[13350] | 1 | /*
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| 2 | * ResettableArrayCache
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| 3 | *
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| 4 | * Author: Lasse Collin <lasse.collin@tukaani.org>
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| 5 | *
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| 6 | * This file has been put into the public domain.
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| 7 | * You can do whatever you want with this file.
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| 8 | */
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| 9 |
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| 10 | package org.tukaani.xz;
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| 11 |
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| 12 | import java.util.ArrayList;
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| 13 | import java.util.List;
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| 14 |
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| 15 | /**
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| 16 | * An ArrayCache wrapper that remembers what has been allocated
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| 17 | * and allows returning all allocations to the underlying cache at once.
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| 18 | *
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| 19 | * @since 1.7
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| 20 | */
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| 21 | public class ResettableArrayCache extends ArrayCache {
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| 22 | private final ArrayCache arrayCache;
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| 23 |
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| 24 | // Lists of arrays that have been allocated from the arrayCache.
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| 25 | private final List<byte[]> byteArrays;
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| 26 | private final List<int[]> intArrays;
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| 27 |
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| 28 | /**
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| 29 | * Creates a new ResettableArrayCache based on the given ArrayCache.
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| 30 | */
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| 31 | public ResettableArrayCache(ArrayCache arrayCache) {
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| 32 | this.arrayCache = arrayCache;
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| 33 |
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| 34 | // Treat the dummy cache as a special case since it's a common case.
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| 35 | // With it we don't need to put the arrays back to the cache and
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| 36 | // thus we don't need to remember what has been allocated.
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| 37 | if (arrayCache == ArrayCache.getDummyCache()) {
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| 38 | byteArrays = null;
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| 39 | intArrays = null;
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| 40 | } else {
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| 41 | byteArrays = new ArrayList<byte[]>();
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| 42 | intArrays = new ArrayList<int[]>();
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| 43 | }
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| 44 | }
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| 45 |
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| 46 | public byte[] getByteArray(int size, boolean fillWithZeros) {
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| 47 | byte[] array = arrayCache.getByteArray(size, fillWithZeros);
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| 48 |
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| 49 | if (byteArrays != null) {
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| 50 | synchronized(byteArrays) {
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| 51 | byteArrays.add(array);
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| 52 | }
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| 53 | }
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| 54 |
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| 55 | return array;
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| 56 | }
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| 57 |
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| 58 | public void putArray(byte[] array) {
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| 59 | if (byteArrays != null) {
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| 60 | // The array is more likely to be near the end of the list so
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| 61 | // start the search from the end.
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| 62 | synchronized(byteArrays) {
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| 63 | int i = byteArrays.lastIndexOf(array);
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| 64 | if (i != -1)
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| 65 | byteArrays.remove(i);
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| 66 | }
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| 67 |
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| 68 | arrayCache.putArray(array);
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| 69 | }
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| 70 | }
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| 71 |
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| 72 | public int[] getIntArray(int size, boolean fillWithZeros) {
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| 73 | int[] array = arrayCache.getIntArray(size, fillWithZeros);
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| 74 |
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| 75 | if (intArrays != null) {
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| 76 | synchronized(intArrays) {
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| 77 | intArrays.add(array);
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| 78 | }
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| 79 | }
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| 80 |
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| 81 | return array;
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| 82 | }
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| 83 |
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| 84 | public void putArray(int[] array) {
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| 85 | if (intArrays != null) {
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| 86 | synchronized(intArrays) {
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| 87 | int i = intArrays.lastIndexOf(array);
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| 88 | if (i != -1)
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| 89 | intArrays.remove(i);
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| 90 | }
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| 91 |
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| 92 | arrayCache.putArray(array);
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| 93 | }
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| 94 | }
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| 95 |
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| 96 | /**
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| 97 | * Puts all allocated arrays back to the underlying ArrayCache
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| 98 | * that haven't already been put there with a call to
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| 99 | * {@code putArray}.
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| 100 | */
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| 101 | public void reset() {
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| 102 | if (byteArrays != null) {
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| 103 | // Put the arrays to the cache in reverse order: the array that
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| 104 | // was allocated first is returned last.
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| 105 | synchronized(byteArrays) {
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| 106 | for (int i = byteArrays.size() - 1; i >= 0; --i)
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| 107 | arrayCache.putArray(byteArrays.get(i));
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| 108 |
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| 109 | byteArrays.clear();
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| 110 | }
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| 111 |
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| 112 | synchronized(intArrays) {
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| 113 | for (int i = intArrays.size() - 1; i >= 0; --i)
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| 114 | arrayCache.putArray(intArrays.get(i));
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| 115 |
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| 116 | intArrays.clear();
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| 117 | }
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| 118 | }
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| 119 | }
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| 120 | }
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