/**
* Compute the xor aggregate using a temporary uncompressed bitmap.
*
* @param container where the aggregate is written
* @param bufSize buffer size used during the computation in 64-bit words
* @param bitmaps the source bitmaps
*/
public static void bufferedxorWithContainer(
final BitmapStorage32 container, final int bufSize, final EWAHCompressedBitmap32... bitmaps) {
int range = 0;
EWAHCompressedBitmap32[] sbitmaps = bitmaps.clone();
Arrays.sort(
sbitmaps,
new Comparator<EWAHCompressedBitmap32>() {
@Override
public int compare(EWAHCompressedBitmap32 a, EWAHCompressedBitmap32 b) {
return b.sizeInBits() - a.sizeInBits();
}
});
java.util.ArrayList<IteratingBufferedRunningLengthWord32> al =
new java.util.ArrayList<IteratingBufferedRunningLengthWord32>();
for (EWAHCompressedBitmap32 bitmap : sbitmaps) {
if (bitmap.sizeInBits() > range) range = bitmap.sizeInBits();
al.add(new IteratingBufferedRunningLengthWord32(bitmap));
}
int[] hardbitmap = new int[bufSize];
int maxr = al.size();
while (maxr > 0) {
int effective = 0;
for (int k = 0; k < maxr; ++k) {
if (al.get(k).size() > 0) {
int eff = IteratorAggregation32.inplacexor(hardbitmap, al.get(k));
if (eff > effective) effective = eff;
} else maxr = k;
}
for (int k = 0; k < effective; ++k) container.addWord(hardbitmap[k]);
Arrays.fill(hardbitmap, 0);
}
container.setSizeInBitsWithinLastWord(range);
}
/**
* Simple algorithm that computes the XOR aggregate.
*
* @param bitmaps input bitmaps
* @return new bitmap containing the aggregate
*/
public static EWAHCompressedBitmap32 xor(final Iterator<EWAHCompressedBitmap32> bitmaps) {
PriorityQueue<EWAHCompressedBitmap32> pq =
new PriorityQueue<EWAHCompressedBitmap32>(
32,
new Comparator<EWAHCompressedBitmap32>() {
@Override
public int compare(EWAHCompressedBitmap32 a, EWAHCompressedBitmap32 b) {
return a.sizeInBytes() - b.sizeInBytes();
}
});
while (bitmaps.hasNext()) pq.add(bitmaps.next());
if (pq.isEmpty()) return new EWAHCompressedBitmap32();
while (pq.size() > 1) {
EWAHCompressedBitmap32 x1 = pq.poll();
EWAHCompressedBitmap32 x2 = pq.poll();
pq.add(x1.xor(x2));
}
return pq.poll();
}
/**
* Simple algorithm that computes the XOR aggregate.
*
* @param bitmaps input bitmaps
* @return new bitmap containing the aggregate
*/
public static EWAHCompressedBitmap32 xor(final EWAHCompressedBitmap32... bitmaps) {
PriorityQueue<EWAHCompressedBitmap32> pq =
new PriorityQueue<EWAHCompressedBitmap32>(
bitmaps.length,
new Comparator<EWAHCompressedBitmap32>() {
@Override
public int compare(EWAHCompressedBitmap32 a, EWAHCompressedBitmap32 b) {
return a.sizeInBytes() - b.sizeInBytes();
}
});
Collections.addAll(pq, bitmaps);
if (pq.isEmpty()) return new EWAHCompressedBitmap32();
while (pq.size() > 1) {
EWAHCompressedBitmap32 x1 = pq.poll();
EWAHCompressedBitmap32 x2 = pq.poll();
pq.add(x1.xor(x2));
}
return pq.poll();
}
/**
* Uses a priority queue to compute the xor aggregate.
*
* <p>The content of the container is overwritten.
*
* <p>This algorithm runs in linearithmic time (O(n log n)) with respect to the number of bitmaps.
*
* @param container where we write the result
* @param bitmaps to be aggregated
*/
public static void xorToContainer(
final BitmapStorage32 container, final EWAHCompressedBitmap32... bitmaps) {
if (bitmaps.length < 2) throw new IllegalArgumentException("We need at least two bitmaps");
PriorityQueue<EWAHCompressedBitmap32> pq =
new PriorityQueue<EWAHCompressedBitmap32>(
bitmaps.length,
new Comparator<EWAHCompressedBitmap32>() {
@Override
public int compare(EWAHCompressedBitmap32 a, EWAHCompressedBitmap32 b) {
return a.sizeInBytes() - b.sizeInBytes();
}
});
Collections.addAll(pq, bitmaps);
while (pq.size() > 2) {
EWAHCompressedBitmap32 x1 = pq.poll();
EWAHCompressedBitmap32 x2 = pq.poll();
pq.add(x1.xor(x2));
}
pq.poll().xorToContainer(pq.poll(), container);
}
@Override
public EWAHIterator32 next() {
this.buffer.clear();
IteratorAggregation32.andToContainer(
this.buffer, this.bufferSize * this.ll.size(), this.ll.get(0), this.ll.get(1));
if (this.ll.size() > 2) {
Iterator<IteratingRLW32> i = this.ll.iterator();
i.next();
i.next();
EWAHCompressedBitmap32 tmpbuffer = new EWAHCompressedBitmap32();
while (i.hasNext() && this.buffer.sizeInBytes() > 0) {
IteratorAggregation32.andToContainer(tmpbuffer, this.buffer.getIteratingRLW(), i.next());
this.buffer.swap(tmpbuffer);
tmpbuffer.clear();
}
}
for (IteratingRLW32 aLl : this.ll) {
if (aLl.size() == 0) {
this.ll.clear();
break;
}
}
return this.buffer.getEWAHIterator();
}
