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Fixes negative advertisement record length handling #29

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Fixes negative advertisement record length handling #29

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18 changes: 9 additions & 9 deletions library/src/main/java/uk/co/alt236/bluetoothlelib/util/AdRecordUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -58,14 +58,14 @@ public static List<AdRecord> parseScanRecordAsList(final byte[] scanRecord) {

int index = 0;
while (index < scanRecord.length) {
final int length = scanRecord[index++];
final int length = scanRecord[index++] & 0xFF;
//Done once we run out of records
if (length == 0) break;
if (length < 1) break;

final int type = ByteUtils.getIntFromByte(scanRecord[index]);

//Done if our record isn't a valid type
if (type == 0) break;
if (type < 1) break;

final byte[] data = Arrays.copyOfRange(scanRecord, index + 1, index + length);

Expand All @@ -84,14 +84,14 @@ public static Map<Integer, AdRecord> parseScanRecordAsMap(final byte[] scanRecor

int index = 0;
while (index < scanRecord.length) {
final int length = scanRecord[index++];
final int length = scanRecord[index++] & 0xFF;
//Done once we run out of records
if (length == 0) break;
if (length < 1) break;

final int type = ByteUtils.getIntFromByte(scanRecord[index]);

//Done if our record isn't a valid type
if (type == 0) break;
if (type < 1) break;

final byte[] data = Arrays.copyOfRange(scanRecord, index + 1, index + length);

Expand All @@ -109,14 +109,14 @@ public static SparseArray<AdRecord> parseScanRecordAsSparseArray(final byte[] sc

int index = 0;
while (index < scanRecord.length) {
final int length = scanRecord[index++];
final int length = scanRecord[index++] & 0xFF;
//Done once we run out of records
if (length == 0) break;
if (length < 1) break;

final int type = ByteUtils.getIntFromByte(scanRecord[index]);

//Done if our record isn't a valid type
if (type == 0) break;
if (type < 1) break;

final byte[] data = Arrays.copyOfRange(scanRecord, index + 1, index + length);

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42 changes: 30 additions & 12 deletions library/src/test/java/uk/co/alt236/bluetoothlelib/util/AdRecordUtilsTest.java
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Original file line number Diff line number Diff line change
@@ -1,23 +1,21 @@
package uk.co.alt236.bluetoothlelib.util;

import junit.framework.TestCase;

import java.util.List;
import java.util.Map;

import junit.framework.TestCase;
import uk.co.alt236.bluetoothlelib.device.adrecord.AdRecord;

/**
*
* Advertisement records related tests.
*/
public class AdRecordUtilsTest extends TestCase {
private static final byte[] NON_IBEACON =
{2, 1, 26, 11, -1, 76, 0, 9, 6, 3, -32, -64, -88,
1, 98, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
private static final byte[] NON_IBEACON = {
2, 1, 26, 11, -1, 76, 0, 9, 6, 3, -32, -64, -88, 1, 98, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0
};

public void testParseScanRecordAsList() throws Exception {
public void testParseScanRecordAsList() {
final List<AdRecord> adRecords = AdRecordUtils.parseScanRecordAsList(NON_IBEACON);
assertNotNull(adRecords);
assertEquals(2, adRecords.size());
Expand All @@ -31,7 +29,7 @@ public void testParseScanRecordAsList() throws Exception {
assertEquals(11, adRecords.get(1).getLength());
}

public void testParseScanRecordAsMap() throws Exception {
public void testParseScanRecordAsMap() {
final Map<Integer, AdRecord> adRecords = AdRecordUtils.parseScanRecordAsMap(NON_IBEACON);
assertNotNull(adRecords);
assertEquals(2, adRecords.size());
Expand All @@ -45,7 +43,27 @@ public void testParseScanRecordAsMap() throws Exception {
assertEquals(11, adRecords.get(type).getLength());
}

public void testParseScanRecordAsSparseArray() throws Exception {
/**
* Test negative record lengths. In Java all primitive types are signed, and we could receive
* a negative length in the record. Thus, we always have to convert it into unsigned.
*/
public void testNegativeRecordLength() {
// (byte)0x80 & 0xFF = 170. In Java (byte)0x80 = -128.
Map<Integer, AdRecord> adRecords =
AdRecordUtils.parseScanRecordAsMap(new byte[] { -128, 1, 0 });
assertNotNull(adRecords);
assertEquals(1, adRecords.size());
assertEquals(128, adRecords.get(1).getLength());

// (byte)0xAA & 0xFF = 170. In Java (byte)0xAA = -86.
adRecords =
AdRecordUtils.parseScanRecordAsMap(new byte[] { -86, 1, 0 });
assertNotNull(adRecords);
assertEquals(1, adRecords.size());
assertEquals(170, adRecords.get(1).getLength());
}

public void testParseScanRecordAsSparseArray() {
//
// Cannot be tested here as it relies on Android code...
//
Expand Down