org.apache.lucene.util.automaton.ByteRunAutomaton.java Source code

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Here is the source code for org.apache.lucene.util.automaton.ByteRunAutomaton.java

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/*
 * 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.automaton;

/**
 * Automaton representation for matching UTF-8 byte[].
 */
public class ByteRunAutomaton extends RunAutomaton {

    /** Converts incoming automaton to byte-based (UTF32ToUTF8) first */
    public ByteRunAutomaton(Automaton a) {
        this(a, false, Operations.DEFAULT_MAX_DETERMINIZED_STATES);
    }

    /** expert: if isBinary is true, the input is already byte-based */
    public ByteRunAutomaton(Automaton a, boolean isBinary, int maxDeterminizedStates) {
        super(isBinary ? a : new UTF32ToUTF8().convert(a), 256, maxDeterminizedStates);
    }

    /**
     * Returns true if the given byte array is accepted by this automaton
     */
    public boolean run(byte[] s, int offset, int length) {
        int p = 0;
        int l = offset + length;
        for (int i = offset; i < l; i++) {
            p = step(p, s[i] & 0xFF);
            if (p == -1)
                return false;
        }
        return accept[p];
    }
}