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

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Revision 96 - (hide annotations) (download)
Fri Mar 2 13:10:43 2007 UTC (7 years, 4 months ago) by nigel
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 r6896@hex:  nm | 2007-03-02 13:09:14 +0000
 Added EOL and keywork properties throughout

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 nigel 87 Copyright (c) 1997-2006 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     #include "pcre_internal.h"
46    
47    
48     /*************************************************
49     * Validate a UTF-8 string *
50     *************************************************/
51    
52     /* This function is called (optionally) at the start of compile or match, to
53     validate that a supposed UTF-8 string is actually valid. The early check means
54     that subsequent code can assume it is dealing with a valid string. The check
55     can be turned off for maximum performance, but the consequences of supplying
56     an invalid string are then undefined.
57    
58     Arguments:
59     string points to the string
60     length length of string, or -1 if the string is zero-terminated
61    
62     Returns: < 0 if the string is a valid UTF-8 string
63     >= 0 otherwise; the value is the offset of the bad byte
64     */
65    
66 nigel 87 int
67 nigel 77 _pcre_valid_utf8(const uschar *string, int length)
68     {
69     register const uschar *p;
70    
71     if (length < 0)
72     {
73     for (p = string; *p != 0; p++);
74     length = p - string;
75     }
76    
77     for (p = string; length-- > 0; p++)
78     {
79     register int ab;
80     register int c = *p;
81     if (c < 128) continue;
82 nigel 93 if (c < 0xc0) return p - string;
83 nigel 77 ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
84     if (length < ab) return p - string;
85     length -= ab;
86    
87     /* Check top bits in the second byte */
88     if ((*(++p) & 0xc0) != 0x80) return p - string;
89    
90     /* Check for overlong sequences for each different length */
91     switch (ab)
92     {
93     /* Check for xx00 000x */
94     case 1:
95     if ((c & 0x3e) == 0) return p - string;
96     continue; /* We know there aren't any more bytes to check */
97    
98     /* Check for 1110 0000, xx0x xxxx */
99     case 2:
100     if (c == 0xe0 && (*p & 0x20) == 0) return p - string;
101     break;
102    
103     /* Check for 1111 0000, xx00 xxxx */
104     case 3:
105     if (c == 0xf0 && (*p & 0x30) == 0) return p - string;
106     break;
107    
108     /* Check for 1111 1000, xx00 0xxx */
109     case 4:
110     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
111     break;
112    
113     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
114     case 5:
115     if (c == 0xfe || c == 0xff ||
116     (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
117     break;
118     }
119    
120     /* Check for valid bytes after the 2nd, if any; all must start 10 */
121     while (--ab > 0)
122     {
123     if ((*(++p) & 0xc0) != 0x80) return p - string;
124     }
125     }
126    
127     return -1;
128     }
129    
130     /* End of pcre_valid_utf8.c */

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