    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;
    021import java.util.Arrays;
    022
    023import org.apache.commons.imaging.ImagingException;
    024import org.apache.commons.imaging.common.Allocator;
    025import org.apache.commons.imaging.formats.tiff.TiffField;
    026
    027public class FieldTypeAscii extends AbstractFieldType {
    028    public FieldTypeAscii(final int type, final String name) {
    029        super(type, name, 1);
    030    }
    031
    032    @Override
    033    public Object getValue(final TiffField entry) {
    034        // According to EXIF specification
    035        // "2 = ASCII An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL."
    036        final byte[] bytes = entry.getByteArrayValue();
    037        int nullCount = 1;
    038        for (int i = 0; i < bytes.length - 1; i++) {
    039            if (bytes[i] == 0) {
    040                nullCount++;
    041            }
    042        }
    043        final String[] strings = Allocator.array(nullCount, String[]::new, 24);
    044        int stringsAdded = 0;
    045        strings[0] = ""; // if we have a 0 length string
    046        int nextStringPos = 0;
    047        // According to the Exiftool FAQ, [BROKEN URL] http://www.metadataworkinggroup.org
    048        // specifies that the TIFF ASCII fields are actually UTF-8.
    049        // Exiftool however allows you to configure the charset used.
    050        for (int i = 0; i < bytes.length; i++) {
    051            if (bytes[i] == 0) {
    052                final String string = new String(bytes, nextStringPos, i - nextStringPos, StandardCharsets.UTF_8);
    053                strings[stringsAdded++] = string;
    054                nextStringPos = i + 1;
    055            }
    056        }
    057        if (nextStringPos < bytes.length) {
    058            // Buggy file, string wasn't null terminated
    059            final String string = new String(bytes, nextStringPos, bytes.length - 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 ImagingException {
    070        if (o instanceof byte[]) {
    071            final byte[] bytes = (byte[]) o;
    072            final byte[] result = Arrays.copyOf(bytes, bytes.length + 1);
    073            result[result.length - 1] = 0;
    074            return result;
    075        }
    076        if (o instanceof String) {
    077            final byte[] bytes = ((String) o).getBytes(StandardCharsets.UTF_8);
    078            final byte[] result = Arrays.copyOf(bytes, bytes.length + 1);
    079            result[result.length - 1] = 0;
    080            return result;
    081        }
    082        if (!(o instanceof String[])) {
    083            throw new ImagingException("Unknown data type: " + o);
    084        }
    085        final String[] strings = (String[]) o;
    086        int totalLength = 0;
    087        for (final String string : strings) {
    088            final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
    089            totalLength += bytes.length + 1;
    090        }
    091        final byte[] result = Allocator.byteArray(totalLength);
    092        int position = 0;
    093        for (final String string : strings) {
    094            final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
    095            System.arraycopy(bytes, 0, result, position, bytes.length);
    096            position += bytes.length + 1;
    097        }
    098        return result;
    099    }
    100
    101}