001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.util;
015
016import java.util.regex.Matcher;
017import java.util.regex.Pattern;
018
019/**
020 * Instances of this class represent the size of a file. Internally, the size is
021 * stored as long.
022 * 
023 * <p>
024 * The {@link #valueOf} method can convert strings such as "3 kb", "5 mb", into
025 * FileSize instances. The recognized unit specifications for file size are the
026 * "kb", "mb", and "gb". The unit name may be followed by an "s". Thus, "2 kbs"
027 * and "2 kb" are equivalent. In the absence of a time unit specification, byte
028 * is assumed.
029 * 
030 * @author Ceki G&uuml;lc&uuml;
031 * 
032 */
033public class FileSize {
034
035    private final static String LENGTH_PART = "([0-9]+)";
036    private final static int DOUBLE_GROUP = 1;
037
038    private final static String UNIT_PART = "(|kb|mb|gb)s?";
039    private final static int UNIT_GROUP = 2;
040
041    private static final Pattern FILE_SIZE_PATTERN = Pattern.compile(LENGTH_PART + "\\s*" + UNIT_PART,
042            Pattern.CASE_INSENSITIVE);
043
044    static public final long KB_COEFFICIENT = 1024;
045    static public final long MB_COEFFICIENT = 1024 * KB_COEFFICIENT;
046    static public final long GB_COEFFICIENT = 1024 * MB_COEFFICIENT;
047
048    final long size;
049
050    public FileSize(long size) {
051        this.size = size;
052    }
053
054    public long getSize() {
055        return size;
056    }
057
058    static public FileSize valueOf(String fileSizeStr) {
059        Matcher matcher = FILE_SIZE_PATTERN.matcher(fileSizeStr);
060
061        long coefficient;
062        if (matcher.matches()) {
063            String lenStr = matcher.group(DOUBLE_GROUP);
064            String unitStr = matcher.group(UNIT_GROUP);
065
066            long lenValue = Long.valueOf(lenStr);
067            if (unitStr.equalsIgnoreCase("")) {
068                coefficient = 1;
069            } else if (unitStr.equalsIgnoreCase("kb")) {
070                coefficient = KB_COEFFICIENT;
071            } else if (unitStr.equalsIgnoreCase("mb")) {
072                coefficient = MB_COEFFICIENT;
073            } else if (unitStr.equalsIgnoreCase("gb")) {
074                coefficient = GB_COEFFICIENT;
075            } else {
076                throw new IllegalStateException("Unexpected " + unitStr);
077            }
078            return new FileSize(lenValue * coefficient);
079        } else {
080            throw new IllegalArgumentException("String value [" + fileSizeStr + "] is not in the expected format.");
081        }
082    }
083
084    @Override
085    public String toString() {
086        long inKB = size / KB_COEFFICIENT;
087
088        if (inKB == 0)
089            return size + " Bytes";
090
091        long inMB = size / MB_COEFFICIENT;
092        if (inMB == 0) {
093            return inKB + " KB";
094        }
095
096        long inGB = size / GB_COEFFICIENT;
097        if (inGB == 0) {
098            return inMB + " MB";
099        }
100
101        return inGB + " GB";
102
103    }
104}