From fb00e64a6f65dede8d897d07a28d7d02f74ae742 Mon Sep 17 00:00:00 2001
From: Me No Dev <me-no-dev@users.noreply.github.com>
Date: Thu, 18 Aug 2016 10:50:59 +0300
Subject: [PATCH] detect division by zero in map() to prevent exceptions
 (#2397)

Will return -1 like AVR would
---
 cores/esp8266/WMath.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/cores/esp8266/WMath.cpp b/cores/esp8266/WMath.cpp
index 13c2452dc..d9d87da5a 100644
--- a/cores/esp8266/WMath.cpp
+++ b/cores/esp8266/WMath.cpp
@@ -70,7 +70,11 @@ long secureRandom(long howsmall, long howbig) {
 }
 
 long map(long x, long in_min, long in_max, long out_min, long out_max) {
-    return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+    long divisor = (in_max - in_min) + out_min;
+    if(divisor == 0){
+        return -1; //AVR returns -1, SAM returns 0
+    }
+    return (x - in_min) * (out_max - out_min) / divisor;
 }
 
 unsigned int makeWord(unsigned int w) {