Subversion Repositories mkgmap

/*
 * Copyright (C) 2007 Steve Ratcliffe
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License 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.
 *
 *
 * Author: Steve Ratcliffe
 * Create date: 27-Oct-2007
 */
package uk.me.parabola.imgfmt.sys;

/**
 * This is a special class for the header.  It makes it easier to bootstrap
 * the directory by having a special implementation that starts up by knowing
 * that the blocks in the header start from 0.
 *
 * @author Steve Ratcliffe
 */
class HeaderDirent extends Dirent {
        HeaderDirent(String name, BlockManager blockManager) {
                super(name, blockManager);
        }

        /**
         * Converts from a logical block to a physical block.  This is a special
         * version that returns the logical block number when the {@link Dirent} is not
         * set up.  This allows us to bootstrap the reading of the header blocks.
         * The header blocks always logical and physical blocks the same.
         *
         * @param lblock The logical block in the file.
         * @return The corresponding physical block in the filesystem.
         */
        public int getPhysicalBlock(int lblock) {
                if (isInitialized()) {
                        log.debug("gpb (ok)");
                        return super.getPhysicalBlock(lblock);
                } else {
                        log.debug("gpb (not setup)");
                        return lblock;
                }
        }

        /**
         * Get the file size.  The file appears large until the first blocks are
         * read in and then it will take on its actual size.
         *
         * @return The size of the file in bytes.
         */
        public int getSize() {
                if (isInitialized())
                        return super.getSize();
                else
                        return getBlockManager().getBlockSize() * 32;
        }

        /**
         * Always returns true as this is only used for the special header
         * directory entry.
         *
         * @return Always returns true.
         */
        public boolean isSpecial() {
                return true;
        }
}