.sname = tgt then begin
            REPEAT
               i := i-1; seek(ndfile, i);
            UNTIL ndfile^.sname <> tgt;
            i := i+1; seek(ndfile, i);  {move back to 1st occurance of 'name'}
         end;

         REPEAT
            seek(ndfile, i);
            n := ndfile^.r_no;
            seek(dbfile, n); Get_names; s := surname;
            indx := i;
                     {count := n; display_entry;}
            i := i+1;
         UNTIL (i>y) OR (pos(target,s)<>0);
         if i>y then n := 0;
      end;
      test_voter := n;
   END;

PROCEDURE user_search(VAR n: s_integer);
   BEGIN
      clearline(23);
      if n=0 then begin
         cursor(10,10); write('No match for ''',target,'''   ');
      end else begin
         Disp_form;
         REPEAT
            disp_Voter(n); cursor(23, 0);
            write('RETURN for next, or EXIT'); i := getint(23,24);
            if final <> 27 then begin
               if final <> 31 then begin   {cursor up}
                  indx := indx+1; 
               end else indx := indx-1;
               if indx = 0 then indx := 1;
               if indx >= xa[26] then indx := indx-1;
               seek(ndfile, indx);
               n := ndfile^.r_no; seek(dbfile, n);
            end;
         UNTIL final=27;
      end;
   END;

FUNCTION find_voter: integer;
   VAR i,j,k: integer;
       n, x, y: s_integer;
       c: char;
       s: string [40];
   BEGIN
      n := 0;
      clearline(23);
      write('Enter (part) Voter Name:'); readln(s);
      clear_from_line(1);
      if s <> '' then begin
            c := s[1];
            if (ord(c)>=ord('a')) AND (ord(c)<=ord('z')) then c := chr(ord(c)-32);
            if c = ' ' then c := 'A';
            s[1] := c;
                                   {Convert 1st char to upper case only}
                             
      {   if length(s) < 4 then for i := length(s) to 4 do s := concat(s, ' ');}
         k := ord(c)-ord('A');
         x := xa[k]; y := xa[k+1]-1;
         target := s; n := test_voter(x, y);
         user_search(n);
      end;
      find_voter := n;
   END;
   

PROCEDURE ask_for_voter;
   VAR n: integer;
   BEGIN
      REPEAT
         n := find_voter;
      UNTIL n = 0;
   END;

BEGIN
END.