--- ray/src/px/closest.c	1989/02/02 14:10:34	1.2
+++ ray/src/px/closest.c	2004/03/28 20:33:13	2.4
@@ -1,9 +1,6 @@
-/* Copyright 1988 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: closest.c,v 2.4 2004/03/28 20:33:13 schorsch Exp $";
 #endif
-
 /*
 CLOSEST - nearest-color lookup by locally ordered search
 we use distance in rgb space as color metric
@@ -15,40 +12,54 @@ About 6 times faster than exhaustive.
 Paul Heckbert
 */
 
+#include <stdlib.h>
+
 #include "ciq.h"
 
 #define inf 3*256*256
-#define key ((r&0xe0)<<1|(g&0xe0)>>2|(b&0xe0)>>5)    /* hash key: rrrgggbbb */
+#define key(r,g,b) (((r)&0xe0)<<1|((g)&0xe0)>>2|((b)&0xe0)>>5)   
+    /* 9-bit hash key: rrrgggbbb */
 
-static struct thing {int mindist,pv;} space[512*257],*next=space,*bucket[512];
+static struct thing {int mindist,pv;} space[512*257],*next,*bucket[512];
 					/* sorted lists of colors */
 
-static int nfill=0,tests=0,calls=0;
+static int nfill,tests,calls;
 static char filled[512];		/* has bucket[key] been filled yet? */
 static int sq[511];
 
-initialize() {				/* reset the buckets */
+static int compare(const void *a, const void *b);
+static void fillbucket(int k);
+
+
+void
+initializeclosest(void) {			/* reset the buckets */
     int k;
     nfill = tests = calls = 0;
     for (k=0; k<512; k++) filled[k] = 0;
     next = space;
 }
 
-closest(r,g,b)		/* find pv of colormap color closest to (r,g,b) */
-int r,g,b;
+int
+closest(		/* find pv of colormap color closest to (r,g,b) */
+	int r,
+	int g,
+	int b
+)
 {
     register struct thing *p;
-    register int *rsq,*gsq,*bsq,dist,min,best;
+    register int *rsq,*gsq,*bsq,dist,min;
+    int best,k;
     struct thing *p0;
 
-    if (!filled[key]) fillbucket(key);
+    k = key(r,g,b);
+    if (!filled[k]) fillbucket(k);
     min = inf;
     rsq = sq+255-r;
     gsq = sq+255-g;
     bsq = sq+255-b;
 
     /* stop looking when best is closer than next could be */
-    for (p0=p=bucket[key]; min>p->mindist; p++) {
+    for (p0=p=bucket[k]; min>p->mindist; p++) {
 	dist = rsq[color[0][p->pv]] + gsq[color[1][p->pv]] +
 	    bsq[color[2][p->pv]];
 	if (dist<min) {
@@ -63,23 +74,28 @@ int r,g,b;
 
 #define H 16	/* half-width of a bucket */
 
-compare(a,b)
-register struct thing *a,*b;
+static int
+compare(
+	const void *a,
+	const void *b
+)
 {
-    return a->mindist-b->mindist;
+    return ((struct thing*)a)->mindist - ((struct thing*)b)->mindist;
 }
 
-fillbucket(k)	/* make list of colormap colors which could be closest */
-int k;		/* matches for colors in bucket #k */
+static void
+fillbucket(	/* make list of colormap colors which could be closest */
+	int k		/* matches for colors in bucket #k */
+)
 {
     register int r,g,b,j,dist,*rsq,*gsq,*bsq,min,best;
     struct thing *p,*q;
 
     if (!sq[0]) for (j= -255; j<256; j++) sq[j+255] = j*j;
 
-    r = k>>1&0xe0|H;			/* center of 32x32x32 cubical bucket */
-    g = k<<2&0xe0|H;
-    b = k<<5&0xe0|H;
+    r = (k>>1&0xe0)|H;			/* center of 32x32x32 cubical bucket */
+    g = (k<<2&0xe0)|H;
+    b = (k<<5&0xe0)|H;
     rsq = sq+255-r;
     gsq = sq+255-g;
     bsq = sq+255-b;