Dépôt officiel du code source de l'ERP OpenConcerto

/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2011 OpenConcerto, by ILM Informatique. All rights reserved.

 *

 * The contents of this file are subject to the terms of the GNU General Public License Version 3

 * only ("GPL"). You may not use this file except in compliance with the License. You can obtain a

 * copy of the License at http://www.gnu.org/licenses/gpl-3.0.html See the License for the specific

 * language governing permissions and limitations under the License.

 *

 * When distributing the software, include this License Header Notice in each file.

 */

 package org.openconcerto.utils;

import java.io.BufferedWriter;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.nio.charset.Charset;

import java.nio.file.Files;

import java.nio.file.StandardCopyOption;

import java.util.logging.Level;

public class StreamUtils {

    public static final OutputStream NULL_OS = new OutputStream() {

        @Override

        public void write(int b) throws IOException {

            // ignore

        }

        public void write(byte b[], int off, int len) throws IOException {

            if (b == null)

                throw new NullPointerException();

            // ignore

        }

    };

    /**

     * Verbatim copy an entry from input to output stream.

     *

     * @param in the source.

     * @param out the destination.

     * @throws IOException if an error occurs while reading or writing.

     */

    public static void copy(InputStream in, OutputStream out) throws IOException {

        // TODO use in.transferTo(out) in Java 9

        copy(in, out, 512 * 1024);

    }

    public static void copy(InputStream in, OutputStream out, final int bufferSize) throws IOException {

        copy(in, out, bufferSize, -1);

    }

    public static long copy(InputStream in, OutputStream out, final int bufferSize, final long length) throws IOException {

        if (bufferSize < 1)

            throw new IllegalArgumentException("Buffer size too small : " + bufferSize);

        final byte[] buffer = new byte[bufferSize];

        long totalCount = 0;

        final boolean copyAll = length < 0;

        while (copyAll || totalCount < length) {

            final long toRead = copyAll ? buffer.length : Math.min(length - totalCount, buffer.length);

            // since buffer.length is an int

            assert 0 < toRead && toRead <= Integer.MAX_VALUE;

            final int count = in.read(buffer, 0, (int) toRead);

            if (count <= 0) {

                // like Files.copy(InputStream, OutputStream), stop if reading 0 bytes

                if (count == 0)

                    Log.get().log(Level.WARNING, "", new IllegalStateException("read() returned 0 for " + in));

                break;

            }

            totalCount += count;

            out.write(buffer, 0, count);

        }

        // < if end of stream

        assert copyAll || totalCount <= length;

        return totalCount;

    }

    public static void copy(InputStream ins, File out) throws IOException {

        Files.copy(ins, out.toPath(), StandardCopyOption.REPLACE_EXISTING);

    }

    /**

     * Read until the end of the stream is reached. NOTE : since this method didn't create the

     * stream, it doesn't close it.

     *

     * @param ins the stream to read from.

     * @return the bytes.

     * @throws IOException if an error occurs.

     */

    public static byte[] read(final InputStream ins) throws IOException {

        final ByteArrayOutputStream out = new ByteArrayOutputStream(512);

        copy(ins, out);

        return out.toByteArray();

    }

    public static void writeln(final String s, final OutputStream out) throws IOException {

        write(s + "\n", out);

    }

    public static void write(final String s, final OutputStream out) throws IOException {

        write(s, out, StringUtils.UTF8);

    }

    public static void write(final String s, final OutputStream out, Charset charset) throws IOException {

        out.write(s.getBytes(charset));

    }

    /**

     * Wrap the output stream into a writer, and write the XML declaration.

     *

     * @param outs an output stream.

     * @return a writer with the same encoding as the XML.

     * @throws IOException if an error occurs.

     */

    public static BufferedWriter createXMLWriter(OutputStream outs) throws IOException {

        return new BufferedWriter(createXMLUnbufferedWriter(outs));

    }

    public static Writer createXMLUnbufferedWriter(OutputStream outs) throws IOException {

        // see http://www.w3.org/TR/REC-xml/#sec-guessing

        // don't use UTF-8 BOM as Java does not support it :

        // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4508058

        final Writer res = new OutputStreamWriter(outs, StringUtils.UTF8);

        res.write("<?xml version='1.0' encoding='UTF-8' ?>\n");

        return res;

    }

}