com.domenicseccareccia.jpegautorotate.util.ImageUtils Maven / Gradle / Ivy

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/**
 * Copyright (c) 2019-2021 Domenic Seccareccia and contributors
 *
 * 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 com.domenicseccareccia.jpegautorotate.util;

import com.domenicseccareccia.jpegautorotate.JpegAutorotateException;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.net.URLConnection;

public final class ImageUtils {

    /**
     * Not intended for instantiation.
     */
    private ImageUtils() {
        throw new IllegalStateException("Not intended for instantiation.");
    }

    /**
     * Attempts to determine if the image file {@code name} is acceptable.
     */
    private static final FilenameFilter FILENAME_FILTER = (File dir, String name) -> {
        for (Extensions ext : Extensions.values()){
            if (name.toUpperCase().contains(ext.name())) {
                return true;
            }
        }

        return false;
    };

    /**
     * Attempts to determine if the {@code bytes} is a JPEG image file.
     *
     * @param bytes
     *              {@code byte[]} containing an image file.
     * @return {@code true} If image is JPEG; otherwise false.
     * @throws JpegAutorotateException
     *              In the event the image file type is unable to be determined.
     */
    public static boolean isJpeg(final byte[] bytes) throws JpegAutorotateException {
        try (InputStream is = new ByteArrayInputStream(bytes)) {
            String contentType = URLConnection.guessContentTypeFromStream(is);

            return FILENAME_FILTER.accept(null, contentType);
        } catch (IOException e) {
            throw new JpegAutorotateException("Unable to determine the type of image file.", e);
        }
    }

    /**
     * Writes image data to a {@code byte[]}.
     *
     * @param is
     *          {@code InputStream} containing image data.
     * @return If successful, a {@code byte[]} containing JPEG image data.
     * @throws JpegAutorotateException
     *              In the event the {@code InputStream} is unable to be read or write
     *              to a {@code byte[]}.
     */
    public static byte[] toByteArray(final InputStream is) throws JpegAutorotateException {
        try {
            return IOUtils.toByteArray(is);
        } catch (IOException e) {
            throw new JpegAutorotateException("Unable to read/write InputStream containing JPEG image data to a byte array.", e);
        }
    }

}