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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