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 net.multiphasicapps.classfile;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;

/**
 * This represents a range of instruction addresses, the start is inclusive
 * and the end is exclusive.
 *
 * @since 2019/03/21
 */
public final class InstructionAddressRange
    implements Comparable<InstructionAddressRange>
{
    /** The start address. */
    protected final int start;
    
    /** The end address. */
    protected final int end;
    
    /** String representation. */
    private Reference<String> _string;
    
    /**
     * Initializes the address range.
     *
     * @param __s The start address.
     * @param __e The end address.
     * @since 2019/03/21
     */
    public InstructionAddressRange(int __s, int __e)
    {
        this.start = __s;
        this.end = __e;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/03/21
     */
    @Override
    public final int compareTo(InstructionAddressRange __b)
    {
        int rv = this.start - __b.start;
        if (rv != 0)
            return rv;
        
        return this.end - __b.end;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/03/21
     */
    @Override
    public final boolean equals(Object __o)
    {
        if (__o == this)
            return true;
        
        if (!(__o instanceof InstructionAddressRange))
            return false;
        
        InstructionAddressRange o = (InstructionAddressRange)__o;
        return this.start == o.start &&
            this.end == o.end;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/03/21
     */
    @Override
    public final int hashCode()
    {
        return this.start ^ (~this.end);
    }
    
    /**
     * Checks if the given address is in the range of this range.
     *
     * @param __pc The address to check.
     * @return If the address is in range.
     * @since 2019/03/22
     */
    public final boolean inRange(int __pc)
    {
        return __pc >= this.start && __pc < this.end;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/03/21
     */
    @Override
    public final String toString()
    {
        Reference<String> ref = this._string;
        String rv;
        
        if (ref == null || null == (rv = ref.get()))
            this._string = new WeakReference<>((rv = "@[" + this.start +
                "-" + this.end + ")"));
        
        return rv;
    }
}