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/*
* 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.io.File;
import java.lang.reflect.Array;
import java.util.*;
import java.util.function.IntFunction;
/**
* Static utility methods for arrays that aren't already included in {@link java.util.Arrays}.
*/
public class ArrayUtils {
private static final int CACHE_SIZE = 73;
private static Object[] sCache = new Object[CACHE_SIZE];
public static final File[] EMPTY_FILE = new File[0];
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;
}
/**
* Returns the same array or an empty one if it's null.
*/
public static @NonNull T[] emptyIfNull(@Nullable T[] items, Class kind) {
return items != null ? items : emptyArray(kind);
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable Collection array) {
return array == null || array.isEmpty();
}
/**
* Checks if given map is null or has zero elements.
*/
public static boolean isEmpty(@Nullable Map map) {
return map == null || map.isEmpty();
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable T[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable int[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable long[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable byte[] array) {
return array == null || array.length == 0;
}
/**
* Checks if given array is null or has zero elements.
*/
public static boolean isEmpty(@Nullable boolean[] array) {
return array == null || array.length == 0;
}
/**
* Length of the given array or 0 if it's null.
*/
public static int size(@Nullable Object[] array) {
return array == null ? 0 : array.length;
}
/**
* Length of the given collection or 0 if it's null.
*/
public static int size(@Nullable Collection collection) {
return collection == null ? 0 : collection.size();
}
/**
* Length of the given map or 0 if it's null.
*/
public static int size(@Nullable Map map) {
return map == null ? 0 : map.size();
}
/**
* 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(@Nullable 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(@Nullable 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(@Nullable T[] array, T[] check) {
if (check == null) return true;
for (T checkItem : check) {
if (!contains(array, checkItem)) {
return false;
}
}
return true;
}
/**
* Test if any {@code check} items are contained in {@code array}.
*/
public static boolean containsAny(@Nullable T[] array, T[] check) {
if (check == null) return false;
for (T checkItem : check) {
if (contains(array, checkItem)) {
return true;
}
}
return false;
}
public static boolean contains(@Nullable int[] array, int value) {
if (array == null) return false;
for (int element : array) {
if (element == value) {
return true;
}
}
return false;
}
public static boolean contains(@Nullable long[] array, long value) {
if (array == null) return false;
for (long element : array) {
if (element == value) {
return true;
}
}
return false;
}
public static boolean contains(@Nullable char[] array, char value) {
if (array == null) return false;
for (char element : array) {
if (element == value) {
return true;
}
}
return false;
}
/**
* Test if all {@code check} items are contained in {@code array}.
*/
public static boolean containsAll(@Nullable char[] array, char[] check) {
if (check == null) return true;
for (char checkItem : check) {
if (!contains(array, checkItem)) {
return false;
}
}
return true;
}
public static long total(@Nullable long[] array) {
long total = 0;
if (array != null) {
for (long value : array) {
total += value;
}
}
return total;
}
/**
* @deprecated use {@code IntArray} instead
*/
@Deprecated
public static int[] convertToIntArray(List list) {
int[] array = new int[list.size()];
for (int i = 0; i < list.size(); i++) {
array[i] = list.get(i);
}
return array;
}
@NonNull
public static int[] convertToIntArray(@NonNull ArraySet set) {
final int size = set.size();
int[] array = new int[size];
for (int i = 0; i < size; i++) {
array[i] = set.valueAt(i);
}
return array;
}
public static @Nullable long[] convertToLongArray(@Nullable int[] intArray) {
if (intArray == null) return null;
long[] array = new long[intArray.length];
for (int i = 0; i < intArray.length; i++) {
array[i] = (long) intArray[i];
}
return array;
}
/**
* Returns the concatenation of the given arrays. Only works for object arrays, not for
* primitive arrays. See {@link #concat(byte[]...)} for a variant that works on byte arrays.
*
* @param kind The class of the array elements
* @param arrays The arrays to concatenate. Null arrays are treated as empty.
* @param The class of the array elements (inferred from kind).
* @return A single array containing all the elements of the parameter arrays.
*/
@SuppressWarnings("unchecked")
public static @NonNull T[] concat(Class kind, @Nullable T[]... arrays) {
if (arrays == null || arrays.length == 0) {
return createEmptyArray(kind);
}
int totalLength = 0;
for (T[] item : arrays) {
if (item == null) {
continue;
}
totalLength += item.length;
}
// Optimization for entirely empty arrays.
if (totalLength == 0) {
return createEmptyArray(kind);
}
final T[] all = (T[]) Array.newInstance(kind, totalLength);
int pos = 0;
for (T[] item : arrays) {
if (item == null || item.length == 0) {
continue;
}
System.arraycopy(item, 0, all, pos, item.length);
pos += item.length;
}
return all;
}
private static @NonNull T[] createEmptyArray(Class kind) {
if (kind == String.class) {
return (T[]) EmptyArray.STRING;
} else if (kind == Object.class) {
return (T[]) EmptyArray.OBJECT;
}
return (T[]) Array.newInstance(kind, 0);
}
/**
* Returns the concatenation of the given byte arrays. Null arrays are treated as empty.
*/
public static @NonNull byte[] concat(@Nullable byte[]... arrays) {
if (arrays == null) {
return new byte[0];
}
int totalLength = 0;
for (byte[] a : arrays) {
if (a != null) {
totalLength += a.length;
}
}
final byte[] result = new byte[totalLength];
int pos = 0;
for (byte[] a : arrays) {
if (a != null) {
System.arraycopy(a, 0, result, pos, a.length);
pos += a.length;
}
}
return result;
}
/**
* 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) {
return appendElement(kind, array, element, false);
}
/**
* Adds value to given array.
*/
@SuppressWarnings("unchecked")
public static @NonNull T[] appendElement(Class kind, @Nullable T[] array, T element,
boolean allowDuplicates) {
final T[] result;
final int end;
if (array != null) {
if (!allowDuplicates && 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.
*/
public static @NonNull int[] appendInt(@Nullable int[] cur, int val,
boolean allowDuplicates) {
if (cur == null) {
return new int[] { val };
}
final int N = cur.length;
if (!allowDuplicates) {
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;
}
/**
* Adds value to given array if not already present, providing set-like
* behavior.
*/
public static @NonNull int[] appendInt(@Nullable int[] cur, int val) {
return appendInt(cur, val, false);
}
/**
* 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,
boolean allowDuplicates) {
if (cur == null) {
return new long[] { val };
}
final int N = cur.length;
if (!allowDuplicates) {
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;
}
/**
* Adds value to given array if not already present, providing set-like
* behavior.
*/
public static @NonNull long[] appendLong(@Nullable long[] cur, long val) {
return appendLong(cur, val, false);
}
/**
* 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 @Nullable long[] cloneOrNull(@Nullable long[] array) {
return (array != null) ? array.clone() : null;
}
/**
* Clones an array or returns null if the array is null.
*/
public static @Nullable T[] cloneOrNull(@Nullable T[] array) {
return (array != null) ? array.clone() : null;
}
public static @Nullable ArraySet cloneOrNull(@Nullable ArraySet array) {
return (array != null) ? new ArraySet(array) : null;
}
public static @NonNull ArraySet add(@Nullable ArraySet cur, T val) {
if (cur == null) {
cur = new ArraySet<>();
}
cur.add(val);
return cur;
}
/**
* Similar to {@link Set#addAll(Collection)}}, but with support for set values of {@code null}.
*/
public static @NonNull ArraySet addAll(@Nullable ArraySet cur,
@Nullable Collection val) {
if (cur == null) {
cur = new ArraySet<>();
}
if (val != null) {
cur.addAll(val);
}
return cur;
}
public static @Nullable ArraySet remove(@Nullable ArraySet cur, T val) {
if (cur == null) {
return null;
}
cur.remove(val);
if (cur.isEmpty()) {
return null;
} else {
return cur;
}
}
public static @NonNull ArrayList add(@Nullable ArrayList cur, T val) {
if (cur == null) {
cur = new ArrayList<>();
}
cur.add(val);
return cur;
}
public static @NonNull ArrayList add(@Nullable ArrayList cur, int index, T val) {
if (cur == null) {
cur = new ArrayList<>();
}
cur.add(index, val);
return cur;
}
public static @Nullable ArrayList remove(@Nullable ArrayList cur, T val) {
if (cur == null) {
return null;
}
cur.remove(val);
if (cur.isEmpty()) {
return null;
} else {
return cur;
}
}
public static boolean contains(@Nullable Collection cur, T val) {
return (cur != null) ? cur.contains(val) : false;
}
public static @Nullable T[] trimToSize(@Nullable T[] array, int size) {
if (array == null || size == 0) {
return null;
} else if (array.length == size) {
return array;
} else {
return Arrays.copyOf(array, size);
}
}
/**
* 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;
}
/**
* Removes elements that match the predicate in an efficient way that alters the order of
* elements in the collection. This should only be used if order is not important.
* @param collection The ArrayList from which to remove elements.
* @param predicate The predicate that each element is tested against.
* @return the number of elements removed.
*/
public static int unstableRemoveIf(@Nullable ArrayList collection,
@NonNull java.util.function.Predicate predicate) {
if (collection == null) {
return 0;
}
final int size = collection.size();
int leftIdx = 0;
int rightIdx = size - 1;
while (leftIdx <= rightIdx) {
// Find the next element to remove moving left to right.
while (leftIdx < size && !predicate.test(collection.get(leftIdx))) {
leftIdx++;
}
// Find the next element to keep moving right to left.
while (rightIdx > leftIdx && predicate.test(collection.get(rightIdx))) {
rightIdx--;
}
if (leftIdx >= rightIdx) {
// Done.
break;
}
Collections.swap(collection, leftIdx, rightIdx);
leftIdx++;
rightIdx--;
}
// leftIdx is now at the end.
for (int i = size - 1; i >= leftIdx; i--) {
collection.remove(i);
}
return size - leftIdx;
}
public static @NonNull int[] defeatNullable(@Nullable int[] val) {
return (val != null) ? val : EmptyArray.INT;
}
public static @NonNull String[] defeatNullable(@Nullable String[] val) {
return (val != null) ? val : EmptyArray.STRING;
}
public static @NonNull File[] defeatNullable(@Nullable File[] val) {
return (val != null) ? val : EMPTY_FILE;
}
/**
* Throws {@link ArrayIndexOutOfBoundsException} if the index is out of bounds.
*
* @param len length of the array. Must be non-negative
* @param index the index to check
* @throws ArrayIndexOutOfBoundsException if the {@code index} is out of bounds of the array
*/
public static void checkBounds(int len, int index) {
if (index < 0 || len <= index) {
throw new ArrayIndexOutOfBoundsException("length=" + len + "; index=" + index);
}
}
/**
* Throws {@link ArrayIndexOutOfBoundsException} if the range is out of bounds.
* @param len length of the array. Must be non-negative
* @param offset start index of the range. Must be non-negative
* @param count length of the range. Must be non-negative
* @throws ArrayIndexOutOfBoundsException if the range from {@code offset} with length
* {@code count} is out of bounds of the array
*/
public static void throwsIfOutOfBounds(int len, int offset, int count) {
if (len < 0) {
throw new ArrayIndexOutOfBoundsException("Negative length: " + len);
}
if ((offset | count) < 0 || offset > len - count) {
throw new ArrayIndexOutOfBoundsException(
"length=" + len + "; regionStart=" + offset + "; regionLength=" + count);
}
}
/**
* Returns an array with values from {@code val} minus {@code null} values
*
* @param arrayConstructor typically {@code T[]::new} e.g. {@code String[]::new}
*/
public static T[] filterNotNull(T[] val, IntFunction arrayConstructor) {
int nullCount = 0;
int size = size(val);
for (int i = 0; i < size; i++) {
if (val[i] == null) {
nullCount++;
}
}
if (nullCount == 0) {
return val;
}
T[] result = arrayConstructor.apply(size - nullCount);
int outIdx = 0;
for (int i = 0; i < size; i++) {
if (val[i] != null) {
result[outIdx++] = val[i];
}
}
return result;
}
/**
* Returns an array containing elements from the given one that match the given predicate.
* The returned array may, in some cases, be the reference to the input array.
*/
public static @Nullable T[] filter(@Nullable T[] items,
@NonNull IntFunction arrayConstructor,
@NonNull java.util.function.Predicate predicate) {
if (isEmpty(items)) {
return items;
}
int matchesCount = 0;
int size = size(items);
final boolean[] tests = new boolean[size];
for (int i = 0; i < size; i++) {
tests[i] = predicate.test(items[i]);
if (tests[i]) {
matchesCount++;
}
}
if (matchesCount == items.length) {
return items;
}
T[] result = arrayConstructor.apply(matchesCount);
if (matchesCount == 0) {
return result;
}
int outIdx = 0;
for (int i = 0; i < size; i++) {
if (tests[i]) {
result[outIdx++] = items[i];
}
}
return result;
}
public static boolean startsWith(byte[] cur, byte[] val) {
if (cur == null || val == null) return false;
if (cur.length < val.length) return false;
for (int i = 0; i < val.length; i++) {
if (cur[i] != val[i]) return false;
}
return true;
}
/**
* Returns the first element from the array for which
* condition {@code predicate} is true, or null if there is no such element
*/
public static @Nullable T find(@Nullable T[] items,
@NonNull java.util.function.Predicate predicate) {
if (isEmpty(items)) return null;
for (final T item : items) {
if (predicate.test(item)) return item;
}
return null;
}
public static String deepToString(Object value) {
if (value != null && value.getClass().isArray()) {
if (value.getClass() == boolean[].class) {
return Arrays.toString((boolean[]) value);
} else if (value.getClass() == byte[].class) {
return Arrays.toString((byte[]) value);
} else if (value.getClass() == char[].class) {
return Arrays.toString((char[]) value);
} else if (value.getClass() == double[].class) {
return Arrays.toString((double[]) value);
} else if (value.getClass() == float[].class) {
return Arrays.toString((float[]) value);
} else if (value.getClass() == int[].class) {
return Arrays.toString((int[]) value);
} else if (value.getClass() == long[].class) {
return Arrays.toString((long[]) value);
} else if (value.getClass() == short[].class) {
return Arrays.toString((short[]) value);
} else {
return Arrays.deepToString((Object[]) value);
}
} else {
return String.valueOf(value);
}
}
/**
* Returns the {@code i}-th item in {@code items}, if it exists and {@code items} is not {@code
* null}, otherwise returns {@code null}.
*/
@Nullable
public static T getOrNull(@Nullable T[] items, int i) {
return (items != null && items.length > i) ? items[i] : null;
}
public static @Nullable T firstOrNull(T[] items) {
return items.length > 0 ? items[0] : null;
}
/**
* Creates a {@link List} from an array. Different from {@link Arrays#asList(Object[])} as that
* will use the parameter as the backing array, meaning changes are not isolated.
*/
public static List toList(T[] array) {
List list = new ArrayList<>(array.length);
//noinspection ManualArrayToCollectionCopy
for (T item : array) {
//noinspection UseBulkOperation
list.add(item);
}
return list;
}
}
