/*
* Licensed 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.facebook.presto.type;
import com.facebook.presto.annotation.UsedByGeneratedCode;
import com.facebook.presto.metadata.Signature;
import com.facebook.presto.metadata.SqlScalarFunction;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.type.DecimalType;
import com.facebook.presto.spi.type.Decimals;
import com.google.common.collect.ImmutableList;
import io.airlift.slice.Slice;
import java.math.BigInteger;
import static com.facebook.presto.metadata.FunctionKind.SCALAR;
import static com.facebook.presto.metadata.Signature.withVariadicBound;
import static com.facebook.presto.spi.StandardErrorCode.INVALID_CAST_ARGUMENT;
import static com.facebook.presto.spi.function.OperatorType.CAST;
import static com.facebook.presto.spi.type.Decimals.longTenToNth;
import static com.facebook.presto.spi.type.Decimals.overflows;
import static com.facebook.presto.spi.type.StandardTypes.DECIMAL;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.spi.type.UnscaledDecimal128Arithmetic.overflows;
import static com.facebook.presto.spi.type.UnscaledDecimal128Arithmetic.rescale;
import static com.facebook.presto.spi.type.UnscaledDecimal128Arithmetic.unscaledDecimal;
import static com.facebook.presto.spi.type.UnscaledDecimal128Arithmetic.unscaledDecimalToBigInteger;
import static com.facebook.presto.spi.type.UnscaledDecimal128Arithmetic.unscaledDecimalToUnscaledLongUnsafe;
import static java.lang.String.format;
public final class DecimalToDecimalCasts
{
public static final Signature SIGNATURE = Signature.builder()
.kind(SCALAR)
.operatorType(CAST)
.typeVariableConstraints(withVariadicBound("F", DECIMAL), withVariadicBound("T", DECIMAL))
.argumentTypes(parseTypeSignature("F"))
.returnType(parseTypeSignature("T"))
.build();
// TODO: filtering mechanism could be used to return NoOp method when only precision is increased
public static final SqlScalarFunction DECIMAL_TO_DECIMAL_CAST = SqlScalarFunction.builder(DecimalToDecimalCasts.class)
.signature(SIGNATURE)
.implementation(b -> b
.methods("shortToShortCast")
.withExtraParameters((context) -> {
DecimalType argumentType = (DecimalType) context.getType("F");
DecimalType resultType = (DecimalType) context.getType("T");
long rescale = longTenToNth(Math.abs(resultType.getScale() - argumentType.getScale()));
return ImmutableList.of(
argumentType.getPrecision(), argumentType.getScale(),
resultType.getPrecision(), resultType.getScale(),
rescale, rescale / 2);
})
)
.implementation(b -> b
.methods("shortToLongCast", "longToShortCast", "longToLongCast")
.withExtraParameters((context) -> {
DecimalType argumentType = (DecimalType) context.getType("F");
DecimalType resultType = (DecimalType) context.getType("T");
return ImmutableList.of(
argumentType.getPrecision(), argumentType.getScale(),
resultType.getPrecision(), resultType.getScale());
})
)
.build();
private DecimalToDecimalCasts() {}
@UsedByGeneratedCode
public static long shortToShortCast(
long value,
long sourcePrecision,
long sourceScale,
long resultPrecision,
long resultScale,
long scalingFactor,
long halfOfScalingFactor)
{
long returnValue;
if (resultScale >= sourceScale) {
returnValue = value * scalingFactor;
}
else {
returnValue = value / scalingFactor;
if (value >= 0) {
if (value % scalingFactor >= halfOfScalingFactor) {
returnValue++;
}
}
else {
if (value % scalingFactor <= -halfOfScalingFactor) {
returnValue--;
}
}
}
if (overflows(returnValue, (int) resultPrecision)) {
throw throwCastException(value, sourcePrecision, sourceScale, resultPrecision, resultScale);
}
return returnValue;
}
@UsedByGeneratedCode
public static Slice shortToLongCast(
long value,
long sourcePrecision,
long sourceScale,
long resultPrecision,
long resultScale)
{
return longToLongCast(unscaledDecimal(value), sourcePrecision, sourceScale, resultPrecision, resultScale);
}
@UsedByGeneratedCode
public static long longToShortCast(
Slice value,
long sourcePrecision,
long sourceScale,
long resultPrecision,
long resultScale)
{
return unscaledDecimalToUnscaledLongUnsafe(longToLongCast(value, sourcePrecision, sourceScale, resultPrecision, resultScale));
}
@UsedByGeneratedCode
public static Slice longToLongCast(
Slice value,
long sourcePrecision,
long sourceScale,
long resultPrecision,
long resultScale)
{
try {
Slice result = rescale(value, (int) (resultScale - sourceScale));
if (overflows(result, (int) resultPrecision)) {
throw throwCastException(unscaledDecimalToBigInteger(value), sourcePrecision, sourceScale, resultPrecision, resultScale);
}
return result;
}
catch (ArithmeticException e) {
throw throwCastException(unscaledDecimalToBigInteger(value), sourcePrecision, sourceScale, resultPrecision, resultScale);
}
}
private static PrestoException throwCastException(long value, long sourcePrecision, long sourceScale, long resultPrecision, long resultScale)
{
return new PrestoException(INVALID_CAST_ARGUMENT, format("Cannot cast DECIMAL '%s' to DECIMAL(%d, %d)",
Decimals.toString(value, (int) sourceScale),
resultPrecision, resultScale));
}
private static PrestoException throwCastException(BigInteger value, long sourcePrecision, long sourceScale, long resultPrecision, long resultScale)
{
return new PrestoException(INVALID_CAST_ARGUMENT, format("Cannot cast DECIMAL '%s' to DECIMAL(%d, %d)",
Decimals.toString(value, (int) sourceScale),
resultPrecision, resultScale));
}
}