util.c

   1 /*
   2  * Copyright (c) 2019, 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 *
  27 aprintf(const char *format, ...)
  28 {
  29         char *mem = 0;
  30         va_list arglist;
  31         size_t len = 0;
  32
  33         va_start(arglist, format);
  34         len = vsnprintf(0, 0, format, arglist);
  35         va_end(arglist);
  36
  37         if (!(mem = malloc(len + 1))) {
  38                 goto done;
  39         }
  40
  41         va_start(arglist, format);
  42         vsprintf(mem, format, arglist);
  43         va_end(arglist);
  44 done:
  45
  46         return mem;
  47 }
  48
  49 /* Calculate how much space we need to print a string */
  50 int
  51 strwidth(const char *s)
  52 {
  53         if (!s) {
  54                 return 0;
  55         }
  56
  57         int width = 0;
  58         wchar_t wc = 0;
  59         mbstate_t mbs = { 0 };
  60         size_t left = strlen(s);
  61         int l = 0;
  62         size_t mbret = 0;
  63
  64         while (*s) {
  65                 mbret = mbrtowc(&wc, s, left, &mbs);
  66
  67                 if (mbret >= (size_t) -2) {
  68                         mbs = (mbstate_t) { 0 };
  69                         s++;
  70                         left--;
  71                         continue;
  72                 }
  73
  74                 l = wcwidth(wc);
  75                 s += mbret;
  76
  77                 if (l >= 0) {
  78                         width += l;
  79                 }
  80         }
  81
  82         return width;
  83 }