Parse UUID from bytes. - Android Hardware

Android examples for Hardware:Device ID

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Description

Parse UUID from bytes.

Demo Code

/*/*from w  w w.j av  a  2  s .co  m*/
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;
import android.os.ParcelUuid;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

import java.util.UUID;

public class Main {
    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;

    /**
     * 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));
    }
}

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