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 com.alibaba.qlexpress4.runtime.operator.number;
  
  import java.math.BigDecimal;
  import java.math.MathContext;
  import java.math.RoundingMode;
  
  /**
   * BigDecimal NumberMath operations
   */
  public final class BigDecimalMath extends NumberMath {
      
      // This is an arbitrary value, picked as a reasonable choice for a precision
      // for typical user math when a non-terminating result would otherwise occur.
      public static final int DIVISION_EXTRA_PRECISION = Integer.getInteger("qlexpress4.division.extra.precision", 10);
      
      //This is an arbitrary value, picked as a reasonable choice for a rounding point
      //for typical user math.
      public static final int DIVISION_MIN_SCALE = Integer.getInteger("qlexpress4.division.min.scale", 10);
      
      public static final BigDecimalMath INSTANCE = new BigDecimalMath();
      
      private BigDecimalMath() {
      }
      
      @Override
      public Number absImpl(Number number) {
          return toBigDecimal(number).abs();
      }
      
      @Override
      public Number addImpl(Number left, Number right) {
          return toBigDecimal(left).add(toBigDecimal(right));
      }
      
      @Override
      public Number subtractImpl(Number left, Number right) {
          return toBigDecimal(left).subtract(toBigDecimal(right));
      }
      
      @Override
      public Number multiplyImpl(Number left, Number right) {
          return toBigDecimal(left).multiply(toBigDecimal(right));
      }
      
      @Override
      public Number divideImpl(Number left, Number right) {
          BigDecimal bigLeft = toBigDecimal(left);
          BigDecimal bigRight = toBigDecimal(right);
          try {
              return bigLeft.divide(bigRight);
          }
          catch (ArithmeticException e) {
              // set a DEFAULT precision if otherwise non-terminating
              int precision = Math.max(bigLeft.precision(), bigRight.precision()) + DIVISION_EXTRA_PRECISION;
              BigDecimal result = bigLeft.divide(bigRight, new MathContext(precision));
              int scale = Math.max(Math.max(bigLeft.scale(), bigRight.scale()), DIVISION_MIN_SCALE);
              if (result.scale() > scale) {
                  result = result.setScale(scale, RoundingMode.HALF_UP);
              }
              return result;
          }
      }
      
      @Override
      public int compareToImpl(Number left, Number right) {
          return toBigDecimal(left).compareTo(toBigDecimal(right));
      }
      
      @Override
      public Number unaryMinusImpl(Number left) {
          return toBigDecimal(left).negate();
      }
      
      @Override
      public Number unaryPlusImpl(Number left) {
          return toBigDecimal(left);
      }
      
      @Override
      public Number remainderImpl(Number left, Number right) {
          return toBigDecimal(left).remainder(toBigDecimal(right));
      }
      
      @Override
      public Number modImpl(Number self, Number divisor) {
          BigDecimal selfDecimal = toBigDecimal(self);
          BigDecimal divDecimal = toBigDecimal(divisor);
          BigDecimal remainder = selfDecimal.remainder(divDecimal);
          return remainder.signum() < 0 ? remainder.add(divDecimal) : remainder;
      }
  }
  