/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.server.types.mcompat.mfuncs;
import com.foundationdb.server.types.LazyList;
import com.foundationdb.server.types.TCustomOverloadResult;
import com.foundationdb.server.types.TExecutionContext;
import com.foundationdb.server.types.TInstance;
import com.foundationdb.server.types.TScalar;
import com.foundationdb.server.types.TOverloadResult;
import com.foundationdb.server.types.TPreptimeContext;
import com.foundationdb.server.types.TPreptimeValue;
import com.foundationdb.server.types.common.types.DoubleAttribute;
import com.foundationdb.server.types.mcompat.mtypes.MApproximateNumber;
import com.foundationdb.server.types.value.ValueSource;
import com.foundationdb.server.types.value.ValueTarget;
import com.foundationdb.server.types.texpressions.TInputSetBuilder;
import com.foundationdb.server.types.texpressions.TScalarBase;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
public class MRoundTruncateDouble extends TScalarBase {
public static final Collection<TScalar> overloads = createAll();
private enum RoundingStrategy {
ROUND(RoundingMode.HALF_UP),
TRUNCATE(RoundingMode.DOWN)
;
public double apply(double input, int scale) {
BigDecimal asDecimal = BigDecimal.valueOf(input);
asDecimal = asDecimal.setScale(scale, roundingMode);
return asDecimal.doubleValue();
}
private RoundingStrategy(RoundingMode roundingMode) {
this.roundingMode = roundingMode;
}
private final RoundingMode roundingMode;
}
@Override
protected void doEvaluate(TExecutionContext context, LazyList<? extends ValueSource> inputs, ValueTarget output) {
double input = inputs.get(0).getDouble();
int scale = signatureStrategy.roundToScale(inputs);
double result = roundingStrategy.apply(input, scale);
output.putDouble(result);
}
@Override
public TOverloadResult resultType() {
return TOverloadResult.custom(new TCustomOverloadResult() {
@Override
public TInstance resultInstance(List<TPreptimeValue> inputs, TPreptimeContext context) {
ValueSource incomingScale = signatureStrategy.getScaleOperand(inputs);
int resultScale = (incomingScale == null)
? inputs.get(0).type().attribute(DoubleAttribute.SCALE)
: incomingScale.getInt32();
int resultPrecision = 17 + resultScale;
return MApproximateNumber.DOUBLE.instance(resultPrecision, resultScale, anyContaminatingNulls(inputs));
}
});
}
@Override
protected void buildInputSets(TInputSetBuilder builder) {
signatureStrategy.buildInputSets(MApproximateNumber.DOUBLE, builder);
}
@Override
public String displayName() {
return roundingStrategy.name();
}
protected MRoundTruncateDouble(RoundingOverloadSignature signatureStrategy,
RoundingStrategy roundingStrategy)
{
this.signatureStrategy = signatureStrategy;
this.roundingStrategy = roundingStrategy;
}
private static Collection<TScalar> createAll() {
List<TScalar> results = new ArrayList<>();
for (RoundingOverloadSignature signature : RoundingOverloadSignature.values()) {
for (RoundingStrategy rounding : RoundingStrategy.values()) {
results.add(new MRoundTruncateDouble(signature, rounding));
}
}
return Collections.unmodifiableCollection(results);
}
private final RoundingOverloadSignature signatureStrategy;
private final RoundingStrategy roundingStrategy;
}