/**
* Copyright (C) 2010-2012 Regis Montoya (aka r3gis - www.r3gis.fr)
* This file is part of CSipSimple.
*
* CSipSimple is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* If you own a pjsip commercial license you can also redistribute it
* and/or modify it under the terms of the GNU Lesser General Public License
* as an android library.
*
* CSipSimple is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CSipSimple. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* This file contains relicensed code from Apache copyright of
* Copyright (C) 2006 The Android Open Source Project
*/
package com.csipsimple.utils;
import java.lang.reflect.Array;
// XXX these should be changed to reflect the actual memory allocator we use.
// it looks like right now objects want to be powers of 2 minus 8
// and the array size eats another 4 bytes
/**
* ArrayUtils contains some methods that you can call to find out
* the most efficient increments by which to grow arrays.
*/
public class ArrayUtils
{
private static Object[] EMPTY = new Object[0];
private static final int CACHE_SIZE = 73;
private static Object[] sCache = new Object[CACHE_SIZE];
private ArrayUtils() { /* cannot be instantiated */ }
public static int idealByteArraySize(int need) {
for (int i = 4; i < 32; i++)
if (need <= (1 << i) - 12)
return (1 << i) - 12;
return need;
}
public static int idealBooleanArraySize(int need) {
return idealByteArraySize(need);
}
public static int idealShortArraySize(int need) {
return idealByteArraySize(need * 2) / 2;
}
public static int idealCharArraySize(int need) {
return idealByteArraySize(need * 2) / 2;
}
public static int idealIntArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
public static int idealFloatArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
public static int idealObjectArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
public static int idealLongArraySize(int need) {
return idealByteArraySize(need * 8) / 8;
}
/**
* Checks if the beginnings of two byte arrays are equal.
*
* @param array1 the first byte array
* @param array2 the second byte array
* @param length the number of bytes to check
* @return true if they're equal, false otherwise
*/
public static boolean equals(byte[] array1, byte[] array2, int length) {
if (array1 == array2) {
return true;
}
if (array1 == null || array2 == null || array1.length < length || array2.length < length) {
return false;
}
for (int i = 0; i < length; i++) {
if (array1[i] != array2[i]) {
return false;
}
}
return true;
}
/**
* Returns an empty array of the specified type. The intent is that
* it will return the same empty array every time to avoid reallocation,
* although this is not guaranteed.
*/
@SuppressWarnings("unchecked")
public static <T> T[] emptyArray(Class<T> kind) {
if (kind == Object.class) {
return (T[]) EMPTY;
}
int bucket = ((System.identityHashCode(kind) / 8) & 0x7FFFFFFF) % CACHE_SIZE;
Object cache = sCache[bucket];
if (cache == null || cache.getClass().getComponentType() != kind) {
cache = Array.newInstance(kind, 0);
sCache[bucket] = cache;
// Log.e("cache", "new empty " + kind.getName() + " at " + bucket);
}
return (T[]) cache;
}
/**
* Checks that value is present as at least one of the elements of the array.
* @param array the array to check in
* @param value the value to check for
* @return true if the value is present in the array
*/
public static <T> boolean contains(T[] array, T value) {
for (T element : array) {
if (element == null) {
if (value == null) return true;
} else {
if (value != null && element.equals(value)) return true;
}
}
return false;
}
public static boolean contains(int[] array, int value) {
for (int element : array) {
if (element == value) {
return true;
}
}
return false;
}
}