Subversion Repositories mkgmap

/*
 * Copyright (C) 2010.
 *
 * 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.srt;

import uk.me.parabola.imgfmt.ReadFailedException;
import uk.me.parabola.imgfmt.app.CommonHeader;
import uk.me.parabola.imgfmt.app.ImgFileReader;
import uk.me.parabola.imgfmt.app.ImgFileWriter;
import uk.me.parabola.imgfmt.app.Section;
import uk.me.parabola.imgfmt.app.SectionWriter;

/**
 * The header of the SRT file.
 *
 * This file determines the sort order of the label characters.
 *
 * @author Steve Ratcliffe
 */
public class SRTHeader extends CommonHeader {
        // The header length we are using for the SRT file
        public static final int HEADER_LEN = 29; // newer files use 37
        protected static final int HEADER2_LEN = 16;
        protected static final int HEADER3_LEN = 52;
        protected static final int HEADER3_MULTI_LEN = 92;

        // The section structure of this file is somewhat different to other
        // files, but I am still going to model it using Section.
        private final Section header2 = new Section();

        private final Section desc = new Section(header2);
        private final Section subheader = new Section(desc);
        private final Section chartab = new Section(3);
        private final Section expansions = new Section(chartab, 2);
        private final Section srt8 = new Section(expansions, 5);
        private final Section srt7 = new Section(srt8, 4);
       

        private Sort sort;

        public SRTHeader() {
                this(HEADER_LEN);
        }

        public SRTHeader(int headerLen) {
                super(headerLen, "GARMIN SRT");
                header2.setPosition(headerLen);
                header2.setSize(16);

                chartab.setPosition(HEADER3_LEN);
        }

        protected void readFileHeader(ImgFileReader reader) throws ReadFailedException {
                reader.get2u(); // expected: 1
                header2.setPosition(reader.get4());
                header2.setSize(reader.get2u());
        }

        /**
         * Write out the application header.  This is unusual as it just points
         * to an area which is itself just a header.
         */
        protected void writeFileHeader(ImgFileWriter writer) {
                if (getHeaderLength() <= 29) {
                        writer.put2u(1);

                        writer.put4(header2.getPosition());
                        writer.put2u(header2.getSize());
                } else {
                        // this appears in unicode maps dated 2016 and 2017
                        writer.put2u(0);
                        writer.put4(header2.getPosition());
                        writer.put2u(header2.getSize());
                        writer.put2u(1);
                        writer.put4(header2.getPosition());
                        writer.put2u(header2.getSize());
                       
                        // older maps contain this variant (note the different order)
//                      writer.putChar((char) 1);
//                      writer.putInt(header2.getPosition());
//                      writer.putChar((char) header2.getSize());
//                      writer.putChar((char) 0);
//                      writer.putInt(desc.getPosition());
//                      writer.putChar((char) 0x10);  
                       
                }
        }

        /**
         * Section writer to write the character and expansions sections. These two sections are embedded within another
         * section and their offsets are relative to that section.
         * @param writer The real underlying writer.
         * @return A new writer where offsets are relative to the start of the sub-header section.
         */
        SectionWriter makeSectionWriter(ImgFileWriter writer) {
                return new SectionWriter(writer, subheader);
        }

        /**
         * This is a header with pointers to the description and the main section.
         * The offsets contained in this section are relative to the beginning of the file.
         * @param writer Header is written here.
         */
        protected void writeHeader2(ImgFileWriter writer) {
                desc.writeSectionInfo(writer);
                subheader.writeSectionInfo(writer);
        }

        /**
         * Header contained within the main section.  Offsets within this section are relative to the beginning
         * of the section.
         * @param writer Header is written here.
         */
        protected void writeHeader3(ImgFileWriter writer) {
                if (sort.isMulti()) {
                        writer.put2u(HEADER3_MULTI_LEN);
                } else {
                        writer.put2u(HEADER3_LEN);
                }

                writer.put2u(sort.getId1());
                writer.put2u(sort.getId2());
                writer.put2u(sort.getCodepage());
                if (sort.isMulti())
                        writer.put4(0x6f02);
                else
                        writer.put4(0x2002);

                chartab.writeSectionInfo(writer, true, true);
                writer.put2u(0);

                expansions.writeSectionInfo(writer, true, true);
                writer.put2u(0);

                // SRT6 A repeat pointer to the single byte character table
                writer.put4(chartab.getPosition());
                writer.put4(0);

                if (sort.isMulti()) {
                        writer.put4(1);
                        writer.put4(sort.getMaxPage());  // max block in srt7

                        srt7.writeSectionInfo(writer, true);
                        writer.put2u(0);
                        writer.put4(0);
                        srt8.writeSectionInfo(writer, true);

                        writer.put2u(0);
                        writer.put4(0);
                }
        }

        public void setSort(Sort sort) {
                this.sort = sort;
                if (sort.isMulti()) {
                        chartab.setPosition(HEADER3_MULTI_LEN);
                        chartab.setItemSize(5);
                        expansions.setItemSize(4);
                }
        }

        /** Called after the description has been written to record the position. */
        public void endDescription(int position) {
                desc.setSize(position - desc.getPosition());
                subheader.setPosition(position);
        }

        /** Called after the character table has been written to record the position. */
        public void endCharTable(int position) {
                chartab.setSize(position - chartab.getPosition());
        }

        /** Called after the expansions has been written to record the position. */
        public void endTab2(int postition) {
                subheader.setSize(postition - subheader.getPosition());
                expansions.setSize(postition - expansions.getPosition());
        }

        public void endSrt8(int position) {
                srt8.setSize(position - srt8.getPosition());
        }

        public void endSrt7(int position) {
                srt7.setSize(position - srt7.getPosition());
        }
}