altoslib: Use GPS seconds as an additional sort key for TeleGPS eeprom

Long idle periods with TeleGPS can easily overflow 16 bits of tick
count. Using the GPS seconds provides an additional sort which will
span the tick wrap-around.

Signed-off-by: Keith Packard <keithp@keithp.com>

3 files changed, 23 insertions, 1 deletions

diff --git a/altoslib/AltosEeprom.java b/altoslib/AltosEeprom.java
index be18ba24..020590eb 100644
--- a/altoslib/AltosEeprom.java
+++ b/altoslib/AltosEeprom.java
@@ -43,6 +43,10 @@ public abstract class AltosEeprom implements AltosStateUpdate {
 		return data8[i] | (data8[i+1] << 8) | (data8[i+2] << 16) | (data8[i+3] << 24);
 	}
 
+	public boolean has_seconds() { return false; }
+
+	public int seconds() { return 0; }
+
 	public final static int header_length = 4;
 
 	public abstract int record_length();
diff --git a/altoslib/AltosEepromGPS.java b/altoslib/AltosEepromGPS.java
index 1820cd61..3c1852c0 100644
--- a/altoslib/AltosEepromGPS.java
+++ b/altoslib/AltosEepromGPS.java
@@ -53,6 +53,17 @@ public class AltosEepromGPS extends AltosEeprom {
 	public int vdop() { return data8(24); }
 	public int mode() { return data8(25); }
 
+	public boolean has_seconds() { return cmd == AltosLib.AO_LOG_GPS_TIME; }
+
+	public int seconds() {
+		switch (cmd) {
+		case AltosLib.AO_LOG_GPS_TIME:
+			return second() + 60 * (minute() + 60 * (hour() + 24 * (day() + 31 * month())));
+		default:
+			return 0;
+		}
+	}
+
 	public AltosEepromGPS (AltosEepromChunk chunk, int start) throws ParseException {
 		parse_chunk(chunk, start);
 	}
diff --git a/altoslib/AltosEepromIterable.java b/altoslib/AltosEepromIterable.java
index 415c5b62..d6832c1b 100644
--- a/altoslib/AltosEepromIterable.java
+++ b/altoslib/AltosEepromIterable.java
@@ -38,6 +38,13 @@ class AltosEepromOrdered implements Comparable<AltosEepromOrdered> {
 		if (cmd_diff != 0)
 			return cmd_diff;
 
+		if (eeprom.has_seconds() && o.eeprom.has_seconds()) {
+			int	seconds_diff = eeprom.seconds() - o.eeprom.seconds();
+
+			if (seconds_diff != 0)
+				return seconds_diff;
+		}
+
 		int	tick_diff = tick - o.tick;
 
 		if (tick_diff != 0)
@@ -116,4 +123,4 @@ public class AltosEepromIterable implements Iterable<AltosEeprom> {
 			eeproms = new LinkedList<AltosEeprom>();
 		return new AltosEepromOrderedIterator(eeproms);
 	}
-}
\ No newline at end of file
+}