From 30222c13d66545b6e3a278059117be104cf341cd Mon Sep 17 00:00:00 2001
From: Su_Laus <sulau@freenet.de>
Date: Sat, 29 Feb 2020 17:59:59 +0100
Subject: [PATCH] tif_dirwrite.c: bugfix DoubleToSrational(), which returns
 plain signed interger values always as unsigned rationals. Add a test into
 rational_precision2double.c for "-1.0" and some editorials in tif_dirwrite.c.
 (code is related to 6df997c786928757caea0dd68d26ea5f098f49df changes).

---
 libtiff/tif_dirwrite.c           | 18 +++++++++---------
 test/rational_precision2double.c |  5 +++--
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c
index 410c8adb..4c622804 100644
--- a/libtiff/tif_dirwrite.c
+++ b/libtiff/tif_dirwrite.c
@@ -162,8 +162,8 @@ static int TIFFWriteDirectoryTagRationalDoubleArray(TIFF* tif, uint32* ndir, TIF
 static int TIFFWriteDirectoryTagSrationalDoubleArray(TIFF* tif, uint32* ndir, TIFFDirEntry* dir, uint16 tag, uint32 count, double* value);
 static int TIFFWriteDirectoryTagCheckedRationalDoubleArray(TIFF* tif, uint32* ndir, TIFFDirEntry* dir, uint16 tag, uint32 count, double* value);
 static int TIFFWriteDirectoryTagCheckedSrationalDoubleArray(TIFF* tif, uint32* ndir, TIFFDirEntry* dir, uint16 tag, uint32 count, double* value);
-static void DoubleToRational(double f, uint32 *num, uint32 *denom);
-static void DoubleToSrational(double f, int32 *num, int32 *denom);
+static void DoubleToRational(double value, uint32 *num, uint32 *denom);
+static void DoubleToSrational(double value, int32 *num, int32 *denom);
 #if 0
 static void DoubleToRational_direct(double value, unsigned long *num, unsigned long *denom);
 static void DoubleToSrational_direct(double value, long *num, long *denom);
@@ -2893,7 +2893,7 @@ void DoubleToSrational(double value, int32 *num, int32 *denom)
 	double dblDiff, dblDiff2;
 	unsigned long long ullNum, ullDenom, ullNum2, ullDenom2;
 
-	/*-- Check for negative values and use then the positive one for internal calculations. */
+	/*-- Check for negative values and use then the positive one for internal calculations, but take the sign into account before returning. */
 	if (value < 0) { neg = -1; value = -value; }
 
 	/*-- Check for too big numbers (> LONG_MAX) -- */
@@ -2903,8 +2903,8 @@ void DoubleToSrational(double value, int32 *num, int32 *denom)
 		return;
 	}
 	/*-- Check for easy numbers -- */
-	if (value == (uint32)(value)) {
-		*num = (uint32)value;
+	if (value == (int32)(value)) {
+		*num = (int32)(neg * value);
 		*denom = 1;
 		return;
 	}
@@ -2936,12 +2936,12 @@ void DoubleToSrational(double value, int32 *num, int32 *denom)
 	dblDiff = fabs(value - ((double)ullNum / (double)ullDenom));
 	dblDiff2 = fabs(value - ((double)ullNum2 / (double)ullDenom2));
 	if (dblDiff < dblDiff2) {
-		*num = (uint32)(neg * (long)ullNum);
-		*denom = (uint32)ullDenom;
+		*num = (int32)(neg * (long)ullNum);
+		*denom = (int32)ullDenom;
 	}
 	else {
-		*num = (uint32)(neg * (long)ullNum2);
-		*denom = (uint32)ullDenom2;
+		*num = (int32)(neg * (long)ullNum2);
+		*denom = (int32)ullDenom2;
 	}
 }  /*-- DoubleToSrational() --------------*/
 
diff --git a/test/rational_precision2double.c b/test/rational_precision2double.c
index 782fb9fa..e33cc97d 100644
--- a/test/rational_precision2double.c
+++ b/test/rational_precision2double.c
@@ -498,7 +498,8 @@ write_test_tiff(TIFF* tif, const char* filenameRead, int blnAllCustomTags) {
 				fprintf(stderr, "Can't set TIFFTAG_RATIONAL_DOUBLE tag.\n");
 				goto failure;
 			}
-			if (!TIFFSetField(tif, TIFFTAG_SRATIONAL_DOUBLE, (-1.0 * auxDoubleArrayW[101]))) {
+			/* test for plain integers */
+			if (!TIFFSetField(tif, TIFFTAG_SRATIONAL_DOUBLE, (-1.0 ))) {
 				fprintf(stderr, "Can't set TIFFTAG_SRATIONAL_DOUBLE tag.\n");
 				goto failure;
 			}
@@ -764,7 +765,7 @@ write_test_tiff(TIFF* tif, const char* filenameRead, int blnAllCustomTags) {
 			auxDblUnion.dbl = 0;
 			retCode = TIFFGetField(tif, TIFFTAG_SRATIONAL_DOUBLE, &auxDblUnion.dbl);
 			if (!retCode) { fprintf(stderr, "Can't read %s\n", "TIFFTAG_SRATIONAL_DOUBLE"); GOTOFAILURE }
-			auxDouble = -1.0 * auxDoubleArrayW[101];
+			auxDouble = -1.0; 
 			dblDiffLimit = RATIONAL_EPS * auxDouble;
 			dblDiff = auxDblUnion.dbl - auxDouble;
 			if (fabs(dblDiff) > fabs(dblDiffLimit)) {