ucar.nc2.iosp.LayoutBB Maven / Gradle / Ivy
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;
import java.io.IOException;
import java.nio.*;
/**
* A Layout that supplies the "source" ByteBuffer.
* This is used when the data must be massaged after being read, eg uncompresed or filtered.
* The modified data is placed in a ByteBuffer, which may change for different chunks, and
* so is supplied by each chunk.
*
*
* Example for Integers:
*
int[] read( LayoutBB index, int[] pa) {
while (index.hasNext()) {
LayoutBB.Chunk chunk = index.next();
IntBuffer buff = chunk.getIntBuffer();
buff.position(chunk.getSrcElem());
int pos = (int) chunk.getDestElem();
for (int i = 0; i < chunk.getNelems(); i++)
pa[pos++] = buff.get();
}
return pa;
}
*
*
* @author caron
* @since Jan 9, 2008
*/
public interface LayoutBB extends 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 ByteBuffer at filePos, store in destination at startElem.
*/
public interface Chunk extends Layout.Chunk {
/**
* Get the position in source Buffer where to read or write: "file position"
* @return position as a element index into the Buffer
*/
public int getSrcElem();
public ByteBuffer getByteBuffer();
public ShortBuffer getShortBuffer();
public IntBuffer getIntBuffer();
public FloatBuffer getFloatBuffer();
public DoubleBuffer getDoubleBuffer();
public LongBuffer getLongBuffer();
/**
* 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();
}
}