/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.sanselan.formats.png.chunks;
import java.io.IOException;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.common.ZLibUtils;
import org.apache.sanselan.formats.png.PngConstants;
import org.apache.sanselan.formats.png.PngText;
public class PNGChunkiTXt extends PNGTextChunk
{
public final String keyword, text;
/*
* The language tag defined in [RFC-3066] indicates the human language used
* by the translated keyword and the text. Unlike the keyword, the language
* tag is case-insensitive. It is an ISO 646.IRV:1991 [ISO 646] string
* consisting of hyphen-separated words of 1-8 alphanumeric characters each
* (for example cn, en-uk, no-bok, x-klingon, x-KlInGoN). If the first word
* is two or three letters long, it is an ISO language code [ISO-639]. If
* the language tag is empty, the language is unspecified.
*/
public final String languageTag;
public final String translatedKeyword;
public PNGChunkiTXt(int length, int chunkType, int crc, byte bytes[])
throws ImageReadException, IOException
{
super(length, chunkType, crc, bytes);
{
int terminator = findNull(bytes);
if (terminator < 0)
throw new ImageReadException(
"PNG iTXt chunk keyword is not terminated.");
keyword = new String(bytes, 0, terminator, "ISO-8859-1");
int index = terminator + 1;
int compressionFlag = bytes[index++];
if (compressionFlag != 0 && compressionFlag != 1)
throw new ImageReadException(
"PNG iTXt chunk has invalid compression flag: "
+ compressionFlag);
boolean compressed = compressionFlag == 1;
int compressionMethod = bytes[index++];
if (compressed)
if (compressionMethod != PngConstants.COMPRESSION_DEFLATE_INFLATE)
throw new ImageReadException(
"PNG iTXt chunk has unexpected compression method: "
+ compressionMethod);
else if (compressionMethod != 0)
throw new ImageReadException(
"PNG iTXt chunk has unexpected compression method: "
+ compressionMethod);
terminator = findNull(bytes, index);
if (terminator < 0)
throw new ImageReadException(
"PNG iTXt chunk language tag is not terminated.");
languageTag = new String(bytes, index, terminator - index,
"ISO-8859-1");
index = terminator + 1;
terminator = findNull(bytes, index);
if (terminator < 0)
throw new ImageReadException(
"PNG iTXt chunk translated keyword is not terminated.");
translatedKeyword = new String(bytes, index, terminator - index,
"utf-8");
index = terminator + 1;
if (compressed)
{
int compressedTextLength = bytes.length - index;
;
byte compressedText[] = new byte[compressedTextLength];
System.arraycopy(bytes, index, compressedText, 0,
compressedTextLength);
text = new String(new ZLibUtils().inflate(compressedText),
"utf-8");
} else
text = new String(bytes, index, bytes.length - index, "utf-8");
}
}
/**
* @return Returns the keyword.
*/
public String getKeyword()
{
return keyword;
}
/**
* @return Returns the text.
*/
public String getText()
{
return text;
}
public PngText getContents()
{
return new PngText.iTXt(keyword, text, languageTag, translatedKeyword);
}
}