--- ray/src/px/clrtab.c	1992/10/13 09:07:51	2.2
+++ ray/src/px/clrtab.c	1993/06/10 15:45:18	2.7
@@ -1,4 +1,4 @@
-/* Copyright (c) 1992 Regents of the University of California */
+/* Copyright (c) 1993 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -32,7 +32,13 @@ static int	CLRCUBE[3][2] = {0,NRED,0,NGRN,0,NBLU};
 				/* maximum propagated error during dithering */
 #define MAXERR		20
 				/* define CLOSEST to get closest colors */
-#define CLOSEST		1
+#ifndef CLOSEST
+#ifdef SPEED
+#if  SPEED > 8
+#define CLOSEST		1	/* this step takes a little longer */
+#endif
+#endif
+#endif
 
 
 new_histo()		/* clear our histogram */
@@ -175,7 +181,7 @@ 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])
@@ -231,9 +237,10 @@ 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;
@@ -248,6 +255,12 @@ 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;
@@ -279,14 +292,14 @@ int	n;
 		neigh[i][0] = i;		/* identity is terminator */
 	}
 					/* make neighbor lists */
-	for (r = 0; r < NRED-1; r++)
-	    for (g = 0; g < NGRN-1; g++)
-		for (b = 0; b < NBLU-1; b++) {
-		    if (histo[r][g][b] != histo[r+1][g][b])
+	for (r = 0; r < NRED; r++)
+	    for (g = 0; g < NGRN; g++)
+		for (b = 0; b < NBLU; b++) {
+		    if (r < NRED-1 && histo[r][g][b] != histo[r+1][g][b])
 			addneigh(neigh, histo[r][g][b], histo[r+1][g][b]);
-		    if (histo[r][g][b] != histo[r][g+1][b])
+		    if (g < NGRN-1 && histo[r][g][b] != histo[r][g+1][b])
 			addneigh(neigh, histo[r][g][b], histo[r][g+1][b]);
-		    if (histo[r][g][b] != histo[r][g][b+1])
+		    if (b < NBLU-1 && histo[r][g][b] != histo[r][g][b+1])
 			addneigh(neigh, histo[r][g][b], histo[r][g][b+1]);
 		}
 					/* assign closest values */
@@ -335,7 +348,7 @@ dist(col, r, g, b)		/* find distance from clrtab entry
 register BYTE	col[3];
 int	r, g, b;
 {
-	register unsigned	tmp;
+	register int	tmp;
 	register unsigned	sum;
 	
 	tmp = col[RED]*NRED/256 - r;