io.trino.operator.aggregation.state.LongDecimalWithOverflowStateSerializer Maven / Gradle / Ivy

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/*
 * 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 io.trino.operator.aggregation.state;

import io.airlift.slice.Slice;
import io.airlift.slice.Slices;
import io.trino.spi.block.Block;
import io.trino.spi.block.BlockBuilder;
import io.trino.spi.block.VariableWidthBlock;
import io.trino.spi.function.AccumulatorStateSerializer;
import io.trino.spi.type.Type;

import static io.trino.spi.type.VarbinaryType.VARBINARY;

public class LongDecimalWithOverflowStateSerializer
        implements AccumulatorStateSerializer
{
    @Override
    public Type getSerializedType()
    {
        return VARBINARY;
    }

    @Override
    public void serialize(LongDecimalWithOverflowState state, BlockBuilder out)
    {
        if (!state.isNotNull()) {
            out.appendNull();
            return;
        }

        long overflow = state.getOverflow();
        long[] decimal = state.getDecimalArray();
        int offset = state.getDecimalArrayOffset();
        Slice buffer = Slices.allocate(Long.BYTES * 3);
        long low = decimal[offset + 1];
        long high = decimal[offset];
        buffer.setLong(0, low);
        buffer.setLong(Long.BYTES, high);
        buffer.setLong(Long.BYTES * 2, overflow);
        // if high == 0 and overflow == 0 we only write low (bufferLength = 1)
        // if high != 0 and overflow == 0 we write both low and high (bufferLength = 2)
        // if overflow != 0 we write all values (bufferLength = 3)
        int decimalsCount = 1 + (high == 0 ? 0 : 1);
        int bufferLength = overflow == 0 ? decimalsCount : 3;
        VARBINARY.writeSlice(out, buffer, 0, bufferLength * Long.BYTES);
    }

    @Override
    public void deserialize(Block block, int index, LongDecimalWithOverflowState state)
    {
        if (block.isNull(index)) {
            return;
        }

        index = block.getUnderlyingValuePosition(index);
        block = block.getUnderlyingValueBlock();
        VariableWidthBlock variableWidthBlock = (VariableWidthBlock) block;
        Slice slice = variableWidthBlock.getRawSlice();
        int sliceOffset = variableWidthBlock.getRawSliceOffset(index);
        int sliceLength = variableWidthBlock.getSliceLength(index);

        long[] decimal = state.getDecimalArray();
        int offset = state.getDecimalArrayOffset();

        long low = slice.getLong(sliceOffset);
        long high = 0;
        long overflow = 0;

        switch (sliceLength) {
            case Long.BYTES * 3:
                overflow = slice.getLong(sliceOffset + Long.BYTES * 2);
                // fall through
            case Long.BYTES * 2:
                high = slice.getLong(sliceOffset + Long.BYTES);
        }

        decimal[offset + 1] = low;
        decimal[offset] = high;
        state.setOverflow(overflow);
        state.setNotNull();
    }
}