001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.util.array;
031
032/**
033 * Utility methods for converting arrays of 
034 * (unsigned) bytes to integers and back.
035 * 
036 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
037 *
038 */
039public class ByteArrayConverter {
040        /**
041         * Convert the given byte array to an array of ints.
042         * The bytes are assumed to actually represent int
043         * values in the range 0..255, and so have 128 added
044         * to each value.
045         * 
046         * @param arr the byte array
047         * @return an array of ints
048         */
049        public static int[] byteToInt(byte [] arr) {
050                int[] ret = new int[arr.length];
051                for(int i = 0; i < arr.length; i++){
052                        ret[i] = arr[i] + 128;
053                }
054                return ret;
055        }
056        
057        /**
058         * Convert the given 2d byte array to a 2d array of ints.
059         * The bytes are assumed to actually represent int
060         * values in the range 0..255, and so have 128 added
061         * to each value.
062         * 
063         * @param arr the byte array
064         * @return an array of ints
065         */
066        public static int[][] byteToInt(byte [][] arr) {
067                int[][] ret = new int[arr.length][];
068                for(int i = 0; i < arr.length; i++){
069                        ret[i] = byteToInt(arr[i]);
070                }
071                return ret;
072        }
073        
074        /**
075         * Convert the given int array to an array of bytes.
076         * The ints are assumed to be in the range 0..255,
077         * and so 128 is subtracted before casting to a byte.
078         * 
079         * @param arr the int array
080         * @return an array of bytes
081         */
082        public static byte[] intToByte(int [] arr) {
083                byte[] ret = new byte[arr.length];
084                for(int i = 0; i < arr.length; i++){
085                        ret[i] = (byte)(arr[i] - 128);
086                }
087                return ret;
088        }
089        
090        /**
091         * Convert the given 2d int array to a 2d array of bytes.
092         * The ints are assumed to be in the range 0..255,
093         * and so 128 is subtracted before casting to a byte.
094         * 
095         * @param arr the int array
096         * @return an array of bytes
097         */
098        public static byte[][] intToByte(int [][] arr) {
099                byte[][] ret = new byte[arr.length][];
100                for(int i = 0; i < arr.length; i++){
101                        ret[i] = intToByte(arr[i]);
102                }
103                return ret;
104        }
105}