/// <summary>
/// Reads data from a file and puts it into a queue for a consumer.
/// </summary>
public void ProduceData()
{
try
{
FileInfo inputFile = new FileInfo(Program.GetInputFile());
using (FileStream inputFileStream = inputFile.OpenRead())
{
ReadFromFileAndEnqueue(inputFileStream);
EnqueueObject(null); // null object is attached to the end of the queue where there are no more bytes to read from the input file => signal the consumer to exit
}
}
catch (DirectoryNotFoundException)
{
ErrorsChecker.SetError(new DirectoryNotFoundException("Error message: The input directory you're looking for doesn't exist."));
}
catch (DriveNotFoundException)
{
ErrorsChecker.SetError(new DriveNotFoundException("Error message: The input drive you're looking for doesn't exist."));
}
catch (FileNotFoundException)
{
ErrorsChecker.SetError(new FileNotFoundException("Error message: The input file you're looking for doesn't exist."));
}
catch (FileLoadException)
{
ErrorsChecker.SetError(new FileLoadException("Error message: The input file you're looking has been found but it can't be loaded."));
}
catch (PathTooLongException)
{
ErrorsChecker.SetError(new PathTooLongException("Error message: The input path is longer or fully qualified file name is longer than the system-defined maximum length."));
}
catch (UnauthorizedAccessException)
{
ErrorsChecker.SetError(new UnauthorizedAccessException("Error message: Access to the input directory or file was denied."));
}
catch (OutOfMemoryException)
{
ErrorsChecker.SetError(new OutOfMemoryException("Error message: There is not enough memory to continue the execution of the program."));
}
catch (Exception e)
{
Console.WriteLine(e.Message);
ErrorsChecker.SetError(new Exception("Error message: An error occured during the execution of the program."));
}
}
/// <summary>
/// Takes data objects from a queue, processes them (compression/decompression) and writes them to the output file.
/// </summary>
/// <param name="outputFileStreamObject">output file stream</param>
public void ConsumeData(object outputFileStreamObject) //takes data from a queue
{
try
{
FileStream outputFileStream = (FileStream)outputFileStreamObject;
while (true) // keeps the consumer thread running
{
IndexedDataObject dataElementFromQueue = null;
lock (lockQueue)
{
if (queue.Count > 0) // queue not empty
{
dataElementFromQueue = queue.Dequeue();
Monitor.PulseAll(lockQueue); // data removed from a queue => wake up the producer to put more data into the queue
if (dataElementFromQueue == null) // null object in queue means end of file reached, nothing more to read
{
ProducerConsumer.lastBlockRead = true; // last block in the queue (there are no more bytes to read from the input file)
return; // Producer ended, all objects from the queue have been already processed => this thread ends
}
}
else
{
if (ProducerConsumer.lastBlockRead)
{
return; // Producer ended, all objects from the queue have been already processed (or are processed by other threads) => this thread ends
}
Monitor.Wait(lockQueue);
}
}
// data object was read from the queue => we can release the lock and enable access to the queue again to the producer or other consumer threads
if (dataElementFromQueue != null)
{
IndexedDataObject processedData = ProcessData(dataElementFromQueue);
lock (lockOutputFile)
{
// thread waits for previous data blocks to be written to the file before it can write its own data block to the file
while ((processedData.Index - 1) != ProducerConsumer.GetProcessedBlocksCount())
{
Monitor.Wait(lockOutputFile);
}
WriteToFile(processedData, outputFileStream);
ProducerConsumer.IncrementProcessedBlocksCount();
Monitor.PulseAll(lockOutputFile);
}
}
}
}
catch (DirectoryNotFoundException)
{
ErrorsChecker.SetError(new DirectoryNotFoundException("Error message: The output directory you're looking for doesn't exist."));
}
catch (DriveNotFoundException)
{
ErrorsChecker.SetError(new DriveNotFoundException("Error message: The output drive you're looking for doesn't exist."));
}
catch (PathTooLongException)
{
ErrorsChecker.SetError(new PathTooLongException("Error message: The output path is longer or fully qualified file name is longer than the system-defined maximum length."));
}
catch (UnauthorizedAccessException)
{
ErrorsChecker.SetError(new UnauthorizedAccessException("Error message: Access to the output directory was denied."));
}
catch (OutOfMemoryException)
{
ErrorsChecker.SetError(new OutOfMemoryException("Error message: There is not enough memory to continue the execution of the program."));
}
catch (Exception e)
{
Console.WriteLine(e.Message);
ErrorsChecker.SetError(new Exception("Error message: An error occured during the execution of the program."));
}
}