| /* |
| * 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.quantiles; |
| |
| import static org.apache.datasketches.quantiles.PreambleUtil.COMPACT_FLAG_MASK; |
| import static org.apache.datasketches.quantiles.PreambleUtil.EMPTY_FLAG_MASK; |
| import static org.apache.datasketches.quantiles.PreambleUtil.ORDERED_FLAG_MASK; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertFamilyID; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertFlags; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertK; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertN; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertPreLongs; |
| import static org.apache.datasketches.quantiles.PreambleUtil.insertSerVer; |
| |
| import java.lang.reflect.Array; |
| import java.util.Arrays; |
| |
| import org.apache.datasketches.ArrayOfItemsSerDe; |
| import org.apache.datasketches.Family; |
| import org.apache.datasketches.memory.WritableMemory; |
| |
| /** |
| * The items to byte array algorithms. |
| * |
| * @author Lee Rhodes |
| * @author Alexander Saydakov |
| */ |
| final class ItemsByteArrayImpl { |
| |
| private ItemsByteArrayImpl() {} |
| |
| static <T> byte[] toByteArray(final ItemsSketch<T> sketch, final boolean ordered, |
| final ArrayOfItemsSerDe<T> serDe) { |
| final boolean empty = sketch.isEmpty(); |
| |
| final int flags = (empty ? EMPTY_FLAG_MASK : 0) |
| | (ordered ? ORDERED_FLAG_MASK : 0) |
| | COMPACT_FLAG_MASK; //always compact |
| |
| if (empty) { |
| final byte[] outByteArr = new byte[Long.BYTES]; |
| final WritableMemory memOut = WritableMemory.writableWrap(outByteArr); |
| final int preLongs = 1; |
| insertPre0(memOut, preLongs, flags, sketch.getK()); |
| return outByteArr; |
| } |
| |
| //not empty |
| final T[] dataArr = combinedBufferToItemsArray(sketch, ordered); //includes min and max |
| |
| final int preLongs = 2; |
| final byte[] itemsByteArr = serDe.serializeToByteArray(dataArr); |
| final int numOutBytes = (preLongs << 3) + itemsByteArr.length; |
| final byte[] outByteArr = new byte[numOutBytes]; |
| final WritableMemory memOut = WritableMemory.writableWrap(outByteArr); |
| |
| //insert preamble |
| insertPre0(memOut, preLongs, flags, sketch.getK()); |
| insertN(memOut, sketch.getN()); |
| |
| //insert data |
| memOut.putByteArray(preLongs << 3, itemsByteArr, 0, itemsByteArr.length); |
| return outByteArr; |
| } |
| |
| /** |
| * Returns an array of items in compact form, including min and max extracted from the |
| * Combined Buffer. |
| * @param <T> the data type |
| * @param sketch a type of ItemsSketch |
| * @param ordered true if the desired form of the resulting array has the base buffer sorted. |
| * @return an array of items, including min and max extracted from the Combined Buffer. |
| */ |
| @SuppressWarnings("unchecked") |
| private static <T> T[] combinedBufferToItemsArray(final ItemsSketch<T> sketch, |
| final boolean ordered) { |
| final int extra = 2; // extra space for min and max values |
| final int outArrCap = sketch.getRetainedItems(); |
| final T minValue = sketch.getMinValue(); |
| final T[] outArr = (T[]) Array.newInstance(minValue.getClass(), outArrCap + extra); |
| |
| //Load min, max |
| outArr[0] = minValue; |
| outArr[1] = sketch.getMaxValue(); |
| final int baseBufferCount = sketch.getBaseBufferCount(); |
| final Object[] combinedBuffer = sketch.getCombinedBuffer(); |
| |
| //Load base buffer |
| System.arraycopy(combinedBuffer, 0, outArr, extra, baseBufferCount); |
| |
| //Load levels |
| long bitPattern = sketch.getBitPattern(); |
| if (bitPattern > 0) { |
| final int k = sketch.getK(); |
| int index = extra + baseBufferCount; |
| for (int level = 0; bitPattern != 0L; level++, bitPattern >>>= 1) { |
| if ((bitPattern & 1L) > 0L) { |
| System.arraycopy(combinedBuffer, (2 + level) * k, outArr, index, k); |
| index += k; |
| } |
| } |
| } |
| if (ordered) { |
| Arrays.sort(outArr, extra, baseBufferCount + extra, sketch.getComparator()); |
| } |
| return outArr; |
| } |
| |
| private static void insertPre0(final WritableMemory wmem, |
| final int preLongs, final int flags, final int k) { |
| insertPreLongs(wmem, preLongs); |
| insertSerVer(wmem, ItemsUtil.ITEMS_SER_VER); |
| insertFamilyID(wmem, Family.QUANTILES.getID()); |
| insertFlags(wmem, flags); |
| insertK(wmem, k); |
| } |
| |
| } |