private void addToStackBottom(Entry<V> e) {
e.stackNext = stack;
e.stackPrev = stack.stackPrev;
e.stackPrev.stackNext = e;
stack.stackPrev = e;
stackSize++;
}
private void addToStack(Entry<V> e) {
e.stackPrev = stack;
e.stackNext = stack.stackNext;
e.stackNext.stackPrev = e;
stack.stackNext = e;
stackSize++;
e.topMove = stackMoveCounter++;
}
/**
* Create a new cache segment.
*
* @param maxMemory the maximum memory to use
* @param stackMoveDistance the number of other entries to be moved to the top of the stack
* before moving an entry to the top
* @param len the number of hash table buckets (must be a power of 2)
*/
Segment(long maxMemory, int stackMoveDistance, int len) {
setMaxMemory(maxMemory);
this.stackMoveDistance = stackMoveDistance;
// the bit mask has all bits set
mask = len - 1;
// initialize the stack and queue heads
stack = new Entry<V>();
stack.stackPrev = stack.stackNext = stack;
queue = new Entry<V>();
queue.queuePrev = queue.queueNext = queue;
queue2 = new Entry<V>();
queue2.queuePrev = queue2.queueNext = queue2;
@SuppressWarnings("unchecked")
Entry<V>[] e = new Entry[len];
entries = e;
}
/**
* Remove the entry from the stack. The head itself must not be removed.
*
* @param e the entry
*/
private void removeFromStack(Entry<V> e) {
e.stackPrev.stackNext = e.stackNext;
e.stackNext.stackPrev = e.stackPrev;
e.stackPrev = e.stackNext = null;
stackSize--;
}