/**
 * Copyright 2010 JBoss Inc
 *
 * 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 bitronix.tm.utils;

/**
 * Number to byte array and byte array to number encoder.
 * <p>© <a href="http://www.bitronix.be">Bitronix Software</a></p>
 *
 * @author lorban
 */
public class Encoder {

    public static byte[] longToBytes(long aLong) {
        byte[] array = new byte[8];

        for (int i=0; i<array.length ;i++) {
            array[array.length - (i+1)] = (byte) ((aLong >> (8 * i)) & 0xff);
        }

        return array;
    }

    public static byte[] intToBytes(long anInt) {
        byte[] array = new byte[4];

        for (int i=0; i<array.length ;i++) {
            array[array.length - (i+1)] = (byte) ((anInt >> (8 * i)) & 0xff);
        }

        return array;
    }

    public static byte[] shortToBytes(short aShort) {
        byte[] array = new byte[2];

        for (int i=0; i<array.length ;i++) {
            array[array.length - (i+1)] = (byte) ((aShort >> (8 * i)) & 0xff);
        }

        return array;
    }

    public static long bytesToLong(byte[] bytes, int pos) {
        if (bytes.length + pos < 8)
            throw new IllegalArgumentException("a long can only be decoded from 8 bytes of an array (got a " + bytes.length + " byte(s) array, must start at position " + pos + ")");

        long result = 0;

        for(int i=0; i < 8 ;i++) {
           result <<= 8;
           result ^= (long) bytes[i + pos] & 0xFF;
        }

        return result;
    }
}