/*
* Copyright 2002-2013 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.photoshop;
import com.drew.imaging.jpeg.JpegSegmentMetadataReader;
import com.drew.imaging.jpeg.JpegSegmentType;
import com.drew.lang.ByteArrayReader;
import com.drew.lang.RandomAccessReader;
import com.drew.lang.SequentialByteArrayReader;
import com.drew.lang.annotations.NotNull;
import com.drew.metadata.Metadata;
import com.drew.metadata.iptc.IptcReader;
import java.io.IOException;
import java.util.Arrays;
/**
* Reads metadata created by Photoshop and stored in the APPD segment of JPEG files.
* Note that IPTC data may be stored within this segment, in which case this reader will
* create both a {@link PhotoshopDirectory} and a {@link com.drew.metadata.iptc.IptcDirectory}.
*
* @author Yuri Binev, Drew Noakes http://drewnoakes.com
*/
public class PhotoshopReader implements JpegSegmentMetadataReader
{
@NotNull
public Iterable<JpegSegmentType> getSegmentTypes()
{
return Arrays.asList(JpegSegmentType.APPD);
}
public boolean canProcess(@NotNull byte[] segmentBytes, @NotNull JpegSegmentType segmentType)
{
return segmentBytes.length > 12 && "Photoshop 3.0".equals(new String(segmentBytes, 0, 13));
}
public void extract(@NotNull byte[] segmentBytes, @NotNull Metadata metadata, @NotNull JpegSegmentType segmentType)
{
extract(new ByteArrayReader(segmentBytes), metadata);
}
public void extract(@NotNull final RandomAccessReader reader, final @NotNull Metadata metadata)
{
final PhotoshopDirectory directory = metadata.getOrCreateDirectory(PhotoshopDirectory.class);
int pos;
try {
pos = reader.getString(0, 13).equals("Photoshop 3.0") ? 14 : 0;
} catch (IOException e) {
directory.addError("Unable to read header");
return;
}
long length;
try {
length = reader.getLength();
} catch (IOException e) {
directory.addError("Unable to read Photoshop data: " + e.getMessage());
return;
}
while (pos < length) {
try {
// 4 bytes for the signature. Should always be "8BIM".
//String signature = new String(data, pos, 4);
pos += 4;
// 2 bytes for the resource identifier (tag type).
int tagType = reader.getUInt16(pos); // segment type
pos += 2;
// A variable number of bytes holding a pascal string (two leading bytes for length).
int descriptionLength = reader.getUInt16(pos);
pos += 2;
// Some basic bounds checking
if (descriptionLength < 0 || descriptionLength + pos > length)
return;
//String description = new String(data, pos, descriptionLength);
pos += descriptionLength;
// The number of bytes is padded with a trailing zero, if needed, to make the size even.
if (pos % 2 != 0)
pos++;
// 4 bytes for the size of the resource data that follows.
int byteCount = reader.getInt32(pos);
pos += 4;
// The resource data.
byte[] tagBytes = reader.getBytes(pos, byteCount);
pos += byteCount;
// The number of bytes is padded with a trailing zero, if needed, to make the size even.
if (pos % 2 != 0)
pos++;
directory.setByteArray(tagType, tagBytes);
// TODO allow rebasing the reader with a new zero-point, rather than copying data here
if (tagType == PhotoshopDirectory.TAG_IPTC)
new IptcReader().extract(new SequentialByteArrayReader(tagBytes), metadata, tagBytes.length);
if (tagType >= 0x0fa0 && tagType <= 0x1387)
PhotoshopDirectory._tagNameMap.put(tagType, String.format("Plug-in %d Data", tagType - 0x0fa0 + 1));
} catch (IOException ex) {
directory.addError(ex.getMessage());
return;
}
}
}
}