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:
// 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)
// Failed to extract character. Guess that the remaining characters
// are one byte/column wide each.
return width + min(n - i, strlen(s + i));
width += max(0, wcwidth(wc));
}
return width;
}
/Ulf
> On Mon, Feb 16, 2015 at 4:36 PM, Chet Ramey <[email protected]> wrote:
>>
>> On 2/16/15 10:26 AM, Ulf Magnusson wrote:
>> > Okay, I'll roll my own then.
>>
>> If you dont't have invisible characters in the prompt string or handle
>> line
>> wrapping, wcswidth(3) can do the job for you. Just assume the line buffer
>> contains multibyte characters, convert it to a wide character string with
>> mbstowcs(3), and compute the number of columns to get to the buffer index
>> indicated by rl_point. If you want to make it easier, strdup
>> rl_line_buffer and null-terminate the new string at rl_point before
>> calling
>> mbstowcs.
>>
>> Chet
>> --
>> ``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/
>
>
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