MODULE findseq;
(*---------------------------------------------------------
File name: findseq.pm
Author: MM, AG
Date: 6/07/05 

Problem: Finds a pattern on a chain of integers.
Pattern is stored on an ARRAY of size N.

Example of Execution:
	Pattern:  0 2 1 2 0
	Sequence:  2  2  0  0  1  2  1  0  0  1  0  1  0  2  0  1  0  2  0  2  2  2  1
	0  0  2  0   2  0  1  0  2  0  1  2  0  1  0  0  0  0  1  1  2  0  0  1  1  0
	 0  1  0  1  2  1  2  1  2  0  2  1  2  2  0  1  1  2  2  1  0  1  1  0  1  0  1
	  1  0  2  1  1  0  0  1  2  2  1  2  0  0  0  1  2  2  2  2  1  1  2  2  0  0
	2  2  1  2  0  2  1  2  1  0  0  0  [0  2  1  2  0]  0  0  2  0  0  1  2  2  0  0
	 2  2  1  0  2  1  [0  2  1  2  0]  1  2  2  1  2  1  2  1  1  2  1  2  1  0  2  0
	  1  2
	Total found:  6
	Result:  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  0  0  0
	  0  0  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	0  0

Cycles: N = length of pattern. Does not depend on the length of the chain searched 
(N + 1) assign + (2N) test + N shift + 1 Reduce.
*)
(*----------------------------------------------------------
		CONFIGURATION
----------------------------------------------------------*)
CONST  MAXCELLS=1024; (* MAXCELLS cells in one line *)

CONFIGURATION chain[0..(MAXCELLS - 1)];
CONNECTION
		left: chain [i] -> chain[(i-1) MOD MAXCELLS];
		right: chain[i] -> chain[(i+1) MOD MAXCELLS];
(*----------------------------------------------------------
		VARIABLES
----------------------------------------------------------*)
VAR 
		L0seq, L1Res: chain OF INTEGER;
		i, N, Tot:INTEGER;
		A: ARRAY[0..(N-1)] OF INTEGER; (* pattern of ints *)
(*----------------------------------------------------------
		MAIN
----------------------------------------------------------*)
BEGIN
	(* initialize data *)
	L0seq:= RandomInt(chain) MOD 3;
	A[0] := 0;
	A[1] := 2;
	A[2] := 1;
	A[3] := 2;
	A[4] := 0; 
	N:=5;	(* pattern length *)
	
	L1Res:= 1;		(* initialize chain to test all *)
	FOR i:= 0 TO (N - 1) DO 
		IF L1Res = 1 THEN	(* if selected *)
			IF L0seq # A[i] THEN		(* if not there*)
				L1Res := 0;		(* deselect *) 
			END; (* IF *)
		END; (* IF *)
		L1Res := MOVE.right(L1Res);	(* shift for next item *)
	END; (* for *)
	Tot:= REDUCE.SUM(L1Res);		(* count 1's= how many times found*)
	
	(* Printing *)
	IF ID(chain) < 160 THEN
		WriteString("Pattern: ");
		FOR i:= 0 TO (N - 1) DO
			WriteInt(A[i], 2);
		END; (* FOR *)
		WriteLn;
		WriteString("Sequence: "); WriteInt(L0seq, 2); WriteLn;
		WriteString("Total found: "); WriteInt(Tot, 2); WriteLn;
		WriteString("Result: "); WriteInt(L1Res, 2); WriteLn;
	END; (* display *)
END findseq.