de.faustedition.collation.DiffCollator.java Source code

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Here is the source code for de.faustedition.collation.DiffCollator.java

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/*
 * Copyright (c) 2014 Faust Edition development team.
 *
 * This file is part of the Faust Edition.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.faustedition.collation;

import com.google.common.collect.Iterables;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

public class DiffCollator {
    public List<Alignment> align(Iterable<Token> a, Iterable<Token> b) {
        final Token[] at = Iterables.toArray(a, Token.class);
        final Token[] bt = Iterables.toArray(b, Token.class);
        int ai = 0;
        int bi = 0;

        final List<Alignment> alignments = new ArrayList<Alignment>(Math.max(at.length, bt.length));
        final Iterator<Difference> diffIterator = new Diff<Token>(at, bt, DEFAULT_MATCHER).diff().iterator();

        Difference diff = (diffIterator.hasNext() ? diffIterator.next() : null);
        do {
            if (diff == null) {
                alignments.add(new Alignment(0, at[ai++], bt[bi++]));
                continue;
            }

            if (ai < diff.getDeletedStart() && bi < diff.getAddedStart()) {
                alignments.add(new Alignment(0, at[ai++], bt[bi++]));
                continue;
            }

            if (ai <= diff.getDeletedEnd() && bi <= diff.getAddedEnd()) {
                alignments.add(new Alignment(1, at[ai++], bt[bi++]));
                continue;
            }

            if (ai <= diff.getDeletedEnd() && bi >= diff.getAddedEnd()) {
                alignments.add(new Alignment(1, at[ai++], null));
                continue;
            }

            if (bi <= diff.getAddedEnd() && ai >= diff.getDeletedEnd()) {
                alignments.add(new Alignment(1, null, bt[bi++]));
                continue;
            }

            diff = (diffIterator.hasNext() ? diffIterator.next() : null);
        } while (ai < at.length || bi < bt.length);

        return alignments;
    }

    private static final Comparator<Token> DEFAULT_MATCHER;

    static {
        DEFAULT_MATCHER = new Comparator<Token>() {

            @Override
            public int compare(Token o1, Token o2) {
                return o1.text().trim().compareToIgnoreCase(o2.text().trim());
            }
        };
    }
}