[libcamera-devel] [PATCH v4 2/7] libcamera: utils: Add method to strip Unicode characters

[Niklas Söderlund]

Hi Kieran,

On 2020-08-14 09:28:59 +0100, Kieran Bingham wrote:
> Hi Niklas,
> 
> On 13/08/2020 23:37, Niklas Söderlund wrote:
> > Add method that strips non-ASCII characters from a string.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> 
> I still would have thought the isprint might be more useful, as I don't
> think we want chars like newlines/or console control characthers getting
> through these strings.

I thought about it but if we used std::isprint() this would not produce 
an ASCII string, instead it would produce an printable string :-) I read 
some post (which I can't find now) that spoke agains using 
std::isprint() to drop non-ASCII charters, but it might have been 
targeted on proprietary OS implementations...

As you say, this is an internal helper and we can switch to 
std::isprint() later if need.

> 
> But if you don't think that's an issue here:
> 
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

Thanks!

> 
> I don't want to block the series, and this is an internal helper so it
> can always be updated if we hit any issue.
> 
> 
> 
> > ---
> > * Changes since v3
> > - Fix spelling in comment.
> > - Rename to toAscii()
> > ---
> >  include/libcamera/internal/utils.h |  2 ++
> >  src/libcamera/utils.cpp            | 21 +++++++++++++++++++++
> >  2 files changed, 23 insertions(+)
> > 
> > diff --git a/include/libcamera/internal/utils.h b/include/libcamera/internal/utils.h
> > index 45cd6f120c51586b..b27f5a2323552058 100644
> > --- a/include/libcamera/internal/utils.h
> > +++ b/include/libcamera/internal/utils.h
> > @@ -197,6 +197,8 @@ private:
> >  
> >  details::StringSplitter split(const std::string &str, const std::string &delim);
> >  
> > +std::string toAscii(const std::string &str);
> > +
> >  std::string libcameraBuildPath();
> >  std::string libcameraSourcePath();
> >  
> > diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
> > index 615df46ac142a2a9..726b84bfbae53ff2 100644
> > --- a/src/libcamera/utils.cpp
> > +++ b/src/libcamera/utils.cpp
> > @@ -342,6 +342,27 @@ details::StringSplitter split(const std::string &str, const std::string &delim)
> >  	return details::StringSplitter(str, delim);
> >  }
> >  
> > +/**
> > + * \brief Strip all Unicode characters from a string
> > + * \param[in] str The string to strip
> > + *
> > + * Strip all non-ASCII characters form a string. A Unicode character that spans
> > + * multiple bytes (and therefore is not also an ASCII character) may be
> > + * identified by the fact that its most significant bit is always set.
> > + *
> > + * \todo When switching to C++ 20 use std::remove_if.
> > + *
> > + * \return An ASCII string
> > + */
> > +std::string toAscii(const std::string &str)
> > +{
> > +	std::string ret;
> > +	for (const char &c : str)
> > +		if (!(c & 0x80))
> > +			ret += c;
> > +	return ret;
> > +}
> > +
> >  /**
> >   * \brief Check if libcamera is installed or not
> >   *
> > 
> 
> -- 
> Regards
> --
> Kieran

-- 
Regards,
Niklas Söderlund