SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// Multi-Phasic Applications: 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 net.multiphasicapps.classfile;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import cc.squirreljme.runtime.cldc.util.UnmodifiableIterator;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;

/**
 * Represents a local variable table.
 *
 * @since 2022/09/21
 */
public final class LocalVariableTable
    implements Iterable<LocalVariableInfo>
{
    /** The entries within the table. */
    private final LocalVariableInfo[] _entries;
    
    /**
     * Initializes the local variable table.
     * 
     * @param __vars the variables to use.
     * @throws NullPointerException On null arguments.
     * @since 2022/09/23
     */
    public LocalVariableTable(LocalVariableInfo... __vars)
        throws NullPointerException
    {
        if (__vars == null)
            throw new NullPointerException("NARG");
        
        __vars = __vars.clone();
        for (LocalVariableInfo var : __vars)
            if (var == null)
                throw new NullPointerException("NARG");
        
        this._entries = __vars;
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/09/23
     */
    @Override
    public boolean equals(Object __o)
    {
        if (this == __o)
            return true;
        if (!(__o instanceof LocalVariableTable))
            return false;
        
        LocalVariableTable that = (LocalVariableTable)__o;
        return Arrays.equals(this._entries, that._entries);
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/09/23
     */
    @Override
    public int hashCode()
    {
        return Arrays.asList(this._entries).hashCode();
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/09/23
     */
    @Override
    public Iterator<LocalVariableInfo> iterator()
    {
        return UnmodifiableIterator.of(this._entries);
    }
    
    /**
     * Returns the number of entries within.
     * 
     * @return The size of the table.
     * @since 2022/09/23
     */
    public int size()
    {
        return this._entries.length;
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/09/23
     */
    @Override
    public String toString()
    {
        return Arrays.asList(this._entries).toString();
    }
    
    /**
     * Parses the local variable tables.
     * 
     * @param __pool The pool used.
     * @param __attrs The attributes to read from.
     * @return The resultant local variable table.
     * @throws IOException On read errors.
     * @throws NullPointerException On null arguments.
     * @since 2022/09/21
     */
    public static LocalVariableTable parse(Pool __pool,
        AttributeTable __attrs)
        throws IOException, NullPointerException
    {
        if (__pool == null || __attrs == null)
            throw new NullPointerException("NARG");
        
        // Get the table if it exists
        Attribute attr = __attrs.get("LocalVariableTable");
        if (attr == null)
            return new LocalVariableTable();
        
        // Parse data
        try (DataInputStream in = attr.open())
        {
            // How many?
            int count = in.readUnsignedShort();
            
            // Setup and load each one
            LocalVariableInfo[] result = new LocalVariableInfo[count];
            for (int i = 0; i < count; i++)
                result[i] = new LocalVariableInfo(
                    in.readUnsignedShort(),
                    in.readUnsignedShort(),
                    new FieldName(__pool.require(UTFConstantEntry.class,
                        in.readUnsignedShort()).toString()),
                    new FieldDescriptor(__pool.require(UTFConstantEntry.class,
                        in.readUnsignedShort()).toString()),
                    in.readUnsignedShort());
            
            return new LocalVariableTable(result);
        }
    }
}