mirror of
https://github.com/alsa-project/alsa-utils
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113 lines
3.1 KiB
C
113 lines
3.1 KiB
C
/*
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* utils.c - multibyte-string helpers
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _XOPEN_SOURCE
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#define _XOPEN_SOURCE
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#endif
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#include "aconfig.h"
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wchar.h>
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#include "utils.h"
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/*
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* mbs_at_width - compute screen position in a string
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*
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* For displaying strings on the screen, we have to know how many character
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* cells are occupied. This function calculates the position in a multibyte
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* string that is at a desired position.
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*
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* Parameters:
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* s: the string
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* width: on input, the desired number of character cells; on output, the actual
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* position, in character cells, of the return value
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* dir: -1 or 1; in which direction to round if a multi-column character goes
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* over the desired width
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*
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* Return value:
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* Pointer to the place in the string that is as near the desired width as
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* possible. If the string is too short, the return value points to the
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* terminating zero. If the last character is a multi-column character that
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* goes over the desired width, the return value may be one character cell
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* earlier or later than desired, depending on the dir parameter.
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* In any case, the return value points after any zero-width characters that
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* follow the last character.
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*/
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const char *mbs_at_width(const char *s, int *width, int dir)
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{
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size_t len;
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wchar_t wc;
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int bytes;
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int width_so_far, w;
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if (*width <= 0)
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return s;
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mbtowc(NULL, NULL, 0); /* reset shift state */
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len = strlen(s);
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width_so_far = 0;
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while (len && (bytes = mbtowc(&wc, s, len)) > 0) {
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w = wcwidth(wc);
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if (width_so_far + w > *width && dir < 0)
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break;
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if (w >= 0)
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width_so_far += w;
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s += bytes;
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len -= bytes;
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if (width_so_far >= *width) {
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while (len && (bytes = mbtowc(&wc, s, len)) > 0) {
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w = wcwidth(wc);
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if (w != 0)
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break;
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s += bytes;
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len -= bytes;
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}
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break;
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}
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}
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*width = width_so_far;
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return s;
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}
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/*
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* get_mbs_width - compute screen width of a string
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*/
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unsigned int get_mbs_width(const char *s)
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{
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int width;
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width = INT_MAX;
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mbs_at_width(s, &width, 1);
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return width;
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}
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/*
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* get_max_mbs_width - get width of longest string in an array
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*/
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unsigned int get_max_mbs_width(const char *const *s, unsigned int count)
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{
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unsigned int max_width, i, len;
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max_width = 0;
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for (i = 0; i < count; ++i) {
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len = get_mbs_width(s[i]);
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if (len > max_width)
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max_width = len;
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}
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return max_width;
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}
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