/*
* 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.lucene.util.packed;
import java.io.IOException;
import org.apache.lucene.store.DataOutput;
/**
* A {@link DataOutput} wrapper to write unaligned, variable-length packed
* integers.
* @see PackedDataInput
* @lucene.internal
*/
public final class PackedDataOutput {
final DataOutput out;
long current;
int remainingBits;
/**
* Create a new instance that wraps <code>out</code>.
*/
public PackedDataOutput(DataOutput out) {
this.out = out;
current = 0;
remainingBits = 8;
}
/**
* Write a value using exactly <code>bitsPerValue</code> bits.
*/
public void writeLong(long value, int bitsPerValue) throws IOException {
assert bitsPerValue == 64 || (value >= 0 && value <= PackedInts.maxValue(bitsPerValue));
while (bitsPerValue > 0) {
if (remainingBits == 0) {
out.writeByte((byte) current);
current = 0L;
remainingBits = 8;
}
final int bits = Math.min(remainingBits, bitsPerValue);
current = current | (((value >>> (bitsPerValue - bits)) & ((1L << bits) - 1)) << (remainingBits - bits));
bitsPerValue -= bits;
remainingBits -= bits;
}
}
/**
* Flush pending bits to the underlying {@link DataOutput}.
*/
public void flush() throws IOException {
if (remainingBits < 8) {
out.writeByte((byte) current);
}
remainingBits = 8;
current = 0L;
}
}