1 /*

     2 * Copyright (c) 2002 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  Event processor class for tone sequence PLAY_BLOCK events

    15 *

    16 */

    17 

    18 

    19 package com.nokia.microedition.media.tone;

    20 

    21 import javax.microedition.media.control.ToneControl;

    22 

    23 /**

    24  * Processor for play block events

    25  */

    26 public class PlayBlockEvent extends Event

    27 {

    28 

    29     // CONSTANTS

    30 

    31     /* Maximum and minimum values for block number */

    32     public static final int PLAY_BLOCK_MAX_VALUE = 127;

    33     public static final int PLAY_BLOCK_MIN_VALUE = 0;

    34 

    35     PlayBlockEvent(byte[] aSequence, MidiSequence aMidiSequence)

    36     {

    37         super(aSequence, aMidiSequence);

    38     }

    39 

    40     /**

    41      * Inherited from Event

    42      */

    43     public int advance(int aPosition)

    44     {

    45         int retVal = doValidate(aPosition);

    46         if (retVal != 0)

    47         {

    48             // Push the position to stack that is going to be

    49             // played after this play block has completed

    50             iReturnPositionStack.push(new Integer(aPosition + EVENT_SIZE));

    51 

    52             int data = iSequence[ aPosition + 1 ];

    53             retVal = findBlock(data) - aPosition;

    54         }

    55         return retVal;

    56     }

    57 

    58     /**

    59      * Child class defined functionality for validate

    60      * @param aPosition position in tone sequence array where to validate

    61      * @return new position offset related to aPosition in tone sequence

    62      * array. Must be positive.

    63      */

    64     protected int doValidate(int aPosition)

    65     throws IllegalArgumentException

    66     {

    67         // it is already checked that there is at least two bytes left

    68         int type = iSequence[ aPosition ];

    69         int data = iSequence[ aPosition + 1 ];

    70         int retVal = 0;

    71 

    72         if (type == ToneControl.PLAY_BLOCK)

    73         {

    74             if (data < PLAY_BLOCK_MIN_VALUE ||

    75                     data > PLAY_BLOCK_MAX_VALUE)

    76             {

    77                 throw new IllegalArgumentException(

    78                     "Block number out of range");

    79             }

    80             findBlock(data);   // for check only

    81             retVal = EVENT_SIZE;

    82         }

    83         return retVal;

    84     }

    85 

    86     /**

    87      * Find block

    88      * @param block number

    89      * @return position of corresponding BLOCK_START event

    90      * @exception IllegalArgumentException if block is not found

    91      */

    92     private int findBlock(int aBlockNumber)

    93     {

    94         for (int i = 0; i < iSequence.length; i += EVENT_SIZE)

    95         {

    96             if (iSequence[ i ] == ToneControl.BLOCK_START &&

    97                     iSequence[ i + 1 ] == aBlockNumber)

    98             {

    99                 return i;

   100             }

   101         }

   102         // if block is not found, input is illegal

   103         throw new IllegalArgumentException("No block found, sequence is corrupted");

   104     }

   105 

   106     /**

   107      * Child class defined functionality for checkEventAtNextPosition

   108      * @param aPosition position in tone sequence array where to check

   109      */

   110     protected void checkEventAtNextPosition(int aPosition)

   111     throws IllegalArgumentException

   112     {

   113         // After this event there can be:

   114         // Tone, BlockEnd PlayBlock, Volume, Repeat or end of sequence

   115 

   116         int type = 0;

   117         try

   118         {

   119             type = iSequence[ aPosition ];

   120         }

   121         catch (ArrayIndexOutOfBoundsException aioobe)

   122         {

   123             return; // end of sequence is OK

   124         }

   125 

   126 

   127         if (type >= ToneControl.SILENCE ||

   128                 type == ToneControl.BLOCK_END ||

   129                 type == ToneControl.PLAY_BLOCK ||

   130                 type == ToneControl.SET_VOLUME ||

   131                 type == ToneControl.REPEAT)

   132         {

   133             return;

   134         }

   135         throw new IllegalArgumentException("Illegal event found, sequence is corrupted");

   136     }

   137 } // end of class

   138