Add parse method to parse UUID from bytes for 16 bit, 32 bit and 128 bit

Bluetooth UUIDs. Added unit tests.

Change-Id: I4ecf0ede02561a5e9815acf8a5a1309d5756b887

1 files changed, 58 insertions, 5 deletions

diff --git a/core/java/android/bluetooth/BluetoothUuid.java b/core/java/android/bluetooth/BluetoothUuid.java
index 4b28516..ab53fb0 100644
--- a/core/java/android/bluetooth/BluetoothUuid.java
+++ b/core/java/android/bluetooth/BluetoothUuid.java
@@ -18,6 +18,8 @@ package android.bluetooth;
 
 import android.os.ParcelUuid;
 
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.UUID;
@@ -76,6 +78,12 @@ public final class BluetoothUuid {
     public static final ParcelUuid BASE_UUID =
             ParcelUuid.fromString("00000000-0000-1000-8000-00805F9B34FB");
 
+    /** Length of bytes for 16 bit UUID */
+    public static final int UUID_BYTES_16_BIT = 2;
+    /** Length of bytes for 32 bit UUID */
+    public static final int UUID_BYTES_32_BIT = 4;
+    /** Length of bytes for 128 bit UUID */
+    public static final int UUID_BYTES_128_BIT = 16;
 
     public static final ParcelUuid[] RESERVED_UUIDS = {
         AudioSink, AudioSource, AdvAudioDist, HSP, Handsfree, AvrcpController, AvrcpTarget,
@@ -216,15 +224,60 @@ public final class BluetoothUuid {
     }
 
     /**
+     * Parse UUID from bytes. The {@code uuidBytes} can represent a 16-bit, 32-bit or 128-bit UUID,
+     * but the returned UUID is always in 128-bit format.
+     * Note UUID is little endian in Bluetooth.
+     *
+     * @param uuidBytes Byte representation of uuid.
+     * @return {@link ParcelUuid} parsed from bytes.
+     * @throws IllegalArgumentException If the {@code uuidBytes} cannot be parsed.
+     */
+    public static ParcelUuid parseUuidFrom(byte[] uuidBytes) {
+        if (uuidBytes == null) {
+            throw new IllegalArgumentException("uuidBytes cannot be null");
+        }
+        int length = uuidBytes.length;
+        if (length != UUID_BYTES_16_BIT && length != UUID_BYTES_32_BIT &&
+                length != UUID_BYTES_128_BIT) {
+            throw new IllegalArgumentException("uuidBytes length invalid - " + length);
+        }
+
+        // Construct a 128 bit UUID.
+        if (length == UUID_BYTES_128_BIT) {
+            ByteBuffer buf = ByteBuffer.wrap(uuidBytes).order(ByteOrder.LITTLE_ENDIAN);
+            long msb = buf.getLong(8);
+            long lsb = buf.getLong(0);
+            return new ParcelUuid(new UUID(msb, lsb));
+        }
+
+        // For 16 bit and 32 bit UUID we need to convert them to 128 bit value.
+        // 128_bit_value = uuid * 2^96 + BASE_UUID
+        long shortUuid;
+        if (length == UUID_BYTES_16_BIT) {
+            shortUuid = uuidBytes[0] & 0xFF;
+            shortUuid += (uuidBytes[1] & 0xFF) << 8;
+        } else {
+            shortUuid = uuidBytes[0] & 0xFF ;
+            shortUuid += (uuidBytes[1] & 0xFF) << 8;
+            shortUuid += (uuidBytes[2] & 0xFF) << 16;
+            shortUuid += (uuidBytes[3] & 0xFF) << 24;
+        }
+        long msb = BASE_UUID.getUuid().getMostSignificantBits() + (shortUuid << 32);
+        long lsb = BASE_UUID.getUuid().getLeastSignificantBits();
+        return new ParcelUuid(new UUID(msb, lsb));
+    }
+
+    /**
      * Check whether the given parcelUuid can be converted to 16 bit bluetooth uuid.
+     *
      * @param parcelUuid
      * @return true if the parcelUuid can be converted to 16 bit uuid, false otherwise.
      */
     public static boolean isShortUuid(ParcelUuid parcelUuid) {
-      UUID uuid = parcelUuid.getUuid();
-      if (uuid.getLeastSignificantBits() != BASE_UUID.getUuid().getLeastSignificantBits()) {
-        return false;
-      }
-      return ((uuid.getMostSignificantBits() & 0xFFFF0000FFFFFFFFL) == 0x1000L);
+        UUID uuid = parcelUuid.getUuid();
+        if (uuid.getLeastSignificantBits() != BASE_UUID.getUuid().getLeastSignificantBits()) {
+            return false;
+        }
+        return ((uuid.getMostSignificantBits() & 0xFFFF0000FFFFFFFFL) == 0x1000L);
     }
 }