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.algorithm.rank;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import java.nio.charset.StandardCharsets;
  import org.apache.arrow.algorithm.sort.DefaultVectorComparators;
  import org.apache.arrow.algorithm.sort.VectorValueComparator;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.memory.RootAllocator;
  import org.apache.arrow.vector.IntVector;
  import org.apache.arrow.vector.VarCharVector;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /** Test cases for {@link org.apache.arrow.algorithm.rank.VectorRank}. */
  public class TestVectorRank {
  
    private BufferAllocator allocator;
  
    private static final int VECTOR_LENGTH = 10;
  
    @BeforeEach
    public void prepare() {
      allocator = new RootAllocator(1024 * 1024);
    }
  
    @AfterEach
    public void shutdown() {
      allocator.close();
    }
  
    @Test
    public void testFixedWidthRank() {
      VectorRank<IntVector> rank = new VectorRank<>(allocator);
      try (IntVector vector = new IntVector("int vec", allocator)) {
        vector.allocateNew(VECTOR_LENGTH);
        vector.setValueCount(VECTOR_LENGTH);
  
        vector.set(0, 1);
        vector.set(1, 5);
        vector.set(2, 3);
        vector.set(3, 7);
        vector.set(4, 9);
        vector.set(5, 8);
        vector.set(6, 2);
        vector.set(7, 0);
        vector.set(8, 4);
        vector.set(9, 6);
  
        VectorValueComparator<IntVector> comparator =
            DefaultVectorComparators.createDefaultComparator(vector);
        assertEquals(7, rank.indexAtRank(vector, comparator, 0));
        assertEquals(0, rank.indexAtRank(vector, comparator, 1));
        assertEquals(6, rank.indexAtRank(vector, comparator, 2));
        assertEquals(2, rank.indexAtRank(vector, comparator, 3));
        assertEquals(8, rank.indexAtRank(vector, comparator, 4));
        assertEquals(1, rank.indexAtRank(vector, comparator, 5));
        assertEquals(9, rank.indexAtRank(vector, comparator, 6));
        assertEquals(3, rank.indexAtRank(vector, comparator, 7));
        assertEquals(5, rank.indexAtRank(vector, comparator, 8));
        assertEquals(4, rank.indexAtRank(vector, comparator, 9));
      }
    }
  
    @Test
    public void testVariableWidthRank() {
      VectorRank<VarCharVector> rank = new VectorRank<>(allocator);
      try (VarCharVector vector = new VarCharVector("varchar vec", allocator)) {
        vector.allocateNew(VECTOR_LENGTH * 5, VECTOR_LENGTH);
        vector.setValueCount(VECTOR_LENGTH);
  
        vector.set(0, String.valueOf(1).getBytes(StandardCharsets.UTF_8));
        vector.set(1, String.valueOf(5).getBytes(StandardCharsets.UTF_8));
        vector.set(2, String.valueOf(3).getBytes(StandardCharsets.UTF_8));
        vector.set(3, String.valueOf(7).getBytes(StandardCharsets.UTF_8));
        vector.set(4, String.valueOf(9).getBytes(StandardCharsets.UTF_8));
        vector.set(5, String.valueOf(8).getBytes(StandardCharsets.UTF_8));
        vector.set(6, String.valueOf(2).getBytes(StandardCharsets.UTF_8));
        vector.set(7, String.valueOf(0).getBytes(StandardCharsets.UTF_8));
        vector.set(8, String.valueOf(4).getBytes(StandardCharsets.UTF_8));
        vector.set(9, String.valueOf(6).getBytes(StandardCharsets.UTF_8));
  
        VectorValueComparator<VarCharVector> comparator =
            DefaultVectorComparators.createDefaultComparator(vector);
  
        assertEquals(7, rank.indexAtRank(vector, comparator, 0));
        assertEquals(0, rank.indexAtRank(vector, comparator, 1));
        assertEquals(6, rank.indexAtRank(vector, comparator, 2));
        assertEquals(2, rank.indexAtRank(vector, comparator, 3));
        assertEquals(8, rank.indexAtRank(vector, comparator, 4));
        assertEquals(1, rank.indexAtRank(vector, comparator, 5));
        assertEquals(9, rank.indexAtRank(vector, comparator, 6));
        assertEquals(3, rank.indexAtRank(vector, comparator, 7));
        assertEquals(5, rank.indexAtRank(vector, comparator, 8));
        assertEquals(4, rank.indexAtRank(vector, comparator, 9));
      }
    }
  
    @Test
    public void testRankNegative() {
      VectorRank<IntVector> rank = new VectorRank<>(allocator);
      try (IntVector vector = new IntVector("int vec", allocator)) {
        vector.allocateNew(VECTOR_LENGTH);
        vector.setValueCount(VECTOR_LENGTH);
  
        vector.set(0, 1);
        vector.set(1, 5);
        vector.set(2, 3);
        vector.set(3, 7);
        vector.set(4, 9);
        vector.set(5, 8);
        vector.set(6, 2);
        vector.set(7, 0);
        vector.set(8, 4);
        vector.set(9, 6);
  
        VectorValueComparator<IntVector> comparator =
            DefaultVectorComparators.createDefaultComparator(vector);
  
        assertThrows(
            IllegalArgumentException.class,
            () -> {
              rank.indexAtRank(vector, comparator, VECTOR_LENGTH + 1);
            });
      }
    }
  }
  