webp-imageio-core/src/main/java/com/luciad/imageio/webp/WebPImageReaderSpi.java

107 lines
2.9 KiB
Java

/*
* Copyright 2013 Luciad (http://www.luciad.com)
*
* 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.
*/
package com.luciad.imageio.webp;
import javax.imageio.ImageReader;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.stream.ImageInputStream;
import java.io.IOException;
import java.nio.ByteOrder;
import java.util.Arrays;
import java.util.Locale;
/**
*
*/
public class WebPImageReaderSpi extends ImageReaderSpi {
private static final byte[] RIFF = new byte[]{ 'R', 'I', 'F', 'F' };
private static final byte[] WEBP = new byte[]{ 'W', 'E', 'B', 'P' };
private static final byte[] VP8_ = new byte[]{ 'V', 'P', '8', ' ' };
private static final byte[] VP8X = new byte[]{ 'V', 'P', '8', 'X' };
public WebPImageReaderSpi() {
super(
"Luciad",
"1.0",
new String[]{ "WebP", "webp" },
new String[]{ "webp" },
new String[]{ "image/webp" },
WebPReader.class.getName(),
new Class[] { ImageInputStream.class },
new String[]{ WebPImageWriterSpi.class.getName() },
false,
null,
null,
null,
null,
false,
null,
null,
null,
null
);
}
@Override
public ImageReader createReaderInstance( Object extension ) throws IOException {
return new WebPReader( this );
}
@Override
public boolean canDecodeInput( Object source ) throws IOException {
if ( !( source instanceof ImageInputStream ) ) {
return false;
}
ImageInputStream stream = ( ImageInputStream ) source;
byte[] b = new byte[ 4 ];
ByteOrder oldByteOrder = stream.getByteOrder();
stream.mark();
stream.setByteOrder( ByteOrder.LITTLE_ENDIAN );
try {
stream.readFully( b );
if ( !Arrays.equals( b, RIFF ) ) {
return false;
}
long chunkLength = stream.readUnsignedInt();
long streamLength = stream.length();
if ( streamLength != -1 && streamLength != chunkLength + 8 ) {
return false;
}
stream.readFully( b );
if ( !Arrays.equals( b, WEBP ) ) {
return false;
}
stream.readFully( b );
if ( !Arrays.equals( b, VP8_ ) && !Arrays.equals( b, VP8X ) ) {
return false;
}
} finally {
stream.setByteOrder( oldByteOrder );
stream.reset();
}
return true;
}
@Override
public String getDescription( Locale locale ) {
return "WebP Reader";
}
}