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The NetCDF-Java Library is a Java interface to NetCDF files,
as well as to many other types of scientific data formats.
/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
* and understandings on the user. The user is granted the right, without
* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
* supporting documentation. Further, UCAR requests that the user credit
* UCAR/Unidata in any publications that result from the use of this
* software or in any product that includes this software. The names UCAR
* and/or Unidata, however, may not be used in any advertising or publicity
* to endorse or promote any products or commercial entity unless specific
* written permission is obtained from UCAR/Unidata. The user also
* understands that UCAR/Unidata is not obligated to provide the user with
* any support, consulting, training or assistance of any kind with regard
* to the use, operation and performance of this software nor to provide
* the user with any updates, revisions, new versions or "bug fixes."
*
* THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package ucar.unidata.io;
import java.io.*;
/**
* Similar to a DataInputStream that keeps track of position.
* position must always increase, no going backwards.
* cant handle byte order yet - assume big endian(?).
* @author caron
* @since Jan 3, 2008
*/
public class PositioningDataInputStream {
private DataInputStream delegate;
private long cpos = 0;
public PositioningDataInputStream(InputStream is) {
if (is instanceof DataInputStream)
delegate = (DataInputStream) is;
else
delegate = new DataInputStream(is);
}
private void seek(long pos) throws IOException {
if (pos < cpos) throw new IllegalArgumentException("Cannot go backwards; current="+cpos+" request="+pos);
long want = pos-cpos;
while (want > 0)
want -= delegate.skip(want);
cpos=pos;
//System.out.println("now at "+pos);
}
public void read(long pos, byte dest[], int off, int len) throws IOException {
seek(pos);
delegate.readFully(dest, off, len);
cpos += len;
}
public void readShort(long pos, short dest[], int off, int len) throws IOException {
seek(pos);
for (int i=0; i