Question

I have a tableview, with a search bar. The table is loaded with 3700 text objects. The search occurs on the “title” text, which on average is 35 characters in length. I am looking for any optimization suggestions that would speed up the search sorting process. Currently, on average the search sort, is taking 0.733 seconds, which is about 95% of the entire search execution time. I am using a predicate that uses CONTAINS (has to, unfortunately) and then sortedArrayUsingComparator:, where I pass a block.

Thanks for taking a look!

Here is what I am doing:

    //My sorting block implementation
    self.mySortBlock = ^NSComparisonResult(id obj1, id obj2) {
        Tip *tip1 = obj1;
        Tip *tip2 = obj2;

        NSString *string1 = [tip1.subject lowercaseString];
        NSString *string2 = [tip2.subject lowercaseString];

        NSUInteger searchStringLocation1 = [string1 rangeOfString:[self.userSearchText lowercaseString]].location;
        NSUInteger searchStringLocation2 = [string2 rangeOfString:[self.userSearchText lowercaseString]].location;

        if (searchStringLocation1 > searchStringLocation2) return NSOrderedDescending;
        if (searchStringLocation1 < searchStringLocation2) return NSOrderedAscending;
        return NSOrderedSame;
    };

 - (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{

    NSPredicate *filter = [NSPredicate predicateWithFormat:@"subject CONTAINS [cd] %@", searchText];
    NSArray *filtered = [myArray filteredArrayUsingPredicate: filter];
    self.sorted = nil; 
    self.sorted = [filtered sortedArrayUsingComparator:self.mySortBlock];

}

EDIT
Per Catfish_Man’s suggestion below, I refactored the sort block to not instantiate objects inside the block unless absolutely necessary. I removed 4 object instantiations. The refactor brought with it, a +300% speed improvement:

Here is the refactored sort block:

self.mySortBlock = ^NSComparisonResult(id obj1, id obj2) {


    NSUInteger searchStringLocation1 = [[obj1 subject] rangeOfString:self.userSearchText options:NSCaseInsensitiveSearch].location;

    NSUInteger searchStringLocation2 = [[obj2 subject] rangeOfString:self.userSearchText options:NSCaseInsensitiveSearch].location;


     if (searchStringLocation1 > searchStringLocation2) return NSOrderedDescending;
     if (searchStringLocation1 < searchStringLocation2) return NSOrderedAscending;
     return NSOrderedSame;
};

Answer 1

Biggest thing I see: you’re allocating 4 objects in your sort function. Object allocation just isn’t very fast! Instead, try using -rangeOfString:options: and passing NSCaseInsensitiveSearch.