Annotation of win32/pcre/pcre_valid_utf8.c, revision 1.2
1.1 misha 1: /*************************************************
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) 1997-2008 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-8 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-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: 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 applied. 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: 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: int
78: _pcre_valid_utf8(const uschar *string, int length)
79: {
80: #ifdef SUPPORT_UTF8
81: 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: if (c < 0xc0) return p - string;
95: ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
96: if (length < ab || ab > 3) return p - string;
97: length -= ab;
98:
99: /* Check top bits in the second byte */
100: if ((*(++p) & 0xc0) != 0x80) return p - string;
101:
102: /* Check for overlong sequences for each different length, and for the
103: excluded range 0xd000 to 0xdfff. */
104:
105: switch (ab)
106: {
107: /* Check for xx00 000x (overlong sequence) */
108:
109: case 1:
110: if ((c & 0x3e) == 0) return p - string;
111: continue; /* We know there aren't any more bytes to check */
112:
113: /* Check for 1110 0000, xx0x xxxx (overlong sequence) or
114: 1110 1101, 1010 xxxx (0xd000 - 0xdfff) */
115:
116: case 2:
117: if ((c == 0xe0 && (*p & 0x20) == 0) ||
118: (c == 0xed && *p >= 0xa0))
119: return p - string;
120: break;
121:
122: /* Check for 1111 0000, xx00 xxxx (overlong sequence) or
123: greater than 0x0010ffff (f4 8f bf bf) */
124:
125: case 3:
126: if ((c == 0xf0 && (*p & 0x30) == 0) ||
127: (c > 0xf4 ) ||
128: (c == 0xf4 && *p > 0x8f))
129: return p - string;
130: break;
131:
132: #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: /* 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: #endif
148:
149: }
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: }
1.2 ! misha 157: #else
! 158: (void)(string); /* Keep picky compilers happy */
! 159: (void)(length);
1.1 misha 160: #endif
161:
162: return -1;
163: }
164:
165: /* End of pcre_valid_utf8.c */
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