public void MergeFiles()
{
int chunks = this.InFiles.Count; // Number of chunks
int recordsize = MergeOptions.EstimatedRecordLength; // estimated record size
long maxusage = MergeOptions.BufferSize; // max memory usage
long buffersize = maxusage / chunks; // bytes of each queue
double recordoverhead = 7.5; // The overhead of using Queue<>
int bufferlen = (int)(buffersize / recordsize /
recordoverhead); // number of records in each queue
// Open the files
StreamReader[] readers = new StreamReader[this.InFiles.Count];
try
{
for (int i = 0; i < chunks; i++)
{
readers[i] = new StreamReader(this.InFiles[i]);
}
// Make the queues
Queue <string>[] queues = new Queue <string> [chunks];
for (int i = 0; i < chunks; i++)
{
queues[i] = new Queue <string>(bufferlen);
}
// Load the queues
for (int i = 0; i < chunks; i++)
{
LoadQueue(queues[i], readers[i], bufferlen);
}
// Merge!
using (StreamWriter sw = new StreamWriter(this.OutFile))
{
bool done = false;
int lowest_index, j, progress = 0;
string lowest_value;
while (!done)
{
// Find the chunk with the lowest value
lowest_index = -1;
lowest_value = "";
for (j = 0; j < chunks; j++)
{
if (queues[j] != null)
{
var peakedItem = queues[j].Peek() + "";
if (lowest_index < 0 ||
Cs.Compare(peakedItem, lowest_value) < 0)
{
lowest_index = j;
lowest_value = peakedItem;
}
}
}
// Was nothing found in any queue? We must be done then.
if (lowest_index == -1)
{
done = true; break;
}
// Output it
sw.WriteLine(lowest_value);
// Remove from queue
queues[lowest_index].Dequeue();
// Have we emptied the queue? Top it up
if (queues[lowest_index].Count == 0)
{
LoadQueue(queues[lowest_index],
readers[lowest_index], bufferlen);
// Was there nothing left to read?
if (queues[lowest_index].Count == 0)
{
queues[lowest_index] = null;
}
}
}
sw.Close();
}
}
catch (System.Exception e)
{
throw;
}
finally
{
// Close and delete the files
for (int i = 0; i < chunks; i++)
{
readers[i].Close();
}
}
}
