Re: Bidi B2 - GetCharacterPlacement order array

[Dimitrie O. Paun]

On May 31, 2003 05:45 am, Shachar Shemesh wrote:
> -
>    /* Treat the case where no special handling was requested in a
>
> fastpath way */ +        /* copy will do if the GCP_REORDER flag is not set
> */
> -
>    if (lpResults->lpOutString)
> -
>        for (i = 0; i < nSet && lpString[i] != 0; ++i)
> -
>            lpResults->lpOutString[i] = lpString[i];

What about a strncpy here:

+        if (lpResults->lpOutString)
+            strncpyW(lpResults->lpOutString, lpString, nSet);

Bidi B2 - GetCharacterPlacement order array

[Shachar Shemesh]

Dimitrie O. Paun wrote:
> On May 31, 2003 05:45 am, Shachar Shemesh wrote:
> > -
> >    /* Treat the case where no special handling was requested in a
> >
> > fastpath way */ +        /* copy will do if the GCP_REORDER flag is not set
> > */
> > -
> >    if (lpResults->lpOutString)
> > -
> >        for (i = 0; i < nSet && lpString[i] != 0; ++i)
> > -
> >            lpResults->lpOutString[i] = lpString[i];
>
> What about a strncpy here:
> -
>    if (lpResults->lpOutString)
> -
>        strncpyW(lpResults->lpOutString, lpString, nSet);

Probably a good idea. These lines predate my involvment in Wine, so I 
did not touch them under the "it works" discipline. I copied them over 
from objects/font.c (GetCharacterPlacementW), and I'm sending out 
another cleanup patch that removes these lines. I'll fix the upstream 
copy, if you think it's woth it (I am touching that function anyways).

Shachar

Bidi B2 - GetCharacterPlacement order array

[David Laight]

> > > -
> > >    if (lpResults->lpOutString)
> > > -
> > >        for (i = 0; i < nSet && lpString[i] != 0; ++i)
> > > -
> > >            lpResults->lpOutString[i] = lpString[i];
> >
> > What about a strncpy here:

Be aware that strncyp() rarely DTRT, in particular:
- it doesn't guarantee to zero terminate the target
- it is required to zero fill the target buffer
Neither of these is usually desirable.

Many systems have a strlcpy() function which does what you want much
more often.

OTOH is the target buffer can be too short with valid data, they you
need to (typically) dynamically allocate a buffer.

David

Bidi B2 - GetCharacterPlacement order array

[Shachar Shemesh]

David Laight wrote:
> Be aware that strncyp() rarely DTRT, in particular:
> - it doesn't guarantee to zero terminate the target
> - it is required to zero fill the target buffer
>
> Neither of these is usually desirable.

Well aware of both. Thanks. I'm routinely giving lectures about them 
(http://shemesh.biz/lectures).

Since the buffer is not zero terminated to begin with, 1 is not a 
problem. Since the loop that strncpy replaces copied n bytes over from 
the old buffer to the new one, neither is 2. This does impose the 
theoretical problem that if the original string WAS zero terminated, and 
the NULL was not the last WCHAR in the buffer, we change the semantics. 
I doubt very much, however, that you will find a program that relies on 
this. I don't even know what Windows does under the same circumstances.
> Many systems have a strlcpy() function which does what you want much
> more often.

Well aware of that too. strncpy is really the most fitting here. Trust me.
> OTOH is the target buffer can be too short with valid data, they you
> need to (typically) dynamically allocate a buffer.

Not applicable to GetCharacterPlacement.
> David

Thanks.

Shachar

Bidi B2 - GetCharacterPlacement order array

[Shachar Shemesh]

Shachar Shemesh wrote:
> David Laight wrote:
> > Be aware that strncyp() rarely DTRT, in particular:
> > - it doesn't guarantee to zero terminate the target
> > - it is required to zero fill the target buffer
> >
> > Neither of these is usually desirable.
>
> Well aware of both. Thanks. I'm routinely giving lectures about them 
> (http://shemesh.biz/lectures).

Seems like it's not my day for URLs.

http://shemesh.biz/lecures.html

Shachar

Bidi B2 - GetCharacterPlacement order array

[Dimitrie O. Paun]

On Mon, 2 Jun 2003, Shachar Shemesh wrote:
> Seems like it's not my day for URLs.
>
> http://shemesh.biz/lecures.html

^t^

No, it really isn't :P

http://shemesh.biz/lectures.html

Bidi B2 - GetCharacterPlacement order array

[Shachar Shemesh]

Dimitrie O. Paun wrote:
> On Mon, 2 Jun 2003, Shachar Shemesh wrote:
> > Seems like it's not my day for URLs.
> >
> > http://shemesh.biz/lecures.html
>                   ^t^
>
> No, it really isn't :P
>
> http://shemesh.biz/lectures.html

I told you it's not my URLs day.

I'll go to sleep now, if you don't mind.

Sh.

Bidi B2 - GetCharacterPlacement order array

[Hetz Ben Hamo]

> Seems like it's not my day for URLs.
>
> http://shemesh.biz/lecures.html

Do you mean: http://shemesh.biz/lectures.html ? :)

Thanks,
Hetz
>       Shachar