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;

/**
 * This represents the class version that a class may be.
 *
 * @since 2016/06/29
 */
public enum ClassVersion
{
    /** CLDC 1.0 (JSR 30). */
    CLDC_1((45 << 16) + 3, (47 << 16) - 1, false, false, false),
    
    /** CLDC 1.1 (JSR 139). */
    CLDC_1_1((47 << 16), (51 << 16) - 1, true, false, false),
    
    /** CLDC 8 (aka Java 7). */
    CLDC_8((51 << 16), (52 << 16), true, false, true),
    
    /* End. */
    ;
    
    /** The minimum supported version. */
    public static final ClassVersion MIN_VERSION = ClassVersion.CLDC_1;
    
    /** The maximum supported version. */
    public static final ClassVersion MAX_VERSION = ClassVersion.CLDC_8;
    
    /** The version ID. */
    protected final int version;
    
    /** The maximum range of the version. */
    protected final int maxversion;
    
    /** Has floating point support? */
    protected final boolean hasfloat;
    
    /** Supports invokedynamic? */
    protected final boolean hasinvokedynamic;
    
    /** Use StackMapTable? */
    protected final boolean usestackmaptable;
    
    /**
     * Initializes the version data.
     *
     * @param __vid The version ID.
     * @param __vmx The max version identifier.
     * @param __float Is floating point supported?
     * @param __hasid Has invoke dynamic support?
     * @param __usesmt Should the StackMapTable attribute be used?
     * @since 2016/03/13
     */
    ClassVersion(int __vid, int __vmx, boolean __float, boolean __hasid,
        boolean __usesmt)
    {
        // Set
        this.version = __vid;
        this.maxversion = __vmx;
        this.hasfloat = __float;
        this.hasinvokedynamic = __hasid;
        this.usestackmaptable = __usesmt;
    }
    
    /**
     * Returns {@code true} if floating point is supported by the virtual
     * machine.
     *
     * @return {@code true} if it is.
     * @since 2016/03/13
     */
    public boolean hasFloatingPoint()
    {
        return this.hasfloat;
    }
    
    /**
     * Returns {@code true} if invokedynamic is supported by the virtual
     * machine.
     *
     * @return {@code true} if it is.
     * @since 2016/03/15
     */
    public boolean hasInvokeDynamic()
    {
        return this.hasinvokedynamic;
    }
    
    /**
     * Should the new StackMapTable attribute be used when veryifying the byte
     * code of a class?
     *
     * @return {@code true} if the "StackMapTable" attribute should be parsed
     * instead of "StackMap".
     * @since 2016/03/20
     */
    public boolean useStackMapTable()
    {
        return this.usestackmaptable;
    }
    
    /**
     * Finds the best matching version with the given ID.
     *
     * @param __vid The version ID to get a match for.
     * @return The matching class version or {@code null} if not found.
     * @since 2016/03/13
     */
    public static ClassVersion findVersion(int __vid)
    {
        // Go through all versions, find the best
        ClassVersion best = null;
        for (ClassVersion v : ClassVersion.values())
            if (__vid >= v.version && __vid <= v.maxversion)
                if (best == null || v.version > best.version)
                    best = v;
        
        // Use the best (if any)
        return best;
    }
}