de.tlabs.ssr.g1.client.XMLChunkInputStream.java Source code

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Here is the source code for de.tlabs.ssr.g1.client.XMLChunkInputStream.java

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/******************************************************************************
 * Copyright (c) 2006-2012 Quality & Usability Lab                            *
 *                         Deutsche Telekom Laboratories, TU Berlin           *
 *                         Ernst-Reuter-Platz 7, 10587 Berlin, Germany        *
 *                                                                            *
 * This file is part of the SoundScape Renderer (SSR).                        *
 *                                                                            *
 * The SSR is free software:  you can redistribute it and/or modify it  under *
 * the terms of the  GNU  General  Public  License  as published by the  Free *
 * Software Foundation, either version 3 of the License,  or (at your option) *
 * any later version.                                                         *
 *                                                                            *
 * The SSR 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 Public License for more details.                       *
 *                                                                            *
 * You should  have received a copy  of the GNU General Public License  along *
 * with this program.  If not, see <http://www.gnu.org/licenses/>.            *
 *                                                                            *
 * The SSR is a tool  for  real-time  spatial audio reproduction  providing a *
 * variety of rendering algorithms.                                           *
 *                                                                            *
 * http://tu-berlin.de/?id=ssr                  SoundScapeRenderer@telekom.de *
 ******************************************************************************/

/* 
 * $LastChangedDate$
 * $LastChangedRevision$
 * $LastChangedBy$
 */

package de.tlabs.ssr.g1.client;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.EncodingUtils;

import android.util.Log;

/**
 * Class to split continuous input stream into chunks. A split is done every
 * time a '\0' character is encountered. The split character is dropped before
 * passing the chunk.
 * 
 * @author Peter Bartz
 */
public class XMLChunkInputStream extends ByteArrayInputStream {
    private static final int TEMPBUFFERSIZE = 2048; //2 kbytes
    private static final String TAG = "XMLChunkInputStream";
    private InputStream inputStream;
    private ByteArrayBuffer arrayBuffer;
    private byte[] tempBuffer; // for faster detecting of delimiters
    private int tempBufferStart; // start index of buffer content
    private int tempBufferEnd; // first unused index

    public boolean printToLog = false;

    public XMLChunkInputStream(ByteArrayBuffer arrayBuffer, InputStream inputStream) {
        super(arrayBuffer.buffer());
        this.arrayBuffer = arrayBuffer;
        this.inputStream = inputStream;
        this.tempBuffer = new byte[TEMPBUFFERSIZE];
        this.tempBufferStart = 0;
        this.tempBufferEnd = 0;
    }

    public boolean bufferNextChunk() throws IOException {
        boolean readDelimiter = false;

        arrayBuffer.clear();

        // read input data until delimiter is encountered
        while (!readDelimiter) {
            // process data which is still in temp buffer
            if (tempBufferEnd - tempBufferStart != 0) {
                // find next '\0'
                for (int i = tempBufferStart; i < tempBufferEnd; i++) {
                    if (tempBuffer[i] == '\0') {
                        // copy chunk to arrayBuffer
                        arrayBuffer.append(tempBuffer, tempBufferStart, i - tempBufferStart);

                        // update tempBufferStart (and skip '\0')
                        tempBufferStart = i + 1;

                        // break loop
                        readDelimiter = true;
                        break;
                    }
                }

                // was delimiter read?
                if (!readDelimiter) {
                    // copy whole temp buffer to array buffer
                    arrayBuffer.append(tempBuffer, tempBufferStart, tempBufferEnd - tempBufferStart);
                    tempBufferStart = 0;
                    tempBufferEnd = 0;
                }
            }

            // was delimiter read out of temp buffer?
            if (!readDelimiter) {
                // temp buffer is definitely empty now and delimiter was not read yet
                // so fill buffer again
                if (fillTempBuffer() == -1)
                    return false;
            }
        }

        // set properties of this ByteArrayInputStream
        this.mark = 0;
        this.pos = 0;
        this.buf = arrayBuffer.buffer();
        this.count = arrayBuffer.length();

        // print to log
        if (printToLog) {
            for (int i = 0; i < count; i += 100) {
                Log.d(TAG, EncodingUtils.getAsciiString(buf, i, Math.min(100, count - i)));
            }
        }

        return true;
    }

    private int fillTempBuffer() throws IOException {
        int numBytes = inputStream.read(tempBuffer);
        if (numBytes != -1) {
            tempBufferStart = 0;
            tempBufferEnd = numBytes;
        }

        return numBytes;
    }
}