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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.photoshop;
import com.drew.lang.BufferBoundsException;
import com.drew.lang.BufferReader;
import com.drew.lang.ByteArrayReader;
import com.drew.lang.annotations.NotNull;
import com.drew.metadata.Metadata;
import com.drew.metadata.MetadataReader;
import com.drew.metadata.iptc.IptcReader;
/**
* 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 MetadataReader
{
public void extract(@NotNull final BufferReader reader, final @NotNull Metadata metadata)
{
final PhotoshopDirectory directory = metadata.getOrCreateDirectory(PhotoshopDirectory.class);
int pos = 0;
try {
pos = reader.getString(0, 13).equals("Photoshop 3.0") ? 14 : 0;
} catch (BufferBoundsException e) {
directory.addError("Unable to read header");
return;
}
while (pos < reader.getLength()) {
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 > reader.getLength())
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_PHOTOSHOP_IPTC)
new IptcReader().extract(new ByteArrayReader(tagBytes), metadata);
if (tagType >= 0x0fa0 && tagType <= 0x1387)
PhotoshopDirectory._tagNameMap.put(tagType, String.format("Plug-in %d Data", tagType - 0x0fa0 + 1));
} catch (BufferBoundsException ex) {
directory.addError(ex.getMessage());
return;
}
}
}
}
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