WiFiOTA.cpp - check for positive return value from read(buff,size)

some libraries return -1 if no data are available

Author: JAndrassy

src/WiFiOTA.cpp

@@ -299,10 +299,12 @@ void WiFiOTAClass::pollServer(Client& client)
     while (client.connected() && read < contentLength) {
       while (client.available()) {
         int l = client.read(buff, sizeof(buff));
-        for (int i = 0; i < l; i++) {
-          _storage->write(buff[i]);
+        if (l > 0) { // some libraries return -1 if no data are available
+          for (int i = 0; i < l; i++) {
+            _storage->write(buff[i]);
+          }
+          read += l;
         }
-        read += l;
       }
     }