/[pcre]/code/trunk/pcre_valid_utf8.c
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Contents of /code/trunk/pcre_valid_utf8.c

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Revision 236 - (hide annotations) (download)
Tue Sep 11 12:57:06 2007 UTC (6 years, 11 months ago) by ph10
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File size: 5497 byte(s)
<config.h> => "config.h" and also some cases of <pcre.h>.

1 nigel 77 /*************************************************
2     * Perl-Compatible Regular Expressions *
3     *************************************************/
4    
5     /* PCRE is a library of functions to support regular expressions whose syntax
6     and semantics are as close as possible to those of the Perl 5 language.
7    
8     Written by Philip Hazel
9 ph10 117 Copyright (c) 1997-2007 University of Cambridge
10 nigel 77
11     -----------------------------------------------------------------------------
12     Redistribution and use in source and binary forms, with or without
13     modification, are permitted provided that the following conditions are met:
14    
15     * Redistributions of source code must retain the above copyright notice,
16     this list of conditions and the following disclaimer.
17    
18     * Redistributions in binary form must reproduce the above copyright
19     notice, this list of conditions and the following disclaimer in the
20     documentation and/or other materials provided with the distribution.
21    
22     * Neither the name of the University of Cambridge nor the names of its
23     contributors may be used to endorse or promote products derived from
24     this software without specific prior written permission.
25    
26     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
27     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29     ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
30     LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36     POSSIBILITY OF SUCH DAMAGE.
37     -----------------------------------------------------------------------------
38     */
39    
40    
41     /* This module contains an internal function for validating UTF-8 character
42     strings. */
43    
44    
45 ph10 200 #ifdef HAVE_CONFIG_H
46 ph10 236 #include "config.h"
47 ph10 200 #endif
48 ph10 199
49 nigel 77 #include "pcre_internal.h"
50    
51    
52     /*************************************************
53     * Validate a UTF-8 string *
54     *************************************************/
55    
56     /* This function is called (optionally) at the start of compile or match, to
57     validate that a supposed UTF-8 string is actually valid. The early check means
58     that subsequent code can assume it is dealing with a valid string. The check
59     can be turned off for maximum performance, but the consequences of supplying
60     an invalid string are then undefined.
61    
62 ph10 211 Originally, this function checked according to RFC 2279, allowing for values in
63     the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
64     the canonical format. Once somebody had pointed out RFC 3629 to me (it
65     obsoletes 2279), additional restrictions were applies. The values are now
66     limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
67     subrange 0xd000 to 0xdfff is excluded.
68    
69 nigel 77 Arguments:
70     string points to the string
71     length length of string, or -1 if the string is zero-terminated
72    
73     Returns: < 0 if the string is a valid UTF-8 string
74     >= 0 otherwise; the value is the offset of the bad byte
75     */
76    
77 nigel 87 int
78 nigel 77 _pcre_valid_utf8(const uschar *string, int length)
79     {
80 ph10 110 #ifdef SUPPORT_UTF8
81 nigel 77 register const uschar *p;
82    
83     if (length < 0)
84     {
85     for (p = string; *p != 0; p++);
86     length = p - string;
87     }
88    
89     for (p = string; length-- > 0; p++)
90     {
91     register int ab;
92     register int c = *p;
93     if (c < 128) continue;
94 nigel 93 if (c < 0xc0) return p - string;
95 ph10 211 ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
96     if (length < ab || ab > 3) return p - string;
97 nigel 77 length -= ab;
98    
99     /* Check top bits in the second byte */
100     if ((*(++p) & 0xc0) != 0x80) return p - string;
101    
102 ph10 211 /* Check for overlong sequences for each different length, and for the
103     excluded range 0xd000 to 0xdfff. */
104    
105 nigel 77 switch (ab)
106     {
107 ph10 211 /* Check for xx00 000x (overlong sequence) */
108    
109 nigel 77 case 1:
110     if ((c & 0x3e) == 0) return p - string;
111     continue; /* We know there aren't any more bytes to check */
112    
113 ph10 211 /* Check for 1110 0000, xx0x xxxx (overlong sequence) or
114     1110 1101, 1010 xxxx (0xd000 - 0xdfff) */
115    
116 nigel 77 case 2:
117 ph10 211 if ((c == 0xe0 && (*p & 0x20) == 0) ||
118     (c == 0xed && *p >= 0xa0))
119     return p - string;
120 nigel 77 break;
121    
122 ph10 211 /* Check for 1111 0000, xx00 xxxx (overlong sequence) or
123     greater than 0x0010ffff (f4 8f bf bf) */
124    
125 nigel 77 case 3:
126 ph10 211 if ((c == 0xf0 && (*p & 0x30) == 0) ||
127     (c > 0xf4 ) ||
128     (c == 0xf4 && *p > 0x8f))
129     return p - string;
130 nigel 77 break;
131    
132 ph10 211 #if 0
133     /* These cases can no longer occur, as we restrict to a maximum of four
134     bytes nowadays. Leave the code here in case we ever want to add an option
135     for longer sequences. */
136    
137 nigel 77 /* Check for 1111 1000, xx00 0xxx */
138     case 4:
139     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
140     break;
141    
142     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
143     case 5:
144     if (c == 0xfe || c == 0xff ||
145     (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
146     break;
147 ph10 211 #endif
148    
149 nigel 77 }
150    
151     /* Check for valid bytes after the 2nd, if any; all must start 10 */
152     while (--ab > 0)
153     {
154     if ((*(++p) & 0xc0) != 0x80) return p - string;
155     }
156     }
157 ph10 110 #endif
158 nigel 77
159     return -1;
160     }
161    
162     /* End of pcre_valid_utf8.c */

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