content: /*
   * Copyright (c) 2007, 2020, Oracle and/or its affiliates.
   *
   * This program is free software; you can redistribute it and/or modify it under
   * the terms of the GNU General Public License, version 2.0, as published by the
   * Free Software Foundation.
   *
   * This program is also distributed with certain software (including but not
   * limited to OpenSSL) that is licensed under separate terms, as designated in a
   * particular file or component or in included license documentation. The
   * authors of MySQL hereby grant you an additional permission to link the
   * program and your derivative works with the separately licensed software that
   * they have included with MySQL.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   * FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
   * for more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
   */
  
  package com.mysql.cj.protocol.a.result;
  
  import com.mysql.cj.exceptions.ExceptionInterceptor;
  import com.mysql.cj.protocol.ColumnDefinition;
  import com.mysql.cj.protocol.ValueDecoder;
  import com.mysql.cj.protocol.a.NativeConstants.IntegerDataType;
  import com.mysql.cj.protocol.a.NativeConstants.StringSelfDataType;
  import com.mysql.cj.protocol.a.NativePacketPayload;
  import com.mysql.cj.result.Row;
  import com.mysql.cj.result.ValueFactory;
  
  /**
   * A ResultSetRow implementation that holds one row packet (which is re-used by the driver, and thus saves memory allocations), and tries when possible to avoid
   * allocations to break out the results as individual byte[]s.
   * 
   * (this isn't possible when doing things like reading floating point values).
   */
  public class TextBufferRow extends AbstractBufferRow {
  
      public TextBufferRow(NativePacketPayload buf, ColumnDefinition cd, ExceptionInterceptor exceptionInterceptor, ValueDecoder valueDecoder) {
          super(exceptionInterceptor);
  
          this.rowFromServer = buf;
          this.homePosition = this.rowFromServer.getPosition();
          this.valueDecoder = valueDecoder;
  
          if (cd.getFields() != null) {
              setMetadata(cd);
          }
      }
  
      @Override
      protected int findAndSeekToOffset(int index) {
  
          if (index == 0) {
              this.lastRequestedIndex = 0;
              this.lastRequestedPos = this.homePosition;
              this.rowFromServer.setPosition(this.homePosition);
  
              return 0;
          }
  
          if (index == this.lastRequestedIndex) {
              this.rowFromServer.setPosition(this.lastRequestedPos);
  
              return this.lastRequestedPos;
          }
  
          int startingIndex = 0;
  
          if (index > this.lastRequestedIndex) {
              if (this.lastRequestedIndex >= 0) {
                  startingIndex = this.lastRequestedIndex;
              } else {
                  startingIndex = 0;
              }
  
              this.rowFromServer.setPosition(this.lastRequestedPos);
          } else {
              this.rowFromServer.setPosition(this.homePosition);
          }
  
          for (int i = startingIndex; i < index; i++) {
              this.rowFromServer.skipBytes(StringSelfDataType.STRING_LENENC);
          }
  
          this.lastRequestedIndex = index;
          this.lastRequestedPos = this.rowFromServer.getPosition();
  
          return this.lastRequestedPos;
      }
  
      @Override
      public byte[] getBytes(int index) {
          if (getNull(index)) {
              return null;
          }
  
          findAndSeekToOffset(index);
          return this.rowFromServer.readBytes(StringSelfDataType.STRING_LENENC);
      }
  
      @Override
      public boolean getNull(int columnIndex) {
          findAndSeekToOffset(columnIndex);
          this.wasNull = this.rowFromServer.readInteger(IntegerDataType.INT_LENENC) == NativePacketPayload.NULL_LENGTH;
          return this.wasNull;
      }
  
      @Override
      public Row setMetadata(ColumnDefinition f) {
          super.setMetadata(f);
          return this;
      }
  
      /**
       * Implementation of getValue() based on the underlying Buffer object. Delegate to superclass for decoding.
       */
      @Override
      public <T> T getValue(int columnIndex, ValueFactory<T> vf) {
          findAndSeekToOffset(columnIndex);
          int length = (int) this.rowFromServer.readInteger(IntegerDataType.INT_LENENC);
          return getValueFromBytes(columnIndex, this.rowFromServer.getByteBuffer(), this.rowFromServer.getPosition(), length, vf);
      }
  }
  