public static CompressedVSizeIntsIndexedSupplier fromByteBuffer(
ByteBuffer buffer, ByteOrder order) {
byte versionFromBuffer = buffer.get();
if (versionFromBuffer == version) {
final int numBytes = buffer.get();
final int totalSize = buffer.getInt();
final int sizePer = buffer.getInt();
final int chunkBytes = sizePer * numBytes + bufferPadding(numBytes);
final CompressedObjectStrategy.CompressionStrategy compression =
CompressedObjectStrategy.CompressionStrategy.forId(buffer.get());
return new CompressedVSizeIntsIndexedSupplier(
totalSize,
sizePer,
numBytes,
GenericIndexed.read(
buffer,
CompressedByteBufferObjectStrategy.getBufferForOrder(order, compression, chunkBytes)),
compression);
}
throw new IAE("Unknown version[%s]", versionFromBuffer);
}
public static CompressedVSizeIntsIndexedSupplier fromList(
final List<Integer> list,
final int maxValue,
final int chunkFactor,
final ByteOrder byteOrder,
CompressedObjectStrategy.CompressionStrategy compression) {
final int numBytes = VSizeIndexedInts.getNumBytesForMax(maxValue);
final int chunkBytes = chunkFactor * numBytes + bufferPadding(numBytes);
Preconditions.checkArgument(
chunkFactor <= maxIntsInBufferForBytes(numBytes),
"Chunks must be <= 64k bytes. chunkFactor was[%s]",
chunkFactor);
return new CompressedVSizeIntsIndexedSupplier(
list.size(),
chunkFactor,
numBytes,
GenericIndexed.fromIterable(
new Iterable<ResourceHolder<ByteBuffer>>() {
@Override
public Iterator<ResourceHolder<ByteBuffer>> iterator() {
return new Iterator<ResourceHolder<ByteBuffer>>() {
int position = 0;
@Override
public boolean hasNext() {
return position < list.size();
}
@Override
public ResourceHolder<ByteBuffer> next() {
ByteBuffer retVal = ByteBuffer.allocate(chunkBytes).order(byteOrder);
if (chunkFactor > list.size() - position) {
retVal.limit((list.size() - position) * numBytes);
} else {
retVal.limit(chunkFactor * numBytes);
}
final List<Integer> ints =
list.subList(position, position + retVal.remaining() / numBytes);
final ByteBuffer buf = ByteBuffer.allocate(Ints.BYTES).order(byteOrder);
final boolean bigEndian = byteOrder.equals(ByteOrder.BIG_ENDIAN);
for (int value : ints) {
buf.putInt(0, value);
if (bigEndian) {
retVal.put(buf.array(), Ints.BYTES - numBytes, numBytes);
} else {
retVal.put(buf.array(), 0, numBytes);
}
}
retVal.rewind();
position += retVal.remaining() / numBytes;
return StupidResourceHolder.create(retVal);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
},
CompressedByteBufferObjectStrategy.getBufferForOrder(
byteOrder, compression, chunkBytes)),
compression);
}
