1 /* 2 * Copyright (C) 2015 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 android.security.keystore; 18 19 import libcore.util.EmptyArray; 20 21 /** 22 * @hide 23 */ 24 public abstract class ArrayUtils { 25 private ArrayUtils() {} 26 27 public static String[] nullToEmpty(String[] array) { 28 return (array != null) ? array : EmptyArray.STRING; 29 } 30 31 public static String[] cloneIfNotEmpty(String[] array) { 32 return ((array != null) && (array.length > 0)) ? array.clone() : array; 33 } 34 35 public static byte[] cloneIfNotEmpty(byte[] array) { 36 return ((array != null) && (array.length > 0)) ? array.clone() : array; 37 } 38 39 public static byte[] concat(byte[] arr1, byte[] arr2) { 40 return concat(arr1, 0, (arr1 != null) ? arr1.length : 0, 41 arr2, 0, (arr2 != null) ? arr2.length : 0); 42 } 43 44 public static byte[] concat(byte[] arr1, int offset1, int len1, byte[] arr2, int offset2, 45 int len2) { 46 if (len1 == 0) { 47 return subarray(arr2, offset2, len2); 48 } else if (len2 == 0) { 49 return subarray(arr1, offset1, len1); 50 } else { 51 byte[] result = new byte[len1 + len2]; 52 System.arraycopy(arr1, offset1, result, 0, len1); 53 System.arraycopy(arr2, offset2, result, len1, len2); 54 return result; 55 } 56 } 57 58 public static byte[] subarray(byte[] arr, int offset, int len) { 59 if (len == 0) { 60 return EmptyArray.BYTE; 61 } 62 if ((offset == 0) && (len == arr.length)) { 63 return arr; 64 } 65 byte[] result = new byte[len]; 66 System.arraycopy(arr, offset, result, 0, len); 67 return result; 68 } 69 70 public static int[] concat(int[] arr1, int[] arr2) { 71 if ((arr1 == null) || (arr1.length == 0)) { 72 return arr2; 73 } else if ((arr2 == null) || (arr2.length == 0)) { 74 return arr1; 75 } else { 76 int[] result = new int[arr1.length + arr2.length]; 77 System.arraycopy(arr1, 0, result, 0, arr1.length); 78 System.arraycopy(arr2, 0, result, arr1.length, arr2.length); 79 return result; 80 } 81 } 82 } 83
