content: /*
   * 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.cassandra.cql3.functions;
  
  import java.nio.ByteBuffer;
  import java.util.Collection;
  import java.util.List;
  import java.util.function.BiFunction;
  
  import com.google.common.collect.ImmutableList;
  import org.apache.cassandra.db.marshal.*;
  import org.apache.cassandra.exceptions.InvalidRequestException;
  
  public final class MathFcts
  {
      public static void addFunctionsTo(NativeFunctions functions)
      {
          final List<NumberType<?>> numericTypes = ImmutableList.of(ByteType.instance,
                                                                    ShortType.instance,
                                                                    Int32Type.instance,
                                                                    FloatType.instance,
                                                                    LongType.instance,
                                                                    DoubleType.instance,
                                                                    IntegerType.instance,
                                                                    DecimalType.instance,
                                                                    CounterColumnType.instance);
  
          numericTypes.stream()
                      .map(t -> ImmutableList.of(absFct(t),
                                                 expFct(t),
                                                 logFct(t),
                                                 log10Fct(t),
                                                 roundFct(t)))
                       .flatMap(Collection::stream)
                       .forEach(functions::add);
      }
  
      public static NativeFunction absFct(final NumberType<?> type)
      {
          return mathFct("abs", type, NumberType::abs);
      }
  
      public static NativeFunction expFct(final NumberType<?> type)
      {
          return mathFct("exp", type, NumberType::exp);
      }
  
      public static NativeFunction logFct(final NumberType<?> type)
      {
          return mathFct("log", type, NumberType::log);
      }
  
      public static NativeFunction log10Fct(final NumberType<?> type)
      {
          return mathFct("log10", type, NumberType::log10);
      }
  
      public static NativeFunction roundFct(final NumberType<?> type)
      {
          return mathFct("round", type, NumberType::round);
      }
  
      private static NativeFunction mathFct(String name,
                                            NumberType<?> type,
                                            BiFunction<NumberType<?>, Number, ByteBuffer> f)
      {
          return new NativeScalarFunction(name, type, type)
          {
              @Override
              public ByteBuffer execute(Arguments arguments) throws InvalidRequestException
              {
                  Number number = arguments.get(0);
  
                  if (number == null)
                      return null;
  
                  return f.apply(type, number);
              }
          };
      }
  
      private MathFcts()
      {
      }
  }
  