On Tue, Feb 17, 2015 at 9:28 PM, Ulf Magnusson <[email protected]> wrote: > Thanks for the feedback! > > The -1 comparison should be safe in practice on non-exotic systems > where the size (rank) of size_t is at least that of int, but yeah, > it's kinda pointless and stupid to leave out the cast. > > I think I'll roll the mbrtowc -2 case into the error case as wc_len < > 0 for now. It'd be weird MB_CUR_MAX gave -2, but it's worth checking > for at least. > > I added control character handling by doing the following btw: > > width += iswcntrl(wc) ? 2 : max(0, wcwidth(wc)); > > Guess that might catch more characters than it should though. > > I also noticed that readline outputs things like "~Z" for some (meta?) > characters. Might want to get back to that later... > > /Ulf
(Excuse the top-posting by the way. Gmail keeps tripping me up. :P) /Ulf > > On Tue, Feb 17, 2015 at 5:44 PM, Chet Ramey <[email protected]> wrote: >> On 2/16/15 4:52 PM, Ulf Magnusson wrote: >>> On Mon, Feb 16, 2015 at 4:43 PM, Ulf Magnusson <[email protected]> wrote: >>>> I'll try it. Thanks for the suggestion! >>>> >>>> /Ulf >>>> >>> >>> Here's what I came up with in case someone else runs into the same >>> problem. I'm sure there's more stuff to handle (not sure what to do >>> for non-printable characters for example), but it seems to handle >>> multibyte (tested using åäö's and Chinese) and combining characters >>> correctly for UTF-8 at least: >> >> This is basically what an implementation of wcswidth looks like. A couple >> of suggestions: >> >>> // Returns the total width (in columns) of the characters in the 'n'-byte >>> // prefix of the null-terminated multibyte string 's'. If 'n' is larger than >>> // 's', returns the total width of the string. Suitable for calculating a >>> // cursor position. >>> // >>> // Makes a guess for malformed strings. >>> static size_t strnwidth(const char *s, size_t n) { >>> mbstate_t shift_state; >>> wchar_t wc; >>> size_t wc_len; >>> size_t width = 0; >>> >>> // Start in the initial shift state. >>> memset(&shift_state, '\0', sizeof shift_state); >>> >>> for (size_t i = 0; i < n; i += wc_len) { >>> // Extract the next multibyte character. >>> wc_len = mbrtowc(&wc, s + i, MB_CUR_MAX, &shift_state); >>> if (wc_len == 0) >>> // Reached the end of the string. >>> break; >>> if (wc_len == -1) >> >> wc_len is a size_t, which is usually unsigned. You need to cast the -1 >> to (size_t)-1. You also need to handle mbrtowc returning (size_t)-2. >> >> >> -- >> ``The lyf so short, the craft so long to lerne.'' - Chaucer >> ``Ars longa, vita brevis'' - Hippocrates >> Chet Ramey, ITS, CWRU [email protected] http://cnswww.cns.cwru.edu/~chet/ _______________________________________________ Bug-readline mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-readline
