Subversion Repositories splitter

/*
 * Copyright (c) 2009.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 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.splitter;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.text.NumberFormat;
import java.util.zip.GZIPInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.tools.bzip2.CBZip2InputStream;

/**
 * Some miscellaneous functions that are used within the .img code.
 *
 * @author Steve Ratcliffe
 */
public class Utils {

        private static final NumberFormat FORMATTER = NumberFormat.getIntegerInstance();

        public static String format(int number) {
                return FORMATTER.format(number);
        }

        public static String format(long number) {
                return FORMATTER.format(number);
        }

        public static double toDegrees(int val) {
                return (double) val / ((1 << 24) / 360.0);
        }

        /**
         * A map unit is an integer value that is 1/(2^24) degrees of latitude or
         * longitude.
         *
         * @param l The lat or long as decimal degrees.
         * @return An integer value in map units.
         */
        public static int toMapUnit(double l) {
                double DELTA = 0.000001; // TODO check if we really mean this
                if (l > 0)
                        return (int) ((l + DELTA) * (1 << 24)/360);
                else
                        return (int) ((l - DELTA) * (1 << 24)/360);
        }
       
        public static double toRadians(int latitude) {
                return toDegrees(latitude) * Math.PI / 180;
        }

        /**
         * @param n the integer to test
         * @return {@code true} if the integer is a power of two, {@code false} otherwise.
         */
        public static boolean isPowerOfTwo(int n) {
                return ((n & (n - 1)) == 0) && n > 0;
        }

        /**
         * Open a file and apply filters necessary to reading it such as decompression.
         *
         * @param name The file to open. gz, zip, bz2 are supported.
         * @return A stream that will read the file, positioned at the beginning.
         * @throws IOException If the file cannot be opened for any reason.
         */
        public static Reader openFile(String name, boolean backgroundReader) throws IOException {
                InputStream is = new BufferedInputStream(new FileInputStream(name), 8192);
                if (name.endsWith(".gz")) {
                        try {
                                is = new GZIPInputStream(is);
                        } catch (IOException e) {
                                throw new IOException( "Could not read " + name + " as a gz compressed file", e);
                        }
                } else if (name.endsWith(".bz2")) {
                        try {
                                is.read(); is.read();
                                is = new CBZip2InputStream(is);
                        } catch (IOException e) {
                                throw new IOException( "Could not read " + name + " as a bz2 compressed file", e);
                        }
                } else if (name.endsWith(".zip")) {
                        ZipInputStream zis = new ZipInputStream(is);
                        name = new File(name).getName();  // Strip off any path
                        ZipEntry entry;
                        while ((entry = zis.getNextEntry()) != null) {
                                if (entry.getName().startsWith(name.substring(0, name.length() - 4))) {
                                        is = zis;
                                        break;
                                }
                        }
                        if (is != zis) {
                                zis.close();
                                throw new IOException("Unable to find a file inside " + name + " that starts with " + name.substring(0, name.length() - 4));
                        }
                }
                if (backgroundReader) {
                        is = new BackgroundInputStream(is);
                }
                return new InputStreamReader(is, Charset.forName("UTF-8"));
        }
}