/*
* Return value of first occurrence of symbol, or -1 if symbol is not
* present.
* - update the cost
*/
int32_t stbl_find(stbl_t *sym_table, const char *symbol) {
uint32_t mask, i, h, steps;
int32_t result;
stbl_rec_t *r;
result = -1;
steps = 0;
mask = sym_table->size - 1;
h = jenkins_hash_string(symbol);
i = h & mask;
for (r = sym_table->data[i]; r != NULL; r = r->next) {
steps ++;
if (r->hash == h && strcmp(symbol, r->string) == 0) {
result = r->value;
break;
}
}
/*
* Check whether the list contains many duplicates and move r to the
* front if possible. If the list has duplicates, we reduce steps to 1,
* since resizing won't help much.
*/
if (steps > STBL_MAXVISITS && list_has_duplicates(sym_table, i, r)) {
steps = 1;
}
/*
* Update cost and counter. Resize if the last NLOOKUPS have a
* high total cost.
*/
assert(sym_table->lctr > 0);
sym_table->cost += steps;
sym_table->lctr --;
if (sym_table->lctr == 0) {
if (sym_table->cost > STBL_RESIZE_THRESHOLD && sym_table->size <= (MAX_STBL_SIZE/2)) {
stbl_extend(sym_table);
}
sym_table->cost = 0;
sym_table->lctr = STBL_NLOOKUPS;
}
return result;
}
/*
* Add new mapping for symbol.
*/
void stbl_add(stbl_t *sym_table, char *symbol, int32_t value) {
uint32_t mask, i, h;
stbl_rec_t *r;
assert(value >= 0);
mask = sym_table->size - 1;
h = jenkins_hash_string(symbol);
i = h & mask;
r = stbl_alloc_record(sym_table);
stbl_init_record(r, h, value, symbol);
r->next = sym_table->data[i];
sym_table->data[i] = r;
sym_table->nelems ++;
if (sym_table->nelems > sym_table->size) {
stbl_extend(sym_table);
}
}