1/* This file is based on the GLIB utf8 validation functions. The
2 * original license text follows. */
3
4/* gutf8.c - Operations on UTF-8 strings.
5 *
6 * Copyright (C) 1999 Tom Tromey
7 * Copyright (C) 2000 Red Hat, Inc.
8 *
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 02111-1307, USA.
23 */
24
25#ifdef HAVE_CONFIG_H
26#include <config.h>
27#endif
28
29#include <stdlib.h>
30
31#include "utf8.h"
32
33#define UNICODE_VALID(Char)                   \
34    ((Char) < 0x110000 &&                     \
35     (((Char) & 0xFFFFF800) != 0xD800) &&     \
36     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \
37     ((Char) & 0xFFFE) != 0xFFFE)
38
39
40#define CONTINUATION_CHAR                           \
41 do {                                     \
42  if ((*(const unsigned char *)p & 0xc0) != 0x80) /* 10xxxxxx */ \
43    goto error;                                     \
44  val <<= 6;                                        \
45  val |= (*(const unsigned char *)p) & 0x3f;                     \
46 } while(0)
47
48
49const char *
50avahi_utf8_valid (const char *str)
51
52{
53  unsigned val = 0;
54  unsigned min = 0;
55  const char *p;
56
57  for (p = str; *p; p++)
58    {
59      if (*(const unsigned char *)p < 128)
60	/* done */;
61      else
62	{
63	  if ((*(const unsigned char *)p & 0xe0) == 0xc0) /* 110xxxxx */
64	    {
65	      if ( ((*(const unsigned char *)p & 0x1e) == 0))
66		goto error;
67	      p++;
68	      if ( ((*(const unsigned char *)p & 0xc0) != 0x80)) /* 10xxxxxx */
69		goto error;
70	    }
71	  else
72	    {
73	      if ((*(const unsigned char *)p & 0xf0) == 0xe0) /* 1110xxxx */
74		{
75		  min = (1 << 11);
76		  val = *(const unsigned char *)p & 0x0f;
77		  goto TWO_REMAINING;
78		}
79	      else if ((*(const unsigned char *)p & 0xf8) == 0xf0) /* 11110xxx */
80		{
81		  min = (1 << 16);
82		  val = *(const unsigned char *)p & 0x07;
83		}
84	      else
85		goto error;
86
87	      p++;
88	      CONTINUATION_CHAR;
89	    TWO_REMAINING:
90	      p++;
91	      CONTINUATION_CHAR;
92	      p++;
93	      CONTINUATION_CHAR;
94
95	      if ( (val < min))
96		goto error;
97
98	      if ( (!UNICODE_VALID(val)))
99		goto error;
100	    }
101
102	  continue;
103
104	error:
105	  return NULL;
106	}
107    }
108
109  return str;
110}
111