NSCache

今天在优化的时候,用了NSCache,感觉没什么两样(视觉上).按理内存缓存,怎么也比从硬盘读取的要快..

    dispatch_async(dispatch_get_global_queue(, ), ^{
        NSLog(@"Start");

        NSMutableArray *arr = [[NSMutableArray alloc] init];

        for (int i = ; i< ; i++) {

            UIImage *ii = [UIImage imageWithData:[Cache objectForKey:@"img"]];

            [arr addObject:ii];
        }

        NSLog(@"End");

    });

    /*  Result With Cache;

     2016-01-12 09:40:28.079 MVVM[67944:4076775] Start
     2016-01-12 09:40:28.088 MVVM[67944:4076775] End    ->9ms

     2016-01-12 09:41:02.894 MVVM[67944:4076798] Start
     2016-01-12 09:41:02.903 MVVM[67944:4076798] End    ->9ms

     2016-01-12 09:41:13.581 MVVM[67944:4077543] Start
     2016-01-12 09:41:13.589 MVVM[67944:4077543] End    ->8ms

     500次
     2016-01-12 09:45:51.976 MVVM[68151:4082651] Start
     2016-01-12 09:45:52.049 MVVM[68151:4082651] End    ->73ms

     2016-01-12 09:46:07.863 MVVM[68151:4082967] Start
     2016-01-12 09:46:07.929 MVVM[68151:4082967] End    ->66ms

     2016-01-12 09:46:36.374 MVVM[68151:4083477] Start
     2016-01-12 09:46:36.433 MVVM[68151:4083477] End    ->59ms

     */

    dispatch_async(dispatch_get_global_queue(, ), ^{
        NSLog(@"Disk_Start");

        NSMutableArray *arr = [[NSMutableArray alloc] init];

        for (int i = ; i< ; i++) {

            NSData *Rdata = [[NSData alloc] initWithContentsOfFile:filePath];

            UIImage *ii = [UIImage imageWithData:Rdata];

            [arr addObject:ii];
        }

        NSLog(@"Disk_End");

    });

    /*  Result With Disk

     2016-01-12 09:41:36.781 MVVM[67991:4078065] Disk_Start
     2016-01-12 09:41:36.846 MVVM[67991:4078065] Disk_End  ->65ms

     2016-01-12 09:41:53.204 MVVM[67991:4078091] Disk_Start
     2016-01-12 09:41:53.251 MVVM[67991:4078091] Disk_End  ->47ms

     2016-01-12 09:41:59.468 MVVM[67991:4078614] Disk_Start
     2016-01-12 09:41:59.514 MVVM[67991:4078614] Disk_End  ->46ms

     500次
     2016-01-12 09:44:32.986 MVVM[68073:4080907] Disk_Start
     2016-01-12 09:44:33.876 MVVM[68073:4080907] Disk_End   ->890ms

     2016-01-12 09:44:57.400 MVVM[68073:4081368] Disk_Start
     2016-01-12 09:44:57.976 MVVM[68073:4081368] Disk_End   ->576ms

     2016-01-12 09:45:12.159 MVVM[68073:4081577] Disk_Start
     2016-01-12 09:45:12.658 MVVM[68073:4081577] Disk_End   ->499ms

     */

cache->disk->Internet request

-(UIImage *)getImageForCacheOrDiskOrNetWithKey:(NSString*)Key
{

    //cache data

    NSCache *cache = [[NSCache alloc] init];

    NSData *CacheData =  [cache objectForKey:Key];

    if (CacheData != nil) {

        return [UIImage imageWithData:CacheData];

    }else{

        //Disk read

        NSArray *arr = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);

        NSString *cachePath = [arr firstObject];

        NSString *filePath = [cachePath stringByAppendingPathComponent:Key];

        NSData *Diskdata = [[NSData alloc] initWithContentsOfFile:filePath];

        if (Diskdata != nil) {

            return [UIImage imageWithData:Diskdata];

        }else{

            //internet request here;

            NSString *imageURLStr = @"http://pic.58pic.com/58pic/15/48/73/04f58PIC37y_1024.png";

            NSData *InternetData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:imageURLStr]];

            return [UIImage imageWithData:InternetData];

        }
    }

}

造轮子是为了学习,真正要用,还是老老实实的用sdwebimage等第三方库吧..