Update - Clean up code

Author: ikelaiah

entries/ikelaiah/src/weatherstation.pas

@@ -29,20 +29,18 @@   TStat = record
     sum: int64;
     cnt: int64;
   public
-    constructor Create(const newMin: int64; const newMax: int64;
-      const newSum: int64; const newCount: int64);
     function ToString: string;
   end;
   {Using pointer to TStat saves approx. 30-60 seconds for processing 1 billion rows}
   PStat = ^TStat;
 
 type
   // Using this dictionary, now approx 4 mins faster than Generics.Collections.TDictionary
-  TWeatherDictionaryLG = specialize TGHashMapQP<string, PStat>;
+  TWeatherDictionaryLG = specialize TGHashMapLP<string, PStat>;
 
 type
   // a type for storing valid lookup temperature
-  TValidTemperatureDictionary = specialize TGHashMapQP<string, int64>;
+  TValidTemperatureDictionary = specialize TGHashMapLP<string, int64>;
 
 type
   // Create a class to encapsulate the temperature observations of each weather station.
@@ -106,15 +104,6 @@ function RemoveDots(const line: string): string;
   end;
 end;
 
-constructor TStat.Create(const newMin: int64; const newMax: int64;
-  const newSum: int64; const newCount: int64);
-begin
-  self.min := newMin;
-  self.max := newMax;
-  self.sum := newSum;
-  self.cnt := newCount;
-end;
-
 function TStat.ToString: string;
 var
   minR, meanR, maxR: double; // Store the rounded values prior saving to TStringList.
@@ -314,7 +303,9 @@ procedure TWeatherStation.ParseStationAndTemp(const line: string);
     // Get the weather station name
     // Using Copy and POS - as suggested by Gemini AI.
     // This part saves 3 mins faster when processing 1 billion rows.
-    //parsedStation := Copy(line, 1, delimiterPos - 1);
+
+    // No need to create a string
+    // parsedStation := Copy(line, 1, delimiterPos - 1);
     strFloatTemp := Copy(line, delimiterPos + 1, Length(line));
 
     // Using a lookup value speeds up 30-45 seconds
@@ -324,49 +315,19 @@ procedure TWeatherStation.ParseStationAndTemp(const line: string);
       self.AddCityTemperatureLG(Copy(line, 1, delimiterPos - 1),
         parsedTemp);
     end;
-
   end;
-
-  {// Get position of the delimiter
-  delimiterPos := Pos(';', line);
-  if delimiterPos > 0 then
-  begin
-    // Get the weather station name
-    // Using Copy and POS - as suggested by Gemini AI.
-    // This part saves 3 mins faster when processing 1 billion rows.
-    parsedStation := Copy(line, 1, delimiterPos - 1);
-
-    // Get the temperature recorded, as string, remove '.' from string float
-    // because we want to save it as int64.
-    strFloatTemp := Copy(line, delimiterPos + 1, Length(line));
-
-    // strFloatTemp := StringReplace(strFloatTemp, '.', '', [rfReplaceAll]);
-    // The above operation is a bit expensive.
-    // Rewrote a simple function which prevents creation of new string
-    // in each iteration. Saved approx 20-30 seconds for 1 billion row.
-    // Remove dots turns a float into an int.
-    strFloatTemp := RemoveDots(strFloatTemp);
-
-    // Add the weather station and the recorded temp (as int64) in the TDictionary
-    Val(strFloatTemp,
-      parsedTemp,
-      valCode);
-    if valCode <> 0 then Exit;
-
-    // Add a record in TWeatherDictionary
-    self.AddCityTemperatureLG(parsedStation, parsedTemp);
-  end;}
 end;
 
 procedure TWeatherStation.ReadMeasurements;
 var
   fileStream: TFileStream;
+  bufStream: TReadBufStream;
   streamReader: TStreamReader;
   line: string;
 begin
 
   // Open the file for reading
-  fileStream := TFileStream.Create(self.fname, fmOpenRead or fmShareDenyNone);
+  fileStream := TFileStream.Create(self.fname, fmOpenRead);
   try
     streamReader := TStreamReader.Create(fileStream, 65536 * 2, False);
     try
@@ -390,11 +351,6 @@ procedure TWeatherStation.ProcessMeasurements;
 begin
   self.CreateLookupTemp;
   self.ReadMeasurements;
-  // self.ReadMeasurementsBuf;
-  // self.ReadMeasurementsClassic;
-  {This chunking method cuts ~ 30 - 40 seconds of processing time from ~6.45 to 6.00
-   But the SHA256 at the end is incorrect}
-  // self.ReadMeasurementsInChunks(self.fname);
   self.SortWeatherStationAndStats;
   self.PrintSortedWeatherStationAndStats;
 end;