/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.collections4.bloomfilter;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests the {@link EnhancedDoubleHasher}.
   */
  public class EnhancedDoubleHasherTest extends AbstractHasherTest {
      int[] expected = {1, 0, 71, 71, 1, 6, 15, 29, 49, 4, 39, 11, 65, 58, 63, 9, 41};
  
      @Override
      protected Hasher createEmptyHasher() {
          return NullHasher.INSTANCE;
      }
  
      @Override
      protected Hasher createHasher() {
          return new EnhancedDoubleHasher(1, 1);
      }
  
      @Override
      protected int getAsIndexArrayBehaviour() {
          // Allows duplicates and may be unordered
          return 0;
      }
  
      @Override
      protected int[] getExpectedIndices() {
          return expected;
      }
  
      @Override
      protected int getHasherSize(final Hasher hasher) {
          return 1;
      }
  
      @Test
      public void testByteConstructor() {
          // single value become increment.
          EnhancedDoubleHasher hasher = new EnhancedDoubleHasher(new byte[] {1});
          assertEquals(0, hasher.getInitial());
          assertEquals(0x01_00_00_00_00_00_00_00L, hasher.getIncrement());
  
          // 2 bytes become initial and increment.
          hasher = new EnhancedDoubleHasher(new byte[] {1, 2});
          assertEquals(0x01_00_00_00_00_00_00_00L, hasher.getInitial());
          assertEquals(0x02_00_00_00_00_00_00_00L, hasher.getIncrement());
  
          // odd values place extra byte in increment.
          hasher = new EnhancedDoubleHasher(new byte[] {1, 2, 3});
          assertEquals(0x01_00_00_00_00_00_00_00L, hasher.getInitial());
          assertEquals(0x02_03_00_00_00_00_00_00L, hasher.getIncrement());
  
          // even short split
          hasher = new EnhancedDoubleHasher(new byte[] {0, 1, 0, 2});
          assertEquals(0x01_00_00_00_00_00_00L, hasher.getInitial());
          assertEquals(0x02_00_00_00_00_00_00L, hasher.getIncrement());
  
          // longs are parse correctly
          hasher = new EnhancedDoubleHasher(new byte[] {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2});
          assertEquals(1, hasher.getInitial());
          assertEquals(2, hasher.getIncrement());
  
          // excess bytes are ignored before mid point and at end
          hasher = new EnhancedDoubleHasher(new byte[] {0, 0, 0, 0, 0, 0, 0, 1, 5, 5, 0, 0, 0, 0, 0, 0, 0, 2, 5, 5});
          assertEquals(1, hasher.getInitial());
          assertEquals(2, hasher.getIncrement());
  
          // odd extra bytes are accounted for correctly
          hasher = new EnhancedDoubleHasher(new byte[] {0, 0, 0, 0, 0, 0, 0, 1, 5, 1, 0, 0, 0, 0, 0, 0, 2, 5, 5});
          assertEquals(1, hasher.getInitial());
          assertEquals(0x01_00_00_00_00_00_00_02L, hasher.getIncrement());
  
          // test empty buffer
          assertThrows(IllegalArgumentException.class, () -> new EnhancedDoubleHasher(new byte[0]));
      }
  }