1 // Copyright 2011 Google Inc. All Rights Reserved. 2 3 package com.google.common.hash; 4 5 import com.google.common.collect.ImmutableList; 6 import com.google.common.hash.HashTestUtils.RandomHasherAction; 7 8 import junit.framework.TestCase; 9 10 import java.io.ByteArrayOutputStream; 11 import java.nio.ByteBuffer; 12 import java.nio.charset.Charset; 13 import java.util.Arrays; 14 import java.util.List; 15 import java.util.Random; 16 17 /** 18 * Tests for AbstractNonStreamingHashFunction. 19 */ 20 public class AbstractNonStreamingHashFunctionTest extends TestCase { 21 /** 22 * Constructs two trivial HashFunctions (output := input), one streaming and one non-streaming, 23 * and checks that their results are identical, no matter which newHasher version we used. 24 */ 25 public void test() { 26 List<Hasher> hashers = ImmutableList.of( 27 new StreamingVersion().newHasher(), 28 new StreamingVersion().newHasher(52), 29 new NonStreamingVersion().newHasher(), 30 new NonStreamingVersion().newHasher(123)); 31 Random random = new Random(0); 32 for (int i = 0; i < 200; i++) { 33 RandomHasherAction.pickAtRandom(random).performAction(random, hashers); 34 } 35 HashCode[] codes = new HashCode[hashers.size()]; 36 for (int i = 0; i < hashers.size(); i++) { 37 codes[i] = hashers.get(i).hash(); 38 } 39 for (int i = 1; i < codes.length; i++) { 40 assertEquals(codes[i - 1], codes[i]); 41 } 42 } 43 44 static class StreamingVersion extends AbstractStreamingHashFunction { 45 @Override 46 public int bits() { 47 return 32; 48 } 49 50 @Override 51 public Hasher newHasher() { 52 return new AbstractStreamingHasher(4, 4) { 53 final ByteArrayOutputStream out = new ByteArrayOutputStream(); 54 @Override 55 HashCode makeHash() { 56 return HashCodes.fromBytes(out.toByteArray()); 57 } 58 59 @Override 60 protected void process(ByteBuffer bb) { 61 while (bb.hasRemaining()) { 62 out.write(bb.get()); 63 } 64 } 65 66 @Override 67 protected void processRemaining(ByteBuffer bb) { 68 while (bb.hasRemaining()) { 69 out.write(bb.get()); 70 } 71 } 72 }; 73 } 74 } 75 76 static class NonStreamingVersion extends AbstractNonStreamingHashFunction { 77 @Override 78 public int bits() { 79 return 32; 80 } 81 82 @Override 83 public HashCode hashBytes(byte[] input) { 84 return HashCodes.fromBytes(input); 85 } 86 87 @Override 88 public HashCode hashBytes(byte[] input, int off, int len) { 89 return HashCodes.fromBytes(Arrays.copyOfRange(input, off, off + len)); 90 } 91 92 @Override 93 public HashCode hashString(CharSequence input) { 94 throw new UnsupportedOperationException(); 95 } 96 97 @Override 98 public HashCode hashString(CharSequence input, Charset charset) { 99 throw new UnsupportedOperationException(); 100 } 101 102 @Override 103 public HashCode hashLong(long input) { 104 throw new UnsupportedOperationException(); 105 } 106 } 107 } 108
