OOM Error on 32 Bit before hitting 2GB boundary?

[wila]

Hi,

I had reported this to Harm before, but as I got no reply... sharing this with the community.
Perhaps I'm overlooking something silly (wouldn''t be the first time)

This is on DataFlex 20.1 (latest), 32 bit.

The following code works on 64 bit and the project now also works fine under 64 bit, so one could argue that this is all hypothetical.
However I'm wondering why I'm getting a Out Of Memory error (OOM Error) when using this.

Demo Code:

Use Windows.pkg
Use Dfpanel.pkg
Use Batchdd.pkg
Use File_dlg.pkg

Object oMain is a Panel
  Set Size to 100 300
  Set Label to "Base64 OOM Error demo"
  
  Use seq_chnl.pkg
  Use cCharTranslate.pkg
  
  Object oCharTranslate is a cCharTranslate
  End_Object
  
  Object oBase64 is a cObject

    Function BinaryEncodeFileToUChar String sFileSource Returns UChar[]
      UChar[] ucFile
      UChar[] ucEncoded
      
      Boolean bExists
      Integer iChIn 
      
      If (sFileSource <> "") Begin
          Get Seq_New_Channel to iChIn
          If (iChIn <> DF_SEQ_CHANNEL_NOT_AVAILABLE) Begin
         
            Direct_Input channel iChIn ("BINARY:" + sFileSource)      
              Read_Block channel iChIn ucFile -1
            Close_Input channel iChIn
            Send Seq_Release_Channel iChIn 
              
            Get Base64EncodeUCharArray of oCharTranslate ucFile to ucEncoded   /// <--- crashing here
          End 
      End
      
      Function_Return ucEncoded
    End_Function 
  End_Object
  
  Object oXmlUpload_bp is a BusinessProcess
    Function UploadFile String sFileName Returns Boolean
      UChar[] ucEncoded
      Get BinaryEncodeFileToUChar  of oBase64 sFileName to ucEncoded 
      // more code here... for the actual chunked upload
    End_Function

  End_Object

  Object oOpenDialog is a OpenDialog
    Set Dialog_Caption to "Select a file"

    Set CreatePrompt_State  to False
    Set FileMustExist_State to True
    Set NoChangeDir_State   to True
    Set Filter_String to 'All Files|*.*'
  End_Object
  
  Object oFileForm is a Form
    Set Label to "Select File:"
    Set Location to 10 75
    Set Size to 13 150
    Set peAnchors to anBottomLeftRight
    Set Prompt_Button_Mode to pb_PromptOn
    Set Form_Button_Bitmap Item 0 to "GlobePlug.ico"
    
    Procedure Prompt
      Boolean bOk
      String  sFileName
    
      Get Show_Dialog of oOpenDialog to bOk
      If (bOk) Begin
        Get File_Name of oOpenDialog to sFileName
        Set Value              to sFileName    // as we do not want to save that
        Set Item_Changed_State to True         // in here.
      End
    End_Procedure
  End_Object

  Object oUploadButton is a Button
    Set Label to "Upload file"
    Set Size to 14 62
    Set Location to 45 122
    Set peAnchors to anBottomRight

    Procedure OnClick
      String  sFileName
      Boolean bExists

      Get Value of oFileForm to sFileName
      Send doUploadFile sFileName
    End_Procedure
  End_Object
  
  Procedure doUploadFile String sFileName
    Boolean bUploadOk
    String  sMsg
    
    Send Cursor_Wait of Cursor_Control

    Get UploadFile of oXmlUpload_Bp sFileName to bUploadOk
    
    Send Cursor_Ready of Cursor_Control

    If (bUploadOk) Move (sFileName*"upload to the server successfully.\n" ) to sMsg
    Else Move (sFileName*"upload to the server FAILED. Please try again\n" ) to sMsg

    Send Info_box sMsg "Upload status"
  End_Procedure
  
End_Object

Start_UI

The code above comes from a heavily trimmed down webservice client to upload any kind of file to a DataFlex webservice.

One of the things I tested it with was the 230MB sized DataFlex installer.. Not because we need to upload that kind of file, but because it was available and I wanted to see the performance and/or see if my code had an obvious issue in the webservice somewhere.

So it's not exactly a small file to test with.

However.. it isn't close to a 2GB limit either.

As pointed out above it crashes on the line:

            Get Base64EncodeUCharArray of oCharTranslate ucFile to ucEncoded   /// <--- crashing here

If you put a breakpoint in that function itself then the crash is on the ResizeArray line below:


So this is just the code above, no webservice in sight or needed to reproduce this.

I though I remembered that arrays are passed as pass by reference when used as a parameter to a function and then via "copy on write" expanded when changed. (see discussions from Sonny https://support.dataaccess.com/Forum...n-depth-Part-V ) but I might misremember and I guess I have to reread that blog series again.

So if what I remember is true, it shouldn't -in theory- use more than 500MB in memory.
If OTOH all of the data goes onto the stack on every call then I suppose it makes more sense.. but I'm still not counting 2GB.
To be frank (Frank help?) it would make sense if the data goes on the stack.

--
Wil