001/* ***** BEGIN LICENSE BLOCK *****
002 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
003 *
004 * The contents of this file are subject to the Mozilla Public License Version
005 * 1.1 (the "License"); you may not use this file except in compliance with
006 * the License. You may obtain a copy of the License at
007 * http://www.mozilla.org/MPL/
008 *
009 * Software distributed under the License is distributed on an "AS IS" basis,
010 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
011 * for the specific language governing rights and limitations under the
012 * License.
013 *
014 * The Original Code is part of dcm4che, an implementation of DICOM(TM) in
015 * Java(TM), hosted at https://github.com/gunterze/dcm4che.
016 *
017 * The Initial Developer of the Original Code is
018 * Agfa Healthcare.
019 * Portions created by the Initial Developer are Copyright (C) 2013
020 * the Initial Developer. All Rights Reserved.
021 *
022 * Contributor(s):
023 * See @authors listed below
024 *
025 * Alternatively, the contents of this file may be used under the terms of
026 * either the GNU General Public License Version 2 or later (the "GPL"), or
027 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
028 * in which case the provisions of the GPL or the LGPL are applicable instead
029 * of those above. If you wish to allow use of your version of this file only
030 * under the terms of either the GPL or the LGPL, and not to allow others to
031 * use your version of this file under the terms of the MPL, indicate your
032 * decision by deleting the provisions above and replace them with the notice
033 * and other provisions required by the GPL or the LGPL. If you do not delete
034 * the provisions above, a recipient may use your version of this file under
035 * the terms of any one of the MPL, the GPL or the LGPL.
036 *
037 * ***** END LICENSE BLOCK ***** */
038
039package org.dcm4che3.image;
040
041import org.dcm4che3.data.Tag;
042import org.dcm4che3.data.Attributes;
043
044/**
045 * @author Gunter Zeilinger <gunterze@gmail.com>
046 *
047 */
048public abstract class StoredValue {
049
050    public abstract int valueOf(int pixel);
051    public abstract int minValue();
052    public abstract int maxValue();
053
054    public static class Unsigned extends StoredValue {
055
056        private final int mask;
057
058        public Unsigned(int bitsStored) {
059            this.mask = (1 << bitsStored) - 1;
060        }
061
062        @Override
063        public int valueOf(int pixel) {
064            return pixel & mask;
065        }
066
067        @Override
068        public int minValue() {
069            return 0;
070        }
071
072        @Override
073        public int maxValue() {
074            return mask;
075        }
076    }
077
078    public static class Signed extends StoredValue {
079
080        private final int bitsStored;
081        private final int shift;
082
083        public Signed(int bitsStored) {
084            this.bitsStored = bitsStored;
085            this.shift = 32 - bitsStored;
086        }
087
088        @Override
089        public int valueOf(int pixel) {
090            return pixel << shift >> shift;
091        }
092
093        @Override
094        public int minValue() {
095            return -(1 << (bitsStored-1));
096        }
097
098        @Override
099        public int maxValue() {
100            return (1 << (bitsStored-1)) - 1;
101        }
102    }
103
104    public static StoredValue valueOf(Attributes attrs) {
105        int bitsStored = attrs.getInt(Tag.BitsStored, 0);
106        if (bitsStored == 0)
107            bitsStored = attrs.getInt(Tag.BitsAllocated, 8);
108        return attrs.getInt(Tag.PixelRepresentation, 0) != 0
109                ? new Signed(bitsStored)
110                : new Unsigned(bitsStored);
111    }
112}