Subversion Repositories mkgmap

/*
 * Copyright (C) 2012.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 or
 * version 2 as published by the Free Software Foundation.
 *
 * 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
 * General Public License for more details.
 */
package uk.me.parabola.imgfmt.app.mdr;

import java.nio.charset.Charset;
import java.text.Collator;
import java.util.ArrayList;
import java.util.List;

import uk.me.parabola.imgfmt.app.ImgFileWriter;
import uk.me.parabola.imgfmt.app.Label;
import uk.me.parabola.imgfmt.app.srt.Sort;

/**
 * Holds an index of name prefixes to record numbers.
 *
 * Extends MdrSection, although is sometimes a subsection, not an actual section.
 *
 * @author Steve Ratcliffe
 */
public class PrefixIndex extends MdrSection {
        private final int prefixLength;
        private int maxIndex;

        // We use mdr8record for all similar indexes.
        private final List<Mdr8Record> index = new ArrayList<Mdr8Record>();

        /**
         * Sets the config and the prefix length for this index.
         *
         * Prefix length may differ depending on the amount of data, so will have
         * to deal with that when it happens.
         *
         * @param config Configuration for sorting methods.
         * @param prefixLength The prefix length for this index.
         */
        public PrefixIndex(MdrConfig config, int prefixLength) {
                setConfig(config);
                this.prefixLength = prefixLength;
        }

        /**
         * We can create an index for any type that has a name.
         * @param list A list of items that have a name.
         */
        public void createFromList(List<? extends NamedRecord> list, boolean grouped) {
                maxIndex = list.size();

                // Prefixes are equal based on the primary unaccented character, so
                // we need to use the collator to test for equality and not equals().
                Sort sort = getConfig().getSort();
                Collator collator = sort.getCollator();
                collator.setStrength(Collator.PRIMARY);

                String lastCountryName = null;
                String lastPrefix = "";
                int inRecord = 0;  // record number of the input list
                int outRecord = 0; // record number of the index
                for (NamedRecord r : list) {
                        inRecord++;

                        String prefix = getPrefix(r.getName());
                        if (collator.compare(prefix, lastPrefix) != 0) {
                                outRecord++;

                                Mdr8Record ind = new Mdr8Record();
                                ind.setPrefix(prefix);
                                ind.setRecordNumber(inRecord);
                                index.add(ind);

                                lastPrefix = prefix;
                               
                                if (grouped) {
                                        // Peek into the real type to support the mdr17 feature of indexes sorted on country.
                                        Mdr5Record city = ((Mdr7Record) r).getCity();
                                        if (city != null) {
                                                String countryName = city.getCountryName();
                                                if (!countryName.equals(lastCountryName)) {
                                                        city.getMdrCountry().getMdr29().setMdr17(outRecord);
                                                        lastCountryName = countryName;
                                                }
                                        }
                                }
                        }
                }
        }
       
        public void createFromList(List<? extends NamedRecord> list) {
                createFromList(list, false);
        }

        /**
         * Write the section or subsection.
         */
        public void writeSectData(ImgFileWriter writer) {
                int size = numberToPointerSize(maxIndex);
                Charset charset = getConfig().getSort().getCharset();
                for (Mdr8Record s : index) {
                        writer.put(s.getPrefix().getBytes(charset), 0, prefixLength);
                        putN(writer, size, s.getRecordNumber());
                }
        }

        public int getItemSize() {
                return prefixLength + numberToPointerSize(maxIndex);
        }

        protected int numberOfItems() {
                return index.size();
        }

        /**
         * Get the prefix of the name at the given record.
         * If the name is shorter than the prefix length, then it padded with nul characters.
         * So it can be longer than the input string.
         *
         * @param in The name to truncate.
         * @return A string prefixLength characters long, consisting of the initial
         * prefix of name and padded with nulls if necessary to make up the length.
         */
        private String getPrefix(String in) {
                String name = Label.stripGarminCodes(in);
                if (prefixLength > name.length()) {
                        StringBuilder sb = new StringBuilder(name);
                        while (sb.length() < prefixLength)
                                sb.append('\0');
                        return sb.toString();
                }
                return name.substring(0, prefixLength);
        }

        public int getPrefixLength() {
                return prefixLength;
        }
}