Re: [libvirt] [PATCH v3 1/3] vsh: Add API for printing tables.

On 08/21/2018 11:18 AM, Simon Kobyda wrote: > On Thu, 2018-08-16 at 12:28 +0100, Daniel P. Berrangé wrote: >> On Thu, Aug 16, 2018 at 12:56:24PM +0200, Simon Kobyda wrote: >>> >> >> After asking around I have found the right solution that we need to >> use >> for measuring string width. mbstowcs()/wcswidth() will get the >> answer >> wrong wrt zero-width characters, combining characters, non-printable >> characters, etc. We need to use the libunistring library: >> >> >> https://www.gnu.org/software/libunistring/manual/libunistring.html#uniwid... >> >> > I've tried what you've suggested, but it seems that it doesn't work > well with all unicode characters. I'm looking into the code of the > library, and each function uN_strwidth calls function uN_width, and > that function calls uc_width for calculation of width of characters. > And if we look into the code of uc_width here: > > http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/uniwidth/wi... > it seems that this library is limited only to certain unicodes, e.g.: > hangul characters, angle brackets, CJK characters... But it doesn't > cover all multiple-width characters. Example: I try to throw any emoji > (e.g. 🙉, 🦀, 🏙), it returns width of 1 column for each charact > er, nevertheless these characters have width of 2 columns on terminal. > > BTW, it seems unistring library imports those funcions from gnulib. I guess the only option then is to try smartcols [1]. If it is good for util-linux it's going to be good for us too. Although, I'd prefer to have our own wrappers over their API. https://github.com/karelzak/util-linux/tree/master/libsmartcols