From c6f41f0176d744de5de1ca48e764148ed18e6489 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sat, 16 Mar 2019 01:51:05 +0100
Subject: ocea: avoid division by zero

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11699
Credit to OSS Fuzz
---
 src/projections/ocea.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/projections/ocea.cpp b/src/projections/ocea.cpp
index 4930e587..4e28f727 100644
--- a/src/projections/ocea.cpp
+++ b/src/projections/ocea.cpp
@@ -87,7 +87,16 @@ PJ *PROJECTION(ocea) {
             lam_p = -lam_p;
 
         /*Equation 9-2 page 80 (http://pubs.usgs.gov/pp/1395/report.pdf)*/
-        phi_p = atan(-cos(lam_p - lam_1) / tan(phi_1));
+        double cos_lamp_m_minus_lam_1 = cos(lam_p - lam_1);
+        double tan_phi_1 = tan(phi_1);
+        if( tan_phi_1 == 0.0 ) {
+            // Not sure if we want to support this case, but at least this avoids
+            // a division by zero, and gives the same result as the below atan()
+            phi_p = (cos_lamp_m_minus_lam_1 >= 0.0 ) ? -M_HALFPI : M_HALFPI;
+        }
+        else {
+            phi_p = atan(- cos_lamp_m_minus_lam_1 / tan_phi_1);
+        }
     }
     P->lam0 = lam_p + M_HALFPI;
     Q->cosphi = cos(phi_p);
-- 
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