}

  /** Returns a hash function implementing the SHA-256 algorithm (256 hash bits). */
  public static HashFunction sha256() {
    return Sha256Holder.SHA_256;
  }

  private static class Sha256Holder {
    static final HashFunction SHA_256 =
        new MessageDigestHashFunction("SHA-256", "Hashing.sha256()");
  }

  /**

  }

  // goodFastHash(256) uses Murmur3_128. Use the same epsilon bounds.
  public void testGoodFastHash256() {
    HashTestUtils.check2BitAvalanche(Hashing.goodFastHash(256), 250, 0.20);
    HashTestUtils.checkAvalanche(Hashing.goodFastHash(256), 500, 0.17);
    HashTestUtils.checkNo2BitCharacteristics(Hashing.goodFastHash(256));
    HashTestUtils.checkNoFunnels(Hashing.goodFastHash(256));

    int hashBytes = hashbits / 8;

    byte[] key = new byte[256];
    byte[] hashes = new byte[hashBytes * 256];

    // Hash keys of the form {}, {0}, {0,1}, {0,1,2}... up to N=255,using 256-N as the seed
    for (int i = 0; i < 256; i++) {
      key[i] = (byte) i;
      int seed = 256 - i;
      byte[] hash = hashFunction.hash(Arrays.copyOf(key, i), seed);

      assertThat(UnsignedBytes.parseUnsignedByte(Integer.toString(i))).isEqualTo((byte) i);
    }
    assertParseFails("1000");
    assertParseFails("-1");
    assertParseFails("-128");
    assertParseFails("256");
  }

  public void testMaxValue() {
    assertThat(UnsignedBytes.compare(UnsignedBytes.MAX_VALUE, (byte) (UnsignedBytes.MAX_VALUE + 1)))
        .isGreaterThan(0);
  }

  public void testResizeTable() {
    verifyTableSize(100, 2, 4);
    verifyTableSize(100, 5, 8);
    verifyTableSize(100, 33, 64);
    verifyTableSize(60, 60, 128);
    verifyTableSize(120, 60, 256);
    // if the table is only double the necessary size, we don't bother resizing it
    verifyTableSize(180, 60, 128);
    // but if it's even bigger than double, we rebuild the table
    verifyTableSize(17, 17, 32);

import sun.misc.Unsafe;

/**
 * Static utility methods pertaining to {@code byte} primitives that interpret values as
 * <i>unsigned</i> (that is, any negative value {@code b} is treated as the positive value {@code
 * 256 + b}). The corresponding methods that treat the values as signed are found in {@link
 * SignedBytes}, and the methods for which signedness is not an issue are in {@link Bytes}.
 *
 * <p>See the Guava User Guide article on <a

      assertThat(UnsignedBytes.parseUnsignedByte(Integer.toString(i))).isEqualTo((byte) i);
    }
    assertParseFails("1000");
    assertParseFails("-1");
    assertParseFails("-128");
    assertParseFails("256");
  }

  public void testMaxValue() {
    assertThat(UnsignedBytes.compare(UnsignedBytes.MAX_VALUE, (byte) (UnsignedBytes.MAX_VALUE + 1)))
        .isGreaterThan(0);
  }

  public void testNewArrayListWithCapacity() {
    ArrayList<Integer> list = Lists.newArrayListWithCapacity(0);
    assertEquals(Collections.emptyList(), list);

    ArrayList<Integer> bigger = Lists.newArrayListWithCapacity(256);
    assertEquals(Collections.emptyList(), bigger);
  }

  public void testNewArrayListWithCapacity_negative() {
    try {
      Lists.newArrayListWithCapacity(-1);
      fail();

        asList(
            64,
            65,
            71,
            72,
            73,
            79,
            80,
            81,
            255,
            256,
            257,
            511,
            512,
            513,
            Double.MAX_EXPONENT - 1,
            Double.MAX_EXPONENT,
            Double.MAX_EXPONENT + 1)) {

        asList(
            64,
            65,
            71,
            72,
            73,
            79,
            80,
            81,
            255,
            256,
            257,
            511,
            512,
            513,
            Double.MAX_EXPONENT - 1,
            Double.MAX_EXPONENT,
            Double.MAX_EXPONENT + 1)) {