get_charge_state hexbright

// charging constants
#define CHARGING 1
#define BATTERY 7
#define CHARGED 3


        // returns CHARGING, CHARGED, or BATTERY
    // This reads the charge state twice with a small delay, then returning
    //  the actual charge state.  BATTERY will never be returned if we are
    //  plugged in.
    // Use this if you take actions based on the charge state (example: you
    //  turn on when you stop charging).  Takes up 56 bytes (34+22).
    static byte get_definite_charge_state();
    // returns CHARGING, CHARGED, or BATTERY
    // This reads and returns the charge state, without any verification.
    //  As a result, it may report BATTERY when switching between CHARGED
    //  and CHARGING.
    // Use this if you don't care if the value is sometimes wrong (charging
    //  notification).  Takes up 34 bytes.
    static byte get_charge_state();


byte hexbright::get_charge_state() {
  int charge_value = analogRead(APIN_CHARGE);
#if (DEBUG==DEBUG_CHARGE)
  Serial.print("Current charge reading: ");
  Serial.println(charge_value);
#endif
  // <128 charging, >768 charged, battery
  if(charge_value<128)
    return CHARGING;
  else if (charge_value>768)
    return CHARGED;
  return BATTERY;
}

// reading twice costs us 28 bytes, but improves reliability.
// The root problem is when the charge value goes from <128 to >768 (or the
//  reverse, from topping off), it passes through the middle range.  If we
//  read at the wrong time, we can get a BATTERY value while we are still
//  plugged in.
// Reading twice with a sufficient delay, we can guarantee that our state is correct.
byte hexbright::get_definite_charge_state() {
  byte val1 = get_charge_state();
  // do something that will take some time...
  // delayMicroseconds costs an extra 20 bytes (because nowhere else is it called)
  // If other code needs delayMicroseconds, switch to it.
  //delayMicroseconds(30);
  read_thermal_sensor(); // delay a little...
  byte val2 = get_charge_state();
  // BATTERY & CHARGING = CHARGING, BATTERY & CHARGED = CHARGED, CHARGED & CHARGING = CHARGING
  // In essence, only return the middle value (BATTERY) if two reads report the same thing.
  return val1 & val2;
}