Sunday, May 12, 2013

NSInputStream initWithFileAtPath example ios


Initializes and returns an NSInputStream object that reads data from the file at a given path.
- (id)initWithFileAtPath:(NSString *)path
The path to the file.
Return Value( NSInputStream initWithFileAtPath example )
An initialized NSInputStream object that reads data from the file at path. If the file specified by pathdoesn’t exist or is unreadable, returns nil.
( NSInputStream initWithFileAtPath example )
NSString *path = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"bin"];
NSInputStream *is = [[NSInputStream alloc] initWithFileAtPath:path];
( NSInputStream initWithFileAtPath example )
- (void)setUpStreamsForInputFile:(NSString *)inpath outputFile:(NSString *)outpath  {
    self.p_iStream = [[NSInputStream alloc] initWithFileAtPath:inpath];
    [p_iStream setDelegate:self];

    // here: change the queue type and use a background queue (you can change priority)
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);
    dispatch_async(queue, ^ {
        [p_iStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
        [p_iStream open];

        // here: start the loop
        [[NSRunLoop currentRunLoop] run];
        // note: all code below this line won't be executed, because the above method NEVER returns.
( NSInputStream initWithFileAtPath example )
@synthesize numberOfBytesTransferred = _numberOfBytesTransferred;

static const NSUInteger blockSize = 65536; // should be adjusted

- (void)startWithSourcePath:(NSString *)srcPath
            destinationPath:(NSString *)dstPath
          completionHandler:(void (^)(NSUInteger, NSError *))completionHandler
    _buffer = malloc(blockSize);
    _numberOfBytesTransferred = _bufferLength = _bufferOffset = 0;
    _completionHandler = [completionHandler copy];
    _srcStream = [[NSInputStream alloc] initWithFileAtPath:srcPath];
    _dstStream = [[NSOutputStream alloc] initToFileAtPath:dstPath append:NO];
    _srcStream.delegate = self;
    _dstStream.delegate = self;
    [_srcStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
    [_dstStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
    [_srcStream open];
    [_dstStream open];