/*
* $RCSfile: ArrayUtil.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:24 $
* $State: Exp $
*
* Class: ArrayUtil
*
* Description: Utillities for arrays.
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
*
*
*
*/
/**
* This class contains a colleaction of utility static methods for arrays.
* */
public class ArrayUtil {
/** The maximum array size to do element by element copying, larger
* arrays are copyied in a n optimized way. */
public static final int MAX_EL_COPYING = 8;
/** The number of elements to copy initially in an optimized array copy */
public static final int INIT_EL_COPYING = 4;
/**
* Reinitializes an int array to the given value in an optimized way. If
* the length of the array is less than MAX_EL_COPYING, then the array
* is set element by element in the normal way, otherwise the first
* INIT_EL_COPYING elements are set element by element and then
* System.arraycopy is used to set the other parts of the array.
*
* @param arr The array to set.
*
* @param val The value to set the array to.
*
*
* */
public static void intArraySet(int arr[], int val) {
int i,len,len2;
len = arr.length;
// Set array to 'val' in an optimized way
if (len < MAX_EL_COPYING) {
// Not worth doing optimized way
for (i=len-1; i>=0; i--) { // Set elements
arr[i] = val;
}
}
else { // Do in optimized way
len2 = len>>1;
for (i=0; i<INIT_EL_COPYING; i++) { // Set first elements
arr[i] = val;
}
for (; i <= len2 ; i<<=1) {
// Copy values doubling size each time
System.arraycopy(arr,0,arr,i,i);
}
if (i < len) { // Copy values to end
System.arraycopy(arr,0,arr,i,len-i);
}
}
}
/**
* Reinitializes a byte array to the given value in an optimized way. If
* the length of the array is less than MAX_EL_COPYING, then the array
* is set element by element in the normal way, otherwise the first
* INIT_EL_COPYING elements are set element by element and then
* System.arraycopy is used to set the other parts of the array.
*
* @param arr The array to set.
*
* @param val The value to set the array to.
*
*
* */
public static void byteArraySet(byte arr[], byte val) {
int i,len,len2;
len = arr.length;
// Set array to 'val' in an optimized way
if (len < MAX_EL_COPYING) {
// Not worth doing optimized way
for (i=len-1; i>=0; i--) { // Set elements
arr[i] = val;
}
}
else { // Do in optimized way
len2 = len>>1;
for (i=0; i<INIT_EL_COPYING; i++) { // Set first elements
arr[i] = val;
}
for (; i <= len2 ; i<<=1) {
// Copy values doubling size each time
System.arraycopy(arr,0,arr,i,i);
}
if (i < len) { // Copy values to end
System.arraycopy(arr,0,arr,i,len-i);
}
}
}
}
|
