// no concurrent read/write is assumed
public V put(double key, V value) {
if (value == null) throw new NullPointerException();
// not incrementing b's refcnt, so need not release it.
Node b = skipListMap.findGrandPredecessor(key);
if (b == null) b = head;
Node n = b.next;
if (n == null) {
n = Node.alloc();
n.put(key, value, this);
n.next = null;
b.next = n;
return null;
}
Node f = n.next;
if (f == null) { // put (key,value) into node n
Object val = n.put(key, value, this);
return (V) val;
} else {
assert f.len() > 0 && f.first() >= key;
if (f.first() == key) {
Object val = f.put(key, value, this);
return (V) val;
} else {
Object val = n.put(key, value, this);
return (V) val;
}
}
}
Node ceilingNode(double key) {
for (; ; ) {
Node b = skipListMap.findGrandPredecessor(key, refCntCallback);
if (b == null) b = head;
if (b != head && key <= b.last()) {
return b;
}
assert b == head || b.last() < key;
Node n = safeNext(b);
release(b);
if (n == null) {
return null;
} else if (key <= n.last()) {
return n;
}
Node f = safeNext(n);
release(n);
if (f == null) {
return null;
} else {
if (isInconsistentNextNode(f, key)) {
release(f);
continue;
}
return f;
}
}
}
V putAtomic(double key, V value, boolean onlyIfAbsent) {
if (value == null) throw new NullPointerException();
for (; ; ) {
Node b = skipListMap.findGrandPredecessor(key, refCntCallback);
if (b == null) b = head;
if (b != head && b.first() <= key && key <= b.last()) {
release(b);
continue;
}
assert b == head || b.last() < key;
Node n = safeNext(b);
if (n == null) {
if (b.appendNewAtomic(key, value, this)) {
release(b);
return null;
} else {
release(b);
continue;
}
} else if (n.first() <= key && key <= n.last()) {
Object val = n.putAtomic(key, value, b, onlyIfAbsent, this);
release(b, n);
if (val == Retry) continue;
return (V) val;
}
Node f = safeNext(n);
if (f == null) {
Object val = n.putAtomic(key, value, b, onlyIfAbsent, this);
release(b, n);
if (val == Retry) continue;
return (V) val;
} else {
if (f.first() == key) {
Object val = f.putAtomic(key, value, n, onlyIfAbsent, this);
release(b, n, f);
if (val == Retry) continue;
return (V) val;
} else {
if (key > f.first()) { // inconsistent read, retry
release(b, n, f);
continue;
}
Object val = n.putAtomic(key, value, b, onlyIfAbsent, this);
release(b, n, f);
if (val == Retry) continue;
return (V) val;
}
}
}
}
V doReplace(double key, V old, V value) {
for (; ; ) {
Node b = skipListMap.findGrandPredecessor(key, refCntCallback);
if (b == null) b = head;
if (b != head && b.first() <= key && key <= b.last()) {
// can happen if there's inconsistency between skipListMap and orderedMap(this).
// The inconsistency can happen from Node.putAtomicReally(),
// where it adds to, and removes from skiplistMap.
Object val = b.replace(key, old, value);
release(b);
if (val == Retry) continue;
return (V) val;
}
assert b == head || b.last() < key;
Node n = safeNext(b);
release(b);
if (n == null) {
return null;
} else if (n.first() <= key && key <= n.last()) {
Object val = n.replace(key, old, value);
release(n);
if (val == Retry) continue;
return (V) val;
}
Node f = safeNext(n);
release(n);
if (f == null) {
return null;
} else {
if (isInconsistentNextNode(f, key)) {
release(f);
continue;
}
Object val = f.replace(key, old, value);
release(f);
if (val == Retry) continue;
return (V) val;
}
}
}