/*
* 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.jdbc.internal.type.block;
import com.facebook.presto.jdbc.internal.type.type.TypeManager;
import com.facebook.presto.jdbc.internal.airlift.slice.Slice;
import com.facebook.presto.jdbc.internal.airlift.slice.SliceInput;
import com.facebook.presto.jdbc.internal.airlift.slice.SliceOutput;
import static com.facebook.presto.jdbc.internal.type.block.EncoderUtil.decodeNullBits;
import static com.facebook.presto.jdbc.internal.type.block.EncoderUtil.encodeNullsAsBits;
public class FixedWidthBlockEncoding
implements BlockEncoding
{
public static final BlockEncodingFactory<FixedWidthBlockEncoding> FACTORY = new FixedWidthBlockEncodingFactory();
private static final String NAME = "FIXED_WIDTH";
private final int fixedSize;
public FixedWidthBlockEncoding(int fixedSize)
{
if (fixedSize < 0) {
throw new IllegalArgumentException("fixedSize is negative");
}
this.fixedSize = fixedSize;
}
@Override
public String getName()
{
return NAME;
}
public int getFixedSize()
{
return fixedSize;
}
@Override
public void writeBlock(SliceOutput sliceOutput, Block block)
{
AbstractFixedWidthBlock fixedWidthBlock = (AbstractFixedWidthBlock) block;
int positionCount = fixedWidthBlock.getPositionCount();
sliceOutput.appendInt(positionCount);
// write null bits 8 at a time
encodeNullsAsBits(sliceOutput, fixedWidthBlock);
// write last null bits
if ((positionCount & 0b111) > 0) {
byte value = 0;
int mask = 0b1000_0000;
for (int position = positionCount & ~0b111; position < positionCount; position++) {
value |= fixedWidthBlock.isNull(position) ? mask : 0;
mask >>>= 1;
}
sliceOutput.appendByte(value);
}
Slice slice = fixedWidthBlock.getRawSlice();
sliceOutput
.appendInt(slice.length())
.writeBytes(slice);
}
@Override
public Block readBlock(SliceInput sliceInput)
{
int positionCount = sliceInput.readInt();
boolean[] valueIsNull = decodeNullBits(sliceInput, positionCount);
int blockSize = sliceInput.readInt();
Slice slice = sliceInput.readSlice(blockSize);
return new FixedWidthBlock(fixedSize, positionCount, slice, valueIsNull);
}
public static class FixedWidthBlockEncodingFactory
implements BlockEncodingFactory<FixedWidthBlockEncoding>
{
@Override
public String getName()
{
return NAME;
}
@Override
public FixedWidthBlockEncoding readEncoding(TypeManager manager, BlockEncodingSerde serde, SliceInput input)
{
int entrySize = input.readInt();
return new FixedWidthBlockEncoding(entrySize);
}
@Override
public void writeEncoding(BlockEncodingSerde serde, SliceOutput output, FixedWidthBlockEncoding blockEncoding)
{
output.writeInt(blockEncoding.getFixedSize());
}
}
}