Annotation of embedaddon/pcre/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: #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: check 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 an
60: 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. However, the format of 5-byte and 6-byte
68: characters is still checked.
69:
70: From release 8.13 more information about the details of the error are passed
71: back in the returned value:
72:
73: PCRE_UTF8_ERR0 No error
74: PCRE_UTF8_ERR1 Missing 1 byte at the end of the string
75: PCRE_UTF8_ERR2 Missing 2 bytes at the end of the string
76: PCRE_UTF8_ERR3 Missing 3 bytes at the end of the string
77: PCRE_UTF8_ERR4 Missing 4 bytes at the end of the string
78: PCRE_UTF8_ERR5 Missing 5 bytes at the end of the string
79: PCRE_UTF8_ERR6 2nd-byte's two top bits are not 0x80
80: PCRE_UTF8_ERR7 3rd-byte's two top bits are not 0x80
81: PCRE_UTF8_ERR8 4th-byte's two top bits are not 0x80
82: PCRE_UTF8_ERR9 5th-byte's two top bits are not 0x80
83: PCRE_UTF8_ERR10 6th-byte's two top bits are not 0x80
84: PCRE_UTF8_ERR11 5-byte character is not permitted by RFC 3629
85: PCRE_UTF8_ERR12 6-byte character is not permitted by RFC 3629
86: PCRE_UTF8_ERR13 4-byte character with value > 0x10ffff is not permitted
87: PCRE_UTF8_ERR14 3-byte character with value 0xd000-0xdfff is not permitted
88: PCRE_UTF8_ERR15 Overlong 2-byte sequence
89: PCRE_UTF8_ERR16 Overlong 3-byte sequence
90: PCRE_UTF8_ERR17 Overlong 4-byte sequence
91: PCRE_UTF8_ERR18 Overlong 5-byte sequence (won't ever occur)
92: PCRE_UTF8_ERR19 Overlong 6-byte sequence (won't ever occur)
93: PCRE_UTF8_ERR20 Isolated 0x80 byte (not within UTF-8 character)
94: PCRE_UTF8_ERR21 Byte with the illegal value 0xfe or 0xff
95:
96: Arguments:
97: string points to the string
98: length length of string, or -1 if the string is zero-terminated
99: errp pointer to an error position offset variable
100:
101: Returns: = 0 if the string is a valid UTF-8 string
102: > 0 otherwise, setting the offset of the bad character
103: */
104:
105: int
106: _pcre_valid_utf8(USPTR string, int length, int *erroroffset)
107: {
108: #ifdef SUPPORT_UTF8
109: register USPTR p;
110:
111: if (length < 0)
112: {
113: for (p = string; *p != 0; p++);
114: length = (int)(p - string);
115: }
116:
117: for (p = string; length-- > 0; p++)
118: {
119: register int ab, c, d;
120:
121: c = *p;
122: if (c < 128) continue; /* ASCII character */
123:
124: if (c < 0xc0) /* Isolated 10xx xxxx byte */
125: {
126: *erroroffset = (int)(p - string);
127: return PCRE_UTF8_ERR20;
128: }
129:
130: if (c >= 0xfe) /* Invalid 0xfe or 0xff bytes */
131: {
132: *erroroffset = (int)(p - string);
133: return PCRE_UTF8_ERR21;
134: }
135:
136: ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
137: if (length < ab)
138: {
139: *erroroffset = (int)(p - string); /* Missing bytes */
140: return ab - length; /* Codes ERR1 to ERR5 */
141: }
142: length -= ab; /* Length remaining */
143:
144: /* Check top bits in the second byte */
145:
146: if (((d = *(++p)) & 0xc0) != 0x80)
147: {
148: *erroroffset = (int)(p - string) - 1;
149: return PCRE_UTF8_ERR6;
150: }
151:
152: /* For each length, check that the remaining bytes start with the 0x80 bit
153: set and not the 0x40 bit. Then check for an overlong sequence, and for the
154: excluded range 0xd800 to 0xdfff. */
155:
156: switch (ab)
157: {
158: /* 2-byte character. No further bytes to check for 0x80. Check first byte
159: for for xx00 000x (overlong sequence). */
160:
161: case 1: if ((c & 0x3e) == 0)
162: {
163: *erroroffset = (int)(p - string) - 1;
164: return PCRE_UTF8_ERR15;
165: }
166: break;
167:
168: /* 3-byte character. Check third byte for 0x80. Then check first 2 bytes
169: for 1110 0000, xx0x xxxx (overlong sequence) or
170: 1110 1101, 1010 xxxx (0xd800 - 0xdfff) */
171:
172: case 2:
173: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
174: {
175: *erroroffset = (int)(p - string) - 2;
176: return PCRE_UTF8_ERR7;
177: }
178: if (c == 0xe0 && (d & 0x20) == 0)
179: {
180: *erroroffset = (int)(p - string) - 2;
181: return PCRE_UTF8_ERR16;
182: }
183: if (c == 0xed && d >= 0xa0)
184: {
185: *erroroffset = (int)(p - string) - 2;
186: return PCRE_UTF8_ERR14;
187: }
188: break;
189:
190: /* 4-byte character. Check 3rd and 4th bytes for 0x80. Then check first 2
191: bytes for for 1111 0000, xx00 xxxx (overlong sequence), then check for a
192: character greater than 0x0010ffff (f4 8f bf bf) */
193:
194: case 3:
195: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
196: {
197: *erroroffset = (int)(p - string) - 2;
198: return PCRE_UTF8_ERR7;
199: }
200: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
201: {
202: *erroroffset = (int)(p - string) - 3;
203: return PCRE_UTF8_ERR8;
204: }
205: if (c == 0xf0 && (d & 0x30) == 0)
206: {
207: *erroroffset = (int)(p - string) - 3;
208: return PCRE_UTF8_ERR17;
209: }
210: if (c > 0xf4 || (c == 0xf4 && d > 0x8f))
211: {
212: *erroroffset = (int)(p - string) - 3;
213: return PCRE_UTF8_ERR13;
214: }
215: break;
216:
217: /* 5-byte and 6-byte characters are not allowed by RFC 3629, and will be
218: rejected by the length test below. However, we do the appropriate tests
219: here so that overlong sequences get diagnosed, and also in case there is
220: ever an option for handling these larger code points. */
221:
222: /* 5-byte character. Check 3rd, 4th, and 5th bytes for 0x80. Then check for
223: 1111 1000, xx00 0xxx */
224:
225: case 4:
226: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
227: {
228: *erroroffset = (int)(p - string) - 2;
229: return PCRE_UTF8_ERR7;
230: }
231: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
232: {
233: *erroroffset = (int)(p - string) - 3;
234: return PCRE_UTF8_ERR8;
235: }
236: if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
237: {
238: *erroroffset = (int)(p - string) - 4;
239: return PCRE_UTF8_ERR9;
240: }
241: if (c == 0xf8 && (d & 0x38) == 0)
242: {
243: *erroroffset = (int)(p - string) - 4;
244: return PCRE_UTF8_ERR18;
245: }
246: break;
247:
248: /* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for
249: 1111 1100, xx00 00xx. */
250:
251: case 5:
252: if ((*(++p) & 0xc0) != 0x80) /* Third byte */
253: {
254: *erroroffset = (int)(p - string) - 2;
255: return PCRE_UTF8_ERR7;
256: }
257: if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
258: {
259: *erroroffset = (int)(p - string) - 3;
260: return PCRE_UTF8_ERR8;
261: }
262: if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
263: {
264: *erroroffset = (int)(p - string) - 4;
265: return PCRE_UTF8_ERR9;
266: }
267: if ((*(++p) & 0xc0) != 0x80) /* Sixth byte */
268: {
269: *erroroffset = (int)(p - string) - 5;
270: return PCRE_UTF8_ERR10;
271: }
272: if (c == 0xfc && (d & 0x3c) == 0)
273: {
274: *erroroffset = (int)(p - string) - 5;
275: return PCRE_UTF8_ERR19;
276: }
277: break;
278: }
279:
280: /* Character is valid under RFC 2279, but 4-byte and 5-byte characters are
281: excluded by RFC 3629. The pointer p is currently at the last byte of the
282: character. */
283:
284: if (ab > 3)
285: {
286: *erroroffset = (int)(p - string) - ab;
287: return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12;
288: }
289: }
290:
291: #else /* SUPPORT_UTF8 */
292: (void)(string); /* Keep picky compilers happy */
293: (void)(length);
294: #endif
295:
296: return PCRE_UTF8_ERR0; /* This indicates success */
297: }
298:
299: /* End of pcre_valid_utf8.c */
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