/*
 * Copyright 2007 Sun Microsystems, Inc.
 *
 * This file is part of jVoiceBridge.
 *
 * jVoiceBridge is free software: you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License version 2 as 
 * published by the Free Software Foundation and distributed hereunder 
 * to you.
 *
 * jVoiceBridge 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/>.
 *
 * Sun designates this particular file as subject to the "Classpath"
 * exception as provided by Sun in the License file that accompanied this 
 * code. 
 */

package com.sun.voip;

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


/** 
 * Read audio samples from a Sun .au file.
 * Up/down sample as necessary.
 */
public class DotAuAudioSource extends FileAudioSource {
    
    private String path;
    private int sampleRate;
    private int channels;
    private int encoding;

    private static final int AUDIO_FILE_HEADER_SIZE = 24;

    private InputStream in;

    /*
     * Read an audio file.  Pad with linear silence.
     */
    public DotAuAudioSource(String path) throws IOException {
    this.path = path;
    initialize();
    }

    private void initialize() throws IOException {
    done();

    in = getInputStream(path);

    /*
     * Audio file header
     *
         * int magic = 0x2e 0x73 0x6e 0x64 which is ".snd"
         * int hdr_size;
         * int data_size;
         * int encoding = 1 for ulaw, 3 for linear;
         * int sample_rate;
         * int channels;
     */
    int bytesAvailable = 0;

    try {
        bytesAvailable = in.available();
    } catch (IOException ioe) {
        throw new IOException("available() failed " + path);
    }

    if (bytesAvailable < AUDIO_FILE_HEADER_SIZE) {
        throw new IOException ("audiofile " + path + " is too small " + 
        bytesAvailable);
    }

    byte[] audioFileHeader = new byte[AUDIO_FILE_HEADER_SIZE];

    try {
        in.read(audioFileHeader, 0, AUDIO_FILE_HEADER_SIZE);
    } catch (Exception e) {
        throw new IOException("error reading " + path + " "
        + e.getMessage());
    }
        
    encoding = audioFileHeader[15];

    channels = audioFileHeader[23];

    if (audioFileHeader[0] != 0x2e || audioFileHeader[1] != 0x73 ||
        audioFileHeader[2] != 0x6e || audioFileHeader[3] != 0x64 ||
        (encoding != ULAW && encoding != LINEAR) ||
        channels > 16) {
    
        throw new IOException("bad audio file header " + path);
    }

    sampleRate = 
        ((((int)audioFileHeader[16]) << 24) & 0xff000000) +
        ((((int)audioFileHeader[17]) << 16) & 0x00ff0000) +
        ((((int)audioFileHeader[18]) << 8) & 0x0000ff00) +
        (((int)audioFileHeader[19]) & 0xff);

    if (Logger.logLevel >= Logger.LOG_MOREINFO) {
        Logger.println("AudioFile is " + path + ".  Resource is " + 
                DotAuAudioSource.class.getResource(path) + ".  size " 
                + in.available() + " encoding " + encoding 
        + " channels " + channels + " sampleRate " 
        + sampleRate);
    }

    try {
            bytesAvailable = in.available();
            
            int hdr_size =
                ((audioFileHeader[4] << 24) & 0xff0000) |
                ((audioFileHeader[5] << 16) & 0xff0000) |
                ((audioFileHeader[6] <<  8) & 0xff00) | 
                (audioFileHeader[7] & 0xff);
                
            if (hdr_size > AUDIO_FILE_HEADER_SIZE) {
                /*
                 * read remainder of the header and discard
                 */
                int excess_hdr_size =
                    hdr_size - AUDIO_FILE_HEADER_SIZE;
                    
                byte[] data = new byte[excess_hdr_size];
                
                in.read(data, 0, excess_hdr_size);

        if (Logger.logLevel >= Logger.LOG_MOREINFO) {
            Logger.println("Reading excess header " 
                + " hdr size " + hdr_size 
            + " excess " + excess_hdr_size);
        }
            }  
    } catch (Exception e) {
            throw new IOException("Can't read data!  " + path + " "
        + e.getMessage());
        }
    }

    public int[] getLinearData(int sampleTime) throws IOException {
    byte[] fileData = readAudioFile(sampleTime);

    if (fileData == null) {
        return null;
    }

    int[] linearData;
    if (encoding == ULAW) {
            // 1 ulaw byte for each int
            linearData = new int[fileData.length];
        AudioConversion.ulawToLinear(fileData, 0, fileData.length, 
        linearData);
    } else {
            // 2 linear bytes for each int
            linearData = new int[fileData.length / 2];

        for (int i = 0; i < linearData.length; i++) {
            linearData[i] = (int) 
            ((short)(((fileData[2 * i] << 8) & 0xff00) |
                (fileData[(2 * i) + 1] & 0xff)));
        }
    }

    return linearData;
    }

    private byte[] readAudioFile(int sampleTime) throws IOException {
    int bytesAvailable;

    if (in == null || (bytesAvailable = in.available()) == 0) {
        done();
        return null;
    }

    int sampleSize = 2;

    if (encoding == AudioSource.ULAW) {
        sampleSize = 1;
    }

    int len = 
        sampleRate * sampleTime * channels * sampleSize / 1000;

    byte[] data = new byte[len];

    try {
        int readSize;

        readSize = Math.min(len, bytesAvailable);
    
        /*
         * Read the file
         */ 
            in.read(data, 0, readSize);

        byte b;

        if (encoding == ULAW) {
        b = AudioConversion.PCMU_SILENCE;
        } else {
        b = AudioConversion.PCM_SILENCE;
        }

        for (int i = readSize; i < len; i++) {
        data[i] = b;
        }
    } catch (IOException e) {
        throw new IOException("Can't read data!  " + path + " "
        + e.getMessage());
    }

    return data;
    }

    public int getSampleRate() {
    return sampleRate;
    }

    public int getChannels() {
    return channels;
    }

    public void rewind() throws IOException {
    initialize();
    }

    public void done() {
    if (in != null) {
        try {
            in.close();
        } catch (IOException e) {
        }
    }
    }

}
