--- ray/src/common/bmpfile.c	2004/03/26 23:30:05	2.4
+++ ray/src/common/bmpfile.c	2004/04/30 17:00:29	2.10
@@ -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 2.10 2004/04/30 17:00:29 greg Exp $";
 #endif
 /*
  *  Windows and OS/2 BMP file support
@@ -10,6 +10,11 @@ static const char RCSid[] = "$Id: bmpfile.c,v 2.4 2004
 #include <string.h>
 #include "bmpfile.h"
 
+#ifdef getc_unlocked		/* avoid horrendous overhead of flockfile */
+#define getc    getc_unlocked
+#define putc    putc_unlocked
+#endif
+
 /* get corresponding error message */
 const char *
 BMPerrorMessage(int ec)
@@ -232,9 +237,8 @@ BMPopenReader(int (*cget)(void *), int (*seek)(uint32,
 				sizeof(br->scanpos[0])*br->hdr->height);
 	}
 	br->scanpos[0] = br->fpos;
-	if (BMPreadScanline(br) != BIR_OK)
-		goto err;
-	return br;
+	if (BMPreadScanline(br) == BIR_OK)
+		return br;
 err:
 	if (br->hdr != NULL)
 		free((void *)br->hdr);
@@ -255,7 +259,7 @@ 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 */
@@ -275,14 +279,14 @@ BMPreadScanline(BMPReader *br)
 	if (br->hdr->compr == BI_UNCOMPR || br->hdr->compr == BI_BITFIELDS)
 		return rdbytes((char *)br->scanline, n, br);
 	/*
-	 * RLE/RLE8 Decoding
+	 * RLE4/RLE8 Decoding
 	 *
 	 * 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.
+	 * Whoever thought this up should be wrestled to the ground and told
+	 * why 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
@@ -291,12 +295,15 @@ 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.
 	 */
 	sp = br->scanline;
+	n = br->hdr->width;
+	if (br->hdr->compr == BI_RLE4)
+		n = (n + 1) >> 1;
 	while (n > 0) {
 		int     skipOdd, len, val;
 
@@ -317,12 +324,14 @@ BMPreadScanline(BMPReader *br)
 				*sp++ = val;
 			continue;
 		}
+					/* check for escape */
 		switch (rdbyte(len, br)) {
 		case EOF:
 			return BIR_TRUNCATED;
 		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 +356,8 @@ 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 +531,7 @@ 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 +558,7 @@ 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 */
@@ -599,13 +608,8 @@ wrseek(uint32 pos, BMPWriter *bw)
 {
 	if (pos == bw->fpos)
 		return BIR_OK;
-	if (bw->seek == NULL) {
-		if (pos < bw->fpos)
-			return BIR_SEEKERR;
-		while (bw->fpos < pos)
-			wrbyte(0, bw);
-		return BIR_OK;
-	}
+	if (bw->seek == NULL)
+		return BIR_SEEKERR;
 	if ((*bw->seek)(pos, bw->c_data) != 0)
 		return BIR_SEEKERR;
 	bw->fpos = pos;
@@ -628,8 +632,10 @@ 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 +702,8 @@ 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 */
 }
@@ -734,9 +740,8 @@ BMPwriteScanline(BMPWriter *bw)
 	n = bw->hdr->width;
 	while (n > 0) {
 		int     cnt, val;
-
 		cnt = findNextRun(sp, n);       /* 0-255 < n */
-		if (cnt >= 3) {			/* output non-run */
+		if (cnt >= 3) {			/* output absolute */
 			int     skipOdd = cnt & 1;
 			wrbyte(0, bw);
 			wrbyte(cnt, bw);
@@ -749,18 +754,21 @@ 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; --n && cnt < 255; cnt++)
+			if (*++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;
-		bw->fpos = 2;
-		wrint32(bw->flen, bw);		/* corrected file length */
+		if (wrseek(2, bw) != BIR_OK)
+			return BIR_OK;		/* no one may care */
+		wrint32(bw->flen, bw);		/* correct file length */
+		if (wrseek(34, bw) != BIR_OK)
+			return BIR_OK;
+		wrint32(bw->flen-bw->fbmp, bw); /* correct bitmap length */
 	} else {
 		wrbyte(0, bw); wrbyte(0, bw);   /* end of line marker */
 	}