| /* |
| * 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.druid.frame.field; |
| |
| import org.apache.datasketches.memory.WritableMemory; |
| import org.apache.druid.segment.BaseFloatColumnValueSelector; |
| |
| /** |
| * Wraps a {@link BaseFloatColumnValueSelector} and writes field values. |
| * |
| * See {@link FloatFieldReader} for format details. |
| */ |
| public class FloatFieldWriter implements FieldWriter |
| { |
| public static final int SIZE = Float.BYTES + Byte.BYTES; |
| |
| // Different from the values in NullHandling, since we want to be able to sort as bytes, and we want |
| // nulls to come before non-nulls. |
| public static final byte NULL_BYTE = 0x00; |
| public static final byte NOT_NULL_BYTE = 0x01; |
| |
| private final BaseFloatColumnValueSelector selector; |
| |
| public FloatFieldWriter(final BaseFloatColumnValueSelector selector) |
| { |
| this.selector = selector; |
| } |
| |
| @Override |
| public long writeTo(final WritableMemory memory, final long position, final long maxSize) |
| { |
| if (maxSize < SIZE) { |
| return -1; |
| } |
| |
| if (selector.isNull()) { |
| memory.putByte(position, NULL_BYTE); |
| memory.putInt(position + Byte.BYTES, transform(0)); |
| } else { |
| memory.putByte(position, NOT_NULL_BYTE); |
| memory.putInt(position + Byte.BYTES, transform(selector.getFloat())); |
| } |
| |
| return SIZE; |
| } |
| |
| @Override |
| public void close() |
| { |
| // Nothing to close. |
| } |
| |
| /** |
| * Transforms a float into a form where it can be compared as unsigned bytes without decoding. |
| */ |
| public static int transform(final float n) |
| { |
| final int bits = Float.floatToIntBits(n); |
| final int mask = ((bits & Integer.MIN_VALUE) >> 8) | Integer.MIN_VALUE; |
| return Integer.reverseBytes(bits ^ mask); |
| } |
| |
| /** |
| * Inverse of {@link #transform}. |
| */ |
| public static float detransform(final int bits) |
| { |
| final int reversedBits = Integer.reverseBytes(bits); |
| final int mask = (((reversedBits ^ Integer.MIN_VALUE) & Integer.MIN_VALUE) >> 8) | Integer.MIN_VALUE; |
| return Float.intBitsToFloat(reversedBits ^ mask); |
| } |
| } |