[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>
author: Thomas Graf <tgraf@suug.ch> 2005-06-23 23:59:16 -0400
committer: David S. Miller <davem@davemloft.net> 2005-06-23 23:59:16 -0400
commit: 6408f79cce401e1bfecf923e7156f84f96e021e3 (patch)
tree: 203624ffacf60d364293adc47d2f59f6ba81dd35
parent: df3fb93ad9ec0b20c785c0ad82d42d159a1af272 (diff)
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 @@
+#ifndef __LINUX_TEXTSEARCH_FSM_H
+#define __LINUX_TEXTSEARCH_FSM_H
+#include <linux/types.h>
+enum {
+        TS_FSM_SPECIFIC,        /* specific character */
+        TS_FSM_WILDCARD,        /* any character */
+        TS_FSM_DIGIT,           /* isdigit() */
+        TS_FSM_XDIGIT,          /* isxdigit() */
+        TS_FSM_PRINT,           /* isprint() */
+        TS_FSM_ALPHA,           /* isalpha() */
+        TS_FSM_ALNUM,           /* isalnum() */
+        TS_FSM_ASCII,           /* isascii() */
+        TS_FSM_CNTRL,           /* iscntrl() */
+        TS_FSM_GRAPH,           /* isgraph() */
+        TS_FSM_LOWER,           /* islower() */
+        TS_FSM_UPPER,           /* isupper() */
+        TS_FSM_PUNCT,           /* ispunct() */
+        TS_FSM_SPACE,           /* isspace() */
+        __TS_FSM_TYPE_MAX,
+};
+#define TS_FSM_TYPE_MAX (__TS_FSM_TYPE_MAX - 1)
+enum {
+        TS_FSM_SINGLE,          /* 1 occurrence */
+        TS_FSM_PERHAPS,         /* 1 or 0 occurrence */
+        TS_FSM_ANY,             /* 0..n occurrences */
+        TS_FSM_MULTI,           /* 1..n occurrences */
+        TS_FSM_HEAD_IGNORE,     /* 0..n ignored occurrences at head */
+        __TS_FSM_RECUR_MAX,
+};
+#define TS_FSM_RECUR_MAX (__TS_FSM_RECUR_MAX - 1)
+/**
+ * struct ts_fsm_token - state machine token (state)
+ * @type: type of token
+ * @recur: number of recurrences
+ * @value: character value for TS_FSM_SPECIFIC
+ */
+struct ts_fsm_token
+{
+        __u16           type;
+        __u8            recur;
+        __u8            value;
+};
+#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
          To compile this code as a module, choose M here: the
          module will be called ts_kmp.
+config TEXTSEARCH_FSM
+        depends on TEXTSEARCH
+        tristate "Finite state machine"
+        help
+          Say Y here if you want to be able to search text using a
+          naive finite state machine approach implementing a subset
+          of regular expressions.
+          To compile this code as a module, choose M here: the
+          module will be called ts_fsm.
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 6cdb10f312df..7f6eda449102 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
 lib-$(CONFIG_TEXTSEARCH) += textsearch.o
 obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
+obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
 hostprogs-y     := gen_crc32table
 clean-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 @@
+/*
+ * lib/ts_fsm.c    A naive finite state machine text search approach
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ * Authors:     Thomas Graf <tgraf@suug.ch>
+ *
+ * ==========================================================================
+ *
+ *   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.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/textsearch.h>
+#include <linux/textsearch_fsm.h>
+struct ts_fsm
+{
+        unsigned int            ntokens;
+        struct ts_fsm_token     tokens[0];
+};
+/* other values derived from ctype.h */
+#define _A              0x100 /* ascii */
+#define _W              0x200 /* wildcard */
+/* Map to _ctype flags and some magic numbers */
+static u16 token_map[TS_FSM_TYPE_MAX+1] = {
+        [TS_FSM_SPECIFIC] = 0,
+        [TS_FSM_WILDCARD] = _W,
+        [TS_FSM_CNTRL]    = _C,
+        [TS_FSM_LOWER]    = _L,
+        [TS_FSM_UPPER]    = _U,
+        [TS_FSM_PUNCT]    = _P,
+        [TS_FSM_SPACE]    = _S,
+        [TS_FSM_DIGIT]    = _D,
+        [TS_FSM_XDIGIT]   = _D | _X,
+        [TS_FSM_ALPHA]    = _U | _L,
+        [TS_FSM_ALNUM]    = _U | _L | _D,
+        [TS_FSM_PRINT]    = _P | _U | _L | _D | _SP,
+        [TS_FSM_GRAPH]    = _P | _U | _L | _D,
+        [TS_FSM_ASCII]    = _A,
+};
+static u16 token_lookup_tbl[256] = {
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*   0-  3 */
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*   4-  7 */
+_W|_A|_C,      _W|_A|_C|_S,  _W|_A|_C|_S,  _W|_A|_C|_S,         /*   8- 11 */
+_W|_A|_C|_S,   _W|_A|_C|_S,  _W|_A|_C,     _W|_A|_C,            /*  12- 15 */
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*  16- 19 */
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*  20- 23 */
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*  24- 27 */
+_W|_A|_C,      _W|_A|_C,     _W|_A|_C,     _W|_A|_C,            /*  28- 31 */
+_W|_A|_S|_SP,  _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  32- 35 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  36- 39 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  40- 43 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  44- 47 */
+_W|_A|_D,      _W|_A|_D,     _W|_A|_D,     _W|_A|_D,            /*  48- 51 */
+_W|_A|_D,      _W|_A|_D,     _W|_A|_D,     _W|_A|_D,            /*  52- 55 */
+_W|_A|_D,      _W|_A|_D,     _W|_A|_P,     _W|_A|_P,            /*  56- 59 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  60- 63 */
+_W|_A|_P,      _W|_A|_U|_X,  _W|_A|_U|_X,  _W|_A|_U|_X,         /*  64- 67 */
+_W|_A|_U|_X,   _W|_A|_U|_X,  _W|_A|_U|_X,  _W|_A|_U,            /*  68- 71 */
+_W|_A|_U,      _W|_A|_U,     _W|_A|_U,     _W|_A|_U,            /*  72- 75 */
+_W|_A|_U,      _W|_A|_U,     _W|_A|_U,     _W|_A|_U,            /*  76- 79 */
+_W|_A|_U,      _W|_A|_U,     _W|_A|_U,     _W|_A|_U,            /*  80- 83 */
+_W|_A|_U,      _W|_A|_U,     _W|_A|_U,     _W|_A|_U,            /*  84- 87 */
+_W|_A|_U,      _W|_A|_U,     _W|_A|_U,     _W|_A|_P,            /*  88- 91 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_P,            /*  92- 95 */
+_W|_A|_P,      _W|_A|_L|_X,  _W|_A|_L|_X,  _W|_A|_L|_X,         /*  96- 99 */
+_W|_A|_L|_X,   _W|_A|_L|_X,  _W|_A|_L|_X,  _W|_A|_L,            /* 100-103 */
+_W|_A|_L,      _W|_A|_L,     _W|_A|_L,     _W|_A|_L,            /* 104-107 */
+_W|_A|_L,      _W|_A|_L,     _W|_A|_L,     _W|_A|_L,            /* 108-111 */
+_W|_A|_L,      _W|_A|_L,     _W|_A|_L,     _W|_A|_L,            /* 112-115 */
+_W|_A|_L,      _W|_A|_L,     _W|_A|_L,     _W|_A|_L,            /* 116-119 */
+_W|_A|_L,      _W|_A|_L,     _W|_A|_L,     _W|_A|_P,            /* 120-123 */
+_W|_A|_P,      _W|_A|_P,     _W|_A|_P,     _W|_A|_C,            /* 124-127 */
+_W,            _W,           _W,           _W,                  /* 128-131 */
+_W,            _W,           _W,           _W,                  /* 132-135 */
+_W,            _W,           _W,           _W,                  /* 136-139 */
+_W,            _W,           _W,           _W,                  /* 140-143 */
+_W,            _W,           _W,           _W,                  /* 144-147 */
+_W,            _W,           _W,           _W,                  /* 148-151 */
+_W,            _W,           _W,           _W,                  /* 152-155 */
+_W,            _W,           _W,           _W,                  /* 156-159 */
+_W|_S|_SP,     _W|_P,        _W|_P,        _W|_P,               /* 160-163 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 164-167 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 168-171 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 172-175 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 176-179 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 180-183 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 184-187 */
+_W|_P,         _W|_P,        _W|_P,        _W|_P,               /* 188-191 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 192-195 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 196-199 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 200-203 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 204-207 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 208-211 */
+_W|_U,         _W|_U,        _W|_U,        _W|_P,               /* 212-215 */
+_W|_U,         _W|_U,        _W|_U,        _W|_U,               /* 216-219 */
+_W|_U,         _W|_U,        _W|_U,        _W|_L,               /* 220-223 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 224-227 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 228-231 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 232-235 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 236-239 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 240-243 */
+_W|_L,         _W|_L,        _W|_L,        _W|_P,               /* 244-247 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L,               /* 248-251 */
+_W|_L,         _W|_L,        _W|_L,        _W|_L};              /* 252-255 */
+static inline int match_token(struct ts_fsm_token *t, u8 d)
+{
+        if (t->type)
+                return (token_lookup_tbl[d] & t->type) != 0;
+        else
+                return t->value == d;
+}
+static unsigned int fsm_find(struct ts_config *conf, struct ts_state *state)
+{
+        struct ts_fsm *fsm = ts_config_priv(conf);
+        struct ts_fsm_token *cur = NULL, *next;
+        unsigned int match_start, block_idx = 0, tok_idx;
+        unsigned block_len = 0, strict, consumed = state->offset;
+        const u8 *data;
+#define GET_NEXT_BLOCK()                \
+({      consumed += block_idx;          \
+        block_idx = 0;                  \
+        block_len = conf->get_next_block(consumed, &data, conf, state); })
+#define TOKEN_MISMATCH()                \
+        do {                            \
+                if (strict)             \
+                        goto no_match;  \
+                block_idx++;            \
+                goto startover;         \
+        } while(0)
+#define end_of_data() unlikely(block_idx >= block_len && !GET_NEXT_BLOCK())
+        if (end_of_data())
+                goto no_match;
+        strict = fsm->tokens[0].recur != TS_FSM_HEAD_IGNORE;
+startover:
+        match_start = consumed + block_idx;
+        for (tok_idx = 0; tok_idx < fsm->ntokens; tok_idx++) {
+                cur = &fsm->tokens[tok_idx];
+                if (likely(tok_idx < (fsm->ntokens - 1)))
+                        next = &fsm->tokens[tok_idx + 1];
+                else
+                        next = NULL;
+                switch (cur->recur) {
+                case TS_FSM_SINGLE:
+                        if (end_of_data())
+                                goto no_match;
+                        if (!match_token(cur, data[block_idx]))
+                                TOKEN_MISMATCH();
+                        break;
+                case TS_FSM_PERHAPS:
+                        if (end_of_data() ||
+                            !match_token(cur, data[block_idx]))
+                                continue;
+                        break;
+                case TS_FSM_MULTI:
+                        if (end_of_data())
+                                goto no_match;
+                        if (!match_token(cur, data[block_idx]))
+                                TOKEN_MISMATCH();
+                        block_idx++;
+                        /* fall through */
+                case TS_FSM_ANY:
+                        if (next == NULL)
+                                goto found_match;
+                        if (end_of_data())
+                                continue;
+                        while (!match_token(next, data[block_idx])) {
+                                if (!match_token(cur, data[block_idx]))
+                                        TOKEN_MISMATCH();
+                                block_idx++;
+                                if (end_of_data())
+                                        goto no_match;
+                        }
+                        continue;
+                /*
+                 * Optimization: Prefer small local loop over jumping
+                 * back and forth until garbage at head is munched.
+                 */
+                case TS_FSM_HEAD_IGNORE:
+                        if (end_of_data())
+                                continue;
+                        while (!match_token(next, data[block_idx])) {
+                                /*
+                                 * Special case, don't start over upon
+                                 * a mismatch, give the user the
+                                 * chance to specify the type of data
+                                 * allowed to be ignored.
+                                 */
+                                if (!match_token(cur, data[block_idx]))
+                                        goto no_match;
+                                block_idx++;
+                                if (end_of_data())
+                                        goto no_match;
+                        }
+                        match_start = consumed + block_idx;
+                        continue;
+                }
+                block_idx++;
+        }
+        if (end_of_data())
+                goto found_match;
+no_match:
+        return UINT_MAX;
+found_match:
+        state->offset = consumed + block_idx;
+        return match_start;
+}
+static struct ts_config *fsm_init(const void *pattern, unsigned int len,
+                                     int gfp_mask)
+{
+        int i, err = -EINVAL;
+        struct ts_config *conf;
+        struct ts_fsm *fsm;
+        struct ts_fsm_token *tokens = (struct ts_fsm_token *) pattern;
+        unsigned int ntokens = len / sizeof(*tokens);
+        size_t priv_size = sizeof(*fsm) + len;
+        if (len  % sizeof(struct ts_fsm_token) || ntokens < 1)
+                goto errout;
+        for (i = 0; i < ntokens; i++) {
+                struct ts_fsm_token *t = &tokens[i];
+                if (t->type > TS_FSM_TYPE_MAX || t->recur > TS_FSM_RECUR_MAX)
+                        goto errout;
+                if (t->recur == TS_FSM_HEAD_IGNORE &&
+                    (i != 0 || i == (ntokens - 1)))
+                        goto errout;
+        }
+        conf = alloc_ts_config(priv_size, gfp_mask);
+        if (IS_ERR(conf))
+                return conf;
+        fsm = ts_config_priv(conf);
+        fsm->ntokens = ntokens;
+        memcpy(fsm->tokens, pattern, len);
+        for (i = 0; i < fsm->ntokens; i++) {
+                struct ts_fsm_token *t = &fsm->tokens[i];
+                t->type = token_map[t->type];
+        }
+        return conf;
+errout:
+        return ERR_PTR(err);
+}
+static void *fsm_get_pattern(struct ts_config *conf)
+{
+        struct ts_fsm *fsm = ts_config_priv(conf);
+        return fsm->tokens;
+}
+static unsigned int fsm_get_pattern_len(struct ts_config *conf)
+{
+        struct ts_fsm *fsm = ts_config_priv(conf);
+        return fsm->ntokens * sizeof(struct ts_fsm_token);
+}
+static struct ts_ops fsm_ops = {
+        .name             = "fsm",
+        .find             = fsm_find,
+        .init             = fsm_init,
+        .get_pattern      = fsm_get_pattern,
+        .get_pattern_len  = fsm_get_pattern_len,
+        .owner            = THIS_MODULE,
+        .list             = LIST_HEAD_INIT(fsm_ops.list)
+};
+static int __init init_fsm(void)
+{
+        return textsearch_register(&fsm_ops);
+}
+static void __exit exit_fsm(void)
+{
+        textsearch_unregister(&fsm_ops);
+}
+MODULE_LICENSE("GPL");
+module_init(init_fsm);
+module_exit(exit_fsm);
author	Thomas Graf <tgraf@suug.ch>	2005-06-23 23:59:16 -0400
committer	David S. Miller <davem@davemloft.net>	2005-06-23 23:59:16 -0400
commit	6408f79cce401e1bfecf923e7156f84f96e021e3 (patch)
tree	203624ffacf60d364293adc47d2f59f6ba81dd35
parent	df3fb93ad9ec0b20c785c0ad82d42d159a1af272 (diff)

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
		6	enum {
		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
		25	enum {
		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	*/
		41	struct 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
		83	config 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
83	endmenu	94	endmenu


diff --git a/lib/Makefile b/lib/Makefile index 6cdb10f312df..7f6eda449102 100644 --- a/lib/Makefile +++ b/lib/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
38		38
39	lib-$(CONFIG_TEXTSEARCH) += textsearch.o	39	lib-$(CONFIG_TEXTSEARCH) += textsearch.o
40	obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o	40	obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
		41	obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
41		42
42	hostprogs-y := gen_crc32table	43	hostprogs-y := gen_crc32table
43	clean-files := crc32table.h	44	clean-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
		37	struct 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 */
		48	static 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
		65	static 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 */
		110	_W\|_P, _W\|_P, _W\|_P, _W\|_P, /* 176-179 */
		111	_W\|_P, _W\|_P, _W\|_P, _W\|_P, /* 180-183 */
		112	_W\|_P, _W\|_P, _W\|_P, _W\|_P, /* 184-187 */
		113	_W\|_P, _W\|_P, _W\|_P, _W\|_P, /* 188-191 */
		114	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 192-195 */
		115	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 196-199 */
		116	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 200-203 */
		117	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 204-207 */
		118	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 208-211 */
		119	_W\|_U, _W\|_U, _W\|_U, _W\|_P, /* 212-215 */
		120	_W\|_U, _W\|_U, _W\|_U, _W\|_U, /* 216-219 */
		121	_W\|_U, _W\|_U, _W\|_U, _W\|_L, /* 220-223 */
		122	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 224-227 */
		123	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 228-231 */
		124	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 232-235 */
		125	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 236-239 */
		126	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 240-243 */
		127	_W\|_L, _W\|_L, _W\|_L, _W\|_P, /* 244-247 */
		128	_W\|_L, _W\|_L, _W\|_L, _W\|_L, /* 248-251 */
		129	_W\|_L, _W\|_L, _W\|_L, _W\|_L}; /* 252-255 */
		130
		131	static inline int match_token(struct ts_fsm_token *t, u8 d)
		132	{
		133	if (t->type)
		134	return (token_lookup_tbl[d] & t->type) != 0;
		135	else
		136	return t->value == d;
		137	}
		138
		139	static unsigned int fsm_find(struct ts_config conf, struct ts_state state)
		140	{
		141	struct ts_fsm *fsm = ts_config_priv(conf);
		142	struct ts_fsm_token cur = NULL, next;
		143	unsigned int match_start, block_idx = 0, tok_idx;
		144	unsigned block_len = 0, strict, consumed = state->offset;
		145	const u8 *data;
		146
		147	#define GET_NEXT_BLOCK() \
		148	({ consumed += block_idx; \
		149	block_idx = 0; \
		150	block_len = conf->get_next_block(consumed, &data, conf, state); })
		151
		152	#define TOKEN_MISMATCH() \
		153	do { \
		154	if (strict) \
		155	goto no_match; \
		156	block_idx++; \
		157	goto startover; \
		158	} while(0)
		159
		160	#define end_of_data() unlikely(block_idx >= block_len && !GET_NEXT_BLOCK())
		161
		162	if (end_of_data())
		163	goto no_match;
		164
		165	strict = fsm->tokens[0].recur != TS_FSM_HEAD_IGNORE;
		166
		167	startover:
		168	match_start = consumed + block_idx;
		169
		170	for (tok_idx = 0; tok_idx < fsm->ntokens; tok_idx++) {
		171	cur = &fsm->tokens[tok_idx];
		172
		173	if (likely(tok_idx < (fsm->ntokens - 1)))
		174	next = &fsm->tokens[tok_idx + 1];
		175	else
		176	next = NULL;
		177
		178	switch (cur->recur) {
		179	case TS_FSM_SINGLE:
		180	if (end_of_data())
		181	goto no_match;
		182
		183	if (!match_token(cur, data[block_idx]))
		184	TOKEN_MISMATCH();
		185	break;
		186
		187	case TS_FSM_PERHAPS:
		188	if (end_of_data() \|\|
		189	!match_token(cur, data[block_idx]))
		190	continue;
		191	break;
		192
		193	case TS_FSM_MULTI:
		194	if (end_of_data())
		195	goto no_match;
		196
		197	if (!match_token(cur, data[block_idx]))
		198	TOKEN_MISMATCH();
		199
		200	block_idx++;
		201	/* fall through */
		202
		203	case TS_FSM_ANY:
		204	if (next == NULL)
		205	goto found_match;
		206
		207	if (end_of_data())
		208	continue;
		209
		210	while (!match_token(next, data[block_idx])) {
		211	if (!match_token(cur, data[block_idx]))
		212	TOKEN_MISMATCH();
		213	block_idx++;
		214	if (end_of_data())
		215	goto no_match;
		216	}
		217	continue;
		218
		219	/*
		220	* Optimization: Prefer small local loop over jumping
		221	* back and forth until garbage at head is munched.
		222	*/
		223	case TS_FSM_HEAD_IGNORE:
		224	if (end_of_data())
		225	continue;
		226
		227	while (!match_token(next, data[block_idx])) {
		228	/*
		229	* Special case, don't start over upon
		230	* a mismatch, give the user the
		231	* chance to specify the type of data
		232	* allowed to be ignored.
		233	*/
		234	if (!match_token(cur, data[block_idx]))
		235	goto no_match;
		236
		237	block_idx++;
		238	if (end_of_data())
		239	goto no_match;
		240	}
		241
		242	match_start = consumed + block_idx;
		243	continue;
		244	}
		245
		246	block_idx++;
		247	}
		248
		249	if (end_of_data())
		250	goto found_match;
		251
		252	no_match:
		253	return UINT_MAX;
		254
		255	found_match:
		256	state->offset = consumed + block_idx;
		257	return match_start;
		258	}
		259
		260	static struct ts_config fsm_init(const void pattern, unsigned int len,
		261	int gfp_mask)
		262	{
		263	int i, err = -EINVAL;
		264	struct ts_config *conf;
		265	struct ts_fsm *fsm;
		266	struct ts_fsm_token tokens = (struct ts_fsm_token ) pattern;
		267	unsigned int ntokens = len / sizeof(*tokens);
		268	size_t priv_size = sizeof(*fsm) + len;
		269
		270	if (len % sizeof(struct ts_fsm_token) \|\| ntokens < 1)
		271	goto errout;
		272
		273	for (i = 0; i < ntokens; i++) {
		274	struct ts_fsm_token *t = &tokens[i];
		275
		276	if (t->type > TS_FSM_TYPE_MAX \|\| t->recur > TS_FSM_RECUR_MAX)
		277	goto errout;
		278
		279	if (t->recur == TS_FSM_HEAD_IGNORE &&
		280	(i != 0 \|\| i == (ntokens - 1)))
		281	goto errout;
		282	}
		283
		284	conf = alloc_ts_config(priv_size, gfp_mask);
		285	if (IS_ERR(conf))
		286	return conf;
		287
		288	fsm = ts_config_priv(conf);
		289	fsm->ntokens = ntokens;
		290	memcpy(fsm->tokens, pattern, len);
		291
		292	for (i = 0; i < fsm->ntokens; i++) {
		293	struct ts_fsm_token *t = &fsm->tokens[i];
		294	t->type = token_map[t->type];
		295	}
		296
		297	return conf;
		298
		299	errout:
		300	return ERR_PTR(err);
		301	}
		302
		303	static void fsm_get_pattern(struct ts_config conf)
		304	{
		305	struct ts_fsm *fsm = ts_config_priv(conf);
		306	return fsm->tokens;
		307	}
		308
		309	static unsigned int fsm_get_pattern_len(struct ts_config *conf)
		310	{
		311	struct ts_fsm *fsm = ts_config_priv(conf);
		312	return fsm->ntokens * sizeof(struct ts_fsm_token);
		313	}
		314
		315	static struct ts_ops fsm_ops = {
		316	.name = "fsm",
		317	.find = fsm_find,
		318	.init = fsm_init,
		319	.get_pattern = fsm_get_pattern,
		320	.get_pattern_len = fsm_get_pattern_len,
		321	.owner = THIS_MODULE,
		322	.list = LIST_HEAD_INIT(fsm_ops.list)
		323	};
		324
		325	static int __init init_fsm(void)
		326	{
		327	return textsearch_register(&fsm_ops);
		328	}
		329
		330	static void __exit exit_fsm(void)
		331	{
		332	textsearch_unregister(&fsm_ops);
		333	}
		334
		335	MODULE_LICENSE("GPL");
		336
		337	module_init(init_fsm);
		338	module_exit(exit_fsm);