private static string[] InitialSort(string inputFile, string tempDir, Options opt)
{
List<string> tempFiles = new List<string>();
var sw = new System.Diagnostics.Stopwatch();
sw.Start();
//read a chunk, sort it, then write it to file
using (StreamReader reader = new StreamReader(inputFile))
{
using (ManualResetEvent mre = new ManualResetEvent(true))
{
NameGen nameGen = new NameGen(tempDir);
string line;
int lineNo = 0;
int maxSortSize = opt.MaxSortSize;
SortParam[] parameters = new SortParam[2];
parameters[0] = new SortParam(maxSortSize, mre, 0);
parameters[1] = new SortParam(maxSortSize, mre, 1);
int currentParam = 0;
int[] buffer = parameters[currentParam].buffer;
int j = 0;
while ((line = reader.ReadLine()) != null)
{
lineNo++;
int data;
//if (Int32.TryParse(line, out data)) //slow
if (StringToInt(line, out data))
{
buffer[j++] = data;
if (j >= maxSortSize)
{
string name = nameGen.NewName();
tempFiles.Add(name);
parameters[currentParam].Reset(j, name);
SortOnThread(parameters[currentParam]);
//swap
currentParam = (currentParam + 1) % 2;
buffer = parameters[currentParam].buffer;
j = 0;
}
}
else
Warn("Skipping line " + lineNo.ToString());
}
if (j > 0)
{
string name = nameGen.NewName();
tempFiles.Add(name);
parameters[currentParam].Reset(j, name);
SortOnThread(parameters[currentParam]);
}
mre.WaitOne();
parameters[0].mre = null; parameters[1].mre = null;
}
reader.Close();
}
sw.Stop();
Console.WriteLine("Time to sort intermediate files: {0}", sw.Elapsed.ToString());
return tempFiles.ToArray();
}
