C / C++ / MFC

Re: Last modified file time, is it fixed everywhere?

27-Sep-09 3:13

If a file (maybe exe, txt, html, chm etc) is copied, installed or uploaded to everywhere - such as compressed or uncompressed Windows OS, UNIX, Apple etc and in different place (US, AU etc) - and viewed, executed (but not modified or edited):

does Last modified file time related to WIN32_FIND_DATA and function FindFirstFile(...) keep constant and unchanged?

I nned the info for auto-update software.

Saurabh.Garg27-Sep-09 17:44

Saurabh.Garg

27-Sep-09 17:44

I will suggest you use a hash function, for example MD5, for checking if a file has been modified ot not.

-Saurabh

How to reduce exe size?

includeh1027-Sep-09 2:31

27-Sep-09 2:31

My static linked MFC exe file is over 7M now, I think it shouldn't be so large.

I have tried two ways to reduce its size:

Change resource bmp files from 24 bits to 16 bits
What software can do the change?
As I tested, both PaintBrush and PhotoShop (version 6) can not do.
How about CorelDraw? I have CorelDraw but didn't install.
Exclude some lib files.
I did nothing for this, because I don't know how to detect which lib is unused and how to disable it.

Do you have any idea to reduce exe size with detail hints?

«_Superman_»27-Sep-09 2:50

«_Superman_»

27-Sep-09 2:50

If you link statically to MFC, you're exe size is going to get bigger.
You should have the option of using the shared version of MFC, if you want to really think about a small exe size.

There are also other techniques of combining sections and using the proper compiler switches.
Here are a few articles on reducing the size of the exe -
http://msdn.microsoft.com/en-us/magazine/cc301696.aspx[^]
http://www.catch22.net/tuts/minexe[^]

«_Superman_»
I love work. It gives me something to do between weekends.

sunlin727-Sep-09 2:54

sunlin7

27-Sep-09 2:54

the mspaint.exe can convert 24bit true color image to 16bit ones.

CPallini27-Sep-09 23:25

CPallini

27-Sep-09 23:25

Member 4470227 wrote:
the mspaint.exe can convert 24bit true color image to 16bit ones.

Paint sucks on decreasing color depth. Irfan View, for instance, is really better.
Smile | :)

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-- Alfonso the Wise, 13th Century King of Castile.

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[My articles]

sunlin727-Sep-09 2:56

sunlin7

27-Sep-09 2:56

try UPX to pack and compress your executeable files.

includeh1027-Sep-09 3:19

27-Sep-09 3:19

Member 4470227,

I don't know software you mentioned.

Is mspaint.exe PaintBrush or Paint program of Windows default tool?

Or how to get them for free?

harold aptroot27-Sep-09 4:20

harold aptroot

27-Sep-09 4:20

Don't you mean UPX[^]?

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer27-Sep-09 10:40

27-Sep-09 10:40

The paint program is pbrush.exe, and has been part of the OS install since Windows 3, if not before. It's got better as the years go on though!

Iain.

I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need cotract work done, give me a job! http://cv.imcsoft.co.uk/[^]

Luc Pattyn27-Sep-09 12:20

Luc Pattyn

27-Sep-09 12:20

couldn't you use JPEG instead of BMP images? depending on size and complexity JPEG tends to compress images by a factor of 3 to 10 to 30.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

Joe Woodbury27-Sep-09 17:00

Joe Woodbury

27-Sep-09 17:00

With Visual Studio 2005, under Linker Optimization, make sure you are eliminating unreferenced data, enable COMDAT folding and set Optimize for Windows98 to No.

Check if you are overusing templates. They tend to chew up a lot of space. You could also turn off intrinsic functions. Under code generation, turn off "Buffer Security Check" (some will disagree, if you read up on it, you'll find it's nearly useless, but does use space.) Under Language, i always turn of Run-Time Type Info (savings is small, but I never use it so why not?) Reexamine everything you are linking to; sometimes you use a tiny function that pulls in a huge amount of code even though you don't really need it.

If your resource bitmaps are big, consider PNG or JPG.

CPallini27-Sep-09 23:34

CPallini

27-Sep-09 23:34

includeh10 wrote:
Change resource bmp files from 24 bits to 16 bits
What software can do the change?
As I tested, both PaintBrush and PhotoShop (version 6) can not do.
How about CorelDraw? I have CorelDraw but didn't install.

Decreasing the color depth may do the trick, provided you have many big images. Anyway this doesn't affect the executable's size when it is loaded in memory, I guess (unless you dynamically load, and then discard, images).
IrfanView [^] a freeware image viewer, is very good in decreasing image color depth.
Smile | :)

includeh1028-Sep-09 5:02

28-Sep-09 5:02

Decreasing the color depth may do the trick, provided you have many big images. Anyway this doesn't affect the executable's size when it is loaded in memory,

//-----------------------------------
It does affect exe size, when I change bmp from 24 bits to 256 color, exe size becomes smaller.

An unexpected output

carter200027-Sep-09 0:34

27-Sep-09 0:34

#include <iostream>

using namespace std;

class CTestA
{
public:
virtual void FuncA()
{}

private:
int m_iValue1;
char m_cValue1;
int m_iValue2;
char m_cValue2;
double m_dValue1;
};

class CTestB : public CTestA
{
public:
virtual void FuncB()
{}

private:
};

void main()
{
cout << sizeof(CTestB) << endl;

system("pause");
}

Why the output is '32', while my expected is '28'.

N a v a n e e t h27-Sep-09 1:07

N a v a n e e t h

27-Sep-09 1:07

carter2000 wrote:
Why the output is '32', while my expected is '28'.

How are you calculating 28? By adding size of individual members? If yes, see what MSDN is saying.

When the sizeof operator is applied to a class, struct, or union type, the result is the number of bytes in an object of that type, plus any padding added to align members on word boundaries. The result does not necessarily correspond to the size calculated by adding the storage requirements of the individual members.

Navaneeth

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carter200028-Sep-09 4:47

28-Sep-09 4:47

Thanks for your answer.

Stuart Dootson27-Sep-09 4:17

Stuart Dootson

27-Sep-09 4:17

Structure sizes don't work that way - there may be (will be in this case) be padding between items of different types in a structure, dependent on the type's default alignment. Have a look at this Wikipedia page[^] that explains the concept.

However, there is a way around the default alignments, using #pragma pack to alter structure packing. So, if you put the following line before your structure definitions, you'll find you get the output you expect:

#pragma pack(1)

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

carter200028-Sep-09 4:59

28-Sep-09 4:59

Thanks. I add "#pragma pack(4)", and it works as I wish.

Stuart Dootson28-Sep-09 6:18

Stuart Dootson

28-Sep-09 6:18

Not #pragma pack(1)?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

carter200028-Sep-09 16:19