NSFileHandle availableData example ios

availableData

Returns the data currently available in the receiver.

- (NSData *)availableData

Return Value of [NSFileHandle availableData]

The data currently available through the receiver, up to the the maximum size that can be represented by an NSDataobject.

Discussion of [NSFileHandle availableData]

If the receiver is a file, this method returns the data obtained by reading the file from the current file pointer to the end of the file. If the receiver is a communications channel, this method reads up to a buffer of data and returns it; if no data is available, the method blocks. Returns an empty data object if the end of file is reached. This method raisesNSFileHandleOperationException if attempts to determine the file-handle type fail or if attempts to read from the file or channel fail.

Example of [NSFileHandle availableData]

- (NSString *)outputFromExporter:(COExporter *)exporter input:(NSString *)input {

  NSString *exportedString = nil;

  NSString *path = [exporter path];

  NSTask *task = [[NSTask alloc] init];

  NSPipe *writePipe = [NSPipe pipe];

  NSFileHandle *writeHandle = [writePipe fileHandleForWriting];

  NSPipe *readPipe = [NSPipe pipe];

  NSFileHandle *readHandle = [readPipe fileHandleForReading];

  NSMutableData *outputData = [[NSMutableData alloc] init];

  NSData *readData = nil;

  // Set the launch path and I/O for the task

  [task setLaunchPath:path];

  [task setStandardInput:writePipe];

  [task setStandardOutput:readPipe];

  // Launch the exporter, it will convert the raw OPML into HTML, Plaintext, etc

  [task launch];

  // Write the raw OPML representation to the exporter's input stream

  [writeHandle writeData:[input dataUsingEncoding:NSUTF8StringEncoding]];

  [writeHandle closeFile];

  while ((readData = [readHandle availableData]) && [readData length]) {

    [outputData appendData:readData];

  }

  exportedString = [[NSString alloc] initWithData:outputData encoding:NSUTF8StringEncoding];

  return exportedString;

}