ucar.nc2.iosp.netcdf3.N3channelWriter Maven / Gradle / Ivy
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/*
* Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
* See LICENSE for license information.
*/
// $Id: $
package ucar.nc2.iosp.netcdf3;
import ucar.ma2.*;
import ucar.nc2.*;
import java.io.*;
import java.nio.channels.WritableByteChannel;
import java.nio.channels.Channels;
import java.nio.ByteBuffer;
/**
* Experimental
*
* @author john
* @deprecated do not use
*/
@Deprecated
public class N3channelWriter extends N3streamWriter {
private static int buffer_size = 1000 * 1000;
private static boolean debugWrite;
public N3channelWriter(ucar.nc2.NetcdfFile ncfile) {
super(ncfile);
}
////////////////////////////////////////////////////////////////////////////////////////////////
public void writeDataAll(WritableByteChannel channel) throws IOException, InvalidRangeException {
for (Vinfo vinfo : vinfoList) {
if (!vinfo.isRecord) {
Variable v = vinfo.v;
int nbytes = (int) v.readToByteChannel(v.getShapeAsSection(), channel);
filePos += nbytes;
filePos += pad(channel, nbytes);
if (debugPos)
System.out.printf(" read=%d vinfo=%s%n", nbytes, vinfo);
}
}
// must use record dimension if it exists+
boolean useRecordDimension = ncfile.hasUnlimitedDimension();
if (useRecordDimension) {
ncfile.sendIospMessage(NetcdfFile.IOSP_MESSAGE_ADD_RECORD_STRUCTURE);
Structure recordVar = (Structure) ncfile.findVariable("record");
Section.Builder sb = Section.builder().appendRangeAll();
long bytesDone = 0;
long done = 0;
long nrecs = (int) recordVar.getSize();
int structureSize = recordVar.getElementSize();
int readAtaTime = Math.max(10, buffer_size / structureSize);
for (int count = 0; count < nrecs; count += readAtaTime) {
long last = Math.min(nrecs, done + readAtaTime); // dont go over nrecs
int need = (int) (last - done); // how many to read this time
sb.setRange(0, new Range(count, count + need - 1));
try {
bytesDone += recordVar.readToByteChannel(sb.build(), channel);
done += need;
} catch (InvalidRangeException e) {
e.printStackTrace();
break;
}
}
assert done == nrecs;
bytesDone /= 1000 * 1000;
if (debugWrite)
System.out.println("write record var; total = " + bytesDone + " Mbytes # recs=" + done);
// remove the record structure this is rather fishy, perhaps better to leave it
ncfile.sendIospMessage(NetcdfFile.IOSP_MESSAGE_REMOVE_RECORD_STRUCTURE);
ncfile.finish();
}
}
// pad to a 4 byte boundary
private ByteBuffer padddingBB;
private int pad(WritableByteChannel channel, int nbytes) throws IOException {
int pad = N3header.padding(nbytes);
if ((null != channel) && (pad > 0)) {
if (padddingBB == null)
padddingBB = ByteBuffer.allocate(4); // just 4 zero bytes
padddingBB.position(0);
padddingBB.limit(pad);
channel.write(padddingBB);
}
return pad;
}
////////////////////////////////////////
public static void writeFromFile(NetcdfFile fileIn, String fileOutName) throws IOException, InvalidRangeException {
try (FileOutputStream stream = new FileOutputStream(fileOutName);
WritableByteChannel channel = stream.getChannel();
DataOutputStream dout = new DataOutputStream(Channels.newOutputStream(channel))) {
N3channelWriter writer = new N3channelWriter(fileIn);
int numrec = fileIn.getUnlimitedDimension() == null ? 0 : fileIn.getUnlimitedDimension().getLength();
writer.writeHeader(dout, numrec);
dout.flush();
writer.writeDataAll(channel);
}
}
/**
* Write ncfile to a WritableByteChannel.
*
* @param ncfile the file to write
* @param wbc write to this WritableByteChannel.
* If its a Socket, must have been opened through a call to java.nio.channels.SocketChannel.open()
* @throws IOException on IO error
* @throws InvalidRangeException range error
*/
public static void writeToChannel(NetcdfFile ncfile, WritableByteChannel wbc)
throws IOException, InvalidRangeException {
try (
DataOutputStream stream = new DataOutputStream(new BufferedOutputStream(Channels.newOutputStream(wbc), 8000))) {
// DataOutputStream stream = new DataOutputStream(Channels.newOutputStream(wbc)); // buffering seems to improve by
// 5%
N3channelWriter writer = new N3channelWriter(ncfile);
int numrec = ncfile.getUnlimitedDimension() == null ? 0 : ncfile.getUnlimitedDimension().getLength();
writer.writeHeader(stream, numrec);
stream.flush();
writer.writeDataAll(wbc);
}
}
}
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