/*
* Copyright 1998-2014 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.nc2.iosp;
import java.io.IOException;
/**
* Iterator to read/write subsets of a multidimensional array, finding the contiguous chunks.
* The iteration is monotonic in both src and dest positions.
* <p/>
* Example for Integers:
* <pre>
int[] read( Layout index, int[] src) {
int[] dest = new int[index.getTotalNelems()];
while (index.hasNext()) {
Layout.Chunk chunk = index.next();
System.arraycopy(src, chunk.getSrcElem(), dest, chunk.getDestElem(), chunk.getNelems());
}
return dest;
}
int[] read( Layout index, RandomAccessFile raf) {
int[] dest = new int[index.getTotalNelems()];
while (index.hasNext()) {
Layout.Chunk chunk = index.next();
raf.seek( chunk.getSrcPos());
raf.readInt(dest, chunk.getDestElem(), chunk.getNelems());
}
return dest;
}
// note src and dest misnamed
void write( Layout index, int[] src, RandomAccessFile raf) {
while (index.hasNext()) {
Layout.Chunk chunk = index.next();
raf.seek ( chunk.getSrcPos());
for (int k=0; k<chunk.getNelems(); k++)
raf.writeInt(src, chunk.getDestElem(), chunk.getNelems());
raf.writeInt( ii.getByteNext());
}
* </pre>
*
* @author caron
* @since Jan 2, 2008
*/
public interface Layout {
/**
* Get total number of elements in the wanted subset.
*
* @return total number of elements in the wanted subset.
*/
public long getTotalNelems();
/**
* Get size of each element in bytes.
*
* @return size of each element in bytes.
*/
public int getElemSize();
/**
* Is there more to do
*
* @return true if theres more to do
*/
public boolean hasNext();
/**
* Get the next chunk
*
* @return next chunk, or null if !hasNext()
* @throws java.io.IOException on i/o error
*/
public Chunk next() throws IOException;
/**
* A chunk of data that is contiguous in both the source and destination.
* Read nelems from src at filePos, store in destination at startElem.
* (or) Write nelems to file at filePos, from array at startElem.
*/
public interface Chunk {
/**
* Get the position in source where to read or write: "file position"
* @return position as a byte count into the source, eg a file
*/
public long getSrcPos();
/**
* Get number of elements to transfer contiguously (Note: elements, not bytes)
* @return number of elements to transfer
*/
public int getNelems();
/**
* Get starting element position as a 1D element index into the destination, eg the requested array with shape "wantSection".
* @return starting element in the array (Note: elements, not bytes)
*/
public long getDestElem();
}
}