lib/dpkg/strwide.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * strwide.c - wide character string handling routines
   4  *
   5  * Copyright © 2004 Changwoo Ryu <cwryu@debian.org>
   6  * Copyright © 2012-2013 Guillem Jover <guillem@debian.org>
   7  *
   8  * This is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <config.h>
  23 #include <compat.h>
  24
  25 #include <string.h>
  26 #include <stdlib.h>
  27 #ifdef ENABLE_NLS
  28 #include <wchar.h>
  29 #endif
  30
  31 #include <dpkg/i18n.h>
  32 #include <dpkg/dpkg.h>
  33 #include <dpkg/string.h>
  34
  35 /**
  36  * Compute the screen width of a string.
  37  *
  38  * @param str The multibyte string.
  39  *
  40  * @return The width of the string.
  41  */
  42 int
  43 str_width(const char *str)
  44 {
  45 #ifdef ENABLE_NLS
  46         mbstate_t state;
  47         wchar_t *wcs;
  48         const char *mbs = str;
  49         size_t len, res;
  50         int width;
  51
  52         len = strlen(str) + 1;
  53         wcs = m_malloc(sizeof(wcs[0]) * len);
  54
  55         memset(&state, 0, sizeof(state));
  56
  57         res = mbsrtowcs(wcs, &mbs, len, &state);
  58         if (res == (size_t)-1) {
  59 #ifdef DPKG_UNIFORM_ENCODING
  60                 ohshit(_("cannot convert multibyte string '%s' "
  61                          "to a wide-character string"), str);
  62 #else
  63                 /* Cannot convert, fallback to ASCII method. */
  64                 free(wcs);
  65                 return strlen(str);
  66 #endif
  67         }
  68
  69         width = wcswidth(wcs, res);
  70
  71         free(wcs);
  72
  73         return width;
  74 #else
  75         return strlen(str);
  76 #endif
  77 }
  78
  79 /**
  80  * Generate the crop values for a string given a maximum screen width.
  81  *
  82  * This function analyzes the string passed and computes the correct point
  83  * where to crop the string, returning the amount of string and maximum
  84  * bytes to use for padding for example.
  85  *
  86  * On NLS enabled builds, in addition the string will be cropped on any
  87  * newline.
  88  *
  89  * @param str        The string to crop.
  90  * @param max_width  The max screen width to use.
  91  * @param[out] crop  The generated crop values for the string.
  92  */
  93 void
  94 str_gen_crop(const char *str, int max_width, struct str_crop_info *crop)
  95 {
  96 #ifdef ENABLE_NLS
  97         mbstate_t state;
  98         size_t str_bytes;
  99         int mbs_bytes = 0;
 100         int mbs_width = 0;
 101
 102         str_bytes = strlen(str) + 1;
 103         memset(&state, 0, sizeof(state));
 104
 105         for (;;) {
 106                 wchar_t wc;
 107                 int wc_width;
 108                 size_t mb_bytes;
 109
 110                 mb_bytes = mbrtowc(&wc, str, str_bytes, &state);
 111                 if (mb_bytes == (size_t)-1 || mb_bytes == (size_t)-2) {
 112 #ifdef DPKG_UNIFORM_ENCODING
 113                         ohshit(_("cannot convert multibyte sequence '%s' "
 114                                  "to a wide character"), str);
 115 #else
 116                         /* Cannot convert, fallback to ASCII method. */
 117                         crop->str_bytes = crop->max_bytes = max_width;
 118                         return;
 119 #endif
 120                 }
 121                 if (mb_bytes == 0)
 122                         break;
 123
 124                 wc_width = wcwidth(wc);
 125                 if (wc_width < 0)
 126                         break;
 127                 if (mbs_width + wc_width > max_width)
 128                         break;
 129
 130                 mbs_width += wc_width;
 131                 mbs_bytes += mb_bytes;
 132                 str_bytes -= mb_bytes;
 133                 str += mb_bytes;
 134         }
 135
 136         crop->str_bytes = mbs_bytes;
 137         crop->max_bytes = mbs_bytes + max_width - mbs_width;
 138 #else
 139         crop->str_bytes = crop->max_bytes = max_width;
 140 #endif
 141 }