1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.internal.util; 18 19 import android.annotation.NonNull; 20 import android.annotation.Nullable; 21 import android.util.ArraySet; 22 23 import dalvik.system.VMRuntime; 24 25 import libcore.util.EmptyArray; 26 27 import java.lang.reflect.Array; 28 import java.util.ArrayList; 29 import java.util.Objects; 30 31 /** 32 * ArrayUtils contains some methods that you can call to find out 33 * the most efficient increments by which to grow arrays. 34 */ 35 public class ArrayUtils { 36 private static final int CACHE_SIZE = 73; 37 private static Object[] sCache = new Object[CACHE_SIZE]; 38 39 private ArrayUtils() { /* cannot be instantiated */ } 40 41 public static byte[] newUnpaddedByteArray(int minLen) { 42 return (byte[])VMRuntime.getRuntime().newUnpaddedArray(byte.class, minLen); 43 } 44 45 public static char[] newUnpaddedCharArray(int minLen) { 46 return (char[])VMRuntime.getRuntime().newUnpaddedArray(char.class, minLen); 47 } 48 49 public static int[] newUnpaddedIntArray(int minLen) { 50 return (int[])VMRuntime.getRuntime().newUnpaddedArray(int.class, minLen); 51 } 52 53 public static boolean[] newUnpaddedBooleanArray(int minLen) { 54 return (boolean[])VMRuntime.getRuntime().newUnpaddedArray(boolean.class, minLen); 55 } 56 57 public static long[] newUnpaddedLongArray(int minLen) { 58 return (long[])VMRuntime.getRuntime().newUnpaddedArray(long.class, minLen); 59 } 60 61 public static float[] newUnpaddedFloatArray(int minLen) { 62 return (float[])VMRuntime.getRuntime().newUnpaddedArray(float.class, minLen); 63 } 64 65 public static Object[] newUnpaddedObjectArray(int minLen) { 66 return (Object[])VMRuntime.getRuntime().newUnpaddedArray(Object.class, minLen); 67 } 68 69 @SuppressWarnings("unchecked") 70 public static <T> T[] newUnpaddedArray(Class<T> clazz, int minLen) { 71 return (T[])VMRuntime.getRuntime().newUnpaddedArray(clazz, minLen); 72 } 73 74 /** 75 * Checks if the beginnings of two byte arrays are equal. 76 * 77 * @param array1 the first byte array 78 * @param array2 the second byte array 79 * @param length the number of bytes to check 80 * @return true if they're equal, false otherwise 81 */ 82 public static boolean equals(byte[] array1, byte[] array2, int length) { 83 if (length < 0) { 84 throw new IllegalArgumentException(); 85 } 86 87 if (array1 == array2) { 88 return true; 89 } 90 if (array1 == null || array2 == null || array1.length < length || array2.length < length) { 91 return false; 92 } 93 for (int i = 0; i < length; i++) { 94 if (array1[i] != array2[i]) { 95 return false; 96 } 97 } 98 return true; 99 } 100 101 /** 102 * Returns an empty array of the specified type. The intent is that 103 * it will return the same empty array every time to avoid reallocation, 104 * although this is not guaranteed. 105 */ 106 @SuppressWarnings("unchecked") 107 public static <T> T[] emptyArray(Class<T> kind) { 108 if (kind == Object.class) { 109 return (T[]) EmptyArray.OBJECT; 110 } 111 112 int bucket = (kind.hashCode() & 0x7FFFFFFF) % CACHE_SIZE; 113 Object cache = sCache[bucket]; 114 115 if (cache == null || cache.getClass().getComponentType() != kind) { 116 cache = Array.newInstance(kind, 0); 117 sCache[bucket] = cache; 118 119 // Log.e("cache", "new empty " + kind.getName() + " at " + bucket); 120 } 121 122 return (T[]) cache; 123 } 124 125 /** 126 * Checks if given array is null or has zero elements. 127 */ 128 public static <T> boolean isEmpty(T[] array) { 129 return array == null || array.length == 0; 130 } 131 132 /** 133 * Checks if given array is null or has zero elements. 134 */ 135 public static boolean isEmpty(int[] array) { 136 return array == null || array.length == 0; 137 } 138 139 /** 140 * Checks if given array is null or has zero elements. 141 */ 142 public static boolean isEmpty(long[] array) { 143 return array == null || array.length == 0; 144 } 145 146 /** 147 * Checks that value is present as at least one of the elements of the array. 148 * @param array the array to check in 149 * @param value the value to check for 150 * @return true if the value is present in the array 151 */ 152 public static <T> boolean contains(T[] array, T value) { 153 return indexOf(array, value) != -1; 154 } 155 156 /** 157 * Return first index of {@code value} in {@code array}, or {@code -1} if 158 * not found. 159 */ 160 public static <T> int indexOf(T[] array, T value) { 161 if (array == null) return -1; 162 for (int i = 0; i < array.length; i++) { 163 if (Objects.equals(array[i], value)) return i; 164 } 165 return -1; 166 } 167 168 /** 169 * Test if all {@code check} items are contained in {@code array}. 170 */ 171 public static <T> boolean containsAll(T[] array, T[] check) { 172 if (check == null) return true; 173 for (T checkItem : check) { 174 if (!contains(array, checkItem)) { 175 return false; 176 } 177 } 178 return true; 179 } 180 181 public static boolean contains(int[] array, int value) { 182 if (array == null) return false; 183 for (int element : array) { 184 if (element == value) { 185 return true; 186 } 187 } 188 return false; 189 } 190 191 public static boolean contains(long[] array, long value) { 192 if (array == null) return false; 193 for (long element : array) { 194 if (element == value) { 195 return true; 196 } 197 } 198 return false; 199 } 200 201 public static long total(long[] array) { 202 long total = 0; 203 for (long value : array) { 204 total += value; 205 } 206 return total; 207 } 208 209 /** 210 * Adds value to given array if not already present, providing set-like 211 * behavior. 212 */ 213 @SuppressWarnings("unchecked") 214 public static @NonNull <T> T[] appendElement(Class<T> kind, @Nullable T[] array, T element) { 215 final T[] result; 216 final int end; 217 if (array != null) { 218 if (contains(array, element)) return array; 219 end = array.length; 220 result = (T[])Array.newInstance(kind, end + 1); 221 System.arraycopy(array, 0, result, 0, end); 222 } else { 223 end = 0; 224 result = (T[])Array.newInstance(kind, 1); 225 } 226 result[end] = element; 227 return result; 228 } 229 230 /** 231 * Removes value from given array if present, providing set-like behavior. 232 */ 233 @SuppressWarnings("unchecked") 234 public static @Nullable <T> T[] removeElement(Class<T> kind, @Nullable T[] array, T element) { 235 if (array != null) { 236 if (!contains(array, element)) return array; 237 final int length = array.length; 238 for (int i = 0; i < length; i++) { 239 if (Objects.equals(array[i], element)) { 240 if (length == 1) { 241 return null; 242 } 243 T[] result = (T[])Array.newInstance(kind, length - 1); 244 System.arraycopy(array, 0, result, 0, i); 245 System.arraycopy(array, i + 1, result, i, length - i - 1); 246 return result; 247 } 248 } 249 } 250 return array; 251 } 252 253 /** 254 * Adds value to given array if not already present, providing set-like 255 * behavior. 256 */ 257 public static @NonNull int[] appendInt(@Nullable int[] cur, int val) { 258 if (cur == null) { 259 return new int[] { val }; 260 } 261 final int N = cur.length; 262 for (int i = 0; i < N; i++) { 263 if (cur[i] == val) { 264 return cur; 265 } 266 } 267 int[] ret = new int[N + 1]; 268 System.arraycopy(cur, 0, ret, 0, N); 269 ret[N] = val; 270 return ret; 271 } 272 273 /** 274 * Removes value from given array if present, providing set-like behavior. 275 */ 276 public static @Nullable int[] removeInt(@Nullable int[] cur, int val) { 277 if (cur == null) { 278 return null; 279 } 280 final int N = cur.length; 281 for (int i = 0; i < N; i++) { 282 if (cur[i] == val) { 283 int[] ret = new int[N - 1]; 284 if (i > 0) { 285 System.arraycopy(cur, 0, ret, 0, i); 286 } 287 if (i < (N - 1)) { 288 System.arraycopy(cur, i + 1, ret, i, N - i - 1); 289 } 290 return ret; 291 } 292 } 293 return cur; 294 } 295 296 /** 297 * Removes value from given array if present, providing set-like behavior. 298 */ 299 public static @Nullable String[] removeString(@Nullable String[] cur, String val) { 300 if (cur == null) { 301 return null; 302 } 303 final int N = cur.length; 304 for (int i = 0; i < N; i++) { 305 if (Objects.equals(cur[i], val)) { 306 String[] ret = new String[N - 1]; 307 if (i > 0) { 308 System.arraycopy(cur, 0, ret, 0, i); 309 } 310 if (i < (N - 1)) { 311 System.arraycopy(cur, i + 1, ret, i, N - i - 1); 312 } 313 return ret; 314 } 315 } 316 return cur; 317 } 318 319 /** 320 * Adds value to given array if not already present, providing set-like 321 * behavior. 322 */ 323 public static @NonNull long[] appendLong(@Nullable long[] cur, long val) { 324 if (cur == null) { 325 return new long[] { val }; 326 } 327 final int N = cur.length; 328 for (int i = 0; i < N; i++) { 329 if (cur[i] == val) { 330 return cur; 331 } 332 } 333 long[] ret = new long[N + 1]; 334 System.arraycopy(cur, 0, ret, 0, N); 335 ret[N] = val; 336 return ret; 337 } 338 339 /** 340 * Removes value from given array if present, providing set-like behavior. 341 */ 342 public static @Nullable long[] removeLong(@Nullable long[] cur, long val) { 343 if (cur == null) { 344 return null; 345 } 346 final int N = cur.length; 347 for (int i = 0; i < N; i++) { 348 if (cur[i] == val) { 349 long[] ret = new long[N - 1]; 350 if (i > 0) { 351 System.arraycopy(cur, 0, ret, 0, i); 352 } 353 if (i < (N - 1)) { 354 System.arraycopy(cur, i + 1, ret, i, N - i - 1); 355 } 356 return ret; 357 } 358 } 359 return cur; 360 } 361 362 public static long[] cloneOrNull(long[] array) { 363 return (array != null) ? array.clone() : null; 364 } 365 366 public static <T> ArraySet<T> add(ArraySet<T> cur, T val) { 367 if (cur == null) { 368 cur = new ArraySet<>(); 369 } 370 cur.add(val); 371 return cur; 372 } 373 374 public static <T> ArraySet<T> remove(ArraySet<T> cur, T val) { 375 if (cur == null) { 376 return null; 377 } 378 cur.remove(val); 379 if (cur.isEmpty()) { 380 return null; 381 } else { 382 return cur; 383 } 384 } 385 386 public static <T> boolean contains(ArraySet<T> cur, T val) { 387 return (cur != null) ? cur.contains(val) : false; 388 } 389 390 public static <T> ArrayList<T> add(ArrayList<T> cur, T val) { 391 if (cur == null) { 392 cur = new ArrayList<>(); 393 } 394 cur.add(val); 395 return cur; 396 } 397 398 public static <T> ArrayList<T> remove(ArrayList<T> cur, T val) { 399 if (cur == null) { 400 return null; 401 } 402 cur.remove(val); 403 if (cur.isEmpty()) { 404 return null; 405 } else { 406 return cur; 407 } 408 } 409 410 public static <T> boolean contains(ArrayList<T> cur, T val) { 411 return (cur != null) ? cur.contains(val) : false; 412 } 413 414 /** 415 * Returns true if the two ArrayLists are equal with respect to the objects they contain. 416 * The objects must be in the same order and be reference equal (== not .equals()). 417 */ 418 public static <T> boolean referenceEquals(ArrayList<T> a, ArrayList<T> b) { 419 if (a == b) { 420 return true; 421 } 422 423 final int sizeA = a.size(); 424 final int sizeB = b.size(); 425 if (a == null || b == null || sizeA != sizeB) { 426 return false; 427 } 428 429 boolean diff = false; 430 for (int i = 0; i < sizeA && !diff; i++) { 431 diff |= a.get(i) != b.get(i); 432 } 433 return !diff; 434 } 435 } 436
