#if MICROPY_OPT_MAP_LOOKUP_CACHE

#define MAP_CACHE_OFFSET(index) ((((uintptr_t)(index)) >> 2) % MICROPY_OPT_MAP_LOOKUP_CACHE_SIZE)

#define MAP_CACHE_ENTRY(index) (MP_STATE_VM(map_lookup_cache)[MAP_CACHE_OFFSET(index)])

#define MAP_CACHE_GET(map, index) (&(map)->table[MAP_CACHE_ENTRY(index) % (map)->alloc])

#define MAP_CACHE_SET(index, pos) MAP_CACHE_ENTRY(index) = (pos) & 0xff;

#define MAP_CACHE_SET(index, pos)

STATIC void mp_map_rehash(mp_map_t *map) {

mp_map_elem_t *MICROPY_WRAP_MP_MAP_LOOKUP(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 only be called for a lookup

assert(!map->is_fixed || lookup_kind == MP_MAP_LOOKUP);

#if MICROPY_OPT_MAP_LOOKUP_CACHE

// Try the cache for lookup or add-if-not-found.

if (lookup_kind != MP_MAP_LOOKUP_REMOVE_IF_FOUND && map->alloc) {

mp_map_elem_t *slot = MAP_CACHE_GET(map, index);

// Note: Just comparing key for value equality will have false negatives, but

// these will be handled by the regular path below.

if (slot->key == index) {

return slot;

}

}

#endif

// Work out if we can compare just pointers

bool compare_only_ptrs = map->all_keys_are_qstrs;

if (compare_only_ptrs) {

if (mp_obj_is_qstr(index)) {

// Index is a qstr, so can just do ptr comparison.

} else if (mp_obj_is_exact_type(index, &mp_type_str)) {

// Index is a non-interned string.

// We can either intern the string, or force a full equality comparison.

// We chose the latter, since interning costs time and potentially RAM,

// and it won't necessarily benefit subsequent calls because these calls

// most likely won't pass the newly-interned string.

compare_only_ptrs = false;

} else if (lookup_kind != MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {

// If we are not adding, then we can return straight away a failed

// lookup because we know that the index will never be found.

return NULL;

}

}

// if the map is an ordered array then we must do a brute force linear search

if (map->is_ordered) {

for (mp_map_elem_t *elem = &map->table[0], *top = &map->table[map->used]; elem < top; elem++) {

if (elem->key == index || (!compare_only_ptrs && mp_obj_equal(elem->key, index))) {

#if MICROPY_PY_COLLECTIONS_ORDEREDDICT

if (MP_UNLIKELY(lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND)) {

// remove the found element by moving the rest of the array down

mp_obj_t value = elem->value;

--map->used;

memmove(elem, elem + 1, (top - elem - 1) * sizeof(*elem));

// put the found element after the end so the caller can access it if needed

// note: caller must NULL the value so the GC can clean up (e.g. see dict_get_helper).

elem = &map->table[map->used];

elem->key = MP_OBJ_NULL;

elem->value = value;

}

#endif

MAP_CACHE_SET(index, elem - map->table);

return elem;

}

}

#if MICROPY_PY_COLLECTIONS_ORDEREDDICT

if (MP_LIKELY(lookup_kind != MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)) {

return NULL;

}

if (map->used == map->alloc) {

// TODO: Alloc policy

map->alloc += 4;

map->table = m_renew(mp_map_elem_t, map->table, map->used, map->alloc);

mp_seq_clear(map->table, map->used, map->alloc, sizeof(*map->table));

}

mp_map_elem_t *elem = map->table + map->used++;

elem->key = index;

elem->value = MP_OBJ_NULL;

if (!mp_obj_is_qstr(index)) {

map->all_keys_are_qstrs = 0;

}

return elem;

#else

return NULL;

#endif

}

// map is a hash table (not an ordered 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;

}

}

// When MICROPY_QSTR_BYTES_IN_HASH is zero, for qstr keys we use the qstr

// value (i.e. the index in the qstr pool) as the hash value as it is

// free to compute and also a very effective hash as it is unique across

// all qstrs.

//

// However, non-qstr strings (i.e. str) still use their "true" hash

// (i.e. computed using qstr_hash) which will be different. So this means

// that identical strings will hash differently depending on whether they

// are qstr or str. It should be rare for a program to be working with

// both but it is possible.

//

// So this means that in certain situations (see below), we cannot rely on

// the linear probing finding an unused slot as the signal that the key

// does not exist, as it's possible the key was inserted using

// its "other" hash, and must fall back to searching the entire table. We

// can still use the hash as a good hint for the starting location

// though. This flag must be set to false in these situations.

bool stop_at_empty = true;

// get hash of index, with fast path for common case of qstr

mp_uint_t hash;

if (mp_obj_is_qstr(index)) {

#if MICROPY_QSTR_BYTES_IN_HASH

hash = qstr_hash(MP_OBJ_QSTR_VALUE(index));

#else

// Optimisation -- use the qstr index directly as the hash.

hash = MP_OBJ_QSTR_VALUE(index);

// If there are non-qstr keys in this map, we must assume that there

// may possibly be str keys.

stop_at_empty = map->all_keys_are_qstrs;

#endif

} else {

hash = MP_OBJ_SMALL_INT_VALUE(mp_unary_op(MP_UNARY_OP_HASH, index));

#if MICROPY_QSTR_BYTES_IN_HASH == 0

if (mp_obj_is_exact_type(index, &mp_type_str)) {

// We must assume there might be qstr keys.

stop_at_empty = false;

}

#endif

}

size_t pos = hash % map->alloc;

size_t 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 an empty slot, remember for later

if (avail_slot == NULL) {

avail_slot = slot;

}

if (stop_at_empty) {

// safe to assume that the key doesn't exist, so pretend like

// we searched the entire table

goto search_over;

}

} 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 || (!compare_only_ptrs && 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

}

MAP_CACHE_SET(index, pos);

return slot;

}

// not yet found, keep searching in this table

pos = (pos + 1) % map->alloc;

if (pos == start_pos) {

search_over:

// search got back to starting position (or found empty slot), 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;

}

}

}

}