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

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Revision 199 - (hide annotations) (download)
Tue Jul 31 14:39:09 2007 UTC (7 years, 1 month ago) by ph10
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File size: 4624 byte(s)
Daniel's patch for config.h and Windows DLL declarations (not fully working).

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 199 #ifdef HAVE_CONFIG_H
46     #include <config.h>
47     #endif
48    
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     Arguments:
63     string points to the string
64     length length of string, or -1 if the string is zero-terminated
65    
66     Returns: < 0 if the string is a valid UTF-8 string
67     >= 0 otherwise; the value is the offset of the bad byte
68     */
69    
70 nigel 87 int
71 nigel 77 _pcre_valid_utf8(const uschar *string, int length)
72     {
73 ph10 110 #ifdef SUPPORT_UTF8
74 nigel 77 register const uschar *p;
75    
76     if (length < 0)
77     {
78     for (p = string; *p != 0; p++);
79     length = p - string;
80     }
81    
82     for (p = string; length-- > 0; p++)
83     {
84     register int ab;
85     register int c = *p;
86     if (c < 128) continue;
87 nigel 93 if (c < 0xc0) return p - string;
88 nigel 77 ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
89     if (length < ab) return p - string;
90     length -= ab;
91    
92     /* Check top bits in the second byte */
93     if ((*(++p) & 0xc0) != 0x80) return p - string;
94    
95     /* Check for overlong sequences for each different length */
96     switch (ab)
97     {
98     /* Check for xx00 000x */
99     case 1:
100     if ((c & 0x3e) == 0) return p - string;
101     continue; /* We know there aren't any more bytes to check */
102    
103     /* Check for 1110 0000, xx0x xxxx */
104     case 2:
105     if (c == 0xe0 && (*p & 0x20) == 0) return p - string;
106     break;
107    
108     /* Check for 1111 0000, xx00 xxxx */
109     case 3:
110     if (c == 0xf0 && (*p & 0x30) == 0) return p - string;
111     break;
112    
113     /* Check for 1111 1000, xx00 0xxx */
114     case 4:
115     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
116     break;
117    
118     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
119     case 5:
120     if (c == 0xfe || c == 0xff ||
121     (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
122     break;
123     }
124    
125     /* Check for valid bytes after the 2nd, if any; all must start 10 */
126     while (--ab > 0)
127     {
128     if ((*(++p) & 0xc0) != 0x80) return p - string;
129     }
130     }
131 ph10 110 #endif
132 nigel 77
133     return -1;
134     }
135    
136     /* End of pcre_valid_utf8.c */

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