/**
* Combine this reduction variable with the given value using the given operation. The result is
* stored back into this reduction variable and is returned.
*
* @param value Value.
* @param op Binary operation.
* @return (This variable) <I>op</I> (<TT>value</TT>).
*/
public boolean reduce(boolean value, BooleanOp op) {
for (; ; ) {
boolean oldvalue = myValue.get();
boolean newvalue = op.op(oldvalue, value);
if (myValue.compareAndSet(oldvalue, newvalue)) return newvalue;
}
}
/**
* Combine this array reduction variable at the given index with the given value using the given
* operation. (This array <TT>[i]</TT>) is set to (this array <TT>[i]</TT>) <I>op</I>
* (<TT>value</TT>), then (this array <TT>[i]</TT>) is returned.
*
* @param i Index.
* @param value Value.
* @param op Binary operation.
* @return (This array <TT>[i]</TT>) <I>op</I> (<TT>value</TT>).
*/
public boolean reduce(int i, boolean value, BooleanOp op) {
for (; ; ) {
int oldvalue = myArray.get(i);
int newvalue = op.op(oldvalue != 0, value) ? 1 : 0;
if (myArray.compareAndSet(i, oldvalue, newvalue)) {
return newvalue != 0;
}
}
}
/**
* Combine a portion of this array reduction variable with a portion of the given array using the
* given operation. For each index <TT>i</TT> from 0 to <TT>len</TT>-1, (this array
* <TT>[dstoff+i]</TT>) is set to (this array <TT>[dstoff+i]</TT>) <I>op</I>
* (<TT>src[srcoff+i]</TT>).
*
* <p>The <TT>reduce()</TT> method is multiple thread safe <I>on a per-element basis.</I> Each
* individual array element is updated atomically, but the array as a whole is not updated
* atomically.
*
* @param dstoff Index of first element to update in this array.
* @param src Source array.
* @param srcoff Index of first element to update from in the source array.
* @param len Number of array elements to update.
* @param op Binary operation.
* @exception NullPointerException (unchecked exception) Thrown if <TT>src</TT> is null. Thrown if
* <TT>op</TT> is null.
* @exception IndexOutOfBoundsException (unchecked exception) Thrown if <TT>len</TT> < 0.
* Thrown if any array index would be out of bounds.
*/
public void reduce(int dstoff, boolean[] src, int srcoff, int len, BooleanOp op) {
if (len < 0
|| dstoff < 0
|| dstoff + len > myArray.length()
|| srcoff < 0
|| srcoff + len > src.length) {
throw new IndexOutOfBoundsException();
}
while (len > 0) {
updateLoop:
for (; ; ) {
int oldvalue = myArray.get(dstoff);
int newvalue = op.op(oldvalue != 0, src[srcoff]) ? 1 : 0;
if (myArray.compareAndSet(dstoff, oldvalue, newvalue)) break updateLoop;
}
++dstoff;
++srcoff;
--len;
}
}
