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/*
* Copyright 2002-2012 Drew Noakes
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* More information about this project is available at:
*
* http://drewnoakes.com/code/exif/
* http://code.google.com/p/metadata-extractor/
*/
package com.drew.metadata.iptc;
import com.drew.lang.BufferBoundsException;
import com.drew.lang.BufferReader;
import com.drew.lang.annotations.NotNull;
import com.drew.metadata.Directory;
import com.drew.metadata.Metadata;
import com.drew.metadata.MetadataReader;
import java.util.Date;
/**
* Decodes IPTC binary data, populating a <code>Metadata</code> object with tag values in an <code>IptcDirectory</code>.
*
* @author Drew Noakes http://drewnoakes.com
*/
public class IptcReader implements MetadataReader
{
// TODO consider breaking the IPTC section up into multiple directories and providing segregation of each IPTC directory
/*
public static final int DIRECTORY_IPTC = 2;
public static final int ENVELOPE_RECORD = 1;
public static final int APPLICATION_RECORD_2 = 2;
public static final int APPLICATION_RECORD_3 = 3;
public static final int APPLICATION_RECORD_4 = 4;
public static final int APPLICATION_RECORD_5 = 5;
public static final int APPLICATION_RECORD_6 = 6;
public static final int PRE_DATA_RECORD = 7;
public static final int DATA_RECORD = 8;
public static final int POST_DATA_RECORD = 9;
*/
/** Performs the IPTC data extraction, adding found values to the specified instance of <code>Metadata</code>. */
public void extract(@NotNull final BufferReader reader, @NotNull final Metadata metadata)
{
IptcDirectory directory = metadata.getOrCreateDirectory(IptcDirectory.class);
int offset = 0;
/*
// find start-of-segment marker (potentially need to skip some ASCII photoshop header info)
try {
while (offset < data.length - 1 && reader.getUInt16(offset) != 0x1c01 && reader.getUInt16(offset) != 0x1c02)
offset++;
} catch (BufferBoundsException e) {
directory.addError("Couldn't find start of IPTC data (invalid segment)");
return;
}
*/
// for each tag
while (offset < reader.getLength()) {
// identifies start of a tag
short startByte;
try {
startByte = reader.getUInt8(offset);
} catch (BufferBoundsException e) {
directory.addError("Unable to read starting byte of IPTC tag");
break;
}
if (startByte != 0x1c) {
directory.addError("Invalid start to IPTC tag");
break;
}
// we need at least five bytes left to read a tag
if (offset + 5 >= reader.getLength()) {
directory.addError("Too few bytes remain for a valid IPTC tag");
break;
}
offset++;
int directoryType;
int tagType;
int tagByteCount;
try {
directoryType = reader.getUInt8(offset++);
tagType = reader.getUInt8(offset++);
tagByteCount = reader.getUInt16(offset);
offset += 2;
} catch (BufferBoundsException e) {
directory.addError("IPTC data segment ended mid-way through tag descriptor");
return;
}
if (offset + tagByteCount > reader.getLength()) {
directory.addError("Data for tag extends beyond end of IPTC segment");
break;
}
try {
processTag(reader, directory, directoryType, tagType, offset, tagByteCount);
} catch (BufferBoundsException e) {
directory.addError("Error processing IPTC tag");
break;
}
offset += tagByteCount;
}
}
private void processTag(@NotNull BufferReader reader, @NotNull Directory directory, int directoryType, int tagType, int offset, int tagByteCount) throws BufferBoundsException
{
int tagIdentifier = tagType | (directoryType << 8);
switch (tagIdentifier) {
case IptcDirectory.TAG_APPLICATION_RECORD_VERSION:
// short
int shortValue = reader.getUInt16(offset);
directory.setInt(tagIdentifier, shortValue);
return;
case IptcDirectory.TAG_URGENCY:
// byte
directory.setInt(tagIdentifier, reader.getUInt8(offset));
return;
case IptcDirectory.TAG_RELEASE_DATE:
case IptcDirectory.TAG_DATE_CREATED:
// Date object
if (tagByteCount >= 8) {
String dateStr = reader.getString(offset, tagByteCount);
try {
int year = Integer.parseInt(dateStr.substring(0, 4));
int month = Integer.parseInt(dateStr.substring(4, 6)) - 1;
int day = Integer.parseInt(dateStr.substring(6, 8));
Date date = new java.util.GregorianCalendar(year, month, day).getTime();
directory.setDate(tagIdentifier, date);
return;
} catch (NumberFormatException e) {
// fall through and we'll store whatever was there as a String
}
}
case IptcDirectory.TAG_RELEASE_TIME:
case IptcDirectory.TAG_TIME_CREATED:
// time...
default:
// fall through
}
// If we haven't returned yet, treat it as a string
String str;
if (tagByteCount < 1) {
str = "";
} else {
str = reader.getString(offset, tagByteCount, System.getProperty("file.encoding")); // "ISO-8859-1"
}
if (directory.containsTag(tagIdentifier)) {
// this fancy string[] business avoids using an ArrayList for performance reasons
String[] oldStrings = directory.getStringArray(tagIdentifier);
String[] newStrings;
if (oldStrings == null) {
newStrings = new String[1];
} else {
newStrings = new String[oldStrings.length + 1];
System.arraycopy(oldStrings, 0, newStrings, 0, oldStrings.length);
}
newStrings[newStrings.length - 1] = str;
directory.setStringArray(tagIdentifier, newStrings);
} else {
directory.setString(tagIdentifier, str);
}
}
}
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