how to search Table cell in iphone application

i have develop an RSS iphone application. as the data come from xml feed in table cell i am fail to implement search functionality in it. following is the code in which the date is displayed in table cell

    int blogEntryIndex1 = [i开发者_开发知识库ndexPath indexAtPosition: [indexPath length] -1];

  NSString  *imgstring=[[blogEntries objectAtIndex: blogEntryIndex1] objectForKey: @"image"];
    NSString *headline=[[blogEntries objectAtIndex: blogEntryIndex1] objectForKey: @"title"];
    //code given to me
    NSURL *url = [NSURL URLWithString:imgstring];
    NSData *data = [NSData dataWithContentsOfURL:url];

    UIImage *img = [[UIImage alloc] initWithData:data];
cell.imageView.image=img;
    cell.textLabel.text=headline;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;

can anybody help me to implement search bar i am trying on this since last 5 days but I have failed in implementing it. I will be waiting for your replies.