SquirrelJME/SquirrelJME

// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the GNU General Public License v3+, or later.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.runtime.media.midi;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.io.ByteArrayInputStream;

/**
 * This is a parser for MIDI's {@code MTrk} which is a single MIDI track, it
 * is able to read events and wait for the next one accordingly.
 *
 * @since 2022/04/24
 */
public final class MTrkParser
{
    /** The MIDI buffer data. */
    private final byte[] _buffer;
    
    /** The offset into the buffer. */
    private final int _offset;
    
    /** The length of the buffer. */
    private final int _length;
    
    /** The tick division duration of the track. */
    private int _tickDivDuration =
        -1;
    
    /**
     * Initializes the parser for MIDI {@code MTrk}.
     * 
     * @param __b The buffer to read data from.
     * @param __o The offset into the buffer.
     * @param __l The length of the buffer.
     * @throws IndexOutOfBoundsException If the offset and/or length are
     * negative or exceed the array bounds.
     * @throws NullPointerException On null arguments.
     * @since 2022/04/24
     */
    public MTrkParser(byte[] __b, int __o, int __l)
        throws IndexOutOfBoundsException, NullPointerException
    {
        if (__b == null)
            throw new NullPointerException("NARG");
        if (__o < 0 || __l < 0 || (__o + __l) > __b.length)
            throw new IndexOutOfBoundsException("IOOB");
        
        this._buffer = __b;
        this._offset = __o;
        this._length = __l;
    }
    
    /**
     * Returns an input stream over the track data.
     *
     * @return The input stream used.
     * @since 2024/02/26
     */
    public ByteArrayInputStream inputStream()
    {
        return new ByteArrayInputStream(this._buffer, this._offset,
            this._length);
    }
    
    /**
     * Returns the length of the track in bytes.
     *
     * @return The length of the track in bytes.
     * @since 2024/02/25
     */
    public int length()
    {
        return this._length;
    }
    
    /**
     * Returns the total tick division duration for this given track.
     * 
     * @return The total tick division duration for this track.
     * @since 2022/04/25
     */
    public final int tickDivDuration()
    {
        // Does the duration need to be figured out?
        int deltaDuration = this._tickDivDuration;
        if (deltaDuration < 0)
            this._tickDivDuration =
                (deltaDuration = this.__calculateTickDivDuration());
        
        return deltaDuration;
    }
    
    /**
     * Calculates the tick division duration of the track.
     * 
     * @return The calculated tick division duration of the track.
     * @since 2022/04/24
     */
    private int __calculateTickDivDuration()
    {
        throw Debugging.todo();
    }
}