Package com.facebook.presto.serde

Source Code of com.facebook.presto.serde.UncompressedEncoder

/*
* 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.serde;

import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.block.BlockBuilderStatus;
import com.facebook.presto.spi.block.BlockCursor;
import com.facebook.presto.spi.block.BlockEncoding;
import io.airlift.slice.SliceOutput;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

public class UncompressedEncoder
        implements Encoder
{
    private final SliceOutput sliceOutput;

    private BlockEncoding encoding;
    private BlockBuilder blockBuilder;
    private boolean finished;

    public UncompressedEncoder(SliceOutput sliceOutput)
    {
        this.sliceOutput = checkNotNull(sliceOutput, "sliceOutput is null");
    }

    @Override
    public Encoder append(Block block)
    {
        checkNotNull(block, "block is null");
        checkState(!finished, "already finished");

        if (encoding == null) {
            blockBuilder = block.getType().createBlockBuilder(new BlockBuilderStatus());
            encoding = blockBuilder.getEncoding();
        }
        BlockCursor cursor = block.cursor();
        while (cursor.advanceNextPosition()) {
            cursor.appendTo(blockBuilder);
            if (blockBuilder.isFull()) {
                writeBlock();
            }
        }

        return this;
    }

    @Override
    public BlockEncoding finish()
    {
        checkState(encoding != null, "nothing appended");
        checkState(!finished, "already finished");
        finished = true;

        if (!blockBuilder.isEmpty()) {
            writeBlock();
        }
        return encoding;
    }

    private void writeBlock()
    {
        Block block = blockBuilder.build();
        encoding.writeBlock(sliceOutput, block);
        blockBuilder = block.getType().createBlockBuilder(new BlockBuilderStatus());
    }
}
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