From: Keith Packard <keithp@keithp.com>
Date: Tue, 23 May 2017 21:53:55 +0000 (-0700)
Subject: altoslib: Don't store computed telemetry fields
X-Git-Tag: 1.8~97
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=7600116a191b3ac252a0f716d200d0e0b3500987

altoslib: Don't store computed telemetry fields

These values are only needed once, so there's no reason to save them.

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

diff --git a/altoslib/AltosTelemetry.java b/altoslib/AltosTelemetry.java
index f830bf35..5600e7be 100644
--- a/altoslib/AltosTelemetry.java
+++ b/altoslib/AltosTelemetry.java
@@ -25,12 +25,15 @@ import java.text.*;
  */
 
 public abstract class AltosTelemetry implements AltosStateUpdate {
+	int[]	bytes;
 
 	/* All telemetry packets have these fields */
-	public int	tick;
-	public int	serial;
-	public int	rssi;
-	public int	status;
+	public int rssi() { return AltosConvert.telem_to_rssi(AltosLib.int8(bytes, bytes.length - 3)); }
+	public int status() { return AltosLib.uint8(bytes, bytes.length - 2); }
+
+	/* All telemetry packets report these fields in some form */
+	public abstract int serial();
+	public abstract int tick();
 
 	/* Mark when we received the packet */
 	long		received_time;
@@ -44,11 +47,11 @@ public abstract class AltosTelemetry implements AltosStateUpdate {
 	}
 
 	public void update_state(AltosState state) {
-		state.set_serial(serial);
+		state.set_serial(serial());
 		if (state.state() == AltosLib.ao_flight_invalid)
 			state.set_state(AltosLib.ao_flight_startup);
-		state.set_tick(tick);
-		state.set_rssi(rssi, status);
+		state.set_tick(tick());
+		state.set_rssi(rssi(), status());
 		state.set_received_time(received_time);
 	}
 
@@ -88,12 +91,6 @@ public abstract class AltosTelemetry implements AltosStateUpdate {
 		if (!cksum(bytes))
 			throw new ParseException(String.format("invalid line \"%s\"", hex), 0);
 
-		int	rssi = AltosLib.int8(bytes, bytes.length - 3) / 2 - 74;
-		int	status = AltosLib.uint8(bytes, bytes.length - 2);
-
-		if ((status & PKT_APPEND_STATUS_1_CRC_OK) == 0)
-			throw new AltosCRCException(rssi);
-
 		/* length, data ..., rssi, status, checksum -- 4 bytes extra */
 		switch (bytes.length) {
 		case AltosLib.ao_telemetry_standard_len + 4:
@@ -108,11 +105,6 @@ public abstract class AltosTelemetry implements AltosStateUpdate {
 		default:
 			throw new ParseException(String.format("Invalid packet length %d", bytes.length), 0);
 		}
-		if (telem != null) {
-			telem.received_time = System.currentTimeMillis();
-			telem.rssi = rssi;
-			telem.status = status;
-		}
 		return telem;
 	}
 
@@ -139,6 +131,17 @@ public abstract class AltosTelemetry implements AltosStateUpdate {
 		return height;
 	}
 
+	public AltosTelemetry() {
+		this.received_time = System.currentTimeMillis();
+	}
+
+	public AltosTelemetry(int[] bytes) throws AltosCRCException {
+		this();
+		this.bytes = bytes;
+		if ((status() & PKT_APPEND_STATUS_1_CRC_OK) == 0)
+			throw new AltosCRCException(rssi());
+	}
+
 	public static AltosTelemetry parse(String line) throws ParseException, AltosCRCException {
 		String[] word = line.split("\\s+");
 		int i =0;
@@ -149,7 +152,7 @@ public abstract class AltosTelemetry implements AltosStateUpdate {
 			throw new AltosCRCException(AltosParse.parse_int(word[i++]));
 		}
 
-		AltosTelemetry telem;
+		AltosTelemetry telem = null;
 
 		if (word[i].equals("TELEM")) {
 			telem = parse_hex(word[i+1]);
diff --git a/altoslib/AltosTelemetryCompanion.java b/altoslib/AltosTelemetryCompanion.java
index a97fda2d..2c05e245 100644
--- a/altoslib/AltosTelemetryCompanion.java
+++ b/altoslib/AltosTelemetryCompanion.java
@@ -19,21 +19,16 @@
 package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryCompanion extends AltosTelemetryStandard {
-	AltosCompanion	companion;
-
-	static final public int max_channels = 12;
-
-	public AltosTelemetryCompanion(int[] bytes) {
-		super(bytes);
 
+	AltosCompanion	companion() {
 		int	channels = uint8(7);
 
 		if (channels > max_channels)
 			channels = max_channels;
 
-		companion = new AltosCompanion(channels);
+		AltosCompanion companion = new AltosCompanion(channels);
 
-		companion.tick = tick;
+		companion.tick = tick();
 		companion.board_id = uint8(5);
 		companion.update_period = uint8(6);
 
@@ -45,11 +40,17 @@ public class AltosTelemetryCompanion extends AltosTelemetryStandard {
 			for (int i = 0; i < channels; i++)
 				companion.companion_data[i] = uint16(8 + i * 2);
 		}
+		return companion;
+	}
+
+	static final public int max_channels = 12;
+
+	public AltosTelemetryCompanion(int[] bytes) throws AltosCRCException {
+		super(bytes);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
-
-		state.set_companion(companion);
+		state.set_companion(companion());
 	}
 }
diff --git a/altoslib/AltosTelemetryConfiguration.java b/altoslib/AltosTelemetryConfiguration.java
index 6ded5461..d91a03fc 100644
--- a/altoslib/AltosTelemetryConfiguration.java
+++ b/altoslib/AltosTelemetryConfiguration.java
@@ -20,43 +20,32 @@ package org.altusmetrum.altoslib_11;
 
 
 public class AltosTelemetryConfiguration extends AltosTelemetryStandard {
-	int	device_type;
-	int	flight;
-	int	config_major;
-	int	config_minor;
-	int	apogee_delay;
-	int	main_deploy;
-	int	v_batt;
-	int	flight_log_max;
-	String	callsign;
-	String	version;
+	int	device_type() { return uint8(5); }
+	int	flight() { return uint16(6); }
+	int	config_major() { return uint8(8); }
+	int	config_minor() { return uint8(9); }
+	int	apogee_delay() { return uint16(10); }
+	int	main_deploy() { return uint16(12); }
+	int	v_batt() { return uint16(10); }
+	int	flight_log_max() { return uint16(14); }
+	String	callsign() { return string(16, 8); }
+	String	version() { return string(24, 8); }
 
-	public AltosTelemetryConfiguration(int[] bytes) {
+	public AltosTelemetryConfiguration(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		device_type    = uint8(5);
-		flight         = uint16(6);
-		config_major   = uint8(8);
-		config_minor   = uint8(9);
-		v_batt	       = uint16(10);
-		apogee_delay   = uint16(10);
-		main_deploy    = uint16(12);
-		flight_log_max = uint16(14);
-		callsign       = string(16, 8);
-		version        = string(24, 8);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
-		state.set_device_type(device_type);
-		state.set_flight(flight);
-		state.set_config(config_major, config_minor, flight_log_max);
-		if (device_type == AltosLib.product_telegps)
-			state.set_battery_voltage(AltosConvert.tele_gps_voltage(v_batt));
+		state.set_device_type(device_type());
+		state.set_flight(flight());
+		state.set_config(config_major(), config_minor(), flight_log_max());
+		if (device_type() == AltosLib.product_telegps)
+			state.set_battery_voltage(AltosConvert.tele_gps_voltage(v_batt()));
 		else
-			state.set_flight_params(apogee_delay, main_deploy);
+			state.set_flight_params(apogee_delay(), main_deploy());
 
-		state.set_callsign(callsign);
-		state.set_firmware_version(version);
+		state.set_callsign(callsign());
+		state.set_firmware_version(version());
 	}
 }
diff --git a/altoslib/AltosTelemetryIterable.java b/altoslib/AltosTelemetryIterable.java
index 0cba86a3..402bbf4f 100644
--- a/altoslib/AltosTelemetryIterable.java
+++ b/altoslib/AltosTelemetryIterable.java
@@ -67,7 +67,7 @@ public class AltosTelemetryIterable implements Iterable<AltosTelemetry> {
 	int index;
 
 	public void add (AltosTelemetry telem) {
-		int	t = telem.tick;
+		int	t = telem.tick();
 		if (!telems.isEmpty()) {
 			while (t < tick - 1000)
 				t += 65536;
diff --git a/altoslib/AltosTelemetryLegacy.java b/altoslib/AltosTelemetryLegacy.java
index 08c52986..2907f111 100644
--- a/altoslib/AltosTelemetryLegacy.java
+++ b/altoslib/AltosTelemetryLegacy.java
@@ -233,6 +233,17 @@ public class AltosTelemetryLegacy extends AltosTelemetry {
 	final static String AO_TELEM_SAT_SVID	= "s_v";
 	final static String AO_TELEM_SAT_C_N_0	= "s_c";
 
+	public int	tick;
+	public int	serial;
+	public int	rssi;
+	public int	status;
+
+	public int tick() { return tick; }
+	public int serial() { return serial; }
+
+	public int rssi() { return rssi; }
+	public int status() { return status; }
+
 	public int	version;
 	public String 	callsign;
 	public int	flight;
@@ -271,7 +282,6 @@ public class AltosTelemetryLegacy extends AltosTelemetry {
 		flight = map.get_int(AO_TELEM_FLIGHT, AltosLib.MISSING);
 		rssi = map.get_int(AO_TELEM_RSSI, AltosLib.MISSING);
 		state = AltosLib.state(map.get_string(AO_TELEM_STATE, "invalid"));
-		tick = map.get_int(AO_TELEM_TICK, 0);
 
 		/* raw sensor values */
 		accel = map.get_int(AO_TELEM_RAW_ACCEL, AltosLib.MISSING);
@@ -420,7 +430,6 @@ public class AltosTelemetryLegacy extends AltosTelemetry {
 	 * Given a hex dump of a legacy telemetry line, construct an AltosRecordTM from that
 	 */
 
-	int[]	bytes;
 	int	adjust;
 
 	/*
@@ -452,8 +461,9 @@ public class AltosTelemetryLegacy extends AltosTelemetry {
 	static final int AO_GPS_DATE_VALID	= (1 << 6);
 	static final int AO_GPS_COURSE_VALID	= (1 << 7);
 
-	public AltosTelemetryLegacy(int[] in_bytes) {
-		bytes = in_bytes;
+	public AltosTelemetryLegacy(int[] in_bytes) throws AltosCRCException {
+		super(in_bytes);
+
 		version = 4;
 		adjust = 0;
 
@@ -463,6 +473,7 @@ public class AltosTelemetryLegacy extends AltosTelemetry {
 		} else
 			serial = uint16(0);
 
+		rssi = super.rssi();
 		callsign = string(62, 8);
 		flight = uint16(2);
 		state = uint8(4);
diff --git a/altoslib/AltosTelemetryLocation.java b/altoslib/AltosTelemetryLocation.java
index 11995640..8ad23ab6 100644
--- a/altoslib/AltosTelemetryLocation.java
+++ b/altoslib/AltosTelemetryLocation.java
@@ -20,76 +20,60 @@ package org.altusmetrum.altoslib_11;
 
 
 public class AltosTelemetryLocation extends AltosTelemetryStandard {
-	int	flags;
-	int	altitude;
-	int	latitude;
-	int	longitude;
-	int	year;
-	int	month;
-	int	day;
-	int	hour;
-	int	minute;
-	int	second;
-	int	pdop;
-	int	hdop;
-	int	vdop;
-	int	mode;
-	int	ground_speed;
-	int	climb_rate;
-	int	course;
+	int	flags() { return uint8(5); }
+	int	altitude() {
+		if ((mode() & AO_GPS_MODE_ALTITUDE_24) != 0)
+			return (int8(31) << 16) | uint16(6);
+		else
+			return int16(6);
+	}
+	int	latitude() { return uint32(8); }
+	int	longitude() { return uint32(12); }
+	int	year() { return uint8(16); }
+	int	month() { return uint8(17); }
+	int	day() { return uint8(18); }
+	int	hour() { return uint8(19); }
+	int	minute() { return uint8(20); }
+	int	second() { return uint8(21); }
+	int	pdop() { return uint8(22); }
+	int	hdop() { return uint8(23); }
+	int	vdop() { return uint8(24); }
+	int	mode() { return uint8(25); }
+	int	ground_speed() { return uint16(26); }
+	int	climb_rate() { return int16(28); }
+	int	course() { return uint8(30); }
 
 	public static final int	AO_GPS_MODE_ALTITUDE_24 = (1 << 0);	/* Reports 24-bits of altitude */
 
-	public AltosTelemetryLocation(int[] bytes) {
+	public AltosTelemetryLocation(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		flags          = uint8(5);
-		latitude       = uint32(8);
-		longitude      = uint32(12);
-		year	       = uint8(16);
-		month	       = uint8(17);
-		day	       = uint8(18);
-		hour	       = uint8(19);
-		minute	       = uint8(20);
-		second	       = uint8(21);
-		pdop	       = uint8(22);
-		hdop	       = uint8(23);
-		vdop	       = uint8(24);
-		mode	       = uint8(25);
-		ground_speed   = uint16(26);
-		climb_rate     = int16(28);
-		course	       = uint8(30);
-
-		if ((mode & AO_GPS_MODE_ALTITUDE_24) != 0) {
-			altitude = (int8(31) << 16) | uint16(6);
-		} else
-			altitude = int16(6);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 		AltosGPS	gps = state.make_temp_gps(false);
 
+		int flags = flags();
 		gps.nsat = flags & 0xf;
 		gps.locked = (flags & (1 << 4)) != 0;
 		gps.connected = (flags & (1 << 5)) != 0;
 
 		if (gps.locked) {
-			gps.lat = latitude * 1.0e-7;
-			gps.lon = longitude * 1.0e-7;
-			gps.alt = altitude;
-			gps.year = 2000 + year;
-			gps.month = month;
-			gps.day = day;
-			gps.hour = hour;
-			gps.minute = minute;
-			gps.second = second;
-			gps.ground_speed = ground_speed * 1.0e-2;
-			gps.course = course * 2;
-			gps.climb_rate = climb_rate * 1.0e-2;
-			gps.pdop = pdop / 10.0;
-			gps.hdop = hdop / 10.0;
-			gps.vdop = vdop / 10.0;
+			gps.lat = latitude() * 1.0e-7;
+			gps.lon = longitude() * 1.0e-7;
+			gps.alt = altitude();
+			gps.year = 2000 + year();
+			gps.month = month();
+			gps.day = day();
+			gps.hour = hour();
+			gps.minute = minute();
+			gps.second = second();
+			gps.ground_speed = ground_speed() * 1.0e-2;
+			gps.course = course() * 2;
+			gps.climb_rate = climb_rate() * 1.0e-2;
+			gps.pdop = pdop() / 10.0;
+			gps.hdop = hdop() / 10.0;
+			gps.vdop = vdop() / 10.0;
 		}
 		state.set_temp_gps();
 	}
diff --git a/altoslib/AltosTelemetryMegaData.java b/altoslib/AltosTelemetryMegaData.java
index 6ea5ec89..916f1e94 100644
--- a/altoslib/AltosTelemetryMegaData.java
+++ b/altoslib/AltosTelemetryMegaData.java
@@ -19,75 +19,54 @@
 package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryMegaData extends AltosTelemetryStandard {
-	int	state;
 
-	int	v_batt;
-	int	v_pyro;
-	int	sense[];
+	int	state() { return uint8(5); }
 
-	int	ground_pres;
-	int	ground_accel;
-	int	accel_plus_g;
-	int	accel_minus_g;
+	int	v_batt() { return int16(6); }
+	int	v_pyro() { return int16(8); }
+	int	sense(int i) { int v = uint8(10+i); return v << 4 | v >> 8; }
 
-	int	acceleration;
-	int	speed;
-	int	height_16;
+	int	ground_pres() { return int32(16); }
+	int	ground_accel() { return int16(20); }
+	int	accel_plus_g() { return int16(22); }
+	int	accel_minus_g() { return int16(24);}
 
-	public AltosTelemetryMegaData(int[] bytes) {
-		super(bytes);
-
-		state = uint8(5);
-
-		v_batt = int16(6);
-		v_pyro = int16(8);
-
-		sense = new int[6];
+	int	acceleration() { return int16(26); }
+	int	speed() { return int16(28); }
+	int	height_16() { return int16(30); }
 
-		for (int i = 0; i < 6; i++) {
-			sense[i] = uint8(10 + i) << 4;
-			sense[i] |= sense[i] >> 8;
-		}
-
-		ground_pres = int32(16);
-		ground_accel = int16(20);
-		accel_plus_g = int16(22);
-		accel_minus_g = int16(24);
-
-		acceleration = int16(26);
-		speed = int16(28);
-
-		height_16 = int16(30);
+	public AltosTelemetryMegaData(int[] bytes) throws AltosCRCException {
+		super(bytes);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_state(this.state);
+		state.set_state(state());
 
-		state.set_battery_voltage(AltosConvert.mega_battery_voltage(v_batt));
-		state.set_pyro_voltage(AltosConvert.mega_pyro_voltage(v_pyro));
+		state.set_battery_voltage(AltosConvert.mega_battery_voltage(v_batt()));
+		state.set_pyro_voltage(AltosConvert.mega_pyro_voltage(v_pyro()));
 
-		state.set_apogee_voltage(AltosConvert.mega_pyro_voltage(sense[4]));
-		state.set_main_voltage(AltosConvert.mega_pyro_voltage(sense[5]));
+		state.set_apogee_voltage(AltosConvert.mega_pyro_voltage(sense(4)));
+		state.set_main_voltage(AltosConvert.mega_pyro_voltage(sense(5)));
 
 		double voltages[] = new double[4];
 		for (int i = 0; i < 4; i++)
-			voltages[i] = AltosConvert.mega_pyro_voltage(sense[i]);
+			voltages[i] = AltosConvert.mega_pyro_voltage(sense(i));
 
 		state.set_ignitor_voltage(voltages);
 
-		state.set_ground_accel(ground_accel);
-		state.set_ground_pressure(ground_pres);
-		state.set_accel_g(accel_plus_g, accel_minus_g);
+		state.set_ground_accel(ground_accel());
+		state.set_ground_pressure(ground_pres());
+		state.set_accel_g(accel_plus_g(), accel_minus_g());
 
 		/* Fill in the high bits of height from recent GPS
 		 * data if available, otherwise guess using the
 		 * previous kalman height
 		 */
 
-		state.set_kalman(extend_height(state, height_16),
-				 speed/16.0, acceleration / 16.0);
+		state.set_kalman(extend_height(state, height_16()),
+				 speed()/16.0, acceleration() / 16.0);
 	}
 }
 
diff --git a/altoslib/AltosTelemetryMegaSensor.java b/altoslib/AltosTelemetryMegaSensor.java
index 2dfc455a..bf560e92 100644
--- a/altoslib/AltosTelemetryMegaSensor.java
+++ b/altoslib/AltosTelemetryMegaSensor.java
@@ -19,61 +19,44 @@
 package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryMegaSensor extends AltosTelemetryStandard {
-	int	accel;
-	int	pres;
-	int	temp;
+	int	orient() { return int8(5); }
 
-	int	accel_x;
-	int	accel_y;
-	int	accel_z;
+	int	accel() { return int16(6); }
+	int	pres() { return int32(8); }
+	int	temp() { return int16(12); }
 
-	int	gyro_x;
-	int	gyro_y;
-	int	gyro_z;
+	int	accel_x() { return int16(14); }
+	int	accel_y() { return int16(16); }
+	int	accel_z() { return int16(18); }
 
-	int	mag_x;
-	int	mag_y;
-	int	mag_z;
+	int	gyro_x() { return int16(20); }
+	int	gyro_y() { return int16(22); }
+	int	gyro_z() { return int16(24); }
 
-	int	orient;
+	int	mag_x() { return int16(26); }
+	int	mag_y() { return int16(28); }
+	int	mag_z() { return int16(30); }
 
-	public AltosTelemetryMegaSensor(int[] bytes) {
+	public AltosTelemetryMegaSensor(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		orient	      = int8(5);
-		accel         = int16(6);
-		pres          = int32(8);
-		temp          = int16(12);
-
-		accel_x	      = int16(14);
-		accel_y	      = int16(16);
-		accel_z	      = int16(18);
-
-		gyro_x	      = int16(20);
-		gyro_y	      = int16(22);
-		gyro_z	      = int16(24);
-
-		mag_x	      = int16(26);
-		mag_y	      = int16(28);
-		mag_z	      = int16(30);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_accel(accel);
-		state.set_pressure(pres);
-		state.set_temperature(temp / 100.0);
+		state.set_accel(accel());
+		state.set_pressure(pres());
+		state.set_temperature(temp() / 100.0);
 
-		state.set_orient(orient);
+		state.set_orient(orient());
 
-		state.set_imu(new AltosIMU(accel_y,	/* along */
-					   accel_x,	/* across */
-					   accel_z,	/* through */
-					   gyro_y,	/* along */
-					   gyro_x,	/* across */
-					   gyro_z));	/* through */
+		state.set_imu(new AltosIMU(accel_y(),	/* along */
+					   accel_x(),	/* across */
+					   accel_z(),	/* through */
+					   gyro_y(),	/* along */
+					   gyro_x(),	/* across */
+					   gyro_z()));	/* through */
 
-		state.set_mag(new AltosMag(mag_x, mag_y, mag_z));
+		state.set_mag(new AltosMag(mag_x(), mag_y(), mag_z()));
 	}
 }
diff --git a/altoslib/AltosTelemetryMetrumData.java b/altoslib/AltosTelemetryMetrumData.java
index 53a10cc4..7ba591ed 100644
--- a/altoslib/AltosTelemetryMetrumData.java
+++ b/altoslib/AltosTelemetryMetrumData.java
@@ -21,23 +21,18 @@ package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryMetrumData extends AltosTelemetryStandard {
 
-	int	ground_pres;
-	int	ground_accel;
-	int	accel_plus_g;
-	int	accel_minus_g;
+	int	ground_pres() { return int32(8); }
+	int	ground_accel() { return int16(12); }
+	int	accel_plus_g() { return int16(14); }
+	int	accel_minus_g() { return int16(16); }
 
-	public AltosTelemetryMetrumData(int[] bytes) {
+	public AltosTelemetryMetrumData(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		ground_pres = int32(8);
-		ground_accel = int16(12);
-		accel_plus_g = int16(14);
-		accel_minus_g = int16(16);
 	}
 
 	public void update_state(AltosState state) {
-		state.set_ground_accel(ground_accel);
-		state.set_accel_g(accel_plus_g, accel_minus_g);
-		state.set_ground_pressure(ground_pres);
+		state.set_ground_accel(ground_accel());
+		state.set_accel_g(accel_plus_g(), accel_minus_g());
+		state.set_ground_pressure(ground_pres());
 	}
 }
diff --git a/altoslib/AltosTelemetryMetrumSensor.java b/altoslib/AltosTelemetryMetrumSensor.java
index e15043b4..e666f4ec 100644
--- a/altoslib/AltosTelemetryMetrumSensor.java
+++ b/altoslib/AltosTelemetryMetrumSensor.java
@@ -20,52 +20,39 @@ package org.altusmetrum.altoslib_11;
 
 
 public class AltosTelemetryMetrumSensor extends AltosTelemetryStandard {
-	int	state;
+	int	state() { return uint8(5); }
 
-	int	accel;
-	int	pres;
-	int	temp;
+	int	accel() { return int16(6); }
+	int	pres() { return int32(8); }
+	int	temp() { return int16(12); }
 
-	int	acceleration;
-	int	speed;
-	int	height_16;
+	int	acceleration() { return int16(14); }
+	int	speed() { return int16(16); }
+	int	height_16() { return int16(18); }
 
-	int	v_batt;
-	int	sense_a;
-	int	sense_m;
+	int	v_batt() { return int16(20); }
+	int	sense_a() { return int16(22); }
+	int	sense_m() { return int16(24); }
 
-	public AltosTelemetryMetrumSensor(int[] bytes) {
+	public AltosTelemetryMetrumSensor(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		state	      = int8(5);
-		accel         = int16(6);
-		pres          = int32(8);
-		temp          = int16(12);
-
-		acceleration  = int16(14);
-		speed         = int16(16);
-		height_16     = int16(18);
-
-		v_batt        = int16(20);
-		sense_a       = int16(22);
-		sense_m       = int16(24);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_state(this.state);
+		state.set_state(state());
 
-		state.set_accel(accel);
-		state.set_pressure(pres);
-		state.set_temperature(temp/100.0);
+		state.set_accel(accel());
+		state.set_pressure(pres());
+		state.set_temperature(temp()/100.0);
 
-		state.set_kalman(extend_height(state, height_16),
-				 speed/16.0, acceleration/16.0);
+		state.set_kalman(extend_height(state, height_16()),
+				 speed()/16.0, acceleration()/16.0);
 
-		state.set_battery_voltage(AltosConvert.mega_battery_voltage(v_batt));
+		state.set_battery_voltage(AltosConvert.mega_battery_voltage(v_batt()));
 
-		state.set_apogee_voltage(AltosConvert.mega_pyro_voltage(sense_a));
-		state.set_main_voltage(AltosConvert.mega_pyro_voltage(sense_m));
+		state.set_apogee_voltage(AltosConvert.mega_pyro_voltage(sense_a()));
+		state.set_main_voltage(AltosConvert.mega_pyro_voltage(sense_m()));
 	}
 }
diff --git a/altoslib/AltosTelemetryMini2.java b/altoslib/AltosTelemetryMini2.java
index 50ec504d..bc151139 100644
--- a/altoslib/AltosTelemetryMini2.java
+++ b/altoslib/AltosTelemetryMini2.java
@@ -20,54 +20,40 @@ package org.altusmetrum.altoslib_11;
 
 
 public class AltosTelemetryMini2 extends AltosTelemetryStandard {
-	int	state;
 
-	int	v_batt;
-	int	sense_a;
-	int	sense_m;
+	int	state() { return uint8(5); }
 
-	int	pres;
-	int	temp;
+	int	v_batt() { return int16(6); }
+	int	sense_a() { return int16(8); }
+	int	sense_m() { return int16(10); }
 
-	int	acceleration;
-	int	speed;
-	int	height;
+	int	pres() { return int32(12); }
+	int	temp() { return int16(16); }
 
-	int	ground_pres;
+	int	acceleration() { return int16(18); }
+	int	speed() { return int16(20); }
+	int	height() { return int16(22); }
 
-	public AltosTelemetryMini2(int[] bytes) {
-		super(bytes);
-
-		state	      = int8(5);
-
-		v_batt        = int16(6);
-		sense_a       = int16(8);
-		sense_m       = int16(10);
+	int	ground_pres() { return int32(24); }
 
-		pres          = int32(12);
-		temp          = int16(16);
-
-		acceleration  = int16(18);
-		speed         = int16(20);
-		height        = int16(22);
-
-		ground_pres   = int32(24);
+	public AltosTelemetryMini2(int[] bytes) throws AltosCRCException {
+		super(bytes);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_state(this.state);
+		state.set_state(state());
 
-		state.set_battery_voltage(AltosConvert.tele_mini_2_voltage(v_batt));
-		state.set_apogee_voltage(AltosConvert.tele_mini_2_voltage(sense_a));
-		state.set_main_voltage(AltosConvert.tele_mini_2_voltage(sense_m));
+		state.set_battery_voltage(AltosConvert.tele_mini_2_voltage(v_batt()));
+		state.set_apogee_voltage(AltosConvert.tele_mini_2_voltage(sense_a()));
+		state.set_main_voltage(AltosConvert.tele_mini_2_voltage(sense_m()));
 
-		state.set_ground_pressure(ground_pres);
+		state.set_ground_pressure(ground_pres());
 
-		state.set_pressure(pres);
-		state.set_temperature(temp/100.0);
+		state.set_pressure(pres());
+		state.set_temperature(temp()/100.0);
 
-		state.set_kalman(height, speed/16.0, acceleration/16.0);
+		state.set_kalman(height(), speed()/16.0, acceleration()/16.0);
 	}
 }
diff --git a/altoslib/AltosTelemetryMini3.java b/altoslib/AltosTelemetryMini3.java
index 21f8c485..b8a507cc 100644
--- a/altoslib/AltosTelemetryMini3.java
+++ b/altoslib/AltosTelemetryMini3.java
@@ -21,56 +21,41 @@ package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryMini3 extends AltosTelemetryStandard {
 
-	int	state;
+	int	state() { return uint8(5); }
 
-	int	v_batt;
-	int	sense_a;
-	int	sense_m;
+	int	v_batt() { return int16(6); }
+	int	sense_a() { return int16(8); }
+	int	sense_m() { return int16(10); }
 
-	int	pres;
-	int	temp;
+	int	pres() { return int32(12); }
+	int	temp() { return int16(16); }
 
-	int	acceleration;
-	int	speed;
-	int	height_16;
+	int	acceleration() { return int16(18); }
+	int	speed() { return int16(20); }
+	int	height_16() { return int16(22); }
 
-	int	ground_pres;
+	int	ground_pres() { return int32(24); }
 
-	public AltosTelemetryMini3(int[] bytes) {
+	public AltosTelemetryMini3(int[] bytes) throws AltosCRCException {
 		super(bytes);
-
-		state         = int8(5);
-
-		v_batt        = int16(6);
-		sense_a       = int16(8);
-		sense_m       = int16(10);
-
-		pres          = int32(12);
-		temp          = int16(16);
-
-		acceleration  = int16(18);
-		speed         = int16(20);
-		height_16     = int16(22);
-
-		ground_pres   = int32(24);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_state(this.state);
+		state.set_state(state());
 
-		state.set_battery_voltage(AltosConvert.tele_mini_3_battery_voltage(v_batt));
+		state.set_battery_voltage(AltosConvert.tele_mini_3_battery_voltage(v_batt()));
 
-		state.set_apogee_voltage(AltosConvert.tele_mini_3_pyro_voltage(sense_a));
-		state.set_main_voltage(AltosConvert.tele_mini_3_pyro_voltage(sense_m));
+		state.set_apogee_voltage(AltosConvert.tele_mini_3_pyro_voltage(sense_a()));
+		state.set_main_voltage(AltosConvert.tele_mini_3_pyro_voltage(sense_m()));
 
-		state.set_pressure(pres);
-		state.set_temperature(temp/100.0);
+		state.set_pressure(pres());
+		state.set_temperature(temp()/100.0);
 
-		state.set_kalman(extend_height(state, height_16),
-				 speed/16.0, acceleration/16.0);
+		state.set_kalman(extend_height(state, height_16()),
+				 speed()/16.0, acceleration()/16.0);
 
-		state.set_ground_pressure(ground_pres);
+		state.set_ground_pressure(ground_pres());
 	}
 }
diff --git a/altoslib/AltosTelemetryRaw.java b/altoslib/AltosTelemetryRaw.java
index 339043a6..12c4623b 100644
--- a/altoslib/AltosTelemetryRaw.java
+++ b/altoslib/AltosTelemetryRaw.java
@@ -19,7 +19,7 @@
 package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetryRaw extends AltosTelemetryStandard {
-	public AltosTelemetryRaw(int[] bytes) {
+	public AltosTelemetryRaw(int[] bytes) throws AltosCRCException {
 		super(bytes);
 	}
 
diff --git a/altoslib/AltosTelemetrySatellite.java b/altoslib/AltosTelemetrySatellite.java
index 6897f0e6..ce12d32d 100644
--- a/altoslib/AltosTelemetrySatellite.java
+++ b/altoslib/AltosTelemetrySatellite.java
@@ -19,13 +19,12 @@
 package org.altusmetrum.altoslib_11;
 
 public class AltosTelemetrySatellite extends AltosTelemetryStandard {
-	int		channels;
-	AltosGPSSat[]	sats;
+	int		channels() { return uint8(5); }
 
-	public AltosTelemetrySatellite(int[] bytes) {
-		super(bytes);
+	AltosGPSSat[]	sats() {
+		int 		channels = channels();
+		AltosGPSSat[]	sats = null;
 
-		channels = uint8(5);
 		if (channels > 12)
 			channels = 12;
 		if (channels == 0)
@@ -38,6 +37,11 @@ public class AltosTelemetrySatellite extends AltosTelemetryStandard {
 				sats[i] = new AltosGPSSat(svid, c_n_1);
 			}
 		}
+		return sats;
+	}
+
+	public AltosTelemetrySatellite(int[] bytes) throws AltosCRCException {
+		super(bytes);
 	}
 
 	public void update_state(AltosState state) {
@@ -45,7 +49,7 @@ public class AltosTelemetrySatellite extends AltosTelemetryStandard {
 
 		AltosGPS	gps = state.make_temp_gps(true);
 
-		gps.cc_gps_sat = sats;
+		gps.cc_gps_sat = sats();
 		state.set_temp_gps();
 	}
 }
diff --git a/altoslib/AltosTelemetrySensor.java b/altoslib/AltosTelemetrySensor.java
index 3c3e6a01..b669b9e6 100644
--- a/altoslib/AltosTelemetrySensor.java
+++ b/altoslib/AltosTelemetrySensor.java
@@ -20,62 +20,45 @@ package org.altusmetrum.altoslib_11;
 
 
 public class AltosTelemetrySensor extends AltosTelemetryStandard {
-	int	state;
-	int	accel;
-	int	pres;
-	int	temp;
-	int	v_batt;
-	int	sense_d;
-	int	sense_m;
+	int	state() { return uint8(5); }
+	int	accel() { return int16(6); }
+	int	pres() { return int16(8); }
+	int	temp() { return int16(10); }
+	int	v_batt() { return int16(12); }
+	int	sense_d() { return int16(14); }
+	int	sense_m() { return int16(16); }
 
-	int	acceleration;
-	int	speed;
-	int	height;
+	int	acceleration() { return int16(18); }
+	int	speed() { return int16(20); }
+	int	height_16() { return int16(22); }
 
-	int	ground_accel;
-	int	ground_pres;
-	int	accel_plus_g;
-	int	accel_minus_g;
+	int	ground_accel() { return int16(24); }
+	int	ground_pres() { return int16(26); }
+	int	accel_plus_g() { return int16(28); }
+	int	accel_minus_g() { return int16(30); }
 
-	public AltosTelemetrySensor(int[] bytes) {
+	public AltosTelemetrySensor(int[] bytes) throws AltosCRCException {
 		super(bytes);
-		state         = uint8(5);
-
-		accel         = int16(6);
-		pres          = int16(8);
-		temp          = int16(10);
-		v_batt        = int16(12);
-		sense_d       = int16(14);
-		sense_m       = int16(16);
-
-		acceleration  = int16(18);
-		speed         = int16(20);
-		height        = int16(22);
-
-		ground_pres   = int16(24);
-		ground_accel  = int16(26);
-		accel_plus_g  = int16(28);
-		accel_minus_g = int16(30);
 	}
 
 	public void update_state(AltosState state) {
 		super.update_state(state);
 
-		state.set_state(this.state);
-		if (type == packet_type_TM_sensor) {
-			state.set_ground_accel(ground_accel);
-			state.set_accel_g(accel_plus_g, accel_minus_g);
-			state.set_accel(accel);
+		state.set_state(state());
+		if (type() == packet_type_TM_sensor) {
+			state.set_ground_accel(ground_accel());
+			state.set_accel_g(accel_plus_g(), accel_minus_g());
+			state.set_accel(accel());
 		}
-		state.set_ground_pressure(AltosConvert.barometer_to_pressure(ground_pres));
-		state.set_pressure(AltosConvert.barometer_to_pressure(pres));
-		state.set_temperature(AltosConvert.thermometer_to_temperature(temp));
-		state.set_battery_voltage(AltosConvert.cc_battery_to_voltage(v_batt));
-		if (type == packet_type_TM_sensor || type == packet_type_Tm_sensor) {
-			state.set_apogee_voltage(AltosConvert.cc_ignitor_to_voltage(sense_d));
-			state.set_main_voltage(AltosConvert.cc_ignitor_to_voltage(sense_m));
+		state.set_ground_pressure(AltosConvert.barometer_to_pressure(ground_pres()));
+		state.set_pressure(AltosConvert.barometer_to_pressure(pres()));
+		state.set_temperature(AltosConvert.thermometer_to_temperature(temp()));
+		state.set_battery_voltage(AltosConvert.cc_battery_to_voltage(v_batt()));
+		if (type() == packet_type_TM_sensor || type() == packet_type_Tm_sensor) {
+			state.set_apogee_voltage(AltosConvert.cc_ignitor_to_voltage(sense_d()));
+			state.set_main_voltage(AltosConvert.cc_ignitor_to_voltage(sense_m()));
 		}
 
-		state.set_kalman(height, speed/16.0, acceleration / 16.0);
+		state.set_kalman(height_16(), speed()/16.0, acceleration()/16.0);
 	}
 }
diff --git a/altoslib/AltosTelemetryStandard.java b/altoslib/AltosTelemetryStandard.java
index 35d315c7..1718e4b7 100644
--- a/altoslib/AltosTelemetryStandard.java
+++ b/altoslib/AltosTelemetryStandard.java
@@ -19,9 +19,6 @@
 package org.altusmetrum.altoslib_11;
 
 public abstract class AltosTelemetryStandard extends AltosTelemetry {
-	int[]	bytes;
-	int	type;
-
 	public int int8(int off) {
 		return AltosLib.int8(bytes, off + 1);
 	}
@@ -50,10 +47,16 @@ public abstract class AltosTelemetryStandard extends AltosTelemetry {
 		return AltosLib.string(bytes, off + 1, l);
 	}
 
-	public static AltosTelemetry parse_hex(int[] bytes) {
-		int	type = AltosLib.uint8(bytes, 4 + 1);
+	public int type() { return uint8(4); }
+
+	public int serial() { return uint16(0); }
+
+	public int tick() { return uint16(2); }
 
+	public static AltosTelemetry parse_hex(int[] bytes) throws AltosCRCException {
 		AltosTelemetry	telem;
+
+		int type = AltosLib.uint8(bytes, 4+1);
 		switch (type) {
 		case packet_type_TM_sensor:
 		case packet_type_Tm_sensor:
@@ -97,12 +100,8 @@ public abstract class AltosTelemetryStandard extends AltosTelemetry {
 		return telem;
 	}
 
-	public AltosTelemetryStandard(int[] bytes) {
-		this.bytes = bytes;
-
-		serial = uint16(0);
-		tick   = uint16(2);
-		type   = uint8(4);
+	public AltosTelemetryStandard(int[] bytes) throws AltosCRCException {
+		super(bytes);
 	}
 
 	public void update_state(AltosState state) {