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      1 /*
      2  * Copyright (C) 2007 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 import java.util.Arrays;
     18 
     19 /**
     20  * System.arraycopy cases
     21  */
     22 public class Main {
     23     public static void main(String args[]) {
     24         testObjectCopy();
     25         testOverlappingMoves();
     26         testFloatAndDouble();
     27     }
     28 
     29     public static void testObjectCopy() {
     30         String[] stringArray = new String[8];
     31         Object[] objectArray = new Object[8];
     32 
     33         for (int i = 0; i < stringArray.length; i++)
     34             stringArray[i] = new String(Integer.toString(i));
     35 
     36         System.out.println("string -> object");
     37         System.arraycopy(stringArray, 0, objectArray, 0, stringArray.length);
     38         System.out.println("object -> string");
     39         System.arraycopy(objectArray, 0, stringArray, 0, stringArray.length);
     40         System.out.println("object -> string (modified)");
     41         objectArray[4] = new ImplA();
     42         try {
     43             System.arraycopy(objectArray, 0, stringArray, 0,stringArray.length);
     44         }
     45         catch (ArrayStoreException ase) {
     46             System.out.println("caught ArrayStoreException (expected)");
     47         }
     48     }
     49 
     50     static final int ARRAY_SIZE = 8;
     51 
     52     static void initByteArray(byte[] array) {
     53         for (int i = 0; i < ARRAY_SIZE; i++) {
     54             array[i] = (byte) i;
     55         }
     56     }
     57     static void initShortArray(short[] array) {
     58         for (int i = 0; i < ARRAY_SIZE; i++) {
     59             array[i] = (short) i;
     60         }
     61     }
     62     static void initIntArray(int[] array) {
     63         for (int i = 0; i < ARRAY_SIZE; i++) {
     64             array[i] = (int) i;
     65         }
     66     }
     67     static void initLongArray(long[] array) {
     68         for (int i = 0; i < ARRAY_SIZE; i++) {
     69             array[i] = (long) i;
     70         }
     71     }
     72     static void initCharArray(char[] array) {
     73         for (int i = 0; i < ARRAY_SIZE; i++) {
     74             array[i] = (char) i;
     75         }
     76     }
     77 
     78     /*
     79      * Perform an array copy operation on primitive arrays with different
     80      * element widths.
     81      */
     82     static void makeCopies(int srcPos, int dstPos, int length) {
     83         byte[] byteArray = new byte[ARRAY_SIZE];
     84         short[] shortArray = new short[ARRAY_SIZE];
     85         int[] intArray = new int[ARRAY_SIZE];
     86         long[] longArray = new long[ARRAY_SIZE];
     87         char[] charArray = new char[ARRAY_SIZE];
     88 
     89         initByteArray(byteArray);
     90         initShortArray(shortArray);
     91         initIntArray(intArray);
     92         initLongArray(longArray);
     93         initCharArray(charArray);
     94 
     95         System.arraycopy(byteArray, srcPos, byteArray, dstPos, length);
     96         System.arraycopy(shortArray, srcPos, shortArray, dstPos, length);
     97         System.arraycopy(intArray, srcPos, intArray, dstPos, length);
     98         System.arraycopy(longArray, srcPos, longArray, dstPos, length);
     99         System.arraycopy(charArray, srcPos, charArray, dstPos, length);
    100 
    101         for (int i = 0; i < ARRAY_SIZE; i++) {
    102             if (intArray[i] != byteArray[i]) {
    103                 System.out.println("mismatch int vs byte at " + i + " : " +
    104                     Arrays.toString(byteArray));
    105                 break;
    106             } else if (intArray[i] != shortArray[i]) {
    107                 System.out.println("mismatch int vs short at " + i + " : " +
    108                     Arrays.toString(shortArray));
    109                 break;
    110             } else if (intArray[i] != longArray[i]) {
    111                 System.out.println("mismatch int vs long at " + i + " : " +
    112                     Arrays.toString(longArray));
    113                 break;
    114             } else if (intArray[i] != charArray[i]) {
    115                 System.out.println("mismatch int vs char at " + i + " : " +
    116                     Arrays.toString(charArray));
    117                 break;
    118             }
    119         }
    120 
    121         System.out.println("copy: " + srcPos + "," + dstPos + "," + length +
    122             ": " + Arrays.toString(intArray));
    123     }
    124 
    125     public static void testOverlappingMoves() {
    126         /* do nothing */
    127         makeCopies(0, 0, 0);
    128 
    129         /* do more nothing */
    130         makeCopies(0, 0, ARRAY_SIZE);
    131 
    132         /* copy forward, even alignment */
    133         makeCopies(0, 2, 4);
    134 
    135         /* copy backward, even alignment */
    136         makeCopies(2, 0, 4);
    137 
    138         /* copy forward, odd alignment */
    139         makeCopies(1, 3, 4);
    140 
    141         /* copy backward, odd alignment */
    142         makeCopies(3, 1, 4);
    143 
    144         /* copy backward, odd length */
    145         makeCopies(3, 1, 5);
    146 
    147         /* copy forward, odd length */
    148         makeCopies(1, 3, 5);
    149 
    150         /* copy forward, mixed alignment */
    151         makeCopies(0, 3, 5);
    152 
    153         /* copy backward, mixed alignment */
    154         makeCopies(3, 0, 5);
    155 
    156         /* copy forward, mixed alignment, trivial length */
    157         makeCopies(0, 5, 1);
    158     }
    159 
    160     private static void testFloatAndDouble() {
    161         // Float & double copies have the same implementation as int & long. However, there are
    162         // protective DCHECKs in the code (there is nothing unifying like ByteSizedArray or
    163         // ShortSizedArray). Just test that we don't fail those checks.
    164         final int len = 10;
    165         System.arraycopy(new float[len], 0, new float[len], 0, len);
    166         System.arraycopy(new double[len], 0, new double[len], 0, len);
    167     }
    168 }
    169