Re: MFC Porting Issues
Re: MFC Porting Issues
- Subject: Re: MFC Porting Issues
- From: Kevin Wojniak <email@hidden>
- Date: Fri, 20 Jan 2006 16:41:32 -0500
I think I realized what the problem is. When I was comparing the
values in the debugger to the actual data it's reading from, some of
the values appeared to not have been byte swapped, while others were.
And this was only on the 2nd time, not the first. But I realized that
when I'm swapping the bytes, I'm only working on the pointer, which
is still pointer to the original data, so the original data is
getting swapped back and forth each time. So I guess I have to change
how it stores and reads this structure.
Thanks for everyone's help.
Kevin
On Jan 20, 2006, at 4:21 PM, Dave Camp wrote:
On Jan 20, 2006, at 12:58 PM, Kevin Wojniak wrote:
Oops, yes WORD = unsigned short, sorry.
I'm not sure what you mean by structure packing..
typedef struct
{
BYTE b1[8];
DWORD height;
DWORD width;
WORD w1;
WORD bitDepth;
DWORD d2;
DWORD blockLen;
} IPOD_PICTURE_HEADER;
BYTE = unsigned char
DWORD = unsigned long
WORD = unsigned char
Structure packing is how the fields of a struct are laid out in
memory. For example, does the bitDepth field immediately follow the
w1 field, or is there two bytes of padding preceding it so that it
will be aligned on a 4 byte boundary. This is usually controlled by
compiler directives and different processors prefer different
packing schemes for efficiency.
Dave
---
The path of least resistance, it's not just for electricity any more.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Cocoa-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden