content: /*
   * 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.arrow.memory.util.hash;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNotEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import java.nio.charset.StandardCharsets;
  import java.util.stream.Stream;
  import org.apache.arrow.memory.ArrowBuf;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.memory.RootAllocator;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.Arguments;
  import org.junit.jupiter.params.provider.MethodSource;
  
  /** Test cases for {@link ArrowBufHasher} and its subclasses. */
  public class TestArrowBufHasher {
  
    private final int BUFFER_LENGTH = 1024;
  
    private BufferAllocator allocator;
  
    @BeforeEach
    public void prepare() {
      allocator = new RootAllocator(1024 * 1024);
    }
  
    @AfterEach
    public void shutdown() {
      allocator.close();
    }
  
    @ParameterizedTest(name = "hasher = {0}")
    @MethodSource("getHasher")
    void testHasher(String name, ArrowBufHasher hasher) {
      try (ArrowBuf buf1 = allocator.buffer(BUFFER_LENGTH);
          ArrowBuf buf2 = allocator.buffer(BUFFER_LENGTH)) {
        // prepare data
        for (int i = 0; i < BUFFER_LENGTH / 4; i++) {
          buf1.setFloat(i * 4L, i / 10.0f);
          buf2.setFloat(i * 4L, i / 10.0f);
        }
  
        verifyHashCodesEqual(hasher, buf1, 0, 100, buf2, 0, 100);
        verifyHashCodesEqual(hasher, buf1, 1, 5, buf2, 1, 5);
        verifyHashCodesEqual(hasher, buf1, 10, 17, buf2, 10, 17);
        verifyHashCodesEqual(hasher, buf1, 33, 25, buf2, 33, 25);
        verifyHashCodesEqual(hasher, buf1, 22, 22, buf2, 22, 22);
        verifyHashCodesEqual(hasher, buf1, 123, 333, buf2, 123, 333);
        verifyHashCodesEqual(hasher, buf1, 374, 1, buf2, 374, 1);
        verifyHashCodesEqual(hasher, buf1, 11, 0, buf2, 11, 0);
        verifyHashCodesEqual(hasher, buf1, 75, 25, buf2, 75, 25);
        verifyHashCodesEqual(hasher, buf1, 0, 1024, buf2, 0, 1024);
      }
    }
  
    private void verifyHashCodesEqual(
        ArrowBufHasher hasher,
        ArrowBuf buf1,
        int offset1,
        int length1,
        ArrowBuf buf2,
        int offset2,
        int length2) {
      int hashCode1 = hasher.hashCode(buf1, offset1, length1);
      int hashCode2 = hasher.hashCode(buf2, offset2, length2);
      assertEquals(hashCode1, hashCode2);
    }
  
    @ParameterizedTest(name = "hasher = {0}")
    @MethodSource("getHasher")
    public void testHasherNegative(String name, ArrowBufHasher hasher) {
      try (ArrowBuf buf = allocator.buffer(BUFFER_LENGTH)) {
        // prepare data
        for (int i = 0; i < BUFFER_LENGTH / 4; i++) {
          buf.setFloat(i * 4L, i / 10.0f);
        }
  
        assertThrows(IllegalArgumentException.class, () -> hasher.hashCode(buf, 0, -1));
  
        assertThrows(IndexOutOfBoundsException.class, () -> hasher.hashCode(buf, 0, 1028));
  
        assertThrows(IndexOutOfBoundsException.class, () -> hasher.hashCode(buf, 500, 1000));
      }
    }
  
    @ParameterizedTest(name = "hasher = {0}")
    @MethodSource("getHasher")
    public void testHasherLessThanInt(String name, ArrowBufHasher hasher) {
      try (ArrowBuf buf1 = allocator.buffer(4);
          ArrowBuf buf2 = allocator.buffer(4)) {
        buf1.writeBytes("foo1".getBytes(StandardCharsets.UTF_8));
        buf2.writeBytes("bar2".getBytes(StandardCharsets.UTF_8));
  
        for (int i = 1; i <= 4; i++) {
          verifyHashCodeNotEqual(hasher, buf1, i, buf2, i);
        }
      }
    }
  
    private void verifyHashCodeNotEqual(
        ArrowBufHasher hasher, ArrowBuf buf1, int length1, ArrowBuf buf2, int length2) {
      int hashCode1 = hasher.hashCode(buf1, 0, length1);
      int hashCode2 = hasher.hashCode(buf2, 0, length2);
      assertNotEquals(hashCode1, hashCode2);
    }
  
    private static Stream<Arguments> getHasher() {
      return Stream.of(
          Arguments.of(SimpleHasher.class.getSimpleName(), SimpleHasher.INSTANCE),
          Arguments.of(MurmurHasher.class.getSimpleName(), new MurmurHasher()));
    }
  }
  