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 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
