--- ray/src/px/clrtab.c	1993/02/05 09:45:40	2.4
+++ ray/src/px/clrtab.c	1993/12/09 11:57:15	2.8
@@ -107,16 +107,17 @@ register BYTE	*bs;
 register COLR	*cs;
 int	n;
 {
-	static short	(*cerr)[3];
+	static short	(*cerr)[3] = NULL;
 	static int	N = 0;
 	int	err[3], errp[3];
 	register int	x, i;
 
 	if (n != N) {		/* get error propogation array */
-		if (N)
-			cerr = (short (*)[3])realloc((char *)cerr,
-					3*n*sizeof(short));
-		else
+		if (N) {
+			free((char *)cerr);
+			cerr = NULL;
+		}
+		if (n)
 			cerr = (short (*)[3])malloc(3*n*sizeof(short));
 		if (cerr == NULL) {
 			N = 0;
@@ -181,7 +182,7 @@ register int	box[3][2];
 #define c0	r
 	register int	r, g, b;
 	int	pri;
-	int	t[HMAX], med;
+	long	t[HMAX], med;
 					/* find dominant axis */
 	pri = RED;
 	if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0])
@@ -237,9 +238,10 @@ mktabent(p, box)	/* compute average color for box and 
 int	p;
 register int	box[3][2];
 {
-	long	sum[3];
-	int	r, g, n;
-	register int	b, c;
+	unsigned long	sum[3];
+	unsigned	r, g;
+	unsigned long	n;
+	register unsigned	b, c;
 						/* sum pixels in box */
 	n = 0;
 	sum[RED] = sum[GRN] = sum[BLU] = 0;
@@ -254,6 +256,12 @@ register int	box[3][2];
 		    }
 		    histo[r][g][b] = p;		/* assign pixel */
 		}
+	if (n >= (1L<<23)/HMAX) {		/* avoid overflow */
+		sum[RED] /= n;
+		sum[GRN] /= n;
+		sum[BLU] /= n;
+		n = 1;
+	}
 	if (n) {				/* compute average */
 		clrtab[p][RED] = sum[RED]*256/NRED/n;
 		clrtab[p][GRN] = sum[GRN]*256/NGRN/n;