/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2020 iText Group NV
 * Authors: Kevin Day, Bruno Lowagie, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Affero General License for more
 * details. You should have received a copy of the GNU Affero General License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General License.
 *
 * In accordance with Section 7(b) of the GNU Affero General License, a covered
 * work must retain the producer line in every PDF that is created or
 * manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing a
 * commercial license. Buying such a license is mandatory as soon as you develop
 * commercial activities involving the iText software without disclosing the
 * source code of your own applications. These activities include: offering paid
 * services to customers as an ASP, serving PDFs on the fly in a web
 * application, shipping iText with a closed source product.
 *
 * For more information, please contact iText Software Corp. at this address:
 * sales@itextpdf.com
 */
package com.itextpdf.text.io;

import java.io.ByteArrayOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Utility class with commonly used stream operations
 * @since 5.3.5
 *
 */
public final class StreamUtil {

    private StreamUtil() {
    }

    /**
     * Reads the full content of a stream and returns them in a byte array
     * @param is the stream to read
     * @return a byte array containing all of the bytes from the stream
     * @throws IOException if there is a problem reading from the input stream
     */
    public static byte[] inputStreamToArray(InputStream is) throws IOException {
        byte b[] = new byte[8192];
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        while (true) {
            int read = is.read(b);
            if (read < 1)
                break;
            out.write(b, 0, read);
        }
        out.close();
        return out.toByteArray();
    }

    public static void CopyBytes(RandomAccessSource source, long start, long length, OutputStream outs) throws IOException {
        if (length <= 0)
            return;
        long idx = start;
        byte[] buf = new byte[8192];
        while (length > 0) {
            long n = source.get(idx, buf,0, (int)Math.min((long)buf.length, length));
            if (n <= 0)
                throw new EOFException();
            outs.write(buf, 0, (int)n);
            idx += n;
            length -= n;
        }
    }

    /**
     * Gets the resource's inputstream.
     * @param key the full name of the resource
     * @return the <CODE>InputStream</CODE> to get the resource or
     * <CODE>null</CODE> if not found
     */
    public static InputStream getResourceStream(String key) {
        return getResourceStream(key, null);
    }

    /**
     * Gets the resource's inputstream
     * .
     * @param key the full name of the resource
     * @param loader the ClassLoader to load the resource or null to try the ones available
     * @return the <CODE>InputStream</CODE> to get the resource or
     * <CODE>null</CODE> if not found
     */
    public static InputStream getResourceStream(String key, ClassLoader loader) {
        if (key.startsWith("/"))
            key = key.substring(1);
        InputStream is = null;
        if (loader != null) {
            is = loader.getResourceAsStream(key);
            if (is != null)
                return is;
        }
        // Try to use Context Class Loader to load the properties file.
        try {
            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
            if (contextClassLoader != null) {
                is = contextClassLoader.getResourceAsStream(key);
            }
        } catch (Throwable e) {
            // empty body
        }

        if (is == null) {
            is = StreamUtil.class.getResourceAsStream("/" + key);
        }
        if (is == null) {
            is = ClassLoader.getSystemResourceAsStream(key);
        }
        return is;
    }
}
