/*
 * 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.operator.aggregation.state;

import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.function.AccumulatorState;
import com.facebook.presto.spi.function.AccumulatorStateMetadata;
import com.facebook.presto.spi.type.Type;

@AccumulatorStateMetadata(stateSerializerClass = TriStateBooleanStateSerializer.class)
public interface TriStateBooleanState
        extends AccumulatorState
{
    byte NULL_VALUE = 0;
    byte TRUE_VALUE = 1;
    byte FALSE_VALUE = -1;

    byte getByte();

    void setByte(byte value);

    static void write(Type type, TriStateBooleanState state, BlockBuilder out)
    {
        if (state.getByte() == NULL_VALUE) {
            out.appendNull();
        }
        else {
            type.writeBoolean(out, state.getByte() == TRUE_VALUE);
        }
    }
}