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.adapter.jdbc.consumer;
  
  import java.nio.charset.StandardCharsets;
  import java.sql.Clob;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import org.apache.arrow.memory.ArrowBuf;
  import org.apache.arrow.memory.util.MemoryUtil;
  import org.apache.arrow.vector.BitVectorHelper;
  import org.apache.arrow.vector.VarCharVector;
  
  /**
   * Consumer which consume clob type values from {@link ResultSet}. Write the data to {@link
   * org.apache.arrow.vector.VarCharVector}.
   */
  public abstract class ClobConsumer extends BaseConsumer<VarCharVector> {
  
    /** Creates a consumer for {@link VarCharVector}. */
    public static ClobConsumer createConsumer(VarCharVector vector, int index, boolean nullable) {
      if (nullable) {
        return new NullableClobConsumer(vector, index);
      } else {
        return new NonNullableClobConsumer(vector, index);
      }
    }
  
    private static final int BUFFER_SIZE = 256;
  
    /** Instantiate a ClobConsumer. */
    public ClobConsumer(VarCharVector vector, int index) {
      super(vector, index);
      if (vector != null) {
        vector.allocateNewSafe();
      }
    }
  
    @Override
    public void resetValueVector(VarCharVector vector) {
      this.vector = vector;
      this.vector.allocateNewSafe();
      this.currentIndex = 0;
    }
  
    /** Nullable consumer for clob data. */
    static class NullableClobConsumer extends ClobConsumer {
  
      /** Instantiate a ClobConsumer. */
      public NullableClobConsumer(VarCharVector vector, int index) {
        super(vector, index);
      }
  
      @Override
      public void consume(ResultSet resultSet) throws SQLException {
        Clob clob = resultSet.getClob(columnIndexInResultSet);
        if (!resultSet.wasNull()) {
          if (clob != null) {
            long length = clob.length();
  
            int read = 1;
            int readSize = length < BUFFER_SIZE ? (int) length : BUFFER_SIZE;
            int totalBytes = 0;
  
            ArrowBuf dataBuffer = vector.getDataBuffer();
            ArrowBuf offsetBuffer = vector.getOffsetBuffer();
            int startIndex = offsetBuffer.getInt(currentIndex * 4L);
            while (read <= length) {
              String str = clob.getSubString(read, readSize);
              byte[] bytes = str.getBytes(StandardCharsets.UTF_8);
  
              while ((dataBuffer.writerIndex() + bytes.length) > dataBuffer.capacity()) {
                vector.reallocDataBuffer();
              }
              MemoryUtil.copyToMemory(
                  bytes, 0, dataBuffer.memoryAddress() + startIndex + totalBytes, bytes.length);
  
              totalBytes += bytes.length;
              read += readSize;
            }
            offsetBuffer.setInt((currentIndex + 1) * 4L, startIndex + totalBytes);
            BitVectorHelper.setBit(vector.getValidityBuffer(), currentIndex);
            vector.setLastSet(currentIndex);
          }
        }
        currentIndex++;
      }
    }
  
    /** Non-nullable consumer for clob data. */
    static class NonNullableClobConsumer extends ClobConsumer {
  
      /** Instantiate a ClobConsumer. */
      public NonNullableClobConsumer(VarCharVector vector, int index) {
        super(vector, index);
      }
  
      @Override
      public void consume(ResultSet resultSet) throws SQLException {
        Clob clob = resultSet.getClob(columnIndexInResultSet);
        if (clob != null) {
          long length = clob.length();
  
          int read = 1;
          int readSize = length < BUFFER_SIZE ? (int) length : BUFFER_SIZE;
          int totalBytes = 0;
  
          ArrowBuf dataBuffer = vector.getDataBuffer();
          ArrowBuf offsetBuffer = vector.getOffsetBuffer();
          int startIndex = offsetBuffer.getInt(currentIndex * 4L);
          while (read <= length) {
            String str = clob.getSubString(read, readSize);
            byte[] bytes = str.getBytes(StandardCharsets.UTF_8);
  
            while ((dataBuffer.writerIndex() + bytes.length) > dataBuffer.capacity()) {
              vector.reallocDataBuffer();
            }
            MemoryUtil.copyToMemory(
                bytes, 0, dataBuffer.memoryAddress() + startIndex + totalBytes, bytes.length);
  
            totalBytes += bytes.length;
            read += readSize;
          }
          offsetBuffer.setInt((currentIndex + 1) * 4L, startIndex + totalBytes);
          BitVectorHelper.setBit(vector.getValidityBuffer(), currentIndex);
          vector.setLastSet(currentIndex);
        }
  
        currentIndex++;
      }
    }
  }
  