
nom.tam.util.array.MultiArrayPointer Maven / Gradle / Ivy
package nom.tam.util.array;
/*
* #%L
* nom.tam FITS library
* %%
* Copyright (C) 1996 - 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.lang.reflect.Array;
/**
* @deprecated ()for internal use) Visibility may be reduced to the
* package level in the future. A multi-dimensional array index.
* Used only by {@link MultiArrayCopier} and
* {@link MultiArrayIterator}.
*/
public class MultiArrayPointer {
/** A dummy object to mark the end. */
public static final Object END = new Object();
private Object array;
private int index;
private int length;
private MultiArrayPointer sub;
private MultiArrayPointer backup;
/**
* Constructs a new pointer for an unspecified multi-dimensional array
* object.
*
* @deprecated ()for internal use) Visibility may be reduced to
* private.
*/
public MultiArrayPointer() {
}
/**
* Constructs a new pointer for the specified multidimensional array object.
*
* @param baseArray
* the multidimensional array to iterate over.
*/
public MultiArrayPointer(Object baseArray) {
this();
set(baseArray);
}
private void activateSub(Object element) {
if (backup == null) {
backup = new MultiArrayPointer();
}
sub = backup;
sub.set(element);
}
private void deactivateSub() {
sub = null;
}
/**
* Returns the next base element in the array
*
* @return the next base element in the array.
*/
public Object next() {
while (true) {
if (sub != null) {
Object subNext = sub.next();
if (subNext != MultiArrayPointer.END) {
return subNext;
}
deactivateSub();
}
if (index >= length) {
return MultiArrayPointer.END;
}
Object element = Array.get(array, index++);
if ((element == null) || !isSubArray(element)) {
return element;
}
activateSub(element);
}
}
/**
* Resets the pointer such that {@link #next()} will return the first
* element again.
*/
public void reset() {
index = 0;
deactivateSub();
}
private void set(Object newArray) {
array = newArray;
length = Array.getLength(array);
sub = null;
index = 0;
}
/**
* Checks whether entries in a given element are also arrays themselves.
*
* @param element
* the element
* @return true
if the entries in the given element are also
* arrays, otherwise false
.
* @deprecated ()for internal use) Visibility may be reduced to
* private.
*/
public static boolean isSubArray(Object element) {
if (!(element instanceof Object[])) {
return false;
}
for (Object o : (Object[]) element) {
if (o != null) {
if (o.getClass().isArray()) {
return true;
}
}
}
return false;
}
}
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