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.vector;
  
  import org.apache.arrow.util.Preconditions;
  
  /**
   * Metadata class that captures the "type" of an Arrow buffer. (e.g. data buffers, offset buffers
   * for variable width types and validity buffers).
   */
  public class BufferLayout {
  
    /**
     * Enumeration of the different logical types a buffer can have. Data buffer is common to most of
     * the layouts. Offset buffer is used for variable width types. Validity buffer is used for
     * nullable types. Type buffer is used for Union types. Size buffer is used for ListView and
     * LargeListView types.
     */
    public enum BufferType {
      DATA("DATA"),
      OFFSET("OFFSET"),
      VALIDITY("VALIDITY"),
      TYPE("TYPE_ID"),
      SIZE("SIZE"),
      VIEWS("VIEWS"),
      VARIADIC_DATA_BUFFERS("VARIADIC_DATA_BUFFERS");
  
      private final String name;
  
      BufferType(String name) {
        this.name = name;
      }
  
      public String getName() {
        return name;
      }
    }
  
    private static final BufferLayout VALIDITY_BUFFER = new BufferLayout(BufferType.VALIDITY, 1);
    private static final BufferLayout OFFSET_BUFFER = new BufferLayout(BufferType.OFFSET, 32);
    private static final BufferLayout LARGE_OFFSET_BUFFER = new BufferLayout(BufferType.OFFSET, 64);
    private static final BufferLayout TYPE_BUFFER = new BufferLayout(BufferType.TYPE, 32);
    private static final BufferLayout BIT_BUFFER = new BufferLayout(BufferType.DATA, 1);
    private static final BufferLayout VALUES_256 = new BufferLayout(BufferType.DATA, 256);
    private static final BufferLayout VALUES_128 = new BufferLayout(BufferType.DATA, 128);
    private static final BufferLayout VALUES_64 = new BufferLayout(BufferType.DATA, 64);
    private static final BufferLayout VALUES_32 = new BufferLayout(BufferType.DATA, 32);
    private static final BufferLayout VALUES_16 = new BufferLayout(BufferType.DATA, 16);
    private static final BufferLayout VALUES_8 = new BufferLayout(BufferType.DATA, 8);
    private static final BufferLayout LARGE_SIZE_BUFFER = new BufferLayout(BufferType.SIZE, 64);
    private static final BufferLayout SIZE_BUFFER = new BufferLayout(BufferType.SIZE, 32);
    private static final BufferLayout VIEW_BUFFER = new BufferLayout(BufferType.VIEWS, 16);
  
    public static BufferLayout typeBuffer() {
      return TYPE_BUFFER;
    }
  
    public static BufferLayout offsetBuffer() {
      return OFFSET_BUFFER;
    }
  
    public static BufferLayout largeOffsetBuffer() {
      return LARGE_OFFSET_BUFFER;
    }
  
    public static BufferLayout sizeBuffer() {
      return SIZE_BUFFER;
    }
  
    public static BufferLayout largeSizeBuffer() {
      return LARGE_SIZE_BUFFER;
    }
  
    /**
     * Returns a databuffer for the given bitwidth. Only supports powers of two between 8 and 128
     * inclusive.
     */
    public static BufferLayout dataBuffer(int typeBitWidth) {
      switch (typeBitWidth) {
        case 8:
          return VALUES_8;
        case 16:
          return VALUES_16;
        case 32:
          return VALUES_32;
        case 64:
          return VALUES_64;
        case 128:
          return VALUES_128;
        case 256:
          return VALUES_256;
        default:
          throw new IllegalArgumentException("only 8, 16, 32, 64, 128, or 256 bits supported");
      }
    }
  
    public static BufferLayout booleanVector() {
      return BIT_BUFFER;
    }
  
    public static BufferLayout validityVector() {
      return VALIDITY_BUFFER;
    }
  
    public static BufferLayout byteVector() {
      return dataBuffer(8);
    }
  
    public static BufferLayout viewVector() {
      return VIEW_BUFFER;
    }
  
    private final short typeBitWidth;
  
    private final BufferType type;
  
    BufferLayout(BufferType type, int typeBitWidth) {
      super();
      this.type = Preconditions.checkNotNull(type);
      this.typeBitWidth = (short) typeBitWidth;
      if (typeBitWidth <= 0) {
        throw new IllegalArgumentException("bitWidth invalid: " + typeBitWidth);
      }
    }
  
    public int getTypeBitWidth() {
      return typeBitWidth;
    }
  
    public BufferType getType() {
      return type;
    }
  
    @Override
    public String toString() {
      return String.format("%s(%s)", type, typeBitWidth);
    }
  
    @Override
    public int hashCode() {
      return 31 * (31 + type.hashCode()) + typeBitWidth;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj == null) {
        return false;
      }
      if (!(obj instanceof BufferLayout)) {
        return false;
      }
      BufferLayout other = (BufferLayout) obj;
      return type.equals(other.type) && (typeBitWidth == other.typeBitWidth);
    }
  }
  