From 2523c3fc2bc9e34c06a71517844d55353f1f904a Mon Sep 17 00:00:00 2001 From: Joonwoo Park Date: Tue, 8 Jul 2008 02:38:09 -0700 Subject: textsearch: ts_kmp: support case insensitive searching in Knuth-Morris-Pratt algorithm Add support for case insensitive search to Knuth-Morris-Pratt algorithm. Signed-off-by: Joonwoo Park Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- lib/ts_kmp.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) (limited to 'lib/ts_kmp.c') diff --git a/lib/ts_kmp.c b/lib/ts_kmp.c index 3ced628cab4b..632f783e65f1 100644 --- a/lib/ts_kmp.c +++ b/lib/ts_kmp.c @@ -33,6 +33,7 @@ #include #include #include +#include #include struct ts_kmp @@ -47,6 +48,7 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state) struct ts_kmp *kmp = ts_config_priv(conf); unsigned int i, q = 0, text_len, consumed = state->offset; const u8 *text; + const int icase = conf->flags & TS_IGNORECASE; for (;;) { text_len = conf->get_next_block(consumed, &text, conf, state); @@ -55,9 +57,11 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state) break; for (i = 0; i < text_len; i++) { - while (q > 0 && kmp->pattern[q] != text[i]) + while (q > 0 && kmp->pattern[q] + != (icase ? toupper(text[i]) : text[i])) q = kmp->prefix_tbl[q - 1]; - if (kmp->pattern[q] == text[i]) + if (kmp->pattern[q] + == (icase ? toupper(text[i]) : text[i])) q++; if (unlikely(q == kmp->pattern_len)) { state->offset = consumed + i + 1; @@ -72,24 +76,28 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state) } static inline void compute_prefix_tbl(const u8 *pattern, unsigned int len, - unsigned int *prefix_tbl) + unsigned int *prefix_tbl, int flags) { unsigned int k, q; + const u8 icase = flags & TS_IGNORECASE; for (k = 0, q = 1; q < len; q++) { - while (k > 0 && pattern[k] != pattern[q]) + while (k > 0 && (icase ? toupper(pattern[k]) : pattern[k]) + != (icase ? toupper(pattern[q]) : pattern[q])) k = prefix_tbl[k-1]; - if (pattern[k] == pattern[q]) + if ((icase ? toupper(pattern[k]) : pattern[k]) + == (icase ? toupper(pattern[q]) : pattern[q])) k++; prefix_tbl[q] = k; } } static struct ts_config *kmp_init(const void *pattern, unsigned int len, - gfp_t gfp_mask) + gfp_t gfp_mask, int flags) { struct ts_config *conf; struct ts_kmp *kmp; + int i; unsigned int prefix_tbl_len = len * sizeof(unsigned int); size_t priv_size = sizeof(*kmp) + len + prefix_tbl_len; @@ -97,11 +105,16 @@ static struct ts_config *kmp_init(const void *pattern, unsigned int len, if (IS_ERR(conf)) return conf; + conf->flags = flags; kmp = ts_config_priv(conf); kmp->pattern_len = len; - compute_prefix_tbl(pattern, len, kmp->prefix_tbl); + compute_prefix_tbl(pattern, len, kmp->prefix_tbl, flags); kmp->pattern = (u8 *) kmp->prefix_tbl + prefix_tbl_len; - memcpy(kmp->pattern, pattern, len); + if (flags & TS_IGNORECASE) + for (i = 0; i < len; i++) + kmp->pattern[i] = toupper(((u8 *)pattern)[i]); + else + memcpy(kmp->pattern, pattern, len); return conf; } -- cgit v1.2.2