/[pcre]/code/trunk/pcre16_valid_utf16.c
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Contents of /code/trunk/pcre16_valid_utf16.c

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Revision 757 - (hide annotations) (download)
Mon Nov 21 11:44:55 2011 UTC (2 years, 11 months ago) by ph10
Original Path: code/branches/pcre16/pcre16_valid_utf16.c
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More 16-bit patches

1 ph10 757 /*************************************************
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     Copyright (c) 1997-2009 University of Cambridge
10    
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-16 character
42     strings. */
43    
44    
45     #ifdef HAVE_CONFIG_H
46     #include "config.h"
47     #endif
48    
49     #include "pcre_internal.h"
50    
51    
52     /*************************************************
53     * Validate a UTF-16 string *
54     *************************************************/
55    
56     /* This function is called (optionally) at the start of compile or match, to
57     check that a supposed UTF-16 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 an
60     invalid string are then undefined.
61    
62     From release 8.21 more information about the details of the error are passed
63     back in the returned value:
64    
65     PCRE_UTF16_ERR0 No error
66     PCRE_UTF16_ERR1 Missing low surrogate at the end of the string
67     PCRE_UTF16_ERR2 Invalid low surrogate
68     PCRE_UTF16_ERR3 Isolated low surrogate
69     PCRE_UTF16_ERR4 Not allowed character.
70    
71     Arguments:
72     string points to the string
73     length length of string, or -1 if the string is zero-terminated
74     errp pointer to an error position offset variable
75    
76     Returns: = 0 if the string is a valid UTF-16 string
77     > 0 otherwise, setting the offset of the bad character
78     */
79    
80     int
81     _pcre16_valid_utf16(USPTR string, int length, int *erroroffset)
82     {
83     #ifdef SUPPORT_UTF16
84     register USPTR p;
85     register uschar c;
86    
87     if (length < 0)
88     {
89     for (p = string; *p != 0; p++);
90     length = p - string;
91     }
92    
93     for (p = string; length-- > 0; p++)
94     {
95     c = *p;
96    
97     if ((c & 0xf800) != 0xd800)
98     {
99     /* Normal UTF-16 code point. Neither high nor low surrogate. */
100    
101     /* This is probably a BOM from a different byte-order.
102     Regardless, the string is rejected. */
103     if (c == 0xfffe)
104     {
105     *erroroffset = p - string;
106     return PCRE_UTF16_ERR4;
107     }
108     }
109     else if ((c & 0x0400) == 0)
110     {
111     /* High surrogate. */
112    
113     /* Must be a followed by a low surrogate. */
114     if (length == 0)
115     {
116     *erroroffset = p - string;
117     return PCRE_UTF16_ERR1;
118     }
119     p++;
120     length--;
121     if ((*p & 0xfc00) != 0xdc00)
122     {
123     *erroroffset = p - string;
124     return PCRE_UTF16_ERR2;
125     }
126     }
127     else
128     {
129     /* Isolated low surrogate. Always an error. */
130     *erroroffset = p - string;
131     return PCRE_UTF16_ERR3;
132     }
133     }
134    
135     #else /* SUPPORT_UTF16 */
136     (void)(string); /* Keep picky compilers happy */
137     (void)(length);
138     #endif
139    
140     return PCRE_UTF16_ERR0; /* This indicates success */
141     }
142    
143     /* End of pcre16_valid_utf16.c */

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