org.h2.expression.function.MathFunction2 Maven / Gradle / Ivy
/*
* Copyright 2004-2022 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression.function;
import org.h2.engine.SessionLocal;
import org.h2.expression.Expression;
import org.h2.expression.TypedValueExpression;
import org.h2.message.DbException;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
import org.h2.value.ValueDouble;
/**
* A math function with two arguments and DOUBLE PRECISION result.
*/
public final class MathFunction2 extends Function2 {
/**
* ATAN2() (non-standard).
*/
public static final int ATAN2 = 0;
/**
* LOG().
*/
public static final int LOG = ATAN2 + 1;
/**
* POWER().
*/
public static final int POWER = LOG + 1;
private static final String[] NAMES = { //
"ATAN2", "LOG", "POWER" //
};
private final int function;
public MathFunction2(Expression arg1, Expression arg2, int function) {
super(arg1, arg2);
this.function = function;
}
@Override
public Value getValue(SessionLocal session, Value v1, Value v2) {
double d1 = v1.getDouble(), d2 = v2.getDouble();
switch (function) {
case ATAN2:
d1 = Math.atan2(d1, d2);
break;
case LOG: {
if (session.getMode().swapLogFunctionParameters) {
double t = d2;
d2 = d1;
d1 = t;
}
if (d2 <= 0) {
throw DbException.getInvalidValueException("LOG() argument", d2);
}
if (d1 <= 0 || d1 == 1) {
throw DbException.getInvalidValueException("LOG() base", d1);
}
if (d1 == Math.E) {
d1 = Math.log(d2);
} else if (d1 == 10d) {
d1 = Math.log10(d2);
} else {
d1 = Math.log(d2) / Math.log(d1);
}
break;
}
case POWER:
d1 = Math.pow(d1, d2);
break;
default:
throw DbException.getInternalError("function=" + function);
}
return ValueDouble.get(d1);
}
@Override
public Expression optimize(SessionLocal session) {
left = left.optimize(session);
right = right.optimize(session);
type = TypeInfo.TYPE_DOUBLE;
if (left.isConstant() && right.isConstant()) {
return TypedValueExpression.getTypedIfNull(getValue(session), type);
}
return this;
}
@Override
public String getName() {
return NAMES[function];
}
}