impl.underdark.transport.bluetooth.discovery.ble.ManufacturerData.java Source code

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Here is the source code for impl.underdark.transport.bluetooth.discovery.ble.ManufacturerData.java

Source

/*
 * Copyright (c) 2016 Vladimir L. Shabanov <virlof@gmail.com>
 *
 * Licensed under the Underdark License, Version 1.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://underdark.io/LICENSE.txt
 *
 * 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 impl.underdark.transport.bluetooth.discovery.ble;

import java.util.ArrayList;
import java.util.List;

import impl.underdark.transport.bluetooth.BtUtils;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;

public class ManufacturerData {
    private static final int deviceAddressLen = 6;

    private int appId;
    private byte[] address;
    private List<Integer> channels;

    private ManufacturerData(int appId, byte[] address, List<Integer> channels) {
        this.appId = appId;
        this.address = address.clone();
        this.channels = new ArrayList<>(channels);
    }

    private static int ipow(int base, int exp) {
        int result = 1;
        while (exp != 0) {
            if ((exp & 1) != 0)
                result *= base;
            exp >>= 1;
            base *= base;
        }

        return result;
    }

    public static ManufacturerData create(int appId, byte[] address, List<Integer> channels) {
        if (address == null || address.length != deviceAddressLen)
            return null;

        if (channels == null)
            return null;

        return new ManufacturerData(appId, address, channels);
    }

    public static ManufacturerData parse(byte[] data) {
        if (data == null || data.length < (1 + 6 + 4))
            return null;

        ByteBuf buf = Unpooled.wrappedBuffer(data);
        byte version = buf.readByte();
        if (version != 1)
            return null;

        int appId = buf.readInt();
        byte[] address = new byte[deviceAddressLen];
        buf.readBytes(address);
        int channelsMask = buf.readInt();

        List<Integer> channels = new ArrayList<>();

        for (int channel = 0; channelsMask != 0; ++channel) {
            if (channelsMask % 2 != 0)
                channels.add(channel);

            channelsMask >>= 1;
        }

        return new ManufacturerData(appId, address, channels);
    } // parseManufacturerData()

    public byte[] build() {
        ByteBuf data = Unpooled.wrappedBuffer(new byte[27]);
        data.clear();
        data.writeByte(1); // Version
        data.writeInt(appId);
        data.writeBytes(address);

        int channelsMask = 0;

        for (int channel : channels) {
            if (channel < 0 || channel > BtUtils.channelNumberMax)
                continue;

            // http://www.vipan.com/htdocs/bitwisehelp.html

            int channelBit = ipow(2, channel);

            channelsMask |= channelBit;
        }

        data.writeInt(channelsMask);

        return data.array();
    } // buildManufacturerData()

    public int getAppId() {
        return appId;
    }

    public byte[] getAddress() {
        return address;
    }

    public List<Integer> getChannels() {
        return channels;
    }
} // ManufacturerData