SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.runtime.cldc.io;

/**
 * Decoder for ASCII.
 *
 * @since 2018/12/23
 */
public final class ASCIIDecoder
    implements Decoder
{
    /**
     * {@inheritDoc}
     * @since 2018/12/23
     */
    @Override
    public final double averageSequenceLength()
    {
        return 1.0;
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/23
     */
    @Override
    public final int decode(byte[] __b, int __o, int __l)
        throws IndexOutOfBoundsException, NullPointerException
    {
        if (__b == null)
            throw new NullPointerException("NARG");
        if (__o < 0 || __l < 0 || (__o + __l) < 0 || (__o + __l) > __b.length)
            throw new IndexOutOfBoundsException("IOOB");
        
        // Not enough to decode a character
        if (__l <= 0)
            return -1;
        
        // Negative values are 128 and up
        byte b = __b[__o];
        if (b < 0)
            return 0x1_0000 | 0xFFFD;
        return 0x1_0000 | (b & 0xFF);
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/23
     */
    @Override
    public final String encodingName()
    {
        return "ascii";
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/23
     */
    @Override
    public final int maximumSequenceLength()
    {
        return 1;
    }
}