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Java example source code file (SipHashFunctionTest.java)

This example Java source code file (SipHashFunctionTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

expected, hashfunction, immutableset, sip_with_key, sip_without_key, siphashfunctiontest, testcase

The SipHashFunctionTest.java Java example source code

/*
 * Copyright (C) 2012 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.hash;

import static com.google.common.base.Charsets.UTF_8;

import com.google.common.collect.ImmutableSet;

import junit.framework.TestCase;

/**
 * Unit tests for {@link SipHashFunction}.
 *
 * @author Kurt Alfred Kluever
 */
public class SipHashFunctionTest extends TestCase {

  // From https://131002.net/siphash/siphash24.c
  // k = 00 01 02 ...
  private static final long K0 = 0x0706050403020100L;
  private static final long K1 = 0x0f0e0d0c0b0a0908L;
  private static final HashFunction SIP_WITH_KEY = Hashing.sipHash24(K0, K1);
  private static final HashFunction SIP_WITHOUT_KEY = Hashing.sipHash24();

  // These constants were originally ported from https://www.131002.net/siphash/siphash24.c. See:
  // https://github.com/nahi/siphash-java-inline/blob/master/src/test/java/SipHashInlineTest.java
  private static final long[] EXPECTED = new long[] {
        0x726fdb47dd0e0e31L,
        0x74f839c593dc67fdL,
        0x0d6c8009d9a94f5aL,
        0x85676696d7fb7e2dL,
        0xcf2794e0277187b7L,
        0x18765564cd99a68dL,
        0xcbc9466e58fee3ceL,
        0xab0200f58b01d137L,
        0x93f5f5799a932462L,
        0x9e0082df0ba9e4b0L,
        0x7a5dbbc594ddb9f3L,
        0xf4b32f46226bada7L,
        0x751e8fbc860ee5fbL,
        0x14ea5627c0843d90L,
        0xf723ca908e7af2eeL,
        0xa129ca6149be45e5L,
        0x3f2acc7f57c29bdbL,
        0x699ae9f52cbe4794L,
        0x4bc1b3f0968dd39cL,
        0xbb6dc91da77961bdL,
        0xbed65cf21aa2ee98L,
        0xd0f2cbb02e3b67c7L,
        0x93536795e3a33e88L,
        0xa80c038ccd5ccec8L,
        0xb8ad50c6f649af94L,
        0xbce192de8a85b8eaL,
        0x17d835b85bbb15f3L,
        0x2f2e6163076bcfadL,
        0xde4daaaca71dc9a5L,
        0xa6a2506687956571L,
        0xad87a3535c49ef28L,
        0x32d892fad841c342L,
        0x7127512f72f27cceL,
        0xa7f32346f95978e3L,
        0x12e0b01abb051238L,
        0x15e034d40fa197aeL,
        0x314dffbe0815a3b4L,
        0x027990f029623981L,
        0xcadcd4e59ef40c4dL,
        0x9abfd8766a33735cL,
        0x0e3ea96b5304a7d0L,
        0xad0c42d6fc585992L,
        0x187306c89bc215a9L,
        0xd4a60abcf3792b95L,
        0xf935451de4f21df2L,
        0xa9538f0419755787L,
        0xdb9acddff56ca510L,
        0xd06c98cd5c0975ebL,
        0xe612a3cb9ecba951L,
        0xc766e62cfcadaf96L,
        0xee64435a9752fe72L,
        0xa192d576b245165aL,
        0x0a8787bf8ecb74b2L,
        0x81b3e73d20b49b6fL,
        0x7fa8220ba3b2eceaL,
        0x245731c13ca42499L,
        0xb78dbfaf3a8d83bdL,
        0xea1ad565322a1a0bL,
        0x60e61c23a3795013L,
        0x6606d7e446282b93L,
        0x6ca4ecb15c5f91e1L,
        0x9f626da15c9625f3L,
        0xe51b38608ef25f57L,
        0x958a324ceb064572L
  };

  public void testVectors() {
    for (int i = 0; i < EXPECTED.length; ++i) {
      byte[] msg = new byte[i];
      for (int j = 0; j < i; ++j) {
        msg[j] = (byte) j;
      }
      assertSip(msg, EXPECTED[i]);
    }
  }

  // This test data comes from "SipHash: a fast short-input PRF", "Appendix A: Test values".
  // It can be downloaded here: https://131002.net/siphash/siphash.pdf
  public void test15ByteStringFromSipHashPaper() {
    byte[] message = new byte[] {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e };
    long k0 = 0x0706050403020100L;
    long k1 = 0x0f0e0d0c0b0a0908L;

    assertEquals(0xa129ca6149be45e5L, Hashing.sipHash24(k0, k1).hashBytes(message).asLong());
  }

  // From https://github.com/BrandonHaynes/siphash-csharp/blob/master/tests/Tests.cs
  public void testKnownValues() {
    assertSip(new byte[] { }, 0x726fdb47dd0e0e31L);
    assertSip(new byte[] { 0x61 }, 0x2ba3e8e9a71148caL);
    assertSip(new byte[1000000], 0x28205108397aa742L);
    assertSip("12345678", 0x02130609caea37ebL);
    assertSip("abcdef", 0x2a6e77e733c7c05dL);
    assertSip("SipHash", 0x8325093242a96f60L);
  }

  // Test for common pitfall regarding sign extension.
  // For example: (long) data[i++] | (long) data[i++] << 8 | ...
  // If data[i] == (byte) 0x80, the first cast will sign-extend it to 0xffffffffffffff80,
  // masking the remaining seven bytes.
  // To test this, we give an input where bit 7 is not cleared. For example:
  // (1) 00 01 02 03 04 05 06 07 80
  // (2) 00 01 02 03 04 05 06 07 81
  // (3) 00 01 02 03 04 05 06 07 ff (or anything in between)
  // A fault implementation will generate collisions for these inputs.
  public void testCollisionsDueToIncorrectSignExtension() {
    byte[] col1 = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0x80 };
    byte[] col2 = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0x81 };
    byte[] col3 = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0xff };

    ImmutableSet<HashCode> hashCodes = ImmutableSet.of(
        SIP_WITH_KEY.hashBytes(col1),
        SIP_WITH_KEY.hashBytes(col2),
        SIP_WITH_KEY.hashBytes(col3));
    assertEquals(3, hashCodes.size());
  }

  public void testToString() {
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITH_KEY.toString());
    assertEquals("Hashing.sipHash24(" + K0 + ", " + K1 + ")", SIP_WITHOUT_KEY.toString());
    assertEquals("Hashing.sipHash24(20, 13)", Hashing.sipHash24(20, 13).toString());
  }

  private static void assertSip(String input, long expected) {
    assertEquals(expected, SIP_WITH_KEY.hashString(input, UTF_8).asLong());
    assertEquals(expected, SIP_WITH_KEY.newHasher().putString(input, UTF_8).hash().asLong());
    assertEquals(expected, SIP_WITHOUT_KEY.hashString(input, UTF_8).asLong());
    assertEquals(expected, SIP_WITHOUT_KEY.newHasher().putString(input, UTF_8).hash().asLong());
  }

  private static void assertSip(byte[] input, long expected) {
    assertEquals(expected, SIP_WITH_KEY.hashBytes(input).asLong());
    assertEquals(expected, SIP_WITH_KEY.newHasher().putBytes(input).hash().asLong());
    assertEquals(expected, SIP_WITHOUT_KEY.hashBytes(input).asLong());
    assertEquals(expected, SIP_WITHOUT_KEY.newHasher().putBytes(input).hash().asLong());
  }
}

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