1 // -*- C++ -*-
2 /* Copyright (C) 2002
3 Free Software Foundation, Inc.
4 Written by Werner Lemberg <wl@gnu.org>
5
6 This file is part of groff.
7
8 groff 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 groff 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 #include "lib.h"
23 #include "cset.h"
24 #include "stringclass.h"
25
26 #include "unicode.h"
27
check_unicode_name(const char * u)28 const char *check_unicode_name(const char *u)
29 {
30 if (*u != 'u')
31 return 0;
32 const char *p = ++u;
33 for (;;) {
34 int val = 0;
35 const char *start = p;
36 for (;;) {
37 // only uppercase hex digits allowed
38 if (!csxdigit(*p))
39 return 0;
40 if (csdigit(*p))
41 val = val*0x10 + (*p-'0');
42 else if (csupper(*p))
43 val = val*0x10 + (*p-'A'+10);
44 else
45 return 0;
46 // biggest Unicode value is U+10FFFF
47 if (val > 0x10FFFF)
48 return 0;
49 p++;
50 if (*p == '\0' || *p == '_')
51 break;
52 }
53 // surrogates not allowed
54 if ((val >= 0xD800 && val <= 0xDBFF) || (val >= 0xDC00 && val <= 0xDFFF))
55 return 0;
56 if (val > 0xFFFF) {
57 if (*start == '0') // no leading zeros allowed if > 0xFFFF
58 return 0;
59 }
60 else if (p - start != 4) // otherwise, check for exactly 4 hex digits
61 return 0;
62 if (*p == '\0')
63 break;
64 p++;
65 }
66 return u;
67 }
68