| /* |
| * 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.fst; |
| |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.store.DataInput; |
| import org.apache.lucene.store.DataOutput; |
| import org.apache.lucene.util.RamUsageEstimator; |
| import org.apache.lucene.util.SuppressForbidden; |
| |
| /** |
| * An FST {@link Outputs} implementation where each output |
| * is a non-negative long value. |
| * |
| * @lucene.experimental |
| */ |
| @SuppressForbidden(reason = "Uses a Long instance as a marker") |
| public final class PositiveIntOutputs extends Outputs<Long> { |
| |
| private final static Long NO_OUTPUT = new Long(0); |
| |
| private final static PositiveIntOutputs singleton = new PositiveIntOutputs(); |
| |
| private PositiveIntOutputs() { |
| } |
| |
| public static PositiveIntOutputs getSingleton() { |
| return singleton; |
| } |
| |
| @Override |
| public Long common(Long output1, Long output2) { |
| assert valid(output1); |
| assert valid(output2); |
| if (output1 == NO_OUTPUT || output2 == NO_OUTPUT) { |
| return NO_OUTPUT; |
| } else { |
| assert output1 > 0; |
| assert output2 > 0; |
| return Math.min(output1, output2); |
| } |
| } |
| |
| @Override |
| public Long subtract(Long output, Long inc) { |
| assert valid(output); |
| assert valid(inc); |
| assert output >= inc; |
| |
| if (inc == NO_OUTPUT) { |
| return output; |
| } else if (output.equals(inc)) { |
| return NO_OUTPUT; |
| } else { |
| return output - inc; |
| } |
| } |
| |
| @Override |
| public Long add(Long prefix, Long output) { |
| assert valid(prefix); |
| assert valid(output); |
| if (prefix == NO_OUTPUT) { |
| return output; |
| } else if (output == NO_OUTPUT) { |
| return prefix; |
| } else { |
| return prefix + output; |
| } |
| } |
| |
| @Override |
| public void write(Long output, DataOutput out) throws IOException { |
| assert valid(output); |
| out.writeVLong(output); |
| } |
| |
| @Override |
| public Long read(DataInput in) throws IOException { |
| long v = in.readVLong(); |
| if (v == 0) { |
| return NO_OUTPUT; |
| } else { |
| return v; |
| } |
| } |
| |
| private boolean valid(Long o) { |
| assert o != null; |
| assert o == NO_OUTPUT || o > 0: "o=" + o; |
| return true; |
| } |
| |
| @Override |
| public Long getNoOutput() { |
| return NO_OUTPUT; |
| } |
| |
| @Override |
| public String outputToString(Long output) { |
| return output.toString(); |
| } |
| |
| @Override |
| public String toString() { |
| return "PositiveIntOutputs"; |
| } |
| |
| @Override |
| public long ramBytesUsed(Long output) { |
| return RamUsageEstimator.sizeOf(output); |
| } |
| } |