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/*
* Copyright (c) 2009, Rambler media
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY Rambler media ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL Rambler BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* OSB tokenizer
*/
#include <sys/types.h>
#include "tokenizers.h"
/* Minimum length of token */
#define MIN_LEN 4
extern const int primes[];
int
osb_tokenize_text (struct tokenizer *tokenizer, memory_pool_t * pool, f_str_t * input, GTree ** tree)
{
token_node_t *new = NULL;
f_str_t token = { NULL, 0, 0 }, *res;
uint32_t hashpipe[FEATURE_WINDOW_SIZE], h1, h2;
int i;
/* First set all bytes of hashpipe to some common value */
for (i = 0; i < FEATURE_WINDOW_SIZE; i++) {
hashpipe[i] = 0xABCDEF;
}
if (*tree == NULL) {
*tree = g_tree_new (token_node_compare_func);
memory_pool_add_destructor (pool, (pool_destruct_func) g_tree_destroy, *tree);
}
msg_debug ("osb_tokenize_text: got input length: %zd", input->len);
while ((res = tokenizer->get_next_word (input, &token)) != NULL) {
/* Skip small words */
if (token.len < MIN_LEN) {
continue;
}
/* Shift hashpipe */
for (i = FEATURE_WINDOW_SIZE - 1; i > 0; i--) {
hashpipe[i] = hashpipe[i - 1];
}
hashpipe[0] = fstrhash (&token);
for (i = 1; i < FEATURE_WINDOW_SIZE; i++) {
h1 = hashpipe[0] * primes[0] + hashpipe[i] * primes[i << 1];
h2 = hashpipe[0] * primes[1] + hashpipe[i] * primes[(i << 1) - 1];
new = memory_pool_alloc (pool, sizeof (token_node_t));
new->h1 = h1;
new->h2 = h2;
if (g_tree_lookup (*tree, new) == NULL) {
g_tree_insert (*tree, new, new);
}
}
}
return TRUE;
}
/*
* vi:ts=4
*/
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