circuitpython/py/map.c

327 lines
11 KiB
C

#include <stdlib.h>
#include <assert.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime0.h"
// approximatelly doubling primes; made with Mathematica command: Table[Prime[Floor[(1.7)^n]], {n, 3, 24}]
// prefixed with zero for the empty case.
STATIC int doubling_primes[] = {0, 7, 19, 43, 89, 179, 347, 647, 1229, 2297, 4243, 7829, 14347, 26017, 47149, 84947, 152443, 273253, 488399, 869927, 1547173, 2745121, 4861607};
STATIC int get_doubling_prime_greater_or_equal_to(int x) {
for (int i = 0; i < sizeof(doubling_primes) / sizeof(int); i++) {
if (doubling_primes[i] >= x) {
return doubling_primes[i];
}
}
// ran out of primes in the table!
// return something sensible, at least make it odd
return x | 1;
}
/******************************************************************************/
/* map */
void mp_map_init(mp_map_t *map, int n) {
if (n == 0) {
map->alloc = 0;
map->table = NULL;
} else {
map->alloc = n;
map->table = m_new0(mp_map_elem_t, map->alloc);
}
map->used = 0;
map->all_keys_are_qstrs = 1;
map->table_is_fixed_array = 0;
}
void mp_map_init_fixed_table(mp_map_t *map, int n, const mp_obj_t *table) {
map->alloc = n;
map->used = n;
map->all_keys_are_qstrs = 1;
map->table_is_fixed_array = 1;
map->table = (mp_map_elem_t*)table;
}
mp_map_t *mp_map_new(int n) {
mp_map_t *map = m_new(mp_map_t, 1);
mp_map_init(map, n);
return map;
}
// Differentiate from mp_map_clear() - semantics is different
void mp_map_deinit(mp_map_t *map) {
if (!map->table_is_fixed_array) {
m_del(mp_map_elem_t, map->table, map->alloc);
}
map->used = map->alloc = 0;
}
void mp_map_free(mp_map_t *map) {
mp_map_deinit(map);
m_del_obj(mp_map_t, map);
}
void mp_map_clear(mp_map_t *map) {
if (!map->table_is_fixed_array) {
m_del(mp_map_elem_t, map->table, map->alloc);
}
map->alloc = 0;
map->used = 0;
map->all_keys_are_qstrs = 1;
map->table_is_fixed_array = 0;
map->table = NULL;
}
STATIC void mp_map_rehash(mp_map_t *map) {
int old_alloc = map->alloc;
mp_map_elem_t *old_table = map->table;
map->alloc = get_doubling_prime_greater_or_equal_to(map->alloc + 1);
map->used = 0;
map->all_keys_are_qstrs = 1;
map->table = m_new0(mp_map_elem_t, map->alloc);
for (int i = 0; i < old_alloc; i++) {
if (old_table[i].key != MP_OBJ_NULL && old_table[i].key != MP_OBJ_SENTINEL) {
mp_map_lookup(map, old_table[i].key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = old_table[i].value;
}
}
m_del(mp_map_elem_t, old_table, old_alloc);
}
// MP_MAP_LOOKUP behaviour:
// - returns NULL if not found, else the slot it was found in with key,value non-null
// MP_MAP_LOOKUP_ADD_IF_NOT_FOUND behaviour:
// - returns slot, with key non-null and value=MP_OBJ_NULL if it was added
// MP_MAP_LOOKUP_REMOVE_IF_FOUND behaviour:
// - returns NULL if not found, else the slot if was found in with key null and value non-null
mp_map_elem_t* mp_map_lookup(mp_map_t *map, mp_obj_t index, mp_map_lookup_kind_t lookup_kind) {
// if the map is a fixed array then we must do a brute force linear search
if (map->table_is_fixed_array) {
if (lookup_kind != MP_MAP_LOOKUP) {
return NULL;
}
for (mp_map_elem_t *elem = &map->table[0], *top = &map->table[map->used]; elem < top; elem++) {
if (elem->key == index || (!map->all_keys_are_qstrs && mp_obj_equal(elem->key, index))) {
return elem;
}
}
return NULL;
}
// map is a hash table (not a fixed array), so do a hash lookup
if (map->alloc == 0) {
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
mp_map_rehash(map);
} else {
return NULL;
}
}
machine_uint_t hash = mp_obj_hash(index);
uint pos = hash % map->alloc;
uint start_pos = pos;
mp_map_elem_t *avail_slot = NULL;
for (;;) {
mp_map_elem_t *slot = &map->table[pos];
if (slot->key == MP_OBJ_NULL) {
// found NULL slot, so index is not in table
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
map->used += 1;
if (avail_slot == NULL) {
avail_slot = slot;
}
slot->key = index;
slot->value = MP_OBJ_NULL;
if (!MP_OBJ_IS_QSTR(index)) {
map->all_keys_are_qstrs = 0;
}
return slot;
} else {
return NULL;
}
} else if (slot->key == MP_OBJ_SENTINEL) {
// found deleted slot, remember for later
if (avail_slot == NULL) {
avail_slot = slot;
}
} else if (slot->key == index || (!map->all_keys_are_qstrs && mp_obj_equal(slot->key, index))) {
// found index
// Note: CPython does not replace the index; try x={True:'true'};x[1]='one';x
if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
// delete element in this slot
map->used--;
if (map->table[(pos + 1) % map->alloc].key == MP_OBJ_NULL) {
// optimisation if next slot is empty
slot->key = MP_OBJ_NULL;
} else {
slot->key = MP_OBJ_SENTINEL;
}
// keep slot->value so that caller can access it if needed
}
return slot;
}
// not yet found, keep searching in this table
pos = (pos + 1) % map->alloc;
if (pos == start_pos) {
// search got back to starting position, so index is not in table
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
if (avail_slot != NULL) {
// there was an available slot, so use that
map->used++;
avail_slot->key = index;
avail_slot->value = MP_OBJ_NULL;
if (!MP_OBJ_IS_QSTR(index)) {
map->all_keys_are_qstrs = 0;
}
return avail_slot;
} else {
// not enough room in table, rehash it
mp_map_rehash(map);
// restart the search for the new element
start_pos = pos = hash % map->alloc;
}
} else {
return NULL;
}
}
}
}
/******************************************************************************/
/* set */
void mp_set_init(mp_set_t *set, int n) {
set->alloc = n;
set->used = 0;
set->table = m_new0(mp_obj_t, set->alloc);
}
STATIC void mp_set_rehash(mp_set_t *set) {
int old_alloc = set->alloc;
mp_obj_t *old_table = set->table;
set->alloc = get_doubling_prime_greater_or_equal_to(set->alloc + 1);
set->used = 0;
set->table = m_new0(mp_obj_t, set->alloc);
for (int i = 0; i < old_alloc; i++) {
if (old_table[i] != MP_OBJ_NULL && old_table[i] != MP_OBJ_SENTINEL) {
mp_set_lookup(set, old_table[i], MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
}
}
m_del(mp_obj_t, old_table, old_alloc);
}
mp_obj_t mp_set_lookup(mp_set_t *set, mp_obj_t index, mp_map_lookup_kind_t lookup_kind) {
if (set->alloc == 0) {
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
mp_set_rehash(set);
} else {
return NULL;
}
}
machine_uint_t hash = mp_obj_hash(index);
uint pos = hash % set->alloc;
uint start_pos = pos;
mp_obj_t *avail_slot = NULL;
for (;;) {
mp_obj_t elem = set->table[pos];
if (elem == MP_OBJ_NULL) {
// found NULL slot, so index is not in table
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
if (avail_slot == NULL) {
avail_slot = &set->table[pos];
}
set->used++;
*avail_slot = index;
return index;
} else {
return MP_OBJ_NULL;
}
} else if (elem == MP_OBJ_SENTINEL) {
// found deleted slot, remember for later
if (avail_slot == NULL) {
avail_slot = &set->table[pos];
}
} else if (mp_obj_equal(elem, index)) {
// found index
if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
// delete element
set->used--;
if (set->table[(pos + 1) % set->alloc] == MP_OBJ_NULL) {
// optimisation if next slot is empty
set->table[pos] = MP_OBJ_NULL;
} else {
set->table[pos] = MP_OBJ_SENTINEL;
}
}
return elem;
}
// not yet found, keep searching in this table
pos = (pos + 1) % set->alloc;
if (pos == start_pos) {
// search got back to starting position, so index is not in table
if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
if (avail_slot != NULL) {
// there was an available slot, so use that
set->used++;
*avail_slot = index;
return index;
} else {
// not enough room in table, rehash it
mp_set_rehash(set);
// restart the search for the new element
start_pos = pos = hash % set->alloc;
}
} else {
return MP_OBJ_NULL;
}
}
}
}
mp_obj_t mp_set_remove_first(mp_set_t *set) {
for (uint pos = 0; pos < set->alloc; pos++) {
if (MP_SET_SLOT_IS_FILLED(set, pos)) {
mp_obj_t elem = set->table[pos];
// delete element
set->used--;
if (set->table[(pos + 1) % set->alloc] == MP_OBJ_NULL) {
// optimisation if next slot is empty
set->table[pos] = MP_OBJ_NULL;
} else {
set->table[pos] = MP_OBJ_SENTINEL;
}
return elem;
}
}
return MP_OBJ_NULL;
}
void mp_set_clear(mp_set_t *set) {
m_del(mp_obj_t, set->table, set->alloc);
set->alloc = 0;
set->used = 0;
set->table = NULL;
}
#if DEBUG_PRINT
void mp_map_dump(mp_map_t *map) {
for (int i = 0; i < map->alloc; i++) {
if (map->table[i].key != NULL) {
mp_obj_print(map->table[i].key, PRINT_REPR);
} else {
printf("(nil)");
}
printf(": %p\n", map->table[i].value);
}
printf("---\n");
}
#endif