* Use binary tree in tokenizers, that would provide us fast checking for unique tokens and have O(log n) difficulty

src/tokenizers/osb.c

 	797, 3277,
 };
 
-token_list_t *
+GTree *
 osb_tokenize_text (struct tokenizer *tokenizer, memory_pool_t *pool, f_str_t *input)
 {
-	token_list_t *new = NULL, *head = NULL, *last = NULL;
+	token_node_t *new = NULL;
+	GTree *tree;
 	f_str_t token = { NULL, 0, 0 };
 	uint32_t hashpipe[FEATURE_WINDOW_SIZE], h1, h2;
 	int i;
 		hashpipe[i] = 0xABCDEF;
 	}
 
+	tree = g_tree_new (token_node_compare_func);
+	memory_pool_add_destructor (pool, (pool_destruct_func)g_tree_destroy, tree);
+
 	while (tokenizer->get_next_word (input, &token)) {
 		/* Shift hashpipe */
 		for (i = FEATURE_WINDOW_SIZE - 1; i > 0; i --) {
 		for (i = 0; i < FEATURE_WINDOW_SIZE - 2; 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_list_t));
+			new = memory_pool_alloc (pool, sizeof (token_node_t));
 			new->h1 = h1;
 			new->h2 = h2;
-			if (last) {
-				last->next = new;
-			}
-			else {
-				head = new;
-			}
-			last = new;
 
-			msg_debug ("osb_tokenize_text: append new token, h1=%u, h2=%u", h1, h2);
+			if (g_tree_lookup (tree, new) == NULL) {
+				msg_debug ("osb_tokenize_text: append new token, h1=%u, h2=%u", h1, h2);
+				g_tree_insert (tree, new, new);
+			}
 		}
 	}
-	if (last) {
-		last->next = NULL;
-	}
 
-	return head;
+	return tree;
 }
 
 /*

src/tokenizers/tokenizers.c

 	return NULL;
 }
 
+int 
+token_node_compare_func (gconstpointer a, gconstpointer b)
+{
+	const token_node_t *aa = a, *bb = b;
+	
+	if (aa->h1 == bb->h1) {
+		return aa->h2 - bb->h2;
+	}
+
+	return aa->h1 - bb->h1;
+}
+
 /* Get next word from specified f_str_t buf */
 f_str_t *
 get_next_word (f_str_t *buf, f_str_t *token)

src/tokenizers/tokenizers.h

 /* Size for features pipe */
 #define FEATURE_WINDOW_SIZE 5
 
-typedef struct token_list_s {
+typedef struct token_node_s {
 	uint32_t h1;
 	uint32_t h2;
-	struct token_list_s *next;
-} token_list_t;
-
+} token_node_t;
 
 /* Common tokenizer structure */
 struct tokenizer {
 	char *name;
-	token_list_t* (*tokenize_func)(struct tokenizer *tokenizer, memory_pool_t *pool, f_str_t *input);
+	GTree* (*tokenize_func)(struct tokenizer *tokenizer, memory_pool_t *pool, f_str_t *input);
 	f_str_t* (*get_next_word)(f_str_t *buf, f_str_t *token);
 };
 
+/* Compare two token nodes */
+int token_node_compare_func (gconstpointer a, gconstpointer b);
 /* Get tokenizer structure by name or return NULL if this name is not found */
 struct tokenizer* get_tokenizer (char *name);
 /* Get next word from specified f_str_t buf */
 f_str_t *get_next_word (f_str_t *buf, f_str_t *token);
 /* OSB tokenize function */
-token_list_t* osb_tokenize_text (struct tokenizer *tokenizer, memory_pool_t *pool, f_str_t *input);
+GTree* osb_tokenize_text (struct tokenizer *tokenizer, memory_pool_t *pool, f_str_t *input);
 
 /* Array of all defined tokenizers */
 extern struct tokenizer tokenizers[];