ucar.nc2.iosp.netcdf3.N3raf Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of cdm Show documentation
The newest version!
/*
 * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
 * See LICENSE for license information.
 */
package ucar.nc2.iosp.netcdf3;

import ucar.ma2.*;
import ucar.nc2.constants.CDM;
import ucar.nc2.iosp.Layout;
import ucar.nc2.iosp.IospHelper;

import java.nio.channels.WritableByteChannel;


/**
 * Use our RandomAccessFile class to read and write.
 * @author caron
 */

public class N3raf extends N3iosp  {

  protected void _open(ucar.unidata.io.RandomAccessFile raf) throws java.io.IOException {
  }

  protected void _create(ucar.unidata.io.RandomAccessFile raf) throws java.io.IOException {
  }

  /**
   * Read data subset from file for a variable, create primitive array.
   * @param index handles skipping around in the file.
   * @param dataType dataType of the variable
   * @return primitive array with data read in
   */
 protected Object readData( Layout index, DataType dataType) throws java.io.IOException {
   return IospHelper.readDataFill(raf, index, dataType, null, -1);
 }

  /**
   * Read data subset from file for a variable, to WritableByteChannel.
   * Will send as bigendian, since thats what the underlying file has.
   * @param index handles skipping around in the file.
   * @param dataType dataType of the variable
   */
  protected long readData( Layout index, DataType dataType, WritableByteChannel out) throws java.io.IOException {
    long count = 0;
    if (dataType.getPrimitiveClassType() == byte.class || dataType == DataType.CHAR) {
      while (index.hasNext()) {
        Layout.Chunk chunk = index.next();
        count += raf.readToByteChannel( out, chunk.getSrcPos(), chunk.getNelems());
      }

    } else if (dataType.getPrimitiveClassType() == short.class) {
      while (index.hasNext()) {
        Layout.Chunk chunk = index.next();
        count += raf.readToByteChannel( out, chunk.getSrcPos(), 2 * chunk.getNelems());
      }

    } else if (dataType.getPrimitiveClassType() == int.class || (dataType == DataType.FLOAT)) {
      while (index.hasNext()) {
        Layout.Chunk chunk = index.next();
        count += raf.readToByteChannel( out, chunk.getSrcPos(), 4 * chunk.getNelems());
      }

    } else if ((dataType == DataType.DOUBLE) || dataType.getPrimitiveClassType() == long.class) {
      while (index.hasNext()) {
        Layout.Chunk chunk = index.next();
        count += raf.readToByteChannel( out, chunk.getSrcPos(), 8 * chunk.getNelems());
      }
    }

    return count;
  }

   /**
    * write data to a file for a variable.
    * @param values write this data.
    * @param index handles skipping around in the file.
    * @param dataType dataType of the variable
    */
  protected void writeData( Array values, Layout index, DataType dataType) throws java.io.IOException {
    if ((dataType == DataType.BYTE) || (dataType == DataType.CHAR)) {
      IndexIterator ii = values.getIndexIterator();
      while (index.hasNext()) {
        Layout.Chunk chunk = index.next();
        raf.seek ( chunk.getSrcPos());
        for (int k=0; k