| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.datasketches; |
| |
| import org.apache.datasketches.memory.Memory; |
| import org.apache.datasketches.memory.UnsafeUtil; |
| import org.apache.datasketches.memory.WritableMemory; |
| |
| /** |
| * Methods of serializing and deserializing arrays of Boolean as a bit array. |
| * |
| * @author Jon Malkin |
| */ |
| public class ArrayOfBooleansSerDe extends ArrayOfItemsSerDe<Boolean> { |
| /** |
| * Computes number of bytes needed for packed bit encoding of the array of booleans. Rounds |
| * partial bytes up to return a whole number of bytes. |
| * |
| * @param arrayLength Number of items in the array to serialize |
| * @return Number of bytes needed to encode the array |
| */ |
| public static int computeBytesNeeded(final int arrayLength) { |
| return (arrayLength >>> 3) + ((arrayLength & 0x7) > 0 ? 1 : 0); |
| } |
| |
| @Override |
| public byte[] serializeToByteArray(final Boolean[] items) { |
| final int bytesNeeded = computeBytesNeeded(items.length); |
| final byte[] bytes = new byte[bytesNeeded]; |
| final WritableMemory mem = WritableMemory.wrap(bytes); |
| |
| byte val = 0; |
| for (int i = 0; i < items.length; ++i) { |
| if (items[i]) { |
| val |= 0x1 << (i & 0x7); |
| } |
| |
| if ((i & 0x7) == 0x7) { |
| mem.putByte(i >>> 3, val); |
| val = 0; |
| } |
| } |
| |
| // write out any remaining values (if val=0, still good to be explicit) |
| if ((items.length & 0x7) > 0) { |
| mem.putByte(bytesNeeded - 1, val); |
| } |
| |
| return bytes; |
| } |
| |
| @Override |
| public Boolean[] deserializeFromMemory(final Memory mem, final int length) { |
| final int numBytes = computeBytesNeeded(length); |
| UnsafeUtil.checkBounds(0, numBytes, mem.getCapacity()); |
| final Boolean[] array = new Boolean[length]; |
| |
| byte srcVal = 0; |
| for (int i = 0, b = 0; i < length; ++i) { |
| if ((i & 0x7) == 0x0) { // should trigger on first iteration |
| srcVal = mem.getByte(b++); |
| } |
| array[i] = ((srcVal >>> (i & 0x7)) & 0x1) == 1; |
| } |
| |
| return array; |
| } |
| } |