dk.netarkivet.common.utils.InputStreamUtils.java Source code

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Here is the source code for dk.netarkivet.common.utils.InputStreamUtils.java

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/*
 * #%L
 * Netarchivesuite - common
 * %%
 * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library,
 *             the National Library of France and the Austrian National Library.
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * 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 General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
 * #L%
 */
package dk.netarkivet.common.utils;

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

/**
 * This class provides various utilities for inputstreams.
 */
public class InputStreamUtils {

    /**
     * Read a line of bytes from an InputStream. Useful when an InputStream may contain both text and binary data.
     *
     * @param inputStream A source of data
     * @return A line of text read from inputStream, with terminating \r\n or \n removed, or null if no data is
     * available.
     * @throws IOException on trouble reading from input stream
     */
    public static String readLine(InputStream inputStream) throws IOException {
        byte[] rawdata = readRawLine(inputStream);
        if (rawdata == null) {
            return null;
        }
        int len = rawdata.length;
        if (len > 0) {
            if (rawdata[len - 1] == '\n') {
                --len;
                if (len > 0) {
                    if (rawdata[len - 1] == '\r') {
                        --len;
                    }
                }
            }
        }
        return new String(rawdata, 0, len);
    }

    /**
     * Reads a raw line from an InputStream, up till \n. Since HTTP allows \r\n and \n as terminators, this gets the
     * whole line. This code is adapted from org.apache.commons.httpclient.HttpParser
     *
     * @param inputStream A stream to read from.
     * @return Array of bytes read or null if none are available.
     * @throws IOException if the underlying reads fail
     */
    public static byte[] readRawLine(InputStream inputStream) throws IOException {
        ByteArrayOutputStream buf = new ByteArrayOutputStream();
        int ch;
        while ((ch = inputStream.read()) >= 0) {
            buf.write(ch);
            if (ch == '\n') {
                break;
            }
        }
        if (buf.size() == 0) {
            return null;
        }
        return buf.toByteArray();
    }

}