/*
 * Copyright (c) 2016, Liu Dong
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 *  Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package github.tornaco.android.nitro.framework.host.install.util.parser.apk.utils;

import java.nio.ByteBuffer;

/**
 * utils method for byte buffer
 *
 * @author Liu Dong im@dongliu.net
 */
public class Buffers {

    /**
     * get one unsigned byte as short type
     */
    public static short readUByte(ByteBuffer buffer) {
        byte b = buffer.get();
        return (short) (b & 0xff);
    }

    /**
     * get one unsigned short as int type
     */
    public static int readUShort(ByteBuffer buffer) {
        short s = buffer.getShort();
        return s & 0xffff;
    }

    /**
     * get one unsigned int as long type
     */
    public static long readUInt(ByteBuffer buffer) {
        int i = buffer.getInt();
        return i & 0xffffffffL;
    }

    /**
     * get bytes
     */
    public static byte[] readBytes(ByteBuffer buffer, int size) {
        byte[] bytes = new byte[size];
        buffer.get(bytes);
        return bytes;
    }

    /**
     * read utf16 strings, use strLen, not ending 0 char.
     */
    public static String readString(ByteBuffer buffer, int strLen) {
        StringBuilder sb = new StringBuilder(strLen);
        for (int i = 0; i < strLen; i++) {
            sb.append(buffer.getChar());
        }
        return sb.toString();
    }

    /**
     * skip count bytes
     */
    public static void skip(ByteBuffer buffer, int count) {
        buffer.position(buffer.position() + count);
    }
}
