textsearch: fix Boyer-Moore text search bug
Joonwoo Park [Mon, 30 Jun 2008 19:42:23 +0000 (12:42 -0700)]
The current logic has a bug which cannot find matching pattern, if the
pattern is matched from the first character of target string.
for example:
pattern=abc, string=abcdefg
pattern=a,   string=abcdefg
Searching algorithm should return 0 for those things.

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>

lib/ts_bm.c

index d90822c..4a7fce7 100644 (file)
@@ -63,7 +63,7 @@ static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
        struct ts_bm *bm = ts_config_priv(conf);
        unsigned int i, text_len, consumed = state->offset;
        const u8 *text;
-       int shift = bm->patlen, bs;
+       int shift = bm->patlen - 1, bs;
 
        for (;;) {
                text_len = conf->get_next_block(consumed, &text, conf, state);