public LogFile MMFConcurrentRead(LogFile logFile, BackgroundWorker backgroundWorker)
{
Debug.Print("MMFConcurrentRead: enter");
GetEncoding(logFile);
// not sure why this here. messing up temp file
//logFile.IsNew = false;
//logFile.Modified = false;
if (!File.Exists(logFile.Tag))
{
Debug.Print("MMFConcurrentRead:error, file does not exist: " + logFile.Tag);
return(logFile);
}
byte[] bytes = new byte[new FileInfo(logFile.Tag).Length];
// 4,8,12
int threadCount = 1;
if (bytes.Length > 1000000)
{
threadCount = 8;
}
int bposition = logFile.HasBom ? logFile.Encoding.GetPreamble().Length : 0;
int blen = bytes.Length / threadCount;
MemoryMappedFile memoryMappedFile = MemoryMappedFile.CreateFromFile(logFile.Tag, FileMode.Open, "mmf", bytes.Length, MemoryMappedFileAccess.Read);
ManualResetEvent[] completedEvents = new ManualResetEvent[threadCount];
List <List <LogFileItem> > list = new List <List <LogFileItem> >();
for (int i = 0; i < threadCount; i++)
{
list.Add(new List <LogFileItem>());
completedEvents[i] = new ManualResetEvent(false);
}
for (int mmfCount = 0; mmfCount < threadCount; mmfCount++)
{
if (mmfCount != 0)
{
bposition += blen;
}
if (mmfCount == threadCount - 1)
{
blen = bytes.Length - bposition;
}
TaskMMFInfo taskInfo = new TaskMMFInfo()
{
mmf = memoryMappedFile,
stringList = list[mmfCount],
logFile = logFile,
position = bposition,
length = blen,
completedEvent = completedEvents[mmfCount],
bgWorker = backgroundWorker
};
ThreadPool.QueueUserWorkItem(new WaitCallback(ParallelMMFRead), taskInfo);
}
Debug.Print(string.Format("mmf thread length: {0}", blen));
WaitHandle.WaitAll(completedEvents);
if (memoryMappedFile != null)
{
memoryMappedFile.Dispose();
}
if (backgroundWorker.CancellationPending)
{
Debug.Print("MMFConcurrentRead:cancelled");
return(logFile);
}
bool patch = false;
List <LogFileItem> finalList = new List <LogFileItem>();
for (int listCount = 0; listCount < threadCount; listCount++)
{
if (patch)
{
// merge last line with first line in current list
finalList[finalList.Count - 1].Content = finalList[finalList.Count - 1].Content + list[listCount][0].Content;
list[listCount].RemoveAt(0);
patch = false;
}
finalList.AddRange(list[listCount]);
list[listCount].Clear();
// need to check for partial lines look in last index for needsPatch string
if (finalList.Count > 0)
{
if (finalList[finalList.Count - 1].Content == _needsPatch)
{
finalList.RemoveAt(finalList.Count - 1);
patch = true;
}
else
{
patch = false;
}
}
}
// set index
int counter = 1;
foreach (LogFileItem item in finalList)
{
item.Index = counter++;
}
Debug.Print("MMFConcurrentRead:exit");
logFile.ContentItems = new ObservableCollection <LogFileItem>(finalList);
return(logFile);
}
public void ParallelMMFRead(object taskMMFInfo)
{
try
{
TaskMMFInfo taskInfo = (TaskMMFInfo)taskMMFInfo;
Debug.Print(string.Format("ParallelMMFRead:enter : position:{0} length:{1} total:{2}",
taskInfo.position, taskInfo.length, taskInfo.length + taskInfo.position));
MemoryMappedViewStream viewStream = taskInfo.mmf.CreateViewStream(taskInfo.position, taskInfo.length, MemoryMappedFileAccess.Read);
byte[] bytes = new byte[taskInfo.length];
viewStream.Read(bytes, 0, taskInfo.length);
byte[] newLine = (taskInfo.logFile.Encoding).GetBytes(Environment.NewLine);
int beginningIndex = 0;
int indexCount = 0;
int fixUp = 0;
int x = 0;
int step = Math.Max(1, newLine.Length / 2);
// check first two bytes to make sure not part of crlf
if (bytes[0] == newLine[0] || bytes[0] == newLine[step])
{
fixUp = step;
if (bytes[step] == newLine[step])
{
fixUp = step * 2;
}
taskInfo.stringList.Add(new LogFileItem());
}
for (x = fixUp; x < bytes.Length; x += step)
{
if (taskInfo.bgWorker.CancellationPending)
{
taskInfo.completedEvent.Set();
Debug.Print("ParallelMMFRead:cancelled");
return;
}
if (bytes[x] == newLine[0])
{
LogFileItem logFileItem = new LogFileItem()
{
Content = (taskInfo.logFile.Encoding).GetString(bytes, beginningIndex, indexCount),
Background = Settings.BackgroundColor,
Foreground = Settings.ForegroundColor,
};
taskInfo.stringList.Add(logFileItem);
if (x + step <= bytes.Length && bytes[x + step] == newLine[step])
{
x += step;
}
beginningIndex = x + step;
indexCount = 0;
}
else
{
indexCount += step;
}
}
if (indexCount > 1)
{
// partial string
LogFileItem logFileItem = new LogFileItem()
{
Content = (taskInfo.logFile.Encoding).GetString(bytes, beginningIndex, bytes.Length - beginningIndex),
Background = Settings.BackgroundColor,
Foreground = Settings.ForegroundColor,
// Index = x
};
taskInfo.stringList.Add(logFileItem);
logFileItem = new LogFileItem()
{
Content = _needsPatch,
Background = Settings.BackgroundColor,
Foreground = Settings.ForegroundColor,
// Index = x
};
taskInfo.stringList.Add(logFileItem);
}
taskInfo.completedEvent.Set();
Debug.Print("ParallelMMFRead:exit");
}
catch (Exception e)
{
Debug.Print("ParallelMMFRead:exception" + e.ToString());
return;
}
}
