--- ray/src/common/color.c	1990/10/19 11:13:02	1.13
+++ ray/src/common/color.c	1991/08/23 12:33:49	1.14
@@ -1,4 +1,4 @@
-/* Copyright (c) 1986 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -14,59 +14,121 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "color.h"
 
+#define  MINELEN	8	/* minimum scanline length for encoding */
+#define  MINRUN		4	/* minimum run length */
 
+
+char *
+tempbuffer(len)			/* get a temporary buffer */
+unsigned  len;
+{
+	extern char  *malloc(), *realloc();
+	static char  *tempbuf = NULL;
+	static int  tempbuflen = 0;
+
+	if (len > tempbuflen) {
+		if (tempbuflen > 0)
+			tempbuf = realloc(tempbuf, len);
+		else
+			tempbuf = malloc(len);
+		tempbuflen = tempbuf==NULL ? 0 : len;
+	}
+	return(tempbuf);
+}
+
+
 fwritecolrs(scanline, len, fp)		/* write out a colr scanline */
 register COLR  *scanline;
 int  len;
 register FILE  *fp;
 {
-	COLR  lastcolr;
-	int  rept;
+	register int  i, j, beg, cnt;
+	int  c2;
 	
-	lastcolr[RED] = lastcolr[GRN] = lastcolr[BLU] = 1;
-	lastcolr[EXP] = 0;
-	rept = 0;
-	
-	while (len > 0) {
-		if (scanline[0][EXP] == lastcolr[EXP] &&
-				scanline[0][RED] == lastcolr[RED] &&
-				scanline[0][GRN] == lastcolr[GRN] &&
-				scanline[0][BLU] == lastcolr[BLU])
-			rept++;
-		else {
-			while (rept) {		/* write out count */
-				putc(1, fp);
-				putc(1, fp);
-				putc(1, fp);
-				putc(rept & 255, fp);
-				rept >>= 8;
-			}
-			putc(scanline[0][RED], fp);	/* new color */
-			putc(scanline[0][GRN], fp);
-			putc(scanline[0][BLU], fp);
-			putc(scanline[0][EXP], fp);
-			copycolr(lastcolr, scanline[0]);
-			rept = 0;
+	if (len < MINELEN)		/* too small to encode */
+		return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
+	if (len > 32767)		/* too big! */
+		return(-1);
+	putc(2, fp);			/* put magic header */
+	putc(2, fp);
+	putc(len>>8, fp);
+	putc(len&255, fp);
+					/* put components seperately */
+	for (i = 0; i < 4; i++) {
+	    for (j = 0; j < len; j += cnt) {	/* find next run */
+		for (beg = j; beg < len; beg += cnt) {
+		    for (cnt = 1; cnt < 127 && beg+cnt < len &&
+			    scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
+			;
+		    if (cnt >= MINRUN)
+			break;			/* long enough */
 		}
-		scanline++;
-		len--;
+		while (j < beg) {		/* write out non-run(s) */
+		    if ((c2 = beg-j) > 128) c2 = 128;
+		    putc(c2, fp);
+		    while (c2--)
+			putc(scanline[j++][i], fp);
+		}
+		if (cnt >= MINRUN) {		/* write out run */
+		    putc(128+cnt, fp);
+		    putc(scanline[beg][i], fp);
+		} else
+		    cnt = 0;
+	    }
 	}
-	while (rept) {		/* write out count */
-		putc(1, fp);
-		putc(1, fp);
-		putc(1, fp);
-		putc(rept & 255, fp);
-		rept >>= 8;
-	}
 	return(ferror(fp) ? -1 : 0);
 }
 
 
-freadcolrs(scanline, len, fp)		/* read in a colr scanline */
+freadcolrs(scanline, len, fp)		/* read in an encoded colr scanline */
 register COLR  *scanline;
 int  len;
 register FILE  *fp;
 {
+	register int  i, j;
+	int  code;
+					/* determine scanline type */
+	if (len < MINELEN)
+		return(oldreadcolrs(scanline, len, fp));
+	if ((i = getc(fp)) == EOF)
+		return(-1);
+	if (i != 2) {
+		ungetc(i, fp);
+		return(oldreadcolrs(scanline, len, fp));
+	}
+	scanline[0][GRN] = getc(fp);
+	scanline[0][BLU] = getc(fp);
+	if ((i = getc(fp)) == EOF)
+		return(-1);
+	if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
+		scanline[0][RED] = 2;
+		scanline[0][EXP] = i;
+		return(oldreadcolrs(scanline+1, len-1, fp));
+	}
+	if ((scanline[0][BLU]<<8 | i) != len)
+		return(-1);		/* length mismatch! */
+					/* read each component */
+	for (i = 0; i < 4; i++)
+	    for (j = 0; j < len; ) {
+		if ((code = getc(fp)) == EOF)
+		    return(-1);
+		if (code > 128) {	/* run */
+		    scanline[j++][i] = getc(fp);
+		    for (code &= 127; --code; j++)
+			scanline[j][i] = scanline[j-1][i];
+		} else			/* non-run */
+		    while (code--)
+			scanline[j++][i] = getc(fp);
+	    }
+	return(feof(fp) ? -1 : 0);
+}
+
+
+oldreadcolrs(scanline, len, fp)		/* read in an old colr scanline */
+register COLR  *scanline;
+int  len;
+register FILE  *fp;
+{
 	int  rshift;
 	register int  i;
 	
@@ -101,86 +163,50 @@ register FILE  *fp;
 fwritescan(scanline, len, fp)		/* write out a scanline */
 register COLOR  *scanline;
 int  len;
-register FILE  *fp;
+FILE  *fp;
 {
-	COLR  lastcolr, thiscolr;
-	int  rept;
-	
-	lastcolr[RED] = lastcolr[GRN] = lastcolr[BLU] = 1;
-	lastcolr[EXP] = 0;
-	rept = 0;
-	
-	while (len > 0) {
-		setcolr(thiscolr, scanline[0][RED],
+	COLR  *clrscan;
+	int  n;
+	register COLR  *sp;
+					/* get scanline buffer */
+	if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
+		return(-1);
+	clrscan = sp;
+					/* convert scanline */
+	n = len;
+	while (n-- > 0) {
+		setcolr(sp[0], scanline[0][RED],
 				  scanline[0][GRN],
 				  scanline[0][BLU]);
-		if (thiscolr[EXP] == lastcolr[EXP] &&
-				thiscolr[RED] == lastcolr[RED] &&
-				thiscolr[GRN] == lastcolr[GRN] &&
-				thiscolr[BLU] == lastcolr[BLU])
-			rept++;
-		else {
-			while (rept) {		/* write out count */
-				putc(1, fp);
-				putc(1, fp);
-				putc(1, fp);
-				putc(rept & 255, fp);
-				rept >>= 8;
-			}
-			putc(thiscolr[RED], fp);	/* new color */
-			putc(thiscolr[GRN], fp);
-			putc(thiscolr[BLU], fp);
-			putc(thiscolr[EXP], fp);
-			copycolr(lastcolr, thiscolr);
-			rept = 0;
-		}
 		scanline++;
-		len--;
+		sp++;
 	}
-	while (rept) {		/* write out count */
-		putc(1, fp);
-		putc(1, fp);
-		putc(1, fp);
-		putc(rept & 255, fp);
-		rept >>= 8;
-	}
-	return(ferror(fp) ? -1 : 0);
+	return(fwritecolrs(clrscan, len, fp));
 }
 
 
 freadscan(scanline, len, fp)		/* read in a scanline */
 register COLOR  *scanline;
 int  len;
-register FILE  *fp;
+FILE  *fp;
 {
-	COLR  thiscolr;
-	int  rshift;
-	register int  i;
-	
-	rshift = 0;
-	
-	while (len > 0) {
-		thiscolr[RED] = getc(fp);
-		thiscolr[GRN] = getc(fp);
-		thiscolr[BLU] = getc(fp);
-		thiscolr[EXP] = getc(fp);
-		if (feof(fp) || ferror(fp))
-			return(-1);
-		if (thiscolr[RED] == 1 &&
-				thiscolr[GRN] == 1 &&
-				thiscolr[BLU] == 1) {
-			for (i = thiscolr[EXP] << rshift; i > 0; i--) {
-				copycolor(scanline[0], scanline[-1]);
-				scanline++;
-				len--;
-			}
-			rshift += 8;
-		} else {
-			colr_color(scanline[0], thiscolr);
-			scanline++;
-			len--;
-			rshift = 0;
-		}
+	register COLR  *clrscan;
+
+	if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
+		return(-1);
+	if (freadcolrs(clrscan, len, fp) < 0)
+		return(-1);
+					/* convert scanline */
+	colr_color(scanline[0], clrscan[0]);
+	while (--len > 0) {
+		scanline++; clrscan++;
+		if (clrscan[0][RED] == clrscan[-1][RED] &&
+			    clrscan[0][GRN] == clrscan[-1][GRN] &&
+			    clrscan[0][BLU] == clrscan[-1][BLU] &&
+			    clrscan[0][EXP] == clrscan[-1][EXP])
+			copycolor(scanline[0], scanline[-1]);
+		else
+			colr_color(scanline[0], clrscan[0]);
 	}
 	return(0);
 }