Root/
1 | /* |
2 | * lib/ts_fsm.c A naive finite state machine text search approach |
3 | * |
4 | * This program is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU General Public License |
6 | * as published by the Free Software Foundation; either version |
7 | * 2 of the License, or (at your option) any later version. |
8 | * |
9 | * Authors: Thomas Graf <tgraf@suug.ch> |
10 | * |
11 | * ========================================================================== |
12 | * |
13 | * A finite state machine consists of n states (struct ts_fsm_token) |
14 | * representing the pattern as a finite automation. The data is read |
15 | * sequentially on an octet basis. Every state token specifies the number |
16 | * of recurrences and the type of value accepted which can be either a |
17 | * specific character or ctype based set of characters. The available |
18 | * type of recurrences include 1, (0|1), [0 n], and [1 n]. |
19 | * |
20 | * The algorithm differs between strict/non-strict mode specifying |
21 | * whether the pattern has to start at the first octet. Strict mode |
22 | * is enabled by default and can be disabled by inserting |
23 | * TS_FSM_HEAD_IGNORE as the first token in the chain. |
24 | * |
25 | * The runtime performance of the algorithm should be around O(n), |
26 | * however while in strict mode the average runtime can be better. |
27 | */ |
28 | |
29 | #include <linux/module.h> |
30 | #include <linux/types.h> |
31 | #include <linux/string.h> |
32 | #include <linux/ctype.h> |
33 | #include <linux/textsearch.h> |
34 | #include <linux/textsearch_fsm.h> |
35 | |
36 | struct ts_fsm |
37 | { |
38 | unsigned int ntokens; |
39 | struct ts_fsm_token tokens[0]; |
40 | }; |
41 | |
42 | /* other values derived from ctype.h */ |
43 | #define _A 0x100 /* ascii */ |
44 | #define _W 0x200 /* wildcard */ |
45 | |
46 | /* Map to _ctype flags and some magic numbers */ |
47 | static const u16 token_map[TS_FSM_TYPE_MAX+1] = { |
48 | [TS_FSM_SPECIFIC] = 0, |
49 | [TS_FSM_WILDCARD] = _W, |
50 | [TS_FSM_CNTRL] = _C, |
51 | [TS_FSM_LOWER] = _L, |
52 | [TS_FSM_UPPER] = _U, |
53 | [TS_FSM_PUNCT] = _P, |
54 | [TS_FSM_SPACE] = _S, |
55 | [TS_FSM_DIGIT] = _D, |
56 | [TS_FSM_XDIGIT] = _D | _X, |
57 | [TS_FSM_ALPHA] = _U | _L, |
58 | [TS_FSM_ALNUM] = _U | _L | _D, |
59 | [TS_FSM_PRINT] = _P | _U | _L | _D | _SP, |
60 | [TS_FSM_GRAPH] = _P | _U | _L | _D, |
61 | [TS_FSM_ASCII] = _A, |
62 | }; |
63 | |
64 | static const u16 token_lookup_tbl[256] = { |
65 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 0- 3 */ |
66 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 4- 7 */ |
67 | _W|_A|_C, _W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C|_S, /* 8- 11 */ |
68 | _W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C, _W|_A|_C, /* 12- 15 */ |
69 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 16- 19 */ |
70 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 20- 23 */ |
71 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 24- 27 */ |
72 | _W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 28- 31 */ |
73 | _W|_A|_S|_SP, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 32- 35 */ |
74 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 36- 39 */ |
75 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 40- 43 */ |
76 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 44- 47 */ |
77 | _W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 48- 51 */ |
78 | _W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 52- 55 */ |
79 | _W|_A|_D, _W|_A|_D, _W|_A|_P, _W|_A|_P, /* 56- 59 */ |
80 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 60- 63 */ |
81 | _W|_A|_P, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, /* 64- 67 */ |
82 | _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U, /* 68- 71 */ |
83 | _W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 72- 75 */ |
84 | _W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 76- 79 */ |
85 | _W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 80- 83 */ |
86 | _W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 84- 87 */ |
87 | _W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_P, /* 88- 91 */ |
88 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 92- 95 */ |
89 | _W|_A|_P, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, /* 96- 99 */ |
90 | _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L, /* 100-103 */ |
91 | _W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 104-107 */ |
92 | _W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 108-111 */ |
93 | _W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 112-115 */ |
94 | _W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 116-119 */ |
95 | _W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_P, /* 120-123 */ |
96 | _W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_C, /* 124-127 */ |
97 | _W, _W, _W, _W, /* 128-131 */ |
98 | _W, _W, _W, _W, /* 132-135 */ |
99 | _W, _W, _W, _W, /* 136-139 */ |
100 | _W, _W, _W, _W, /* 140-143 */ |
101 | _W, _W, _W, _W, /* 144-147 */ |
102 | _W, _W, _W, _W, /* 148-151 */ |
103 | _W, _W, _W, _W, /* 152-155 */ |
104 | _W, _W, _W, _W, /* 156-159 */ |
105 | _W|_S|_SP, _W|_P, _W|_P, _W|_P, /* 160-163 */ |
106 | _W|_P, _W|_P, _W|_P, _W|_P, /* 164-167 */ |
107 | _W|_P, _W|_P, _W|_P, _W|_P, /* 168-171 */ |
108 | _W|_P, _W|_P, _W|_P, _W|_P, /* 172-175 */ |
109 | _W|_P, _W|_P, _W|_P, _W|_P, /* 176-179 */ |
110 | _W|_P, _W|_P, _W|_P, _W|_P, /* 180-183 */ |
111 | _W|_P, _W|_P, _W|_P, _W|_P, /* 184-187 */ |
112 | _W|_P, _W|_P, _W|_P, _W|_P, /* 188-191 */ |
113 | _W|_U, _W|_U, _W|_U, _W|_U, /* 192-195 */ |
114 | _W|_U, _W|_U, _W|_U, _W|_U, /* 196-199 */ |
115 | _W|_U, _W|_U, _W|_U, _W|_U, /* 200-203 */ |
116 | _W|_U, _W|_U, _W|_U, _W|_U, /* 204-207 */ |
117 | _W|_U, _W|_U, _W|_U, _W|_U, /* 208-211 */ |
118 | _W|_U, _W|_U, _W|_U, _W|_P, /* 212-215 */ |
119 | _W|_U, _W|_U, _W|_U, _W|_U, /* 216-219 */ |
120 | _W|_U, _W|_U, _W|_U, _W|_L, /* 220-223 */ |
121 | _W|_L, _W|_L, _W|_L, _W|_L, /* 224-227 */ |
122 | _W|_L, _W|_L, _W|_L, _W|_L, /* 228-231 */ |
123 | _W|_L, _W|_L, _W|_L, _W|_L, /* 232-235 */ |
124 | _W|_L, _W|_L, _W|_L, _W|_L, /* 236-239 */ |
125 | _W|_L, _W|_L, _W|_L, _W|_L, /* 240-243 */ |
126 | _W|_L, _W|_L, _W|_L, _W|_P, /* 244-247 */ |
127 | _W|_L, _W|_L, _W|_L, _W|_L, /* 248-251 */ |
128 | _W|_L, _W|_L, _W|_L, _W|_L}; /* 252-255 */ |
129 | |
130 | static inline int match_token(struct ts_fsm_token *t, u8 d) |
131 | { |
132 | if (t->type) |
133 | return (token_lookup_tbl[d] & t->type) != 0; |
134 | else |
135 | return t->value == d; |
136 | } |
137 | |
138 | static unsigned int fsm_find(struct ts_config *conf, struct ts_state *state) |
139 | { |
140 | struct ts_fsm *fsm = ts_config_priv(conf); |
141 | struct ts_fsm_token *cur = NULL, *next; |
142 | unsigned int match_start, block_idx = 0, tok_idx; |
143 | unsigned block_len = 0, strict, consumed = state->offset; |
144 | const u8 *data; |
145 | |
146 | #define GET_NEXT_BLOCK() \ |
147 | ({ consumed += block_idx; \ |
148 | block_idx = 0; \ |
149 | block_len = conf->get_next_block(consumed, &data, conf, state); }) |
150 | |
151 | #define TOKEN_MISMATCH() \ |
152 | do { \ |
153 | if (strict) \ |
154 | goto no_match; \ |
155 | block_idx++; \ |
156 | goto startover; \ |
157 | } while(0) |
158 | |
159 | #define end_of_data() unlikely(block_idx >= block_len && !GET_NEXT_BLOCK()) |
160 | |
161 | if (end_of_data()) |
162 | goto no_match; |
163 | |
164 | strict = fsm->tokens[0].recur != TS_FSM_HEAD_IGNORE; |
165 | |
166 | startover: |
167 | match_start = consumed + block_idx; |
168 | |
169 | for (tok_idx = 0; tok_idx < fsm->ntokens; tok_idx++) { |
170 | cur = &fsm->tokens[tok_idx]; |
171 | |
172 | if (likely(tok_idx < (fsm->ntokens - 1))) |
173 | next = &fsm->tokens[tok_idx + 1]; |
174 | else |
175 | next = NULL; |
176 | |
177 | switch (cur->recur) { |
178 | case TS_FSM_SINGLE: |
179 | if (end_of_data()) |
180 | goto no_match; |
181 | |
182 | if (!match_token(cur, data[block_idx])) |
183 | TOKEN_MISMATCH(); |
184 | break; |
185 | |
186 | case TS_FSM_PERHAPS: |
187 | if (end_of_data() || |
188 | !match_token(cur, data[block_idx])) |
189 | continue; |
190 | break; |
191 | |
192 | case TS_FSM_MULTI: |
193 | if (end_of_data()) |
194 | goto no_match; |
195 | |
196 | if (!match_token(cur, data[block_idx])) |
197 | TOKEN_MISMATCH(); |
198 | |
199 | block_idx++; |
200 | /* fall through */ |
201 | |
202 | case TS_FSM_ANY: |
203 | if (next == NULL) |
204 | goto found_match; |
205 | |
206 | if (end_of_data()) |
207 | continue; |
208 | |
209 | while (!match_token(next, data[block_idx])) { |
210 | if (!match_token(cur, data[block_idx])) |
211 | TOKEN_MISMATCH(); |
212 | block_idx++; |
213 | if (end_of_data()) |
214 | goto no_match; |
215 | } |
216 | continue; |
217 | |
218 | /* |
219 | * Optimization: Prefer small local loop over jumping |
220 | * back and forth until garbage at head is munched. |
221 | */ |
222 | case TS_FSM_HEAD_IGNORE: |
223 | if (end_of_data()) |
224 | continue; |
225 | |
226 | while (!match_token(next, data[block_idx])) { |
227 | /* |
228 | * Special case, don't start over upon |
229 | * a mismatch, give the user the |
230 | * chance to specify the type of data |
231 | * allowed to be ignored. |
232 | */ |
233 | if (!match_token(cur, data[block_idx])) |
234 | goto no_match; |
235 | |
236 | block_idx++; |
237 | if (end_of_data()) |
238 | goto no_match; |
239 | } |
240 | |
241 | match_start = consumed + block_idx; |
242 | continue; |
243 | } |
244 | |
245 | block_idx++; |
246 | } |
247 | |
248 | if (end_of_data()) |
249 | goto found_match; |
250 | |
251 | no_match: |
252 | return UINT_MAX; |
253 | |
254 | found_match: |
255 | state->offset = consumed + block_idx; |
256 | return match_start; |
257 | } |
258 | |
259 | static struct ts_config *fsm_init(const void *pattern, unsigned int len, |
260 | gfp_t gfp_mask, int flags) |
261 | { |
262 | int i, err = -EINVAL; |
263 | struct ts_config *conf; |
264 | struct ts_fsm *fsm; |
265 | struct ts_fsm_token *tokens = (struct ts_fsm_token *) pattern; |
266 | unsigned int ntokens = len / sizeof(*tokens); |
267 | size_t priv_size = sizeof(*fsm) + len; |
268 | |
269 | if (len % sizeof(struct ts_fsm_token) || ntokens < 1) |
270 | goto errout; |
271 | |
272 | if (flags & TS_IGNORECASE) |
273 | goto errout; |
274 | |
275 | for (i = 0; i < ntokens; i++) { |
276 | struct ts_fsm_token *t = &tokens[i]; |
277 | |
278 | if (t->type > TS_FSM_TYPE_MAX || t->recur > TS_FSM_RECUR_MAX) |
279 | goto errout; |
280 | |
281 | if (t->recur == TS_FSM_HEAD_IGNORE && |
282 | (i != 0 || i == (ntokens - 1))) |
283 | goto errout; |
284 | } |
285 | |
286 | conf = alloc_ts_config(priv_size, gfp_mask); |
287 | if (IS_ERR(conf)) |
288 | return conf; |
289 | |
290 | conf->flags = flags; |
291 | fsm = ts_config_priv(conf); |
292 | fsm->ntokens = ntokens; |
293 | memcpy(fsm->tokens, pattern, len); |
294 | |
295 | for (i = 0; i < fsm->ntokens; i++) { |
296 | struct ts_fsm_token *t = &fsm->tokens[i]; |
297 | t->type = token_map[t->type]; |
298 | } |
299 | |
300 | return conf; |
301 | |
302 | errout: |
303 | return ERR_PTR(err); |
304 | } |
305 | |
306 | static void *fsm_get_pattern(struct ts_config *conf) |
307 | { |
308 | struct ts_fsm *fsm = ts_config_priv(conf); |
309 | return fsm->tokens; |
310 | } |
311 | |
312 | static unsigned int fsm_get_pattern_len(struct ts_config *conf) |
313 | { |
314 | struct ts_fsm *fsm = ts_config_priv(conf); |
315 | return fsm->ntokens * sizeof(struct ts_fsm_token); |
316 | } |
317 | |
318 | static struct ts_ops fsm_ops = { |
319 | .name = "fsm", |
320 | .find = fsm_find, |
321 | .init = fsm_init, |
322 | .get_pattern = fsm_get_pattern, |
323 | .get_pattern_len = fsm_get_pattern_len, |
324 | .owner = THIS_MODULE, |
325 | .list = LIST_HEAD_INIT(fsm_ops.list) |
326 | }; |
327 | |
328 | static int __init init_fsm(void) |
329 | { |
330 | return textsearch_register(&fsm_ops); |
331 | } |
332 | |
333 | static void __exit exit_fsm(void) |
334 | { |
335 | textsearch_unregister(&fsm_ops); |
336 | } |
337 | |
338 | MODULE_LICENSE("GPL"); |
339 | |
340 | module_init(init_fsm); |
341 | module_exit(exit_fsm); |
342 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9