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authorThomas Graf <tgraf@suug.ch>2005-06-23 23:59:16 -0400
committerDavid S. Miller <davem@davemloft.net>2005-06-23 23:59:16 -0400
commit6408f79cce401e1bfecf923e7156f84f96e021e3 (patch)
tree203624ffacf60d364293adc47d2f59f6ba81dd35
parentdf3fb93ad9ec0b20c785c0ad82d42d159a1af272 (diff)
[LIB]: Naive finite state machine based textsearch
A finite state machine consists of n states (struct ts_fsm_token) representing the pattern as a finite automation. The data is read sequentially on a octet basis. Every state token specifies the number of recurrences and the type of value accepted which can be either a specific character or ctype based set of characters. The available type of recurrences include 1, (0|1), [0 n], and [1 n]. The algorithm differs between strict/non-strict mode specyfing whether the pattern has to start at the first octect. Strict mode is enabled by default and can be disabled by inserting TS_FSM_HEAD_IGNORE as the first token in the chain. The runtime performance of the algorithm should be around O(n), however while in strict mode the average runtime can be better. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat
-rw-r--r--include/linux/textsearch_fsm.h48
-rw-r--r--lib/Kconfig11
-rw-r--r--lib/Makefile1
-rw-r--r--lib/ts_fsm.c338
4 files changed, 398 insertions, 0 deletions
diff --git a/include/linux/textsearch_fsm.h b/include/linux/textsearch_fsm.h
new file mode 100644
index 000000000000..fdfa078c66e5
--- /dev/null
+++ b/include/linux/textsearch_fsm.h
@@ -0,0 +1,48 @@
1#ifndef __LINUX_TEXTSEARCH_FSM_H
2#define __LINUX_TEXTSEARCH_FSM_H
3
4#include <linux/types.h>
5
6enum {
7 TS_FSM_SPECIFIC, /* specific character */
8 TS_FSM_WILDCARD, /* any character */
9 TS_FSM_DIGIT, /* isdigit() */
10 TS_FSM_XDIGIT, /* isxdigit() */
11 TS_FSM_PRINT, /* isprint() */
12 TS_FSM_ALPHA, /* isalpha() */
13 TS_FSM_ALNUM, /* isalnum() */
14 TS_FSM_ASCII, /* isascii() */
15 TS_FSM_CNTRL, /* iscntrl() */
16 TS_FSM_GRAPH, /* isgraph() */
17 TS_FSM_LOWER, /* islower() */
18 TS_FSM_UPPER, /* isupper() */
19 TS_FSM_PUNCT, /* ispunct() */
20 TS_FSM_SPACE, /* isspace() */
21 __TS_FSM_TYPE_MAX,
22};
23#define TS_FSM_TYPE_MAX (__TS_FSM_TYPE_MAX - 1)
24
25enum {
26 TS_FSM_SINGLE, /* 1 occurrence */
27 TS_FSM_PERHAPS, /* 1 or 0 occurrence */
28 TS_FSM_ANY, /* 0..n occurrences */
29 TS_FSM_MULTI, /* 1..n occurrences */
30 TS_FSM_HEAD_IGNORE, /* 0..n ignored occurrences at head */
31 __TS_FSM_RECUR_MAX,
32};
33#define TS_FSM_RECUR_MAX (__TS_FSM_RECUR_MAX - 1)
34
35/**
36 * struct ts_fsm_token - state machine token (state)
37 * @type: type of token
38 * @recur: number of recurrences
39 * @value: character value for TS_FSM_SPECIFIC
40 */
41struct ts_fsm_token
42{
43 __u16 type;
44 __u8 recur;
45 __u8 value;
46};
47
48#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index 16b8fa2175e4..455833a9e31a 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -80,4 +80,15 @@ config TEXTSEARCH_KMP
80 To compile this code as a module, choose M here: the 80 To compile this code as a module, choose M here: the
81 module will be called ts_kmp. 81 module will be called ts_kmp.
82 82
83config TEXTSEARCH_FSM
84 depends on TEXTSEARCH
85 tristate "Finite state machine"
86 help
87 Say Y here if you want to be able to search text using a
88 naive finite state machine approach implementing a subset
89 of regular expressions.
90
91 To compile this code as a module, choose M here: the
92 module will be called ts_fsm.
93
83endmenu 94endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 6cdb10f312df..7f6eda449102 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
38 38
39lib-$(CONFIG_TEXTSEARCH) += textsearch.o 39lib-$(CONFIG_TEXTSEARCH) += textsearch.o
40obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o 40obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
41obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
41 42
42hostprogs-y := gen_crc32table 43hostprogs-y := gen_crc32table
43clean-files := crc32table.h 44clean-files := crc32table.h
diff --git a/lib/ts_fsm.c b/lib/ts_fsm.c
new file mode 100644
index 000000000000..d27c0a072940
--- /dev/null
+++ b/lib/ts_fsm.c
@@ -0,0 +1,338 @@
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 a 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 specyfing
21 * whether the pattern has to start at the first octect. 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/config.h>
30#include <linux/module.h>
31#include <linux/types.h>
32#include <linux/string.h>
33#include <linux/ctype.h>
34#include <linux/textsearch.h>
35#include <linux/textsearch_fsm.h>
36
37struct ts_fsm
38{
39 unsigned int ntokens;
40 struct ts_fsm_token tokens[0];
41};
42
43/* other values derived from ctype.h */
44#define _A 0x100 /* ascii */
45#define _W 0x200 /* wildcard */
46
47/* Map to _ctype flags and some magic numbers */
48static u16 token_map[TS_FSM_TYPE_MAX+1] = {
49 [TS_FSM_SPECIFIC] = 0,
50 [TS_FSM_WILDCARD] = _W,
51 [TS_FSM_CNTRL] = _C,
52 [TS_FSM_LOWER] = _L,
53 [TS_FSM_UPPER] = _U,
54 [TS_FSM_PUNCT] = _P,
55 [TS_FSM_SPACE] = _S,
56 [TS_FSM_DIGIT] = _D,
57 [TS_FSM_XDIGIT] = _D | _X,
58 [TS_FSM_ALPHA] = _U | _L,
59 [TS_FSM_ALNUM] = _U | _L | _D,
60 [TS_FSM_PRINT] = _P | _U | _L | _D | _SP,
61 [TS_FSM_GRAPH] = _P | _U | _L | _D,
62 [TS_FSM_ASCII] = _A,
63};
64
65static u16 token_lookup_tbl[256] = {
66_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 0- 3 */
67_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 4- 7 */
68_W|_A|_C, _W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C|_S, /* 8- 11 */
69_W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C, _W|_A|_C, /* 12- 15 */
70_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 16- 19 */
71_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 20- 23 */
72_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 24- 27 */
73_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 28- 31 */
74_W|_A|_S|_SP, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 32- 35 */
75_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 36- 39 */
76_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 40- 43 */
77_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 44- 47 */
78_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 48- 51 */
79_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 52- 55 */
80_W|_A|_D, _W|_A|_D, _W|_A|_P, _W|_A|_P, /* 56- 59 */
81_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 60- 63 */
82_W|_A|_P, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, /* 64- 67 */
83_W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U, /* 68- 71 */
84_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 72- 75 */
85_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 76- 79 */
86_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 80- 83 */
87_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 84- 87 */
88_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_P, /* 88- 91 */
89_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 92- 95 */
90_W|_A|_P, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, /* 96- 99 */
91_W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L, /* 100-103 */
92_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 104-107 */
93_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 108-111 */
94_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 112-115 */
95_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 116-119 */
96_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_P, /* 120-123 */
97_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_C, /* 124-127 */
98_W, _W, _W, _W, /* 128-131 */
99_W, _W, _W, _W, /* 132-135 */
100_W, _W, _W, _W, /* 136-139 */
101_W, _W, _W, _W, /* 140-143 */
102_W, _W, _W, _W, /* 144-147 */
103_W, _W, _W, _W, /* 148-151 */
104_W, _W, _W, _W, /* 152-155 */
105_W, _W, _W, _W, /* 156-159 */
106_W|_S|_SP, _W|_P, _W|_P, _W|_P, /* 160-163 */
107_W|_P, _W|_P, _W|_P, _W|_P, /* 164-167 */
108_W|_P, _W|_P, _W|_P, _W|_P, /* 168-171 */
109_W|_P, _W|_P, _W|_P, _W|_P, /* 172-175 */