get totally files size in directory

NSStirng+Util.m

@impelementaton NSString(Utils)
+ (uint64_t)sizeAtPath:(NSString *)filePath diskMode:(BOOL)diskMode
{
    uint64_t totalSize = 0;
    NSMutableArray *searchPaths = [NSMutableArray arrayWithObject:filePath];
    while ([searchPaths count] > 0)
    {
        @autoreleasepool
        {
            NSString *fullPath = [searchPaths objectAtIndex:0];
            [searchPaths removeObjectAtIndex:0];
            
            struct stat fileStat;
            if (lstat([fullPath fileSystemRepresentation], &fileStat) == 0)
            {
                if (fileStat.st_mode & S_IFDIR)
                {
                    NSArray *childSubPaths = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:fullPath error:nil];
                    for (NSString *childItem in childSubPaths)
                    {
                        NSString *childPath = [fullPath stringByAppendingPathComponent:childItem];
                        [searchPaths insertObject:childPath atIndex:0];
                    }
                }else
                {
                    if (diskMode)
                        totalSize += fileStat.st_blocks*512;
                    else
                        totalSize += fileStat.st_size;
                }
            }
        }
    }
    
    return totalSize;
}
@end