/**

* Copyright (c) Rich Hickey. All rights reserved.

* The use and distribution terms for this software are covered by the

* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

* which can be found in the file epl-v10.html at the root of this distribution.

* By using this software in any fashion, you are agreeing to be bound by

* the terms of this license.

* You must not remove this notice, or any other, from this software.

**/

/* rich Nov 8, 2009 */

package clojure.lang;

import java.util.Map;

public final class MethodImplCache{

static public class Entry{

final public Class c;

final public IFn fn;

public Entry(Class c, IFn fn){

this.c = c;

this.fn = fn;

}

}

public final IPersistentMap protocol;

public final Symbol sym;

public final Keyword methodk;

public final int shift;

public final int mask;

public final Object[] table; //[class, entry. class, entry ...]

public final Map map;

Entry mre = null;

public MethodImplCache(Symbol sym,IPersistentMap protocol, Keyword methodk){

this(sym, protocol, methodk, 0, 0, RT.EMPTY_ARRAY);

}

public MethodImplCache(Symbol sym, IPersistentMap protocol, Keyword methodk, int shift, int mask, Object[] table){

this.sym = sym;

this.protocol = protocol;

this.methodk = methodk;

this.shift = shift;

this.mask = mask;

this.table = table;

this.map = null;

}

public MethodImplCache(Symbol sym, IPersistentMap protocol, Keyword methodk, Map map){

this.sym = sym;

this.protocol = protocol;

this.methodk = methodk;

this.shift = 0;

this.mask = 0;

this.table = null;

this.map = map;

}

public IFn fnFor(Class c){

Entry last = mre;

if(last != null && last.c == c)

return last.fn;

return findFnFor(c);

}

IFn findFnFor(Class c){

if (map != null)

{

Entry e = (Entry) map.get(c);

mre = e;

return e != null ? e.fn : null;

}

else

{

int idx = ((Util.hash(c) >> shift) & mask) << 1;

if(idx < table.length && table[idx] == c)

{

Entry e = ((Entry) table[idx + 1]);

mre = e;

return e != null ? e.fn : null;

}

return null;

}

}

}