Java Array Range Copy copyOfRange(byte[] original, int from, int to)

Description

Copies the specified range of the specified array into a new array.

License

Apache License

Parameter

Parameter	Description
original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)

Exception

Parameter	Description
ArrayIndexOutOfBoundsException	if <tt>from < 0</tt>or <tt>from > original.length()</tt>
IllegalArgumentException	if <tt>from > to</tt>
NullPointerException	if <tt>original</tt> is null

Return

a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length

Declaration

public static byte[] copyOfRange(byte[] original, int from, int to)

Method Source Code

//package com.java2s;
/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You 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
    /*from   w w w  .j  a v a 2 s . c  o  m*/
   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.
==================================================================== */

public class Main {
    /**
     * Copies the specified range of the specified array into a new array.
     * The initial index of the range (<tt>from</tt>) must lie between zero
     * and <tt>original.length</tt>, inclusive.  The value at
     * <tt>original[from]</tt> is placed into the initial element of the copy
     * (unless <tt>from == original.length</tt> or <tt>from == to</tt>).
     * Values from subsequent elements in the original array are placed into
     * subsequent elements in the copy.  The final index of the range
     * (<tt>to</tt>), which must be greater than or equal to <tt>from</tt>,
     * may be greater than <tt>original.length</tt>, in which case
     * <tt>(byte)0</tt> is placed in all elements of the copy whose index is
     * greater than or equal to <tt>original.length - from</tt>.  The length
     * of the returned array will be <tt>to - from</tt>.
     *
     * This method is temporary
     * replace for Arrays.copyOfRange() until we start to require JDK 1.6.
     *
     * @param original the array from which a range is to be copied
     * @param from the initial index of the range to be copied, inclusive
     * @param to the final index of the range to be copied, exclusive.
     *     (This index may lie outside the array.)
     * @return a new array containing the specified range from the original array,
     *     truncated or padded with zeros to obtain the required length
     * @throws ArrayIndexOutOfBoundsException if <tt>from &lt; 0</tt>
     *     or <tt>from &gt; original.length()</tt>
     * @throws IllegalArgumentException if <tt>from &gt; to</tt>
     * @throws NullPointerException if <tt>original</tt> is null
     * @since 1.6
     */
    public static byte[] copyOfRange(byte[] original, int from, int to) {
        int newLength = to - from;
        if (newLength < 0)
            throw new IllegalArgumentException(from + " > " + to);
        byte[] copy = new byte[newLength];
        System.arraycopy(original, from, copy, 0, Math.min(original.length - from, newLength));
        return copy;
    }

    /**
     * This is really a debugging version of <code>System.arraycopy()</code>.
     * Use it to provide better exception messages when copying arrays around.
     * For production use it's better to use the original for speed.
     */
    public static void arraycopy(byte[] src, int src_position, byte[] dst, int dst_position, int length) {
        if (src_position < 0)
            throw new IllegalArgumentException("src_position was less than 0.  Actual value " + src_position);
        if (src_position >= src.length)
            throw new IllegalArgumentException(
                    "src_position was greater than src array size.  Tried to write starting at position "
                            + src_position + " but the array length is " + src.length);
        if (src_position + length > src.length)
            throw new IllegalArgumentException(
                    "src_position + length would overrun the src array.  Expected end at " + (src_position + length)
                            + " actual end at " + src.length);
        if (dst_position < 0)
            throw new IllegalArgumentException("dst_position was less than 0.  Actual value " + dst_position);
        if (dst_position >= dst.length)
            throw new IllegalArgumentException(
                    "dst_position was greater than dst array size.  Tried to write starting at position "
                            + dst_position + " but the array length is " + dst.length);
        if (dst_position + length > dst.length)
            throw new IllegalArgumentException(
                    "dst_position + length would overrun the dst array.  Expected end at " + (dst_position + length)
                            + " actual end at " + dst.length);

        System.arraycopy(src, src_position, dst, dst_position, length);
    }
}