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[/] [test_project/] [trunk/] [linux_sd_driver/] [lib/] [ts_fsm.c] - Blame information for rev 79

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1 62 marcus.erl
/*
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)
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
        for (i = 0; i < ntokens; i++) {
273
                struct ts_fsm_token *t = &tokens[i];
274
 
275
                if (t->type > TS_FSM_TYPE_MAX || t->recur > TS_FSM_RECUR_MAX)
276
                        goto errout;
277
 
278
                if (t->recur == TS_FSM_HEAD_IGNORE &&
279
                    (i != 0 || i == (ntokens - 1)))
280
                        goto errout;
281
        }
282
 
283
        conf = alloc_ts_config(priv_size, gfp_mask);
284
        if (IS_ERR(conf))
285
                return conf;
286
 
287
        fsm = ts_config_priv(conf);
288
        fsm->ntokens = ntokens;
289
        memcpy(fsm->tokens, pattern, len);
290
 
291
        for (i = 0; i < fsm->ntokens; i++) {
292
                struct ts_fsm_token *t = &fsm->tokens[i];
293
                t->type = token_map[t->type];
294
        }
295
 
296
        return conf;
297
 
298
errout:
299
        return ERR_PTR(err);
300
}
301
 
302
static void *fsm_get_pattern(struct ts_config *conf)
303
{
304
        struct ts_fsm *fsm = ts_config_priv(conf);
305
        return fsm->tokens;
306
}
307
 
308
static unsigned int fsm_get_pattern_len(struct ts_config *conf)
309
{
310
        struct ts_fsm *fsm = ts_config_priv(conf);
311
        return fsm->ntokens * sizeof(struct ts_fsm_token);
312
}
313
 
314
static struct ts_ops fsm_ops = {
315
        .name             = "fsm",
316
        .find             = fsm_find,
317
        .init             = fsm_init,
318
        .get_pattern      = fsm_get_pattern,
319
        .get_pattern_len  = fsm_get_pattern_len,
320
        .owner            = THIS_MODULE,
321
        .list             = LIST_HEAD_INIT(fsm_ops.list)
322
};
323
 
324
static int __init init_fsm(void)
325
{
326
        return textsearch_register(&fsm_ops);
327
}
328
 
329
static void __exit exit_fsm(void)
330
{
331
        textsearch_unregister(&fsm_ops);
332
}
333
 
334
MODULE_LICENSE("GPL");
335
 
336
module_init(init_fsm);
337
module_exit(exit_fsm);

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