[FFmpeg-devel] [RFC][PATCH] Windows Television (WTV) file system handling

[Peter Ross]

On Sat, Jan 22, 2011 at 12:02:13PM +0100, Reimar D?ffinger wrote:
> On Sat, Jan 22, 2011 at 09:20:20PM +1100, Peter Ross wrote:
> > > > I do not know of any. While there are wchar functions, one cannot rely on
> > > > sizeof(wchar_t)==2.
> > > 
> > > If you insist on comparing strings, all strings being compared here
> > > are always static strings. This allows for tricks, e.g. declaring them
> > > as wchar_t strings, which you apparently don't want to do, or just
> > > creating one manually by doing "s\0t\0r\0i\0n\0g"; </ugly>. The
> > > advantage of these approaches (easiest is really to look for a
> > > wchar-style thing that ensures 16-bit unicode formatting) is that you
> > > can use memcmp() instead of this slow compare function, and memcmp()
> > > is probably better-optimized. Also saves code.
> > 
> > You're right, that looks horrid. I have updated to use wcscmp().
> 
> I am not really very comfortable of getting into the compatibility
> nightmare of wchar_t.
> In particular I think you are assuming that wchar is compatible with
> UCS-2, but I think that there have been other wchar formats.

Originally the patch had a unicode_compare() function for comparing the 
unicode string against UTF-8. Will go back to that then.

> > +/**
> > + * Convert 16-bit litte endian string to wchar string
> > + * @param[in] src  Source string
> > + * @param srclen   Length of source string in characters
> > + * @param[out] dst Detination
> > + * @param dstlen   Length of destination string (characters)
> > + */
> > +static void str16le_to_wcs(const uint8_t *src, int srclen, wchar_t *dst, int dstlen)
> > +{
> > +    int i;
> > +    for (i = 0; i < FFMIN(srclen, dstlen - 1); i++)
> > +        dst[i] = AV_RL16(src + 2*i);
> > +    dst[i] = 0;
> > +}
> 
> Also you are treating the string as UCS-2, are you really sure it
> isn't really UTF-16?

Your guess is as good as mine. Given the undocumented nature of the
file format, we may never know.

-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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