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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.rcfile.binary;
import io.airlift.slice.Slice;
import io.airlift.slice.SliceOutput;
import io.airlift.slice.Slices;
import io.trino.rcfile.ColumnData;
import io.trino.rcfile.EncodeOutput;
import io.trino.spi.block.Block;
import io.trino.spi.block.BlockBuilder;
import io.trino.spi.type.DecimalType;
import io.trino.spi.type.Int128;
import io.trino.spi.type.Int128Math;
import io.trino.spi.type.Type;
import java.math.BigInteger;
import static com.google.common.base.Preconditions.checkState;
import static io.trino.rcfile.RcFileDecoderUtils.decodeVIntSize;
import static io.trino.rcfile.RcFileDecoderUtils.readVInt;
import static io.trino.rcfile.RcFileDecoderUtils.writeVInt;
import static io.trino.spi.type.Decimals.isShortDecimal;
import static io.trino.spi.type.Decimals.rescale;
import static java.lang.Math.toIntExact;
public class DecimalEncoding
implements BinaryColumnEncoding
{
private static final int BITS_IN_BYTE = 8;
private static final int BYTES_IN_LONG_DECIMAL = 16;
private final DecimalType type;
private final byte[] resultBytes = new byte[BYTES_IN_LONG_DECIMAL];
private final Slice resultSlice = Slices.wrappedBuffer(resultBytes);
public DecimalEncoding(Type type)
{
this.type = (DecimalType) type;
}
@Override
public void encodeColumn(Block block, SliceOutput output, EncodeOutput encodeOutput)
{
for (int position = 0; position < block.getPositionCount(); position++) {
if (!block.isNull(position)) {
encodeValueInto(block, position, output);
}
encodeOutput.closeEntry();
}
}
@Override
public void encodeValueInto(Block block, int position, SliceOutput output)
{
if (isShortDecimal(type)) {
writeLong(output, type.getLong(block, position));
}
else {
writeSlice(output, block, position);
}
}
@Override
public Block decodeColumn(ColumnData columnData)
{
int size = columnData.rowCount();
BlockBuilder builder = type.createBlockBuilder(null, size);
Slice slice = columnData.getSlice();
for (int i = 0; i < size; i++) {
int offset = columnData.getOffset(i);
int length = columnData.getLength(i);
if (length == 0) {
builder.appendNull();
}
else if (isShortDecimal(type)) {
type.writeLong(builder, parseLong(slice, offset));
}
else {
type.writeObject(builder, parseSlice(slice, offset));
}
}
return builder.build();
}
@Override
public int getValueOffset(Slice slice, int offset)
{
return 0;
}
@Override
public int getValueLength(Slice slice, int offset)
{
// first vint is scale
int scaleLength = decodeVIntSize(slice, offset);
// second vint is data length
int dataLengthLength = decodeVIntSize(slice, offset + scaleLength);
int dataLength = toIntExact(readVInt(slice, offset + scaleLength));
return scaleLength + dataLengthLength + dataLength;
}
@Override
public void decodeValueInto(BlockBuilder builder, Slice slice, int offset, int length)
{
if (isShortDecimal(type)) {
type.writeLong(builder, parseLong(slice, offset));
}
else {
type.writeObject(builder, parseSlice(slice, offset));
}
}
private long parseLong(Slice slice, int offset)
{
// first vint is scale
int scale = toIntExact(readVInt(slice, offset));
offset += decodeVIntSize(slice, offset);
// second vint is length
int length = toIntExact(readVInt(slice, offset));
offset += decodeVIntSize(slice, offset);
checkState(length <= 8);
// reset the results buffer
if (slice.getByte(offset) >= 0) {
resultSlice.setLong(0, 0L);
}
else {
resultSlice.setLong(0, 0xFFFF_FFFF_FFFF_FFFFL);
}
resultSlice.setBytes(8 - length, slice, offset, length);
long value = Long.reverseBytes(resultSlice.getLong(0));
if (scale != type.getScale()) {
return rescale(value, scale, type.getScale());
}
return value;
}
private Int128 parseSlice(Slice slice, int offset)
{
// first vint is scale
int scale = toIntExact(readVInt(slice, offset));
offset += decodeVIntSize(slice, offset);
// second vint is length
int length = toIntExact(readVInt(slice, offset));
offset += decodeVIntSize(slice, offset);
checkState(length <= BYTES_IN_LONG_DECIMAL);
// reset the results buffer
if (slice.getByte(offset) >= 0) {
resultSlice.setLong(0, 0L);
resultSlice.setLong(8, 0L);
}
else {
resultSlice.setLong(0, 0xFFFF_FFFF_FFFF_FFFFL);
resultSlice.setLong(8, 0xFFFF_FFFF_FFFF_FFFFL);
}
resultSlice.setBytes(BYTES_IN_LONG_DECIMAL - length, slice, offset, length);
Int128 result = Int128.fromBigEndian(resultBytes);
return Int128Math.rescale(result, type.getScale() - scale);
}
private void writeLong(SliceOutput output, long value)
{
// first vint is scale
writeVInt(output, type.getScale());
// second vint is length
int length = getWriteByteCount(value);
writeVInt(output, length);
// write value (big endian)
for (int i = length - 1; i >= 0; i--) {
output.writeByte((int) (value >> (i * 8)));
}
}
private static int getWriteByteCount(long value)
{
// if the value is negative flip the bits, so we can always count leading zero bytes
if (value < 0) {
value = ~value;
}
// count number of leading zero bytes
return (Long.SIZE - Long.numberOfLeadingZeros(value)) / BITS_IN_BYTE + 1;
}
private void writeSlice(SliceOutput output, Block block, int position)
{
// first vint is scale
writeVInt(output, type.getScale());
// second vint is length
// todo get rid of BigInteger
BigInteger decimal = ((Int128) type.getObject(block, position)).toBigInteger();
byte[] decimalBytes = decimal.toByteArray();
writeVInt(output, decimalBytes.length);
// write value (big endian)
// NOTE: long decimals are stored in a slice in big endian encoding
for (byte decimalByte : decimalBytes) {
output.write(decimalByte);
}
}
}
