/// <see cref="IIntegerFileInfoCollector.GetIntegerFileInfo(string, int)"/>
public IntegerFileInfo GetIntegerFileInfo(string filePath, int chunkSize)
{
Debug.Assert(filePath != null);
Debug.Assert(chunkSize > 0);
IntegerFileInfo fileInfo = new IntegerFileInfo()
{
NumOfChunks = 0,
NumOfIntegers = 0
};
//Open a text reader to the file
using (StreamReader fileReader = fileIO.CreateFileStreamReader(filePath))
{
while (!fileReader.EndOfStream)
{
//Read each line to count the number of lines in the file
fileReader.ReadLine();
fileInfo.NumOfIntegers++;
}
}
//Now that we have the number of integers, calculate the number of chunks
fileInfo.NumOfChunks = (int)Math.Ceiling(Decimal.Divide(fileInfo.NumOfIntegers, chunkSize));
return(fileInfo);
}
/// <summary>
/// Merges an input file group into a single output file
/// </summary>
/// <param name="fileGroup">The names of the input files to be merged</param>
/// <param name="outputDirectory">The directory the output file is to be written in</param>
/// <param name="fileTemplate">The template for the output file</param>
/// <param name="fileGroupNumber">The file group number</param>
/// <param name="updateProgress">A method that will be called to update chunk file creation progress. The
/// number of integers that have been merged so far in the file group will be passed to this method
/// whenever an integer is merged.</param>
/// <returns>The path of the output file that was written</returns>
private string MergeInputFileGroup(List <string> fileGroup, string outputDirectory, string fileTemplate,
int fileGroupNumber, Action <int> updateProgress = null)
{
//Create the input stream readers
List <StreamReader> inputStreamReaders = fileGroup
.Select(file => fileIO.CreateFileStreamReader(file))
.ToList();
//Create the output file and output file stream writer
string outputFilePath = Path.Combine(outputDirectory, string.Format(fileTemplate, fileGroupNumber));
using (Stream outputFileStream = fileIO.CreateFile(outputFilePath))
using (StreamWriter outputStreamWriter = new StreamWriter(outputFileStream))
{
//Merge the input streams into the output stream
integerStreamMerger.MergeIntegerStreams(inputStreamReaders, outputStreamWriter, updateProgress);
}
//Close the input stream readers
inputStreamReaders.ForEach(inputStreamReader => inputStreamReader.Close());
return(outputFilePath);
}
/// <summary>
/// Creates sorted chunks files from an input file
/// </summary>
/// <param name="inputFile">The input file from which the integers are to be read</param>
/// <param name="chunkSize">The chunk size to use when chunking the input</param>
/// <param name="outputDirectory">The output directory where the intermediate files are to be written</param>
///
/// <returns>The names of the chunk files that were created</returns>
private static List <string> CreateSortedChunkFiles(string inputFile, int chunkSize, string outputDirectory,
string chunkFileTemplate, Action <int> updateChunkProgress)
{
IFileIO fileIO = serviceProvider.GetService <IFileIO>();
//Create the chunk stream generator from the input file
IChunkStreamCreator chunkStreamCreator = serviceProvider.GetService <IChunkStreamCreator>();
StreamReader inputStreamReader = fileIO.CreateFileStreamReader(inputFile);
//Create the chunk generator and add a transformation that sorts each chunk as it is emitted
IEnumerable <List <int> > sortedChunkGenerator = chunkStreamCreator
.CreateIntegerChunkGenerator(inputStreamReader, chunkSize)
.Select(chunk => chunk.OrderBy(integer => integer).ToList());
//Create the chunk files
IChunkFileCreator chunkFileCreator = serviceProvider.GetService <IChunkFileCreator>();
List <string> chunkFiles = chunkFileCreator.CreateChunkFiles(sortedChunkGenerator, chunkFileTemplate, outputDirectory,
updateChunkProgress);
return(chunkFiles);
}