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

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Revision 836 - (hide annotations) (download)
Wed Dec 28 17:16:11 2011 UTC (2 years, 8 months ago) by ph10
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Merging all the changes from the pcre16 branch into the trunk.

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 ph10 830 Copyright (c) 1997-2012 University of Cambridge
10 ph10 757
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 zherczeg 782 /* Generate code with 16 bit character support. */
50     #define COMPILE_PCRE16
51    
52 ph10 757 #include "pcre_internal.h"
53    
54    
55     /*************************************************
56     * Validate a UTF-16 string *
57     *************************************************/
58    
59     /* This function is called (optionally) at the start of compile or match, to
60     check that a supposed UTF-16 string is actually valid. The early check means
61     that subsequent code can assume it is dealing with a valid string. The check
62     can be turned off for maximum performance, but the consequences of supplying an
63     invalid string are then undefined.
64    
65     From release 8.21 more information about the details of the error are passed
66     back in the returned value:
67    
68     PCRE_UTF16_ERR0 No error
69     PCRE_UTF16_ERR1 Missing low surrogate at the end of the string
70     PCRE_UTF16_ERR2 Invalid low surrogate
71     PCRE_UTF16_ERR3 Isolated low surrogate
72 zherczeg 764 PCRE_UTF16_ERR4 Not allowed character
73 ph10 757
74     Arguments:
75     string points to the string
76     length length of string, or -1 if the string is zero-terminated
77     errp pointer to an error position offset variable
78    
79     Returns: = 0 if the string is a valid UTF-16 string
80     > 0 otherwise, setting the offset of the bad character
81     */
82    
83     int
84 zherczeg 781 PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
85 ph10 757 {
86 zherczeg 794 #ifdef SUPPORT_UTF
87 zherczeg 763 register PCRE_PUCHAR p;
88 zherczeg 781 register pcre_uchar c;
89 ph10 757
90     if (length < 0)
91     {
92     for (p = string; *p != 0; p++);
93     length = p - string;
94     }
95    
96     for (p = string; length-- > 0; p++)
97     {
98     c = *p;
99    
100     if ((c & 0xf800) != 0xd800)
101     {
102     /* Normal UTF-16 code point. Neither high nor low surrogate. */
103    
104     /* This is probably a BOM from a different byte-order.
105     Regardless, the string is rejected. */
106     if (c == 0xfffe)
107     {
108     *erroroffset = p - string;
109     return PCRE_UTF16_ERR4;
110     }
111     }
112     else if ((c & 0x0400) == 0)
113     {
114     /* High surrogate. */
115    
116     /* Must be a followed by a low surrogate. */
117     if (length == 0)
118     {
119     *erroroffset = p - string;
120     return PCRE_UTF16_ERR1;
121     }
122     p++;
123     length--;
124     if ((*p & 0xfc00) != 0xdc00)
125     {
126     *erroroffset = p - string;
127     return PCRE_UTF16_ERR2;
128     }
129     }
130     else
131     {
132     /* Isolated low surrogate. Always an error. */
133     *erroroffset = p - string;
134     return PCRE_UTF16_ERR3;
135     }
136     }
137    
138 zherczeg 794 #else /* SUPPORT_UTF */
139 ph10 757 (void)(string); /* Keep picky compilers happy */
140     (void)(length);
141 zherczeg 794 #endif /* SUPPORT_UTF */
142 ph10 757
143     return PCRE_UTF16_ERR0; /* This indicates success */
144     }
145    
146     /* End of pcre16_valid_utf16.c */

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