altosui: Clean up eeprom parsing a bit

Export basic parsing and checksum functions for shared use.
Create 'erased' function to check a chunk of eeprom data for data.

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

3 files changed, 30 insertions, 27 deletions

diff --git a/altosui/AltosConvert.java b/altosui/AltosConvert.java
index c2ae9a50..207470a5 100644
--- a/altosui/AltosConvert.java
+++ b/altosui/AltosConvert.java
@@ -220,4 +220,24 @@ public class AltosConvert {
 	static double radio_channel_to_frequency(int channel) {
 		return 434.550 + channel * 0.100;
 	}
+
+	static int[] ParseHex(String line) {
+		String[] tokens = line.split("\\s+");
+		int[] array = new int[tokens.length];
+
+		for (int i = 0; i < tokens.length; i++)
+			try {
+				array[i] = Integer.parseInt(tokens[i], 16);
+			} catch (NumberFormatException ne) {
+				return null;
+			}
+		return array;
+	}
+
+	static int checksum(int[] data, int start, int length) {
+		int	csum = 0x5a;
+		for (int i = 0; i < length; i++)
+			csum += data[i + start];
+		return csum & 0xff;
+	}
 }
diff --git a/altosui/AltosEepromChunk.java b/altosui/AltosEepromChunk.java
index 1e42077f..fb632a3f 100644
--- a/altosui/AltosEepromChunk.java
+++ b/altosui/AltosEepromChunk.java
@@ -52,6 +52,13 @@ public class AltosEepromChunk {
 		return data[offset] | (data[offset + 1] << 8);
 	}
 
+	boolean erased(int start, int len) {
+		for (int i = 0; i < len; i++)
+			if (data[start+i] != 0xff)
+				return false;
+		return true;
+	}
+
 	public AltosEepromChunk(AltosSerial serial_line, int block)
 		throws TimeoutException, InterruptedException {
 
diff --git a/altosui/AltosEepromRecord.java b/altosui/AltosEepromRecord.java
index c0f97035..d8a07951 100644
--- a/altosui/AltosEepromRecord.java
+++ b/altosui/AltosEepromRecord.java
@@ -40,42 +40,18 @@ public class AltosEepromRecord {
 
 	static final int	record_length = 8;
 
-	int[] ParseHex(String line) {
-		String[] tokens = line.split("\\s+");
-		int[] array = new int[tokens.length];
-
-		for (int i = 0; i < tokens.length; i++)
-			try {
-				array[i] = Integer.parseInt(tokens[i], 16);
-			} catch (NumberFormatException ne) {
-				return null;
-			}
-		return array;
-	}
-
-	int checksum(int[] data, int start) {
-		int	csum = 0x5a;
-		for (int i = 0; i < record_length; i++)
-			csum += data[i + start];
-		return csum & 0xff;
-	}
-
 	public AltosEepromRecord (AltosEepromChunk chunk, int start) throws ParseException {
 
 		cmd = chunk.data(start);
 		tick_valid = true;
 
-		int i;
-		for (i = 0; i < record_length; i++)
-			if (chunk.data[start + i] != 0xff)
-				break;
-		if (i != 8) {
-			if (checksum(chunk.data, start) != 0)
+		tick_valid = !chunk.erased(start, record_length);
+		if (tick_valid) {
+			if (AltosConvert.checksum(chunk.data, start, record_length) != 0)
 				throw new ParseException(String.format("invalid checksum at 0x%x",
 								       chunk.address + start), 0);
 		} else {
 			cmd = Altos.AO_LOG_INVALID;
-			tick_valid = false;
 		}
 
 		tick = chunk.data16(start + 2);