Fix map() division by zero (#2848)

ArturBieniek4 · me-no-dev · commit 89feacb813f3 · 2019-06-05T13:48:13.000+02:00
diff --git a/cores/esp32/WMath.cpp b/cores/esp32/WMath.cpp
@@ -65,9 +65,12 @@ long random(long howsmall, long howbig)
     return random(diff) + howsmall;
 }
 
-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 map(long x, long in_min, long in_max, long out_min, long out_max) {
+    long divisor = (in_max - in_min);
+    if(divisor == 0){
+        return -1; //AVR returns -1, SAM returns 0
+    }
+    return (x - in_min) * (out_max - out_min) / divisor + out_min;
 }
 
 unsigned int makeWord(unsigned int w)

Original file line number	Diff line number	Diff line change
`@@ -65,9 +65,12 @@ long random(long howsmall, long howbig)`
`65`	`65`	`return random(diff) + howsmall;`
`66`	`66`	`}`
`67`	`67`
`68`		`-long map(long x, long in_min, long in_max, long out_min, long out_max)`
`69`		`-{`
`70`		`- return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;`
	`68`	`+long map(long x, long in_min, long in_max, long out_min, long out_max) {`
	`69`	`+ long divisor = (in_max - in_min);`
	`70`	`+ if(divisor == 0){`
	`71`	`+ return -1; //AVR returns -1, SAM returns 0`
	`72`	`+ }`
	`73`	`+ return (x - in_min) * (out_max - out_min) / divisor + out_min;`
`71`	`74`	`}`
`72`	`75`
`73`	`76`	`unsigned int makeWord(unsigned int w)`