IOS Cocos2d How to gen animation with CCRepeatForever

+ (CCRepeatForever*) genAnimation:(NSString*) shadowName delay:(float) delay _nRow:(int) nRow _nCol:(int) nCol lastNum:(int) num {
   
    int rFrame,cFrame;
    if(num!=0) {
        rFrame = nRow - 1;
        cFrame = num - 1;
    } else {
        rFrame = nRow ;
        cFrame = nCol;
    }
   
    /* setting animation for sprite */
    if([shadowName length] > 0 ) {
        CGSize size = [Global getImageSize:shadowName];
        int width = size.width/nCol;
        int height = size.height/nRow;
   
        NSMutableArray *animationFrames = [NSMutableArray arrayWithCapacity:nRow*nCol];
       
        for (int i = 0; i < nRow; i++) {
            for (int j = 0; j < nCol; j++) {
                [animationFrames addObject:[self getFrameFromImage:shadowName x:j y:i w:width h:height]];
                if(num > 0) {
                    if((i == nRow - 1) && (j == num - 1)) break;
                }
            }
        }   
       
        CCAnimation *animation = [CCAnimation animationWithSpriteFrames:animationFrames delay:delay];
        CCAnimate *animate = [CCAnimate actionWithAnimation:animation];
        CCRepeatForever *repeat = [CCRepeatForever actionWithAction:animate];
        return repeat;
       
    }
   
    return nil;
}
// Gen animation from list image
+ (CCRepeatForever*) genAnimationFromImages:(NSMutableArray*) imageArray delay:(float) delay {
   
    /* setting animation for sprite */

    NSMutableArray *animationFrames = [NSMutableArray arrayWithCapacity:[imageArray count]];
   
    for (int i = 0; i < [imageArray count]; i++) {
        CGSize size = [Global getImageSize:(NSString*)[imageArray objectAtIndex:i]];
        int width = size.width;
        int height = size.height;
        [animationFrames addObject:[self getFrameFromImage:(NSString*)[imageArray objectAtIndex:i] x:0 y:0 w:width h:height]];              
    }   
    CCAnimation *animation = [CCAnimation animationWithSpriteFrames:animationFrames delay:delay];
    CCAnimate *animate = [CCAnimate actionWithAnimation:animation];
    CCRepeatForever *repeat = [CCRepeatForever actionWithAction:animate];
    return repeat;
  
}