    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.imaging.formats.tiff.fieldtypes;
    018
    019import java.nio.ByteOrder;
    020import java.nio.charset.StandardCharsets;
    021
    022import org.apache.commons.imaging.ImageWriteException;
    023import org.apache.commons.imaging.formats.tiff.TiffField;
    024
    025public class FieldTypeAscii extends FieldType {
    026    public FieldTypeAscii(final int type, final String name) {
    027        super(type, name, 1);
    028    }
    029
    030    @Override
    031    public Object getValue(final TiffField entry) {
    032        // According to EXIF specification
    033        // "2 = ASCII An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL."
    034        final byte[] bytes = entry.getByteArrayValue();
    035        int nullCount = 1;
    036        for (int i = 0; i < bytes.length - 1; i++) {
    037            if (bytes[i] == 0) {
    038                nullCount++;
    039            }
    040        }
    041        final String[] strings = new String[nullCount];
    042        int stringsAdded = 0;
    043        strings[0] = ""; // if we have a 0 length string
    044        int nextStringPos = 0;
    045        // According to the Exiftool FAQ, http://www.metadataworkinggroup.org
    046        // specifies that the TIFF ASCII fields are actually UTF-8.
    047        // Exiftool however allows you to configure the charset used.
    048        for (int i = 0; i < bytes.length; i++) {
    049            if (bytes[i] == 0) {
    050                final String string = new String(bytes, nextStringPos, i
    051                        - nextStringPos, StandardCharsets.UTF_8);
    052                strings[stringsAdded++] = string;
    053                nextStringPos = i + 1;
    054            }
    055        }
    056        if (nextStringPos < bytes.length) {
    057            // Buggy file, string wasn't null terminated
    058            final String string = new String(bytes, nextStringPos, bytes.length
    059                    - nextStringPos, StandardCharsets.UTF_8);
    060            strings[stringsAdded++] = string;
    061        }
    062        if (strings.length == 1) {
    063            return strings[0];
    064        }
    065        return strings;
    066    }
    067
    068    @Override
    069    public byte[] writeData(final Object o, final ByteOrder byteOrder) throws ImageWriteException {
    070        if (o instanceof byte[]) {
    071            final byte[] bytes = (byte[]) o;
    072            final byte[] result = new byte[bytes.length + 1];
    073            System.arraycopy(bytes, 0, result, 0, bytes.length);
    074            result[result.length - 1] = 0;
    075            return result;
    076        } else if (o instanceof String) {
    077            final byte[] bytes = ((String) o).getBytes(StandardCharsets.UTF_8);
    078            final byte[] result = new byte[bytes.length + 1];
    079            System.arraycopy(bytes, 0, result, 0, bytes.length);
    080            result[result.length - 1] = 0;
    081            return result;
    082        } else if (o instanceof String[]) {
    083            final String[] strings = (String[]) o;
    084            int totalLength = 0;
    085            for (final String string : strings) {
    086                final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
    087                totalLength += (bytes.length + 1);
    088            }
    089            final byte[] result = new byte[totalLength];
    090            int position = 0;
    091            for (final String string : strings) {
    092                final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
    093                System.arraycopy(bytes, 0, result, position, bytes.length);
    094                position += (bytes.length + 1);
    095            }
    096            return result;
    097        } else {
    098            throw new ImageWriteException("Unknown data type: " + o);
    099        }
    100    }
    101
    102}