Re: Trying to extract different types of data from a singe file.
On Aug 1, 5:47 am, JoeC <enki...@yahoo.com> wrote:
I am trying to create a windows program that reads binary
graphics as a resource. This has nothing to do with win32 but
conversion of data with memcpy.
memcpy doesn't convert; it just copies bits. If the original
data came from an external source, that's generally not what is
needed.
graphic::graphic(UINT uiResID, HINSTANCE hinstance){
size = 32;
bitData.clear();
void * p = NULL; // point to the data
int end;
BYTE data;
static HGLOBAL hglob;
HRSRC hRes =
FindResource(hinstance,MAKEINTRESOURCE(uiResID),TEXT("BINARY"));
if(hRes){
hglob = LoadResource(hinstance,hRes);
p = LockResource(hglob);
memcpy((int*) &end, p, sizeof(int)); // puts the first but of
data to int.
Note that you've got a reintepret_cast here. That's a sure sign
that something is wrong.
How are the integer values formatted in the file? Until you
know that, you can't do anything reasonable.
for(int lp = 0; lp != end; lp++){
bitData.push_back(0);
}
for(int lp = 0; lp != end; lp++){
memcpy((BYTE*) &bitData[lp], p, sizeof(BYTE)); puts the rest
of the data in BYTE type.
If BYTE is unsigned char, memcpy might just work. But did you
really mean to not increment p in the loop? If so, this is
just:
bitData.insert( bitData.end(), end, *p ) ;
would do the trick (without the previous loop. Otherwise,
you could replace the two loops with:
bitData.resize( end ) ;
memcpy( &bitData[ 0 ], p, end ) ;
(In both cases, of course, only if BYTE is unsigned char, and
bitData is std::vector< BYTE >.)
[...]
My question is how do I extract each but of data from p first
to the int type with is the number of data bits then each bit
of data to put into my bitData vector. I can't increase the
pointer p++ to get to the next bit of data.
What is the format of the input? Until we know that, we can't
really say anything. A lot of formats---almost all, I would
imagine---do pack bitmaps as 8 bits to an unsigned char. If
such is the case, and end gives the number of bits, you'll have
to scale it before using it with memcpy or your loops. On the
other hand, I wouldn't be surprised if some graphic formats have
"bitmaps" that aren't actually bitmaps: bitmaps were the most
basic graphic representation back in the days of black and
white, where a pixel was one bit, but I would imagine that a lot
of graphic formats today would use a string or an array of
pixels, rather than a true bitmap.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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