Annotation of embedaddon/php/ext/pcre/pcrelib/pcre_valid_utf8.c, revision 1.1.1.1
1.1 misho 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) 1997-2009 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-8 character
42: strings. */
43:
44:
45: #include "config.h"
46:
47: #include "pcre_internal.h"
48:
49:
50: /*************************************************
51: * Validate a UTF-8 string *
52: *************************************************/
53:
54: /* This function is called (optionally) at the start of compile or match, to
55: validate that a supposed UTF-8 string is actually valid. The early check means
56: that subsequent code can assume it is dealing with a valid string. The check
57: can be turned off for maximum performance, but the consequences of supplying
58: an invalid string are then undefined.
59:
60: Originally, this function checked according to RFC 2279, allowing for values in
61: the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
62: the canonical format. Once somebody had pointed out RFC 3629 to me (it
63: obsoletes 2279), additional restrictions were applied. The values are now
64: limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
65: subrange 0xd000 to 0xdfff is excluded.
66:
67: Arguments:
68: string points to the string
69: length length of string, or -1 if the string is zero-terminated
70:
71: Returns: < 0 if the string is a valid UTF-8 string
72: >= 0 otherwise; the value is the offset of the bad byte
73:
74: Bad bytes can be:
75:
76: . An isolated byte whose most significant bits are 0x80, because this
77: can only correctly appear within a UTF-8 character;
78:
79: . A byte whose most significant bits are 0xc0, but whose other bits indicate
80: that there are more than 3 additional bytes (i.e. an RFC 2279 starting
81: byte, which is no longer valid under RFC 3629);
82:
83: .
84:
85: The returned offset may also be equal to the length of the string; this means
86: that one or more bytes is missing from the final UTF-8 character.
87: */
88:
89: int
90: _pcre_valid_utf8(USPTR string, int length)
91: {
92: #ifdef SUPPORT_UTF8
93: register USPTR p;
94:
95: if (length < 0)
96: {
97: for (p = string; *p != 0; p++);
98: length = p - string;
99: }
100:
101: for (p = string; length-- > 0; p++)
102: {
103: register int ab;
104: register int c = *p;
105: if (c < 128) continue;
106: if (c < 0xc0) return p - string;
107: ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
108: if (ab > 3) return p - string; /* Too many for RFC 3629 */
109: if (length < ab) return p + 1 + length - string; /* Missing bytes */
110: length -= ab;
111:
112: /* Check top bits in the second byte */
113: if ((*(++p) & 0xc0) != 0x80) return p - string;
114:
115: /* Check for overlong sequences for each different length, and for the
116: excluded range 0xd000 to 0xdfff. */
117:
118: switch (ab)
119: {
120: /* Check for xx00 000x (overlong sequence) */
121:
122: case 1:
123: if ((c & 0x3e) == 0) return p - string;
124: continue; /* We know there aren't any more bytes to check */
125:
126: /* Check for 1110 0000, xx0x xxxx (overlong sequence) or
127: 1110 1101, 1010 xxxx (0xd000 - 0xdfff) */
128:
129: case 2:
130: if ((c == 0xe0 && (*p & 0x20) == 0) ||
131: (c == 0xed && *p >= 0xa0))
132: return p - string;
133: break;
134:
135: /* Check for 1111 0000, xx00 xxxx (overlong sequence) or
136: greater than 0x0010ffff (f4 8f bf bf) */
137:
138: case 3:
139: if ((c == 0xf0 && (*p & 0x30) == 0) ||
140: (c > 0xf4 ) ||
141: (c == 0xf4 && *p > 0x8f))
142: return p - string;
143: break;
144:
145: #if 0
146: /* These cases can no longer occur, as we restrict to a maximum of four
147: bytes nowadays. Leave the code here in case we ever want to add an option
148: for longer sequences. */
149:
150: /* Check for 1111 1000, xx00 0xxx */
151: case 4:
152: if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
153: break;
154:
155: /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
156: case 5:
157: if (c == 0xfe || c == 0xff ||
158: (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
159: break;
160: #endif
161:
162: }
163:
164: /* Check for valid bytes after the 2nd, if any; all must start 10 */
165: while (--ab > 0)
166: {
167: if ((*(++p) & 0xc0) != 0x80) return p - string;
168: }
169: }
170: #else
171: (void)(string); /* Keep picky compilers happy */
172: (void)(length);
173: #endif
174:
175: return -1;
176: }
177:
178: /* End of pcre_valid_utf8.c */
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