src/lib-roff/unicode.cpp

   1 /*@
   2  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   3  *
   4  * Copyright (C) 2002
   5  *    Free Software Foundation, Inc.
   6  *      Written by Werner Lemberg <wl@gnu.org>
   7  *
   8  * This is free software; you can redistribute it and/or modify it under
   9  * the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2, or (at your option) any later
  11  * version.
  12  *
  13  * This is distributed in the hope that it will be useful, but WITHOUT ANY
  14  * WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with groff; see the file COPYING.  If not, write to the Free Software
  20  * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
  21  */
  22
  23 #include "config.h"
  24
  25 #include "cset.h"
  26 #include "lib.h"
  27 #include "stringclass.h"
  28 #include "unicode.h"
  29
  30 const char *check_unicode_name(const char *u)
  31 {
  32   if (*u != 'u')
  33     return 0;
  34   const char *p = ++u;
  35   for (;;) {
  36     int val = 0;
  37     const char *start = p;
  38     for (;;) {
  39       // only uppercase hex digits allowed
  40       if (!csxdigit(*p))
  41         return 0;
  42       if (csdigit(*p))
  43         val = val*0x10 + (*p-'0');
  44       else if (csupper(*p))
  45         val = val*0x10 + (*p-'A'+10);
  46       else
  47         return 0;
  48       // biggest Unicode value is U+10FFFF
  49       if (val > 0x10FFFF)
  50         return 0;
  51       p++;
  52       if (*p == '\0' || *p == '_')
  53         break;
  54     }
  55     // surrogates not allowed
  56     if ((val >= 0xD800 && val <= 0xDBFF) || (val >= 0xDC00 && val <= 0xDFFF))
  57       return 0;
  58     if (val > 0xFFFF) {
  59       if (*start == '0')        // no leading zeros allowed if > 0xFFFF
  60         return 0;
  61     }
  62     else if (p - start != 4)    // otherwise, check for exactly 4 hex digits
  63       return 0;
  64     if (*p == '\0')
  65       break;
  66     p++;
  67   }
  68   return u;
  69 }
  70
  71 // s-it2-mode