From f0cdbba1116e02efb38de2b3a976489cb57d5491 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ghostscript.com>
Date: Mon, 23 Aug 2010 16:30:12 +0000
Subject: Guard against divide-by-zero in stitched function evaluations where
 the bounds for an entry are zero-sized.

---
 mupdf/pdf_function.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mupdf/pdf_function.c b/mupdf/pdf_function.c
index 603759e1..a7e26e24 100644
--- a/mupdf/pdf_function.c
+++ b/mupdf/pdf_function.c
@@ -65,8 +65,14 @@ struct pdf_function_s
 
 #define RADIAN 57.2957795
 
-#define LERP(x, xmin, xmax, ymin, ymax) \
-	(ymin) + ((x) - (xmin)) * ((ymax) - (ymin)) / ((xmax) - (xmin))
+static inline float LERP(float x, float xmin, float xmax, float ymin, float ymax)
+{
+	if (xmin == xmax)
+		return ymin;
+	if (ymin == ymax)
+		return ymin;
+	return ymin + (x - xmin) * (ymax - ymin) / (xmax - xmin);
+}
 
 enum { PSBOOL, PSINT, PSREAL, PSOPERATOR, PSBLOCK };
 
-- 
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