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Hello , could you please help me with this ?
I have wrote the following code which open a file ( binary file )
Search for bytes sequence and return the position at first occurs ,
It's work in some cases , like if file fill's with Zero's and my searched bytes only !
and it's give me headache !
Here is my code :
int main()
{
unsigned int data[6] = {
0x11, 0x22, 0x33, 0x44, 0x55, 0x66
};
cout << "pos : " << FindBytes(data , 6 , "c:\\test.a") << endl;
return 0;
}
The Function :
int FindBytes ( unsigned int data [], int datalength, char *filename )
{
FILE *file;
file = fopen(filename, "r");
int pos = 0;
int length = datalength - 1;
int ch;
int cpos = 0;
do
{
ch = getc(file);
if(ch == data[0])
{
pos += length - 1;
fseek(file , pos , SEEK_SET);
ch = getc(file);
if(ch == data[length])
{
for(int i = 0;i <= length;i++)
{
cpos = pos - length + i;
fseek(file, cpos, SEEK_SET);
ch = getc(file);
if(ch != data[i])
{
fseek(file , cpos, SEEK_SET);
goto resume;
}
}
return pos - length;
}
}
else
{
resume:
fseek(file, pos, SEEK_SET);
}
pos++;
}
while ( ch != EOF );
return -1;
}
thank you ,
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This isn't great code, first off, if you're comparing bytes, why use unsigned int to store your target array? Use char, or BYTE, or something similar (that's 8 bits)... now the other question is if you're looking for specific bytes, why open the file in text mode? ...and finally, you can probably do without the goto statement... as for your question, what do you want help with, what doesn't work or what is the error?
This doesn't look like its what you want:
pos += length - 1;
fseek(file , pos , SEEK_SET);
What you're doing there is if you find the first byte matches then you offset by some number of bytes? What if the first byte of the file matches your first byte? You won't even compare the next four bytes since you're offsetting right off the back.
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Thank you sir ,
I know it's look bad , I am not a c++ Programer , I know a little bit about c++ ,
I am C# one , so I copy code from here and there , to achieve my goal 
The Error is : some times the function never find my bytes , I think it's the EOF ,
so I replaced the While (EOF) things with FOR . and it'w work
Albert Holguin wrote: This isn't great code, first off, if you're comparing bytes, why use unsigned int to store your target array? Use char, or BYTE, or something similar (that's 8 bits)... now the other question is if you're looking for specific bytes, why open the file in text mode? ...and finally, you can probably do without the goto statement... as for your question, what do you want help with, what doesn't work or what is the error?
I did as you said ,
int FindBytes ( unsigned char data [], int datalength, char *filename )
{
int sz = GetszFile(filename);
FILE *file;
file = fopen(filename, "rb");
int pos = 0;
int length = datalength - 1;
char ch;
int cpos = 0;
for (int ic = 0;ic < sz; ic++)
{
ch = getc(file);
if(ch == data[0])
{
pos += length - 1;
fseek(file , pos , SEEK_SET);
ch = getc(file);
if(ch == data[length])
{
for(int i = 0;i <= length;i++)
{
cpos = pos - length + i;
fseek(file, cpos, SEEK_SET);
ch = getc(file);
if(ch != data[i])
{
fseek(file , cpos, SEEK_SET);
goto resume;
}
}
return pos - length;
}
}
else
{
resume:
fseek(file, pos, SEEK_SET);
}
pos++;
}
return pos;
}
I still want to find a good function to search bytes in binary file 
But this one , is worked !
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Smart Arab wrote:
I still want to find a good function to search bytes in binary file
One thing I'd try is the Boyer-Moore search algorithm. I don't know if it'd be any better given the amount of file I/O involved, but it would be worth it to find out.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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If the size of the sequence is fixed, a better solution would be a state machine (this would also only find the first occurance of the byte sequence, but you can put it in a function and find all occurrences of the sequence)...
bool found = false;
int m_State = 1, origin = 0;
while((ch = getc(file) != EOF) && (!found))
{
switch(m_State)
{
case 1:
if(ch == data[0]){
origin = ftell(file)- 1;
m_State = 2;
}
break;
case 2:
if(ch == data[1])
m_State = 3;
else m_State = 1;
break;
case 3:
if(ch == data[2])
m_State = 4;
else m_State =1;
break;
case 4:
if(ch == data[3])
found = true;
else m_State = 1;
break;
}
}
modified on Friday, May 20, 2011 4:15 PM
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I'm using Visual Studio 2005 C++.
I want to update the controls on a form from within a function. The function is in a seperate file from the main form so the function can not "see" the memebers of the form.
Do I have to pass the form to the function? The form controls seem to be "private" to the main form so I dont know if it will allow them to be changed from another function.
Can someone give me some guidance on this, or a sample function call would be great.
Thanks.
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Figured it out....
You need to go to the Class View, right click on your Form, Add New Function then choose the file that you want to add the function to. Make sure that the file you add the function to is #included into the project. Make sure the file you add the function to has #include "stdafx.h" as the first line of the file.
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Hi All,
I have declared a pointer type variable of DWORD type in CFormView type class.
I am allocating memory using new DWORD[ records ].
And I am freeing the memory in the destructor using delete[].
But I am getting mfc exception
damage after normal block( #24094)at hex address.
Can any body give me reason why I am getting that exception?
I am not able to trace the problem.
Please help me.
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you have written past the end of the memory you allocated.
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You've written in the memory block beyond the allocated memory size. If you are using the pointer arithmetic, check for your logic for advancing through the items in the array. Check for your memory writing logic too...
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hello Friends
I am having one rotation matrix [3x3] of one object at some position,and then I rotate at some angle that object and i found the rotation matrix[3x3] at that place also.
How can I found the offset of object in matrix[3x3] from one place to other?
And then how can i add the offset to rotation matrix?
I know this is not related to c++ but too many genious are here on this Forum.And after all i have to implement it in c++ 
Any Ideas?
Thanks In Advance.
Regards
Yogesh
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I'm assuming you have an affine transformation matrix M as defined here[^].
The translation component is in the last column. When you add some number to M[0,2] you shift horizontally; to M[1,2] you shift vertically.
Therefore, if the object gets translated (not rotated, not scaled, not sheared) from one position to another, just look at the difference of the respective M[0,2] and M[1,2] values. BTW: Once a rotation/scaling/shearing occurs in between, the "translation" becomes ambiguous.
Suggestion: whatever transformation you do, watch what it does to the matrix, and things should become pretty clear.
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.
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Hello Luc, You are Right..I am using transformation Matrix.
I am having two matrix one with original value and other iwth final matrix values but no idea of getting the difference between them.
Thanks for your reply.
regards
yogesh
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yogeshs wrote: I know this is not related to c++...i have to implement it in c++
Yeah, that's not confusing at all. 
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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Hi Guys,
Looking for help in finding Timestamp of a text file.
i have tried googling ,seems Stat can help but dont know how to use it.
any help is much apprciated.
Thank you.
vikas da
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stat is probably not used so much theses days, GetFileTime()[^] will probably be what you need.
The best things in life are not things.
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Sorry! Dint get your question.
Do you want file creation time?
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I didn't post a question, I posted an answer.
The best things in life are not things.
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Hi,
I am drwaing image using Image::DrawImage and same image using CDC::BitBlt with same x,y position.
But both methods are drawing image on diffrent axis(x,y). How could I draw on same position for both?
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show code snippet or give more info..
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using BitMlt:
CRect rect;
this->GetWindowRect( &rect );
this->GetParent()->ScreenToClient( rect );
CBitmap img;
CDC dc;
BITMAP bmp;
img.LoadBitmap(m_nImageID);
img.GetBitmap(&bmp);
CDC* pDC = this->GetDC();
dc.CreateCompatibleDC(pDC);
CBitmap* pOld = dc.SelectObject(&img);
pDC->BitBlt(rect.left, rect.top, bmp.bmWidth, bmp.bmHeight, &dc, 0, 0, SRCCOPY);
using Image::DrawImage
CRect rect;
this->GetWindowRect( &rect );
this->GetParent()->ScreenToClient( rect );
m_img = Gdiplus::Bitmap::FromResource(GetModuleHandle(0),MAKEINTRESOURCE(nImage));
grpx.DrawImage(m_img, 0, 0, m_img->GetWidth(),m_img->GetHeight());
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What are the values of rect.left and rect.top in case 1?
The best things in life are not things.
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left = 50 and top = 50 in both cases
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Fine, but in the second case you are drawing at Point(0, 0)!
The best things in life are not things.
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