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package nom.tam.fits;
/*
* #%L
* nom.tam FITS library
* %%
* Copyright (C) 2004 - 2024 nom-tam-fits
* %%
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
* #L%
*/
import java.io.IOException;
import nom.tam.util.ArrayDataInput;
import nom.tam.util.ArrayDataOutput;
import nom.tam.util.ByteArrayIO;
import nom.tam.util.FitsDecoder;
import nom.tam.util.FitsEncoder;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
* Heap for storing variable-length entries in binary tables. FITS binary tables store variable length arrays on a heap,
* following the regular array data. The newer implementation of the heap now provides proper random access to the byte
* buffer as of version 1.16.
*/
public class FitsHeap implements FitsElement {
/** The minimum stoprage size to allocate for the heap, from which it can grow as necessary */
private static final int MIN_HEAP_CAPACITY = 16384;
// TODO
// AK: In principle we could use ReadWriteAccess interface as the storage, which can be either an in-memory
// array or a buffered file region. The latter could support heaps over 2G, and could reduce memory overhead
// for heap access in some future release...
/** The underlying storage space of the heap */
private ByteArrayIO store;
/** conversion from Java arrays to FITS binary representation */
private FitsEncoder encoder;
/** conversion from FITS binary representation to Java arrays */
private FitsDecoder decoder;
/**
* Construct a new uninitialized FITS heap object.
*/
private FitsHeap() {
}
/**
* Creates a heap of a given initial size. The new heap is initialized with 0's, and up to the specified number of
* bytes are immediately available for reading (as zeroes). The heap can grow as needed if more data is written into
* it.
*
* @throws IllegalArgumentException if the size argument is negative.
*/
FitsHeap(int size) throws IllegalArgumentException {
if (size < 0) {
throw new IllegalArgumentException("Illegal size for FITS heap: " + size);
}
ByteArrayIO data = new ByteArrayIO(Math.max(size, MIN_HEAP_CAPACITY));
data.setLength(Math.max(0, size));
setData(data);
encoder = new FitsEncoder(store);
decoder = new FitsDecoder(store);
}
/**
* Sets the underlying data storage for this heap instance. Constructors should call this.
*
* @param data the new underlying storage object for this heap instance.
*/
protected synchronized void setData(ByteArrayIO data) {
store = data;
}
/**
* Add a copy constructor to allow us to duplicate a heap. This would be necessary if we wanted to copy an HDU that
* included variable length columns.
*/
synchronized FitsHeap copy() {
FitsHeap copy = new FitsHeap();
synchronized (copy) {
copy.setData(store.copy());
copy.encoder = new FitsEncoder(copy.store);
copy.decoder = new FitsDecoder(copy.store);
}
return copy;
}
/**
* Gets data for a Java array from the heap. The array may be a multi-dimensional array of arrays.
*
* @param offset the heap byte offset at which the data begins.
* @param array The array of primitives to be extracted.
*
* @throws FitsException if the operation failed
*/
public synchronized void getData(int offset, Object array) throws FitsException {
try {
store.position(offset);
decoder.readArrayFully(array);
} catch (Exception e) {
throw new FitsException("Error decoding heap area at offset=" + offset + ", size="
+ FitsEncoder.computeSize(array) + " (heap size " + size() + "): " + e.getMessage(), e);
}
}
@Override
public long getFileOffset() {
throw new IllegalStateException("FitsHeap should only be reset from inside its parent, never alone");
}
@Override
public synchronized long getSize() {
return size();
}
/**
* Puts data to the end of the heap.
*
* @param data a primitive array object, which may be multidimensional
*
* @return the number of bytes used by the data.
*
* @see #putData(Object, long)
* @see #getData(int, Object)
*/
synchronized long putData(Object data) throws FitsException {
return putData(data, store.length());
}
/**
* Puts data onto the heap at a specific heap position.
*
* @param data a primitive array object, which may be multidimensional
* @param pos the byte offset at which the data should begin.
*
* @return the number of bytes used by the data.
*
* @see #putData(Object, long)
* @see #getData(int, Object)
*/
synchronized long putData(Object data, long pos) throws FitsException {
long lsize = pos + FitsEncoder.computeSize(data);
if (lsize > Integer.MAX_VALUE) {
throw new FitsException("FITS Heap > 2 G");
}
try {
store.position(pos);
encoder.writeArray(data);
} catch (Exception e) {
throw new FitsException("Unable to write variable column length data: " + e.getMessage(), e);
}
return store.position() - pos;
}
/**
* Copies a segment of data from another heap to the end of this heap
*
* @param src the heap to source data from
* @param offset the byte offset of the data in the source heap
* @param len the number of bytes to copy
*
* @return the position of the copied data in this heap.
*/
synchronized int copyFrom(FitsHeap src, int offset, int len) {
int pos = (int) store.length();
store.setLength(pos + len);
synchronized (src) {
System.arraycopy(src.store.getBuffer(), offset, store.getBuffer(), pos, len);
}
return pos;
}
@SuppressFBWarnings(value = "RR_NOT_CHECKED", justification = "this read will never return less than the requested length")
@Override
public synchronized void read(ArrayDataInput str) throws FitsException {
if (store.length() == 0) {
return;
}
try {
str.readFully(store.getBuffer(), 0, (int) store.length());
} catch (IOException e) {
throw new FitsException("Error reading heap " + e.getMessage(), e);
}
}
@Override
public boolean reset() {
throw new IllegalStateException("FitsHeap should only be reset from inside its parent, never alone");
}
@Override
public void rewrite() throws IOException, FitsException {
throw new FitsException("FitsHeap should only be rewritten from inside its parent, never alone");
}
@Override
public boolean rewriteable() {
return false;
}
/**
* Returns the current heap size.
*
* @return the size of the heap in bytes
*/
public synchronized int size() {
return (int) store.length();
}
@Override
public synchronized void write(ArrayDataOutput str) throws FitsException {
try {
str.write(store.getBuffer(), 0, (int) store.length());
} catch (IOException e) {
throw new FitsException("Error writing heap:" + e.getMessage(), e);
}
}
}
