com.luciad.imageio.webp.WebPImageReaderSpi Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of ework-cloud-starter-image Show documentation

Ework Cloud Starter Image

There is a newer version: 2.5.8

Show newest version

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[] VP8L = new byte[]{'V', 'P', '8', 'L'};
    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, VP8L) && !Arrays.equals(b, VP8X)) {
                return false;
            }
        } finally {
            stream.setByteOrder(oldByteOrder);
            stream.reset();
        }

        return true;
    }

    @Override
    public String getDescription(Locale locale) {
        return "WebP Reader";
    }
}