org.apache.hadoop.hive.ql.io.orc.BitFieldWriter Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.hive.ql.io.orc;
import java.io.IOException;
class BitFieldWriter {
private RunLengthByteWriter output;
private final int bitSize;
private byte current = 0;
private int bitsLeft = 8;
BitFieldWriter(PositionedOutputStream output,
int bitSize) throws IOException {
this.output = new RunLengthByteWriter(output);
this.bitSize = bitSize;
}
private void writeByte() throws IOException {
output.write(current);
current = 0;
bitsLeft = 8;
}
void flush() throws IOException {
if (bitsLeft != 8) {
writeByte();
}
output.flush();
}
void write(int value) throws IOException {
int bitsToWrite = bitSize;
while (bitsToWrite > bitsLeft) {
// add the bits to the bottom of the current word
current |= value >>> (bitsToWrite - bitsLeft);
// subtract out the bits we just added
bitsToWrite -= bitsLeft;
// zero out the bits above bitsToWrite
value &= (1 << bitsToWrite) - 1;
writeByte();
}
bitsLeft -= bitsToWrite;
current |= value << bitsLeft;
if (bitsLeft == 0) {
writeByte();
}
}
void getPosition(PositionRecorder recorder) throws IOException {
output.getPosition(recorder);
recorder.addPosition(8 - bitsLeft);
}
}