detect division by zero in map() to prevent exceptions (esp8266#2397)

me-no-dev · web-flow · commit fb00e64a6f65 · 2016-08-18T10:50:59.000+03:00
Will return -1 like AVR would
diff --git 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) {

Original file line number	Diff line number	Diff line change
`@@ -70,7 +70,11 @@ long secureRandom(long howsmall, long howbig) {`
`70`	`70`	`}`
`71`	`71`
`72`	`72`	`long map(long x, long in_min, long in_max, long out_min, long out_max) {`
`73`		`- return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;`
	`73`	`+ long divisor = (in_max - in_min) + out_min;`
	`74`	`+ if(divisor == 0){`
	`75`	`+ return -1; //AVR returns -1, SAM returns 0`
	`76`	`+ }`
	`77`	`+ return (x - in_min) * (out_max - out_min) / divisor;`
`74`	`78`	`}`
`75`	`79`
`76`	`80`	`unsigned int makeWord(unsigned int w) {`