// Parse service UUIDs. private static int parseServiceUuid( byte[] scanRecord, int currentPos, int dataLength, int uuidLength, List<ParcelUuid> serviceUuids) { while (dataLength > 0) { byte[] uuidBytes = extractBytes(scanRecord, currentPos, uuidLength); serviceUuids.add(BluetoothUuid.parseUuidFrom(uuidBytes)); dataLength -= uuidLength; currentPos += uuidLength; } return currentPos; }
/** * Parse scan record bytes to {@link ScanRecord}. * * <p>The format is defined in Bluetooth 4.1 specification, Volume 3, Part C, Section 11 and 18. * * <p>All numerical multi-byte entities and values shall use little-endian <strong>byte</strong> * order. * * @param scanRecord The scan record of Bluetooth LE advertisement and/or scan response. * @hide */ public static ScanRecord parseFromBytes(byte[] scanRecord) { if (scanRecord == null) { return null; } int currentPos = 0; int advertiseFlag = -1; List<ParcelUuid> serviceUuids = new ArrayList<ParcelUuid>(); String localName = null; int txPowerLevel = Integer.MIN_VALUE; SparseArray<byte[]> manufacturerData = new SparseArray<byte[]>(); Map<ParcelUuid, byte[]> serviceData = new ArrayMap<>(); try { while (currentPos < scanRecord.length) { // length is unsigned int. int length = scanRecord[currentPos++] & 0xFF; if (length == 0) { break; } // Note the length includes the length of the field type itself. int dataLength = length - 1; // fieldType is unsigned int. int fieldType = scanRecord[currentPos++] & 0xFF; switch (fieldType) { case DATA_TYPE_FLAGS: advertiseFlag = scanRecord[currentPos] & 0xFF; break; case DATA_TYPE_SERVICE_UUIDS_16_BIT_PARTIAL: case DATA_TYPE_SERVICE_UUIDS_16_BIT_COMPLETE: parseServiceUuid( scanRecord, currentPos, dataLength, BluetoothUuid.UUID_BYTES_16_BIT, serviceUuids); break; case DATA_TYPE_SERVICE_UUIDS_32_BIT_PARTIAL: case DATA_TYPE_SERVICE_UUIDS_32_BIT_COMPLETE: parseServiceUuid( scanRecord, currentPos, dataLength, BluetoothUuid.UUID_BYTES_32_BIT, serviceUuids); break; case DATA_TYPE_SERVICE_UUIDS_128_BIT_PARTIAL: case DATA_TYPE_SERVICE_UUIDS_128_BIT_COMPLETE: parseServiceUuid( scanRecord, currentPos, dataLength, BluetoothUuid.UUID_BYTES_128_BIT, serviceUuids); break; case DATA_TYPE_LOCAL_NAME_SHORT: case DATA_TYPE_LOCAL_NAME_COMPLETE: localName = new String(extractBytes(scanRecord, currentPos, dataLength)); break; case DATA_TYPE_TX_POWER_LEVEL: txPowerLevel = scanRecord[currentPos]; break; case DATA_TYPE_SERVICE_DATA: // The first two bytes of the service data are service data UUID in little // endian. The rest bytes are service data. int serviceUuidLength = BluetoothUuid.UUID_BYTES_16_BIT; byte[] serviceDataUuidBytes = extractBytes(scanRecord, currentPos, serviceUuidLength); ParcelUuid serviceDataUuid = BluetoothUuid.parseUuidFrom(serviceDataUuidBytes); byte[] serviceDataArray = extractBytes( scanRecord, currentPos + serviceUuidLength, dataLength - serviceUuidLength); serviceData.put(serviceDataUuid, serviceDataArray); break; case DATA_TYPE_MANUFACTURER_SPECIFIC_DATA: // The first two bytes of the manufacturer specific data are // manufacturer ids in little endian. int manufacturerId = ((scanRecord[currentPos + 1] & 0xFF) << 8) + (scanRecord[currentPos] & 0xFF); byte[] manufacturerDataBytes = extractBytes(scanRecord, currentPos + 2, dataLength - 2); manufacturerData.put(manufacturerId, manufacturerDataBytes); break; default: // Just ignore, we don't handle such data type. break; } currentPos += dataLength; } if (serviceUuids.isEmpty()) { serviceUuids = null; } return new ScanRecord( serviceUuids, manufacturerData, serviceData, advertiseFlag, txPowerLevel, localName, scanRecord); } catch (Exception e) { // Log.e(TAG, "unable to parse scan record: " + Arrays.toString(scanRecord)); // As the record is invalid, ignore all the parsed results for this packet // and return an empty record with raw scanRecord bytes in results return new ScanRecord(null, null, null, -1, Integer.MIN_VALUE, null, scanRecord); } }