|
Yeah, but you wouldn't be testing the system itself then, just the input from the file header. 
--
100% natural. No superstitious additives.
|
|
|
|
|
True, you wouldn't need to directly test your system - if you hard coded the endianness of it into your code.
If you want portable code then you will need functions such as:
SysToBig( long& ), BigToSys( long& ), SysToLittle(), ...
Those functions need to know if they are a no-op (e.g. SysToLittle() on a PC), or actually perform a swap.
To me, i generally treat endianness like socket code, always call the ntols, ... functions.
On a PC they do swaps but on other (big-endian) systems they are a no-op.
_I_ don't need to know the system endianness, but the ntols funstions do.
...cmk
Save the whales - collect the whole set
|
|
|
|
|
I too use ntol functions, mainly because of the reasons you mention. It's fool proof.
--
100% natural. No superstitious additives.
|
|
|
|
|
|
Joshua Quick wrote: That means endianess is not determined at compile time.
Yes it is. PowerPC nor Intel have variable endianess. Nor is it possible to run Intel code directly on a PowerPC and vice versa, so it's not like the same code is shared between the platforms. The Universal Binary contains sections (I think they call it bundles or forks or something like that at Apple) for each platform - copies of eachother. The Intel section is executed on an Intel machine, and the PPC section is executed on the PPC.
The data however may be of varying endianess - I don't know. If you look at the guidelines you provided a link to, it only speaks of data having different endians, and that you have to guard against that - and something that may be a real problem, as the OS is released on platform with differing endianess.
|
|
|
|
|
Jörgen Sigvardsson wrote: Yes it is. PowerPC nor Intel have variable endianess.
I was referring to the Apple "development" platform.
You are correct though. A universal binary does contain both a PowerPC and Intel build of the executable.
|
|
|
|
|
union
{
int iValue;
BYTE bytes[sizeof(int)];
};
iValue = 1;
if ( bytes[0] == 1 )
// then little endian
else
// big endian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<A HREF="http://www.soonr.com">SoonR Inc.</A>
|
|
|
|
|
It seems a bug of VC++ 6 that although RFX_Text is under Unicode mode, it converts input unicode text into ansi code, it's no problem if each character is ansi charecter, but for those asian characters e.g chinese, the problem is that the input text to RFX_Text will be cut half, which causes the output text from database is a half of original input text, I think it's because of the ansic conversion of RFX_Text under unicode mode. Does anyone have any idea to solve this problem? thanks in advance.
|
|
|
|
|
Well, if your database backend is using single byte characters, then you're not going to get far, so that's item#1 to check.
Other than that, VC6 comes with source (including RFX_Text) so you could write your own that doesn't do a conversion down to ANSI 
Steve S
Developer for hire
|
|
|
|
|
Hello!
How can I store data easily and free? I tried mysql++ but it has a conflict with managed classes. I would like to use the advantages of basic SQL commands, but without having to buy a server...
Thank you in advance,
Alin Stoian
|
|
|
|
|
|
Sorry, maybe i didn't make myself very clear..
I want to use it in a C++ program.. are there any libraries for Access?
Alin Stoian
|
|
|
|
|
yes please see again my post
whitesky
|
|
|
|
|
Yup. If you're using VC6, there's the CDao* classes.
Personally, I'd use the ATL Database classes. Of course, these aren't available in the Express edition of 2005. You can use ADO classes, or ODBC as well.
There is no 'Access' library per se, since Access uses either a desktop engine (MSDE) which is API compatible to SQL Server, or it can use JET, which uses DAO or ISAM internally, depending on the data source.
Steve S
Developer for hire
|
|
|
|
|
|
hi all
I have to read(write) large amount of data from(into) file.
I want to make decision whether to load this data(whole) to buffer directly (using CFile::Read() ) method, then modify data and write to file(using CFile::Write()) method.
Or using loop and fread and fwrite methods, read per 5 bytes (for example), modify each 5 bytes and then write to file and so on.
How do you think which will be faster solution ?
thank you.
|
|
|
|
|
big_denny_200 wrote: large amount of data
So probally a good solution is to limit the number of HD access, I think that this can be a reason to Read and write the data in only one access using Read/Write and a big buffer.
If this will required a lot of memory, there is the usefull class CArchive, (very simple to be used) where you can set the buffer length to a big value (like 10000 or more) and reduce the HD access according to the amount of memory required.
|
|
|
|
|
If you are going to be modifying almost all of the data you read in, then it *might* be faster to load, modify, write all at once, however that would also lock your program up. If you need to keep things moving along, then doing so in a second thread, using a loop, might make more sense, plus using a much larger value than 5 bytes at a time, maybe 1024 or 4096 bytes at a time?
¡El diablo está en mis pantalones! ¡Mire, mire!
Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!
SELECT * FROM User WHERE Clue > 0
0 rows returned
Save an Orange - Use the VCF!
|
|
|
|
|
I have owner-drawn list box.
when calling GetScrollPos on scrolling, it is always returning 0.
how can I solve this?
-Sarath
|
|
|
|
|
Hi,
I created a list of images and want to display the image dimension.
Is there an other solution than loading the images and extract the width and hight?
Thanks,
Joachim
|
|
|
|
|
It depends on what the type of image file it is.
Normally the width and height is stored in the header, i.e. the first few bytes of the bitmap file.
To find out about file formats see http://www.wotsit.org/search.asp?s=graphics[^]
So all you do it read the first few bytes of the file.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for - in order to get to the job you need to pay for the clothes and the car, and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
|
|
|
|
|
|
|
Thanks for that link (one constructive reply)!
There I found the position of the dimension at once.
Thx,
Joachim
|
|
|
|
|
You are welcome.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for - in order to get to the job you need to pay for the clothes and the car, and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
