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 <joonwpark81@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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parent
3b76d08190
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2523c3fc2b
1 changed files with 21 additions and 8 deletions
29
lib/ts_kmp.c
29
lib/ts_kmp.c
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@ -33,6 +33,7 @@
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#include <linux/module.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/types.h>
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#include <linux/string.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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#include <linux/textsearch.h>
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struct ts_kmp
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struct ts_kmp
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@ -47,6 +48,7 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state)
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struct ts_kmp *kmp = ts_config_priv(conf);
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struct ts_kmp *kmp = ts_config_priv(conf);
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unsigned int i, q = 0, text_len, consumed = state->offset;
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unsigned int i, q = 0, text_len, consumed = state->offset;
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const u8 *text;
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const u8 *text;
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const int icase = conf->flags & TS_IGNORECASE;
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for (;;) {
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for (;;) {
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text_len = conf->get_next_block(consumed, &text, conf, state);
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text_len = conf->get_next_block(consumed, &text, conf, state);
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@ -55,9 +57,11 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state)
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break;
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break;
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for (i = 0; i < text_len; i++) {
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for (i = 0; i < text_len; i++) {
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while (q > 0 && kmp->pattern[q] != text[i])
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while (q > 0 && kmp->pattern[q]
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!= (icase ? toupper(text[i]) : text[i]))
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q = kmp->prefix_tbl[q - 1];
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q = kmp->prefix_tbl[q - 1];
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if (kmp->pattern[q] == text[i])
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if (kmp->pattern[q]
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== (icase ? toupper(text[i]) : text[i]))
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q++;
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q++;
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if (unlikely(q == kmp->pattern_len)) {
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if (unlikely(q == kmp->pattern_len)) {
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state->offset = consumed + i + 1;
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state->offset = consumed + i + 1;
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@ -72,24 +76,28 @@ static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state)
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}
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}
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static inline void compute_prefix_tbl(const u8 *pattern, unsigned int len,
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static inline void compute_prefix_tbl(const u8 *pattern, unsigned int len,
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unsigned int *prefix_tbl)
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unsigned int *prefix_tbl, int flags)
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{
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{
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unsigned int k, q;
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unsigned int k, q;
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const u8 icase = flags & TS_IGNORECASE;
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for (k = 0, q = 1; q < len; q++) {
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for (k = 0, q = 1; q < len; q++) {
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while (k > 0 && pattern[k] != pattern[q])
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while (k > 0 && (icase ? toupper(pattern[k]) : pattern[k])
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!= (icase ? toupper(pattern[q]) : pattern[q]))
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k = prefix_tbl[k-1];
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k = prefix_tbl[k-1];
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if (pattern[k] == pattern[q])
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if ((icase ? toupper(pattern[k]) : pattern[k])
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== (icase ? toupper(pattern[q]) : pattern[q]))
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k++;
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k++;
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prefix_tbl[q] = k;
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prefix_tbl[q] = k;
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}
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}
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}
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}
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static struct ts_config *kmp_init(const void *pattern, unsigned int len,
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static struct ts_config *kmp_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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{
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struct ts_config *conf;
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struct ts_config *conf;
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struct ts_kmp *kmp;
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struct ts_kmp *kmp;
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int i;
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unsigned int prefix_tbl_len = len * sizeof(unsigned int);
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unsigned int prefix_tbl_len = len * sizeof(unsigned int);
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size_t priv_size = sizeof(*kmp) + len + prefix_tbl_len;
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size_t priv_size = sizeof(*kmp) + len + prefix_tbl_len;
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@ -97,11 +105,16 @@ static struct ts_config *kmp_init(const void *pattern, unsigned int len,
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if (IS_ERR(conf))
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if (IS_ERR(conf))
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return conf;
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return conf;
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conf->flags = flags;
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kmp = ts_config_priv(conf);
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kmp = ts_config_priv(conf);
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kmp->pattern_len = len;
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kmp->pattern_len = len;
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compute_prefix_tbl(pattern, len, kmp->prefix_tbl);
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compute_prefix_tbl(pattern, len, kmp->prefix_tbl, flags);
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kmp->pattern = (u8 *) kmp->prefix_tbl + prefix_tbl_len;
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kmp->pattern = (u8 *) kmp->prefix_tbl + prefix_tbl_len;
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memcpy(kmp->pattern, pattern, len);
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if (flags & TS_IGNORECASE)
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for (i = 0; i < len; i++)
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kmp->pattern[i] = toupper(((u8 *)pattern)[i]);
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else
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memcpy(kmp->pattern, pattern, len);
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return conf;
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return conf;
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}
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}
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