alsa-utils/alsamixer/utils.c
Clemens Ladisch 5b6b5fd14b alsamixer: show channel names for multichannel controls
For multichannel mixer controls, add the channel name to each screen
control.

Also make some other small changes.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
2009-05-25 10:26:22 +02:00

111 lines
3 KiB
C

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