//

 //  Target.m

 //  MYUtilities

 //

 //  Created by Jens Alfke on 2/11/08.

 //  Copyright 2008 Jens Alfke. All rights reserved.

 //

 #import "Target.h"

 NSInvocation* _mktarget( id rcvr, SEL action )

 {

     NSMethodSignature *sig = [rcvr methodSignatureForSelector: action];

     CAssert(sig,@"%@<%p> does not respond to %@",[rcvr class],rcvr,NSStringFromSelector(action));

     CAssert(sig.numberOfArguments==3,

            @"-[%@ %@] can't be used as a target because it takes >1 param",

            [rcvr class],NSStringFromSelector(action));

     CAssert(0==strcmp([sig getArgumentTypeAtIndex: 2],"@"),

            @"-[%@ %@] can't be used as a target because it takes a non-object param",

            [rcvr class],NSStringFromSelector(action));

     NSInvocation *inv = [NSInvocation invocationWithMethodSignature: sig];

     inv.target = rcvr;

     inv.selector = action;

     return inv;

 }

 id $calltarget( NSInvocation *target, id param )

 {

     if( target && target.target ) {

         [target setArgument: &param atIndex: 2];

         [target invoke];

         NSMethodSignature *sig = target.methodSignature;

         NSUInteger returnLength = sig.methodReturnLength;

         if( returnLength==0 )

             return nil; // void

         else {

             const char *returnType = sig.methodReturnType;

             if( returnType[0]=='@' ) {

                 id returnObject;

                 [target getReturnValue: &returnObject];

                 return returnObject;

             } else {

                 UInt8 returnBuffer[returnLength];

                 [target getReturnValue: &returnBuffer];

                 return [NSValue valueWithBytes: &returnBuffer objCType: returnType];

             }

         }

     } else

         return nil;

 }