Search for mail by subject using libetpan for iOS

Mail_Search.m

/* 
This function searches a mailimap session for messages with a certain string in their subject line, and returns those messages udid numbers.  NOTE: This is called synchronously, so do it in a background thread.
*/

+(NSArray*)searchFolderForString:(NSString*)string withFolderSession:(struct mailimap *)session {
    if([string length] == 0) {
        return nil;
    }
    
    int err;
    const char *charset = [@"UTF-8" cStringUsingEncoding:NSUTF8StringEncoding];
    const char *search = [string cStringUsingEncoding:NSUTF8StringEncoding];
    clist * fetch_result = NULL;
    
    struct mailimap_search_key *searchKey = mailimap_search_key_new_subject((char *)search);
    
    err = mailimap_uid_search(session, charset, searchKey, &fetch_result);

    if(err != MAIL_NO_ERROR) {
        NSLog(@"Error searching mailbox");
        return nil;
    }
    
    int len = clist_count(fetch_result);
    NSMutableArray *tempArray = [[NSMutableArray alloc] initWithCapacity:len];
    clistiter *fetchResultIter = clist_begin(fetch_result);
    for(int i=0; i<len; i++) {
        uint32_t * mes = (uint32_t*)clist_content(fetchResultIter);
        [tempArray addObject:[NSNumber numberWithUnsignedInt:*mes]];
        fetchResultIter = clist_next(fetchResultIter);
    }

    clist_free(fetch_result);
        
    return [NSArray arrayWithArray:tempArray];
}