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A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* Copyright (C) 2006 The Android Open Source Project
*
* 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 com.android.internal.util;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.util.ArraySet;
import dalvik.system.VMRuntime;
import libcore.util.EmptyArray;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Objects;
/**
* 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 final int CACHE_SIZE = 73;
private static Object[] sCache = new Object[CACHE_SIZE];
private ArrayUtils() { /* cannot be instantiated */ }
public static byte[] newUnpaddedByteArray(int minLen) {
return (byte[])VMRuntime.getRuntime().newUnpaddedArray(byte.class, minLen);
}
public static char[] newUnpaddedCharArray(int minLen) {
return (char[])VMRuntime.getRuntime().newUnpaddedArray(char.class, minLen);
}
public static int[] newUnpaddedIntArray(int minLen) {
return (int[])VMRuntime.getRuntime().newUnpaddedArray(int.class, minLen);
}
public static boolean[] newUnpaddedBooleanArray(int minLen) {
return (boolean[])VMRuntime.getRuntime().newUnpaddedArray(boolean.class, minLen);
}
public static long[] newUnpaddedLongArray(int minLen) {
return (long[])VMRuntime.getRuntime().newUnpaddedArray(long.class, minLen);
}
public static float[] newUnpaddedFloatArray(int minLen) {
return (float[])VMRuntime.getRuntime().newUnpaddedArray(float.class, minLen);
}
public static Object[] newUnpaddedObjectArray(int minLen) {
return (Object[])VMRuntime.getRuntime().newUnpaddedArray(Object.class, minLen);
}
@SuppressWarnings("unchecked")
public static T[] newUnpaddedArray(Class clazz, int minLen) {
return (T[])VMRuntime.getRuntime().newUnpaddedArray(clazz, minLen);
}
/**
* 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 (length < 0) {
throw new IllegalArgumentException();
}
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[] emptyArray(Class kind) {
if (kind == Object.class) {
return (T[]) EmptyArray.OBJECT;
}
int bucket = (kind.hashCode() & 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 if given array is null or has zero elements.
*/
public static boolean isEmpty(T[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(int[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(long[] array) {
return array == null || array.length == 0;
}
/**
* 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 boolean contains(T[] array, T value) {
return indexOf(array, value) != -1;
}
/**
* Return first index of {@code value} in {@code array}, or {@code -1} if
* not found.
*/
public static int indexOf(T[] array, T value) {
if (array == null) return -1;
for (int i = 0; i < array.length; i++) {
if (Objects.equals(array[i], value)) return i;
}
return -1;
}
/**
* Test if all {@code check} items are contained in {@code array}.
*/
public static boolean containsAll(T[] array, T[] check) {
if (check == null) return true;
for (T checkItem : check) {
if (!contains(array, checkItem)) {
return false;
}
}
return true;
}
public static boolean contains(int[] array, int value) {
if (array == null) return false;
for (int element : array) {
if (element == value) {
return true;
}
}
return false;
}
public static boolean contains(long[] array, long value) {
if (array == null) return false;
for (long element : array) {
if (element == value) {
return true;
}
}
return false;
}
public static long total(long[] array) {
long total = 0;
for (long value : array) {
total += value;
}
return total;
}
/**
* Adds value to given array if not already present, providing set-like
* behavior.
*/
@SuppressWarnings("unchecked")
public static @NonNull T[] appendElement(Class kind, @Nullable T[] array, T element) {
final T[] result;
final int end;
if (array != null) {
if (contains(array, element)) return array;
end = array.length;
result = (T[])Array.newInstance(kind, end + 1);
System.arraycopy(array, 0, result, 0, end);
} else {
end = 0;
result = (T[])Array.newInstance(kind, 1);
}
result[end] = element;
return result;
}
/**
* Removes value from given array if present, providing set-like behavior.
*/
@SuppressWarnings("unchecked")
public static @Nullable T[] removeElement(Class kind, @Nullable T[] array, T element) {
if (array != null) {
if (!contains(array, element)) return array;
final int length = array.length;
for (int i = 0; i < length; i++) {
if (Objects.equals(array[i], element)) {
if (length == 1) {
return null;
}
T[] result = (T[])Array.newInstance(kind, length - 1);
System.arraycopy(array, 0, result, 0, i);
System.arraycopy(array, i + 1, result, i, length - i - 1);
return result;
}
}
}
return array;
}
/**
* Adds value to given array if not already present, providing set-like
* behavior.
*/
public static @NonNull int[] appendInt(@Nullable int[] cur, int val) {
if (cur == null) {
return new int[] { val };
}
final int N = cur.length;
for (int i = 0; i < N; i++) {
if (cur[i] == val) {
return cur;
}
}
int[] ret = new int[N + 1];
System.arraycopy(cur, 0, ret, 0, N);
ret[N] = val;
return ret;
}
/**
* Removes value from given array if present, providing set-like behavior.
*/
public static @Nullable int[] removeInt(@Nullable int[] cur, int val) {
if (cur == null) {
return null;
}
final int N = cur.length;
for (int i = 0; i < N; i++) {
if (cur[i] == val) {
int[] ret = new int[N - 1];
if (i > 0) {
System.arraycopy(cur, 0, ret, 0, i);
}
if (i < (N - 1)) {
System.arraycopy(cur, i + 1, ret, i, N - i - 1);
}
return ret;
}
}
return cur;
}
/**
* Removes value from given array if present, providing set-like behavior.
*/
public static @Nullable String[] removeString(@Nullable String[] cur, String val) {
if (cur == null) {
return null;
}
final int N = cur.length;
for (int i = 0; i < N; i++) {
if (Objects.equals(cur[i], val)) {
String[] ret = new String[N - 1];
if (i > 0) {
System.arraycopy(cur, 0, ret, 0, i);
}
if (i < (N - 1)) {
System.arraycopy(cur, i + 1, ret, i, N - i - 1);
}
return ret;
}
}
return cur;
}
/**
* Adds value to given array if not already present, providing set-like
* behavior.
*/
public static @NonNull long[] appendLong(@Nullable long[] cur, long val) {
if (cur == null) {
return new long[] { val };
}
final int N = cur.length;
for (int i = 0; i < N; i++) {
if (cur[i] == val) {
return cur;
}
}
long[] ret = new long[N + 1];
System.arraycopy(cur, 0, ret, 0, N);
ret[N] = val;
return ret;
}
/**
* Removes value from given array if present, providing set-like behavior.
*/
public static @Nullable long[] removeLong(@Nullable long[] cur, long val) {
if (cur == null) {
return null;
}
final int N = cur.length;
for (int i = 0; i < N; i++) {
if (cur[i] == val) {
long[] ret = new long[N - 1];
if (i > 0) {
System.arraycopy(cur, 0, ret, 0, i);
}
if (i < (N - 1)) {
System.arraycopy(cur, i + 1, ret, i, N - i - 1);
}
return ret;
}
}
return cur;
}
public static long[] cloneOrNull(long[] array) {
return (array != null) ? array.clone() : null;
}
public static ArraySet add(ArraySet cur, T val) {
if (cur == null) {
cur = new ArraySet<>();
}
cur.add(val);
return cur;
}
public static ArraySet remove(ArraySet cur, T val) {
if (cur == null) {
return null;
}
cur.remove(val);
if (cur.isEmpty()) {
return null;
} else {
return cur;
}
}
public static boolean contains(ArraySet cur, T val) {
return (cur != null) ? cur.contains(val) : false;
}
public static ArrayList add(ArrayList cur, T val) {
if (cur == null) {
cur = new ArrayList<>();
}
cur.add(val);
return cur;
}
public static ArrayList remove(ArrayList cur, T val) {
if (cur == null) {
return null;
}
cur.remove(val);
if (cur.isEmpty()) {
return null;
} else {
return cur;
}
}
public static boolean contains(ArrayList cur, T val) {
return (cur != null) ? cur.contains(val) : false;
}
/**
* Returns true if the two ArrayLists are equal with respect to the objects they contain.
* The objects must be in the same order and be reference equal (== not .equals()).
*/
public static boolean referenceEquals(ArrayList a, ArrayList b) {
if (a == b) {
return true;
}
final int sizeA = a.size();
final int sizeB = b.size();
if (a == null || b == null || sizeA != sizeB) {
return false;
}
boolean diff = false;
for (int i = 0; i < sizeA && !diff; i++) {
diff |= a.get(i) != b.get(i);
}
return !diff;
}
}
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