components/keyboard_indicators.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <ctype.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <X11/Xlib.h>
   6
   7 #include "../util.h"
   8
   9 /*
  10  * fmt consists of uppercase or lowercase 'c' for caps lock and/or 'n' for num
  11  * lock, each optionally followed by '?', in the order of indicators desired.
  12  * If followed by '?', the letter with case preserved is included in the output
  13  * if the corresponding indicator is on.  Otherwise, the letter is always
  14  * included, lowercase when off and uppercase when on.
  15  */
  16 const char *
  17 keyboard_indicators(const char *fmt)
  18 {
  19         Display *dpy;
  20         XKeyboardState state;
  21         size_t fmtlen, i, n;
  22         int togglecase, isset;
  23         char key;
  24
  25         if (!(dpy = XOpenDisplay(NULL))) {
  26                 warn("XOpenDisplay: Failed to open display");
  27                 return NULL;
  28         }
  29         XGetKeyboardControl(dpy, &state);
  30         XCloseDisplay(dpy);
  31
  32         fmtlen = strnlen(fmt, 4);
  33         for (i = n = 0; i < fmtlen; i++) {
  34                 key = tolower(fmt[i]);
  35                 if (key != 'c' && key != 'n') {
  36                         continue;
  37                 }
  38                 togglecase = (i + 1 >= fmtlen || fmt[i + 1] != '?');
  39                 isset = (state.led_mask & (1 << (key == 'n')));
  40                 if (togglecase) {
  41                         buf[n++] = isset ? toupper(key) : key;
  42                 } else if (isset) {
  43                         buf[n++] = fmt[i];
  44                 }
  45         }
  46         buf[n] = 0;
  47         return buf;
  48 }