textsearch: ts_bm: support case insensitive searching in Boyer-Moore algorithm
Add support for case insensitive search to Boyer-Moore algorithm. Signed-off-by: Joonwoo Park <joonwpark81@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Родитель
b9c7967831
Коммит
3b76d08190
26
lib/ts_bm.c
26
lib/ts_bm.c
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@ -39,6 +39,7 @@
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <linux/textsearch.h>
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/* Alphabet size, use ASCII */
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@ -64,6 +65,7 @@ static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
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unsigned int i, text_len, consumed = state->offset;
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const u8 *text;
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int shift = bm->patlen - 1, bs;
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const u8 icase = conf->flags & TS_IGNORECASE;
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for (;;) {
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text_len = conf->get_next_block(consumed, &text, conf, state);
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@ -75,7 +77,9 @@ static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
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DEBUGP("Searching in position %d (%c)\n",
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shift, text[shift]);
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for (i = 0; i < bm->patlen; i++)
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if (text[shift-i] != bm->pattern[bm->patlen-1-i])
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if ((icase ? toupper(text[shift-i])
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: text[shift-i])
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!= bm->pattern[bm->patlen-1-i])
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goto next;
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/* London calling... */
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@ -111,14 +115,18 @@ static int subpattern(u8 *pattern, int i, int j, int g)
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return ret;
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}
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static void compute_prefix_tbl(struct ts_bm *bm)
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static void compute_prefix_tbl(struct ts_bm *bm, int flags)
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{
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int i, j, g;
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for (i = 0; i < ASIZE; i++)
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bm->bad_shift[i] = bm->patlen;
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for (i = 0; i < bm->patlen - 1; i++)
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for (i = 0; i < bm->patlen - 1; i++) {
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bm->bad_shift[bm->pattern[i]] = bm->patlen - 1 - i;
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if (flags & TS_IGNORECASE)
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bm->bad_shift[tolower(bm->pattern[i])]
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= bm->patlen - 1 - i;
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}
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/* Compute the good shift array, used to match reocurrences
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* of a subpattern */
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@ -135,10 +143,11 @@ static void compute_prefix_tbl(struct ts_bm *bm)
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}
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static struct ts_config *bm_init(const void *pattern, unsigned int len,
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gfp_t gfp_mask)
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gfp_t gfp_mask, int flags)
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{
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struct ts_config *conf;
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struct ts_bm *bm;
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int i;
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unsigned int prefix_tbl_len = len * sizeof(unsigned int);
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size_t priv_size = sizeof(*bm) + len + prefix_tbl_len;
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@ -146,11 +155,16 @@ static struct ts_config *bm_init(const void *pattern, unsigned int len,
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if (IS_ERR(conf))
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return conf;
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conf->flags = flags;
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bm = ts_config_priv(conf);
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bm->patlen = len;
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bm->pattern = (u8 *) bm->good_shift + prefix_tbl_len;
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memcpy(bm->pattern, pattern, len);
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compute_prefix_tbl(bm);
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if (flags & TS_IGNORECASE)
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for (i = 0; i < len; i++)
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bm->pattern[i] = toupper(((u8 *)pattern)[i]);
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else
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memcpy(bm->pattern, pattern, len);
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compute_prefix_tbl(bm, flags);
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return conf;
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}
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