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>
diff --git a/lib/ts_bm.c b/lib/ts_bm.c
index 4a7fce7..9e66ee4 100644
--- a/lib/ts_bm.c
+++ b/lib/ts_bm.c
@@ -39,6 +39,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
+#include <linux/ctype.h>
#include <linux/textsearch.h>
/* Alphabet size, use ASCII */
@@ -64,6 +65,7 @@
unsigned int i, text_len, consumed = state->offset;
const u8 *text;
int shift = bm->patlen - 1, bs;
+ const u8 icase = conf->flags & TS_IGNORECASE;
for (;;) {
text_len = conf->get_next_block(consumed, &text, conf, state);
@@ -75,7 +77,9 @@
DEBUGP("Searching in position %d (%c)\n",
shift, text[shift]);
for (i = 0; i < bm->patlen; i++)
- if (text[shift-i] != bm->pattern[bm->patlen-1-i])
+ if ((icase ? toupper(text[shift-i])
+ : text[shift-i])
+ != bm->pattern[bm->patlen-1-i])
goto next;
/* London calling... */
@@ -111,14 +115,18 @@
return ret;
}
-static void compute_prefix_tbl(struct ts_bm *bm)
+static void compute_prefix_tbl(struct ts_bm *bm, int flags)
{
int i, j, g;
for (i = 0; i < ASIZE; i++)
bm->bad_shift[i] = bm->patlen;
- for (i = 0; i < bm->patlen - 1; i++)
+ for (i = 0; i < bm->patlen - 1; i++) {
bm->bad_shift[bm->pattern[i]] = bm->patlen - 1 - i;
+ if (flags & TS_IGNORECASE)
+ bm->bad_shift[tolower(bm->pattern[i])]
+ = bm->patlen - 1 - i;
+ }
/* Compute the good shift array, used to match reocurrences
* of a subpattern */
@@ -135,10 +143,11 @@
}
static struct ts_config *bm_init(const void *pattern, unsigned int len,
- gfp_t gfp_mask)
+ gfp_t gfp_mask, int flags)
{
struct ts_config *conf;
struct ts_bm *bm;
+ int i;
unsigned int prefix_tbl_len = len * sizeof(unsigned int);
size_t priv_size = sizeof(*bm) + len + prefix_tbl_len;
@@ -146,11 +155,16 @@
if (IS_ERR(conf))
return conf;
+ conf->flags = flags;
bm = ts_config_priv(conf);
bm->patlen = len;
bm->pattern = (u8 *) bm->good_shift + prefix_tbl_len;
- memcpy(bm->pattern, pattern, len);
- compute_prefix_tbl(bm);
+ if (flags & TS_IGNORECASE)
+ for (i = 0; i < len; i++)
+ bm->pattern[i] = toupper(((u8 *)pattern)[i]);
+ else
+ memcpy(bm->pattern, pattern, len);
+ compute_prefix_tbl(bm, flags);
return conf;
}