From 9a935c7e2350d3bd3d06fa53db58905fbae2dc63 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sat, 12 Dec 2020 15:31:05 +0100
Subject: [PATCH] DoubleToRational(): avoid casting NaN to uint32 (fixes #227)

---
 libtiff/tif_dirwrite.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c
index 952d107b..f481250e 100644
--- a/libtiff/tif_dirwrite.c
+++ b/libtiff/tif_dirwrite.c
@@ -2826,7 +2826,8 @@ void DoubleToRational(double value, uint32 *num, uint32 *denom)
 	unsigned long long ullNum, ullDenom, ullNum2, ullDenom2;
 
 	/*-- Check for negative values. If so it is an error. */
-	if (value < 0) {
+        /* Test written that way to catch NaN */
+	if (!(value >= 0)) {
 		*num = *denom = 0;
 		TIFFErrorExt(0, "TIFFLib: DoubleToRational()", " Negative Value for Unsigned Rational given.");
 		return;