py: Allow mp_map_t to be initialised by a fixed-size, const table.
This allows keyword maps to be created directly from stack data.
diff --git a/py/map.c b/py/map.c
index 2bae8b2..29de182 100644
--- a/py/map.c
+++ b/py/map.c
@@ -28,10 +28,24 @@
/* map */
void mp_map_init(mp_map_t *map, int n) {
- map->alloc = get_doubling_prime_greater_or_equal_to(n + 1);
+ if (n == 0) {
+ map->alloc = 0;
+ map->table = NULL;
+ } else {
+ map->alloc = get_doubling_prime_greater_or_equal_to(n + 1);
+ map->table = m_new0(mp_map_elem_t, map->alloc);
+ }
map->used = 0;
map->all_keys_are_qstrs = 1;
- map->table = m_new0(mp_map_elem_t, map->alloc);
+ 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) {
@@ -42,7 +56,9 @@
// Differentiate from mp_map_clear() - semantics is different
void mp_map_deinit(mp_map_t *map) {
- m_del(mp_map_elem_t, map->table, map->alloc);
+ if (!map->table_is_fixed_array) {
+ m_del(mp_map_elem_t, map->table, map->alloc);
+ }
map->used = map->alloc = 0;
}
@@ -52,15 +68,14 @@
}
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;
- machine_uint_t a = map->alloc;
- map->alloc = 0;
- map->table = m_renew(mp_map_elem_t, map->table, a, map->alloc);
- mp_map_elem_t nul = {NULL, NULL};
- for (uint i=0; i<map->alloc; i++) {
- map->table[i] = nul;
- }
+ map->table_is_fixed_array = 0;
+ map->table = NULL;
}
static void mp_map_rehash(mp_map_t *map) {
@@ -79,21 +94,37 @@
}
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
+
machine_uint_t hash;
hash = mp_obj_hash(index);
if (map->alloc == 0) {
- if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
+ if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
mp_map_rehash(map);
} else {
return NULL;
}
}
+
uint pos = hash % map->alloc;
for (;;) {
mp_map_elem_t *elem = &map->table[pos];
if (elem->key == NULL) {
// not in table
- if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
+ if (lookup_kind & MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
if (map->used + 1 >= map->alloc) {
// not enough room in table, rehash it
mp_map_rehash(map);
@@ -117,7 +148,7 @@
elem->key = index;
}
*/
- if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
+ if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
map->used--;
// this leaks this memory (but see dict_get_helper)
mp_map_elem_t *retval = m_new(mp_map_elem_t, 1);
@@ -195,7 +226,7 @@
} else {
return MP_OBJ_NULL;
}
- } else if (lookup_kind & MP_MAP_LOOKUP_FIRST || mp_obj_equal(elem, index)) {
+ } else if ((lookup_kind & MP_MAP_LOOKUP_FIRST) || mp_obj_equal(elem, index)) {
// found it
if (lookup_kind & MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
set->used--;
@@ -210,11 +241,8 @@
}
void mp_set_clear(mp_set_t *set) {
- set->used = 0;
- machine_uint_t a = set->alloc;
+ m_del(mp_obj_t, set->table, set->alloc);
set->alloc = 0;
- set->table = m_renew(mp_obj_t, set->table, a, set->alloc);
- for (uint i=0; i<set->alloc; i++) {
- set->table[i] = NULL;
- }
+ set->used = 0;
+ set->table = NULL;
}