util.c

   1 /*
   2  * Copyright (c) 2018, De Rais <derais@cock.li>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for
   5  * any purpose with or without fee is hereby granted, provided that the
   6  * above copyright notice and this permission notice appear in all
   7  * copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  10  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  11  * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
  12  * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  13  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  14  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  15  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  16  * PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <stdarg.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <wchar.h>
  24
  25 /* snprintf + malloc + sprintf */
  26 char * aprintf(const char *format, ...)
  27 {
  28         char *mem = 0;
  29         va_list arglist;
  30         size_t len = 0;
  31
  32         va_start(arglist, format);
  33         len = vsnprintf(0, 0, format, arglist);
  34         va_end(arglist);
  35
  36         if (!(mem = malloc(len + 1))) {
  37                 goto done;
  38         }
  39
  40         va_start(arglist, format);
  41         vsprintf(mem, format, arglist);
  42         va_end(arglist);
  43 done:
  44
  45         return mem;
  46 }
  47
  48 /* Calculate how much space we need to print a string */
  49 int strwidth(const char *s)
  50 {
  51         if (!s) {
  52                 return 0;
  53         }
  54
  55         int width = 0;
  56         wchar_t wc = 0;
  57         mbstate_t mbs = { 0 };
  58         size_t left = strlen(s);
  59         int l = 0;
  60         size_t mbret = 0;
  61
  62         while (*s) {
  63                 mbret = mbrtowc(&wc, s, left, &mbs);
  64
  65                 if (mbret >= (size_t) -2) {
  66                         mbs = (mbstate_t) { 0 };
  67                         s++;
  68                         left--;
  69                         continue;
  70                 }
  71
  72                 l = wcwidth(wc);
  73                 s += mbret;
  74
  75                 if (l >= 0) {
  76                         width += l;
  77                 }
  78         }
  79
  80         return width;
  81 }