/**
* 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.common.funcs;
import com.foundationdb.server.explain.CompoundExplainer;
import com.foundationdb.server.explain.ExplainContext;
import com.foundationdb.server.explain.Label;
import com.foundationdb.server.explain.PrimitiveExplainer;
import com.foundationdb.server.types.LazyList;
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.aksql.aktypes.AkBool;
import com.foundationdb.server.types.value.ValueSource;
import com.foundationdb.server.types.value.ValueTarget;
import com.foundationdb.server.types.texpressions.Constantness;
import com.foundationdb.server.types.texpressions.TInputSetBuilder;
import com.foundationdb.server.types.texpressions.TScalarBase;
import com.foundationdb.server.types.texpressions.TPreparedExpression;
import com.google.common.base.Objects;
import java.util.List;
public class BoolLogic extends TScalarBase
{
public static final TScalar BINARIES[] = new TScalar[Op.values().length];
private static final int OUT_VAL = 0;
static
{
Op op[] = Op.values();
for (int n = 0; n < op.length; ++n)
BINARIES[n] = new BoolLogic(op[n]);
}
public static final TScalar NOT = new TScalarBase() {
@Override
protected void buildInputSets(TInputSetBuilder builder) {
builder.covers(AkBool.INSTANCE, 0);
}
@Override
protected void doEvaluate(TExecutionContext context, LazyList<? extends ValueSource> inputs,
ValueTarget output) {
output.putBool(!inputs.get(0).getBoolean());
}
@Override
public String displayName() {
return "NOT";
}
@Override
public TOverloadResult resultType() {
return TOverloadResult.fixed(AkBool.INSTANCE);
}
};
private static enum Op
{
AND(Boolean.FALSE),
OR(Boolean.TRUE),
XOR(null)
{
@Override
boolean evaluate(boolean first, boolean second) {
return first ^ second;
}
};
private Op(Boolean contaminant) {
this.contaminant = contaminant;
}
private final Boolean contaminant;
boolean evaluate(boolean first, boolean second) {
// this implementation works for both AND and OR.
// Since AND's contaminant is FALSE, if we get to this method we know first is true.
// In that case, the result is true iff second is true.
// Likewise, since OR's contaminant is TRUE, if we get to this method we know first is false, and
// the result is true iff second is true.
// This means we'll only ever need to override this method for XOR. Since that's a relatively rare
// method, hopefully we'll never need it and the JIT can optimize assuming that this method is not
// overridden.
return second;
}
}
private final Op op;
BoolLogic (Op op)
{
this.op = op;
}
@Override
public CompoundExplainer getExplainer(ExplainContext context, List<? extends TPreparedExpression> inputs, TInstance resultType)
{
CompoundExplainer ex = super.getExplainer(context, inputs, resultType);
ex.addAttribute(Label.INFIX_REPRESENTATION, PrimitiveExplainer.getInstance(op.name()));
return ex;
}
@Override
protected Constantness constness(TPreptimeContext context, int inputIndex, LazyList<? extends TPreptimeValue> values) {
// The expression is const iff either argument is a const whose value is equal to op.contaminant.
// The first argument can never make the expression non-const (though it can make it const), and the second
// argument can never leave the constness unknown.
ValueSource preptimeValue = constSource(values, inputIndex);
if ((preptimeValue != null) && Objects.equal(op.contaminant, getBoolean(preptimeValue)))
{
context.set(OUT_VAL, op.contaminant);
return Constantness.CONST;
}
return (inputIndex == 0) ? Constantness.UNKNOWN : Constantness.NOT_CONST;
}
@Override
protected boolean nullContaminates(int inputIndex) {
return false; // we'll deal with contamination ourselves
}
@Override
protected void doEvaluate(TExecutionContext context, LazyList<? extends ValueSource> inputs, ValueTarget output)
{
Object outVal = context.preptimeObjectAt(OUT_VAL);
if (outVal != null)
{
output.putBool((Boolean)outVal);
return;
}
Boolean firstArg = getBoolean(inputs, 0);
final Boolean result;
if (Objects.equal(op.contaminant, firstArg)) {
result = firstArg;
}
else {
// need to look at the second arg
Boolean secondArg = getBoolean(inputs, 1);
if (Objects.equal(op.contaminant, secondArg)) {
result = secondArg;
}
else if ( (firstArg == null) || (secondArg == null) ) {
result = null;
}
else {
result = op.evaluate(firstArg, secondArg);
}
}
if (result == null)
output.putNull();
else
output.putBool(result);
}
private Boolean getBoolean(LazyList<? extends ValueSource> inputs, int i) {
return getBoolean(inputs.get(i));
}
private Boolean getBoolean(ValueSource firstInput) {
return firstInput.isNull() ? null : firstInput.getBoolean();
}
@Override
protected void buildInputSets(TInputSetBuilder builder)
{
builder.covers(AkBool.INSTANCE, 0, 1);
}
@Override
public String displayName()
{
return op.name();
}
@Override
public TOverloadResult resultType()
{
return TOverloadResult.fixed(AkBool.INSTANCE);
}
}