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Thread: Converting cross-platform C++ timer code to pascal...

  1. #1

    Converting cross-platform C++ timer code to pascal...

    Hi all,
    I found this page today:
    http://www.songho.ca/misc/timer/timer.html

    and I want to convert it over to pascal so I can have a high-resolution timer that works in Delphi and Freepascal

    Any ideas how I can go about converting it the non-Delphi part? I am not sure what FPC units I would need for the time of day stuff - they use time.h...

    cheers,
    Paul

  2. #2
    This is my conversion attempt, but I'm sure it won't compile under Linux/Mac OSX as I don't know the correct units to include for those platforms:


    Code:
    unit xeEngine_timer;
    
    interface
    
    {$I xeEngine_include.inc}
    
    procedure Timer_Init;                        cdecl; // initialize timer (like constructor)
    procedure Timer_Start;                       cdecl; // start timer
    procedure Timer_Stop;                        cdecl; // stop the timer
    function  Timer_GetElapsedTime: Double;      cdecl; // get elapsed time in second
    function  Timer_GetElapsedTime_Sec: Double;  cdecl; // get elapsed time in second (same as getElapsedTime)
    function  Timer_GetElapsedTime_mSec: Double; cdecl; // get elapsed time in milli-second
    function  Timer_GetElapsedTime_uSec: Double; cdecl; // get elapsed time in micro-second
    
    implementation
    
    uses
    {$ifdef windows}
      windows
    {$endif}
      ;
    
    var
      startTimeInMicroSec : Double;  // starting time in micro-second
      endTimeInMicroSec   : Double;  // ending time in micro-second
      stopped             : Boolean; // stop flag
    {$ifdef windows}
      frequency           : Int64;   // ticks per second
      startCount          : Int64;   //
      endCount            : Int64;   //
    {$else}
      startCount          : timeval; //
      endCount            : timeval  //
    {$endif}
    
    procedure Timer_Init;
    begin
    {$ifdef windows}
      QueryPerformanceFrequency(frequency);
      startCount := 0;
      endCount   := 0;
    {$else}
      startCount.tv_sec  := 0;
      startCount.tv_usec := 0;
      endCount.tv_sec    := 0;
      endCount.tv_usec   := 0;
    {$endif}
    
      stopped             := False;
      startTimeInMicroSec := 0;
      endTimeInMicroSec   := 0;
    end;
    
    procedure Timer_Start;
    begin
      stopped := False; // reset stop flag
    {$ifdef windows}
      QueryPerformanceCounter(startCount);
    {$else}
      gettimeofday(startCount, nil);
    {$endif}
    end;
    
    procedure Timer_Stop;
    begin
      stopped := True; // set timer stopped flag
    
    {$ifdef windows}
      QueryPerformanceCounter(endCount);
    {$else}
      gettimeofday(endCount, NULL);
    {$endif}
    end;
    
    function  Timer_GetElapsedTime: Double;
    begin
      Result := Timer_GetElapsedTime_Sec;
    end;
    
    function  Timer_GetElapsedTime_Sec: Double;
    begin
      Result := Timer_GetElapsedTime_uSec * 0.000001;
    end;
    
    function  Timer_GetElapsedTime_mSec: Double;
    begin
      Result := Timer_GetElapsedTime_uSec * 0.001;
    end;
    
    function  Timer_GetElapsedTime_uSec: Double;
    begin
    {$ifdef windows}
      if not stopped then
        QueryPerformanceCounter(endCount);
    
      startTimeInMicroSec := startCount * (1000000.0 / frequency);
      endTimeInMicroSec   := endCount   * (1000000.0 / frequency);
    {$else}
      if not stopped then
        gettimeofday(endCount, nil);
    
      startTimeInMicroSec := (startCount.tv_sec * 1000000.0) + startCount.tv_usec;
      endTimeInMicroSec   := (endCount.tv_sec   * 1000000.0) + endCount.tv_usec;
    {$endif}
    
      Result := endTimeInMicroSec - startTimeInMicroSec;
    end;
    
    end.
    What do you guys/gals think?

    cheers,
    Paul

  3. #3
    Code:
    gettimeofday
    Will not work with FreePascal. You should use fpGetTimeOfDay instead, and unit Unix.

  4. #4
    PGD Staff / News Reporter phibermon's Avatar
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    you may want to wrap it up in a class or put the timer vars in a record that you can pass to the functions to allow multiple timers.
    When the moon hits your eye like a big pizza pie - that's an extinction level impact event.

  5. #5
    @Andru: thanks mate, that sort of information was what I was hoping for
    @philbermon: I think I will go the record route, thanks for the idea!

    cheers,
    Paul

  6. #6
    PGDCE Developer Carver413's Avatar
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    The X window system I am working on has a 3 stage timer built into the TApplication. it is a stak based timer adding timers is as easy as
    Code:
    Application.AddMsTask('OnTimer',Window,@OnTimer,10);
    Application.AddSecTask('OnTimer',Window,@OnTimer,13);
    Application.AddMinTask('OnTimer',Window,@OnTimer,22);
    the Ontimer is the event handling code and if it return's a True the event will remove itself.
    to test it I opened 12 windows with a rotationing object in each. it seems to work very well as long as the load can be handled. I've only tested the AddMsTask so far but I see no reason why the others shouldn't work as expected. My system is built around a very custom linked list design. that allows for managing many lists from a single object. so it made since to build the timer functions into the application rather then creating a bunch of timer objects. this way all events are processed in a single loop including all of the X events.

  7. #7
    PGD Staff code_glitch's Avatar
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    Turns out that Andru's right as always. Seems like his soltuion works for me on a Ubuntu 10.10 x64 Box with fpc 2.4.0 (ppcx64) if anyone is after the technicalities. Good find though.
    I once tried to change the world. But they wouldn't give me the source code. Damned evil cunning.

  8. #8
    PGDCE Developer Carver413's Avatar
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    I believe the correct unit is SysUtils as this has crossplatform support.
    http://www.freepascal.org/docs-html/...ils/index.html

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