@Override
public final long getJoinPosition(BlockCursor... cursors) {
int pos = ((int) Murmur3.hash64(hashCursor(cursors))) & mask;
while (key[pos] != -1) {
if (positionEqualsCurrentRow(key[pos], cursors)) {
return key[pos];
}
// increment position and mask to handler wrap around
pos = (pos + 1) & mask;
}
return -1;
}
public InMemoryJoinHash(
LongArrayList addresses,
PagesHashStrategy pagesHashStrategy,
OperatorContext operatorContext) {
this.addresses = checkNotNull(addresses, "addresses is null");
this.pagesHashStrategy = checkNotNull(pagesHashStrategy, "pagesHashStrategy is null");
this.channelCount = pagesHashStrategy.getChannelCount();
checkNotNull(operatorContext, "operatorContext is null");
// reserve memory for the arrays
int hashSize = HashCommon.arraySize(addresses.size(), 0.75f);
operatorContext.reserveMemory(sizeOfIntArray(hashSize) + sizeOfIntArray(addresses.size()));
mask = hashSize - 1;
key = new int[hashSize];
Arrays.fill(key, -1);
this.positionLinks = new int[addresses.size()];
Arrays.fill(positionLinks, -1);
// index pages
for (int position = 0; position < addresses.size(); position++) {
int pos = ((int) Murmur3.hash64(hashPosition(position))) & mask;
// look for an empty slot or a slot containing this key
while (key[pos] != -1) {
int currentKey = key[pos];
if (positionEqualsPosition(currentKey, position)) {
// found a slot for this key
// link the new key position to the current key position
positionLinks[position] = currentKey;
// key[pos] updated outside of this loop
break;
}
// increment position and mask to handler wrap around
pos = (pos + 1) & mask;
}
key[pos] = position;
}
}
