Use a single variable to track isAwake() state

Author: sandeepmistry

src/WiFi.cpp

@@ -173,6 +173,7 @@ WiFiClass::WiFiClass()
 	_mode = WL_RESET_MODE;
 	_status = WL_NO_SHIELD;
 	_init = 0;
+	_wakeUpMillis = 0;
 }
 
 void WiFiClass::setPins(int8_t cs, int8_t irq, int8_t rst, int8_t en)
@@ -783,23 +784,14 @@ void WiFiClass::noLowPowerMode(void)
 
 void WiFiClass::sleepFor(uint32_t thisTime)
 {
-  m2m_wifi_set_sleep_mode(M2M_PS_MANUAL, false);
-  _sleepTime = thisTime + 150; //150 ms must elapse for complete awakening
-  _startSleepTime = millis();
-  m2m_wifi_request_sleep(thisTime);
+	m2m_wifi_set_sleep_mode(M2M_PS_MANUAL, false);
+	_wakeUpMillis = millis() + thisTime + 150; //150 ms must elapse for complete awakening
+	m2m_wifi_request_sleep(thisTime);
 }
 
 bool WiFiClass::isAwake(void)
 {
-  if (_sleepTime == 0)
-    return true;
-
-  if (millis() - _startSleepTime > _sleepTime) {
-    _sleepTime = 0;
-    return true;
-  }
-  else
-    return false;
+	return (millis() > _wakeUpMillis);
 }
 
 uint8_t WiFiClass::ping(const char* hostname, uint8_t ttl)

src/WiFi101.h

@@ -164,7 +164,7 @@ class WiFiClass
 	int _init;
 	char _version[9];
 
-	unsigned long _startSleepTime, _sleepTime;
+	uint32_t _wakeUpMillis;
 
 	uint8_t startConnect(const char *ssid, uint8_t u8SecType, const void *pvAuthInfo);
 	uint8_t startAP(const char *ssid, uint8_t u8SecType, const void *pvAuthInfo, uint8_t channel);