--- ray/src/common/bmpfile.c	2004/03/26 23:30:05	2.4
+++ ray/src/common/bmpfile.c	2004/03/27 16:33:31	2.6
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bmpfile.c,v 2.4 2004/03/26 23:30:05 schorsch Exp $";
+static const char RCSid[] = "$Id: bmpfile.c,v 2.6 2004/03/27 16:33:31 greg Exp $";
 #endif
 /*
  *  Windows and OS/2 BMP file support
@@ -255,7 +255,7 @@ BMPisGrayscale(const BMPHeader *hdr)
 		return -1;
 	if (hdr->bpp > 8)		/* assume they had a reason for it */
 		return 0;
-	for (rgbp = hdr->palette, n = hdr->impColors; n-- > 0; rgbp++)
+	for (rgbp = hdr->palette, n = hdr->nColors; n-- > 0; rgbp++)
 		if (((rgbp->r != rgbp->g) | (rgbp->g != rgbp->b)))
 			return 0;
 	return 1;			/* all colors neutral in map */
@@ -279,10 +279,10 @@ BMPreadScanline(BMPReader *br)
 	 *
 	 * Certain aspects of this scheme are completely insane, so
 	 * we don't support them.  Fortunately, they rarely appear.
-	 * One is the mid-file EOD (0x0001) and another is the insane
+	 * One is the mid-file EOD (0x0001) and another is the ill-conceived
 	 * "delta" (0x0002), which is like a "goto" statement for bitmaps.
 	 * Whoever thought this up should be shot, then told why
-	 * it's impossible to support in any reasonable way.
+	 * it's impossible to support such a scheme in any reasonable way.
 	 * Also, RLE4 mode allows runs to stop halfway through a byte,
 	 * which is likewise uncodeable, so we don't even try.
 	 * Finally, the scanline break is ambiguous -- we assume here that
@@ -291,7 +291,7 @@ BMPreadScanline(BMPReader *br)
 	 * the end of the scanline, assuming the next bit of data belongs
 	 * the following scan.  If a break follows the last pixel, as it
 	 * seems to in the files I've tested out of Photoshop, you end up
-	 * painting every other line black.  BTW, I assume any skipped
+	 * painting every other line black.  Also, I assume any skipped
 	 * pixels are painted with color 0, which is often black.  Nowhere
 	 * is it specified what we should assume for missing pixels.  This
 	 * is undoubtedly the most brain-dead format I've ever encountered.
@@ -323,6 +323,7 @@ BMPreadScanline(BMPReader *br)
 		case 0:			/* end of line */
 			while (n--)
 				*sp++ = 0;
+			/* leaves n == -1 as flag for test after loop */
 			continue;
 		case 1:			/* end of bitmap */
 		case 2:			/* delta */
@@ -347,8 +348,8 @@ BMPreadScanline(BMPReader *br)
 			return BIR_TRUNCATED;
 	}
 					/* verify break at end of line */
-	if (rdbyte(n, br) != 0 || (rdbyte(n, br) != 0 &&
-				(n != 1 || br->yscan != br->hdr->height-1)))
+	if (!n && (rdbyte(n, br) != 0 || (rdbyte(n, br) != 0 &&
+				(n != 1 || br->yscan != br->hdr->height-1))))
 		return BIR_RLERROR;
 	if (br->seek != NULL)		/* record next scanline position */
 		br->scanpos[br->yscan + 1] = br->fpos;
@@ -522,7 +523,7 @@ BMPtruecolorHeader(int xr, int yr, int infolen)
 	return hdr;
 }
 
-/* allocate color-mapped header (defaults minimal grayscale) */
+/* allocate color-mapped header (defaults to minimal grayscale) */
 BMPHeader *
 BMPmappedHeader(int xr, int yr, int infolen, int ncolors)
 {
@@ -549,7 +550,7 @@ BMPmappedHeader(int xr, int yr, int infolen, int ncolo
 	hdr->height = yr;
 	hdr->yIsDown = 0;			/* default to upwards order */
 	hdr->bpp = n;
-	hdr->compr = BI_UNCOMPR;
+	hdr->compr = BI_UNCOMPR;		/* compression needs seek */
 	hdr->hRes = hdr->vRes = 2835;		/* default to 72 ppi */
 	hdr->nColors = ncolors;
 	hdr->impColors = 0;			/* says all colors important */
@@ -628,8 +629,10 @@ BMPopenWriter(void (*cput)(int, void *), int (*seek)(u
 		return NULL;
 	if ((hdr->bpp == 16) | (hdr->compr == BI_RLE4))
 		return NULL;			/* unsupported */
+/* no seek means we may have the wrong file length, but most app's don't care
 	if (seek == NULL && ((hdr->compr == BI_RLE8) | (hdr->compr == BI_RLE4)))
 		return NULL;
+*/
 						/* compute sizes */
 	hdrSiz = 2 + 6*4 + 2*2 + 6*4;
 	if (hdr->compr == BI_BITFIELDS)
@@ -696,8 +699,8 @@ findNextRun(const int8 *bp, int len)
 			continue;
 		cnt = 1;			/* else let's try it */
 		while (bp[cnt] == bp[0])
-			if (++cnt >= 5)		/* long enough */
-				return pos;
+			if (++cnt >= 5)
+				return pos;     /* long enough */
 	}
 	return pos;				/* didn't find any */
 }
@@ -749,18 +752,19 @@ BMPwriteScanline(BMPWriter *bw)
 		if (n <= 0)			/* was that it? */
 			break;
 		val = *sp;			/* output run */
-		for (cnt = 1; (--n > 0) & (*++sp == val); cnt++)
-			;
+		for (cnt = 1; cnt < 255; cnt++)
+			if (!--n | *++sp != val)
+				break;
 		wrbyte(cnt, bw);
 		wrbyte(val, bw);
 	}
-	bw->yscan++;				/* write file length at end */
+	bw->yscan++;				/* write line break or EOD */
 	if (bw->yscan == bw->hdr->height) {
 		wrbyte(0, bw); wrbyte(1, bw);   /* end of bitmap marker */
 		if (bw->seek == NULL || (*bw->seek)(2, bw->c_data) != 0)
-			return BIR_SEEKERR;
+			return BIR_OK;		/* no one may care */
 		bw->fpos = 2;
-		wrint32(bw->flen, bw);		/* corrected file length */
+		wrint32(bw->flen-bw->fbmp, bw); /* correct bitmap length */
 	} else {
 		wrbyte(0, bw); wrbyte(0, bw);   /* end of line marker */
 	}