de.digitalcollections.turbojpeg.imageio.TurboJpegImageReaderSpi Maven / Gradle / Ivy

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ImageIO plugin for reading and writing JPEG images via libjpeg-turbo/turbojpeg. Requires the libjpeg-turbo and turbojpeg shared native libraries to be installed on the system.

There is a newer version: 0.6.8

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package de.digitalcollections.turbojpeg.imageio;

import de.digitalcollections.turbojpeg.TurboJpeg;
import java.io.IOException;
import java.util.Arrays;
import java.util.Locale;
import java.util.stream.Stream;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.spi.ServiceRegistry;
import javax.imageio.stream.ImageInputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TurboJpegImageReaderSpi extends ImageReaderSpi {

  private static final Logger LOGGER = LoggerFactory.getLogger(TurboJpegImageReaderSpi.class);
  private static byte[] HEADER_MAGIC = new byte[]{(byte) 0xff, (byte) 0xd8};
  private static final String vendorName = "Münchener Digitalisierungszentrum/Digitale Bibliothek, Bayerische Staatsbibliothek";
  private static final String version = "0.2.6";
  private static final String readerClassName = "de.digitalcollections.openjpeg.turbojpeg.TurboJpegImageReader";
  private static final String[] names = {"JPEG", "jpeg", "JPG", "jpg"};
  private static final String[] suffixes = {"jpg", "jpeg"};
  private static final String[] MIMETypes = {"image/jpeg"};
  private static final String[] writerSpiNames = {"de.digitalcollections.turbojpeg.imageio.TurboJpegImageWriterSpi"};

  private TurboJpeg lib;

  public TurboJpegImageReaderSpi() {
    super(vendorName, version, names, suffixes, MIMETypes, readerClassName,
            new Class[]{ImageInputStream.class}, writerSpiNames,
            false, null, null,
            null, null, false,
            null, null, null,
            null);
  }

  private void loadLibrary() throws IOException {
    if (this.lib == null) {
      try {
        this.lib = new TurboJpeg();
      } catch (UnsatisfiedLinkError e) {
        LOGGER.warn("Could not load libturbojpeg, plugin will be disabled");
        throw new IOException(e);
      }
    }
  }

  /** Instruct registry to prioritize this ReaderSpi over other JPEG readers. **/
  @SuppressWarnings("unchecked")
  @Override
  public void onRegistration(final ServiceRegistry registry, final Class category) {
    Stream.of(
            "com.twelvemonkeys.imageio.plugins.jpeg.JPEGImageReaderSpi",
            "com.sun.imageio.plugins.jpeg.JPEGImageReaderSpi").forEach((clsName) -> {
              try {
                ImageReaderSpi defaultProvider = (ImageReaderSpi) registry.getServiceProviderByClass(Class.forName(clsName));
                registry.setOrdering((Class) category, this, defaultProvider);
              } catch (ClassNotFoundException e) {
                // NOP
              }
            });
  }

  @Override
  public boolean canDecodeInput(Object input) throws IOException {
    loadLibrary();
    if (!(input instanceof ImageInputStream)) {
      input = ImageIO.createImageInputStream(input);
    }
    if (input == null) {
      return false;
    }
    ImageInputStream stream = (ImageInputStream) input;
    byte[] b = new byte[2];
    try {
      stream.mark();
      stream.readFully(b);
    } catch (IOException e) {
      return false;
    }
    return Arrays.equals(b, HEADER_MAGIC);
  }

  @Override
  public ImageReader createReaderInstance(Object extension) throws IOException {
    loadLibrary();
    return new TurboJpegImageReader(this, lib);
  }

  @Override
  public String getDescription(Locale locale) {
    return "JPEG reader plugin based on libjpeg-turbo/turbojpeg.";
  }
}