Solved

Slow CString creation

Posted on 2008-06-09
8
305 Views
Last Modified: 2013-11-20
After I collect up to 600,000 points of data I have to process each point into a text string and display it in an edit control and/or save it as a text file, but as I process the string the processing gets very slow very soon. I update the process after every 2k points and it gets noticabley slower after each set, untill after 10,000 it is unacceptably slow.

What is going on and what can I do to remedy?



for( i=0; i<m_DataCount; i++ )
	{
		MSG msg;
		while( ::PeekMessage( &msg, NULL, 0, 0, PM_NOREMOVE ) )
		{
			AfxGetApp()->PumpMessage();  // does a ::GetMessage() (waits...)
		}
// VOLTAGE
		cdword._dword = dwArray[i];
		wVoltage = cdword.word1;
		if( wVoltage < 100 )
			break;
	// CURRENT
		wCurrent = cdword.byte1 & 0xFC;
 
		f = wVoltage;
		str.Format("%.3f\t", f / 1000 );
		strData += str;
 
		j = wCurrent;
		f = j;
		str.Format("%.3f\t", f / 100 );
		strData += str;
 
		j = wTemperature;
		str.Format("%d\r\n", j);
		strData += str;
 
		if( i % 2000 == 0 )
		{
			str.Format("Logging complete\r\n\r\nProcessing data please wait... %dk points", i /1000 );
			m_editData.Clear();
			m_editData.SetWindowText( str );
		}
	}
	m_editData.SetWindowText( strData );

Open in new window

0
Comment
Question by:EnergyStorage
  • 3
  • 2
8 Comments
 
LVL 44

Accepted Solution

by:
AndyAinscow earned 500 total points
ID: 21748945
strData += str

As the contents of strData are continually growing I suspect you have memory allocation/copy problems.

Reduce the number of times you perform the 'strData += str' action.
0
 

Author Comment

by:EnergyStorage
ID: 21752965
I knew it was due to the constant changing of CString buffer size and I solved it myself using CString function GetBufferSetLength.

0
 
LVL 44

Expert Comment

by:AndyAinscow
ID: 21753118
excerpt of question
>>What is going on

later comment by questioner after a comment suggesting where the problem could lie and a solution
>>I knew it was due to the constant changing of CString buffer size

Seems to be some mismatch of information in those two statements.
0
 

Author Comment

by:EnergyStorage
ID: 21798552
a21748945 was not a solution.

I said "What is going on and how do I remedy this. Not Doing what need to be done is not a remedy.

I found the remedy on my own as I said above by using the CString function GetBufferSetLength().

0
 
LVL 44

Expert Comment

by:AndyAinscow
ID: 21800165
In your original question you stated you did NOT know what was slow in your code.  When you know that then you can then remedy it.
I pointed out what I thought was slow and one potential change to improve the performance.
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction: Dialogs (1) modal - maintaining the database. Continuing from the ninth article about sudoku.   You might have heard of modal and modeless dialogs.  Here with this Sudoku application will we use one of each type: a modal dialog …
Have you tried to learn about Unicode, UTF-8, and multibyte text encoding and all the articles are just too "academic" or too technical? This article aims to make the whole topic easy for just about anyone to understand.
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…

778 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question