public static int binarySearch(
@NotNull final IByteIterableComparator comparator,
final ByteIterable key,
int low,
int high,
final int bytesPerLong,
Log log,
long startAddress) {
final LogCache cache = log.cache;
final int pageSize = log.getCachePageSize();
final int mask = pageSize - 1; // page size is always a power of 2
long leftAddress = -1L;
byte[] leftPage = null;
long rightAddress = -1L;
byte[] rightPage = null;
final BinarySearchIterator it = new BinarySearchIterator(pageSize);
while (low <= high) {
final int mid = (low + high + 1) >>> 1;
final long midAddress = startAddress + (mid * bytesPerLong);
it.offset = ((int) midAddress) & mask;
it.address = midAddress - it.offset;
boolean loaded = false;
if (it.address == leftAddress) {
it.page = leftPage;
} else if (it.address == rightAddress) {
it.page = rightPage;
} else {
it.page = cache.getPage(log, it.address).getBytesUnsafe();
loaded = true;
}
final int cmp;
final long address;
final byte[] page;
if (pageSize - it.offset < bytesPerLong) {
final long nextAddress = (address = it.address) + pageSize;
if (rightAddress == nextAddress) {
it.nextPage = rightPage;
} else {
it.nextPage = cache.getPage(log, nextAddress).getBytesUnsafe();
loaded = true;
}
page = it.page;
cmp =
comparator.compare(LongBinding.entryToUnsignedLong(it.asCompound(), bytesPerLong), key);
} else {
cmp = comparator.compare(LongBinding.entryToUnsignedLong(it, bytesPerLong), key);
page = it.page;
address = it.address;
}
if (cmp < 0) {
// left < right
low = mid + 1;
if (loaded) {
leftAddress = it.address;
leftPage = it.page;
}
} else if (cmp > 0) {
// left > right
high = mid - 1;
if (loaded) {
rightAddress = address;
rightPage = page;
}
} else {
return mid; // key found
}
}
return -(low + 1); // key not found.
}
@Override
public long nextLong(final int length) {
final long result = LongBinding.entryToUnsignedLong(page, offset, length);
offset += length;
return result;
}