Skip to content

dict: Add dk_log2_index_bytes #31439

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
markshannon merged 2 commits into from
Feb 22, 2022
Merged

dict: Add dk_log2_index_bytes #31439

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4e2a417
dict: Add dk_log2_index_bytes
methane Feb 20, 2022
b81da96
fix typo
methane Feb 20, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 4 additions & 1 deletion Include/internal/pycore_dict.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,9 @@ struct _dictkeysobject {
/* Size of the hash table (dk_indices). It must be a power of 2. */
uint8_t dk_log2_size;

/* Size of the hash table (dk_indices) by bytes. */
uint8_t dk_log2_index_bytes;

/* Kind of keys */
uint8_t dk_kind;

Expand Down Expand Up @@ -129,7 +132,7 @@ struct _dictvalues {
2 : sizeof(int32_t))
#endif
#define DK_ENTRIES(dk) \
((PyDictKeyEntry*)(&((int8_t*)((dk)->dk_indices))[DK_SIZE(dk) * DK_IXSIZE(dk)]))
((PyDictKeyEntry*)(&((int8_t*)((dk)->dk_indices))[(size_t)1 << (dk)->dk_log2_index_bytes]))

extern uint64_t _pydict_global_version;

Expand Down
50 changes: 27 additions & 23 deletions Objects/dictobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,19 +16,20 @@ As of Python 3.6, this is compact and ordered. Basic idea is described here:

layout:

+---------------+
| dk_refcnt |
| dk_log2_size |
| dk_kind |
| dk_usable |
| dk_nentries |
+---------------+
| dk_indices |
| |
+---------------+
| dk_entries |
| |
+---------------+
+---------------------+
| dk_refcnt |
| dk_log2_size |
| dk_log2_index_bytes |
| dk_kind |
| dk_usable |
| dk_nentries |
+---------------------+
| dk_indices[] |
| |
+---------------------+
| dk_entries[] |
| |
+---------------------+

dk_indices is actual hashtable. It holds index in entries, or DKIX_EMPTY(-1)
or DKIX_DUMMY(-2).
Expand Down Expand Up @@ -444,6 +445,7 @@ estimate_log2_keysize(Py_ssize_t n)
static PyDictKeysObject empty_keys_struct = {
1, /* dk_refcnt */
0, /* dk_log2_size */
0, /* dk_log2_index_bytes */
DICT_KEYS_SPLIT, /* dk_kind */
1, /* dk_version */
0, /* dk_usable (immutable) */
Expand Down Expand Up @@ -562,24 +564,25 @@ static PyDictKeysObject*
new_keys_object(uint8_t log2_size)
{
PyDictKeysObject *dk;
Py_ssize_t es, usable;
Py_ssize_t usable;
int log2_bytes;

assert(log2_size >= PyDict_LOG_MINSIZE);

usable = USABLE_FRACTION(1<<log2_size);
if (log2_size <= 7) {
es = 1;
if (log2_size < 8) {
log2_bytes = log2_size;
}
else if (log2_size <= 15) {
es = 2;
else if (log2_size < 16) {
log2_bytes = log2_size + 1;
}
#if SIZEOF_VOID_P > 4
else if (log2_size <= 31) {
es = 4;
else if (log2_size >= 32) {
log2_bytes = log2_size + 3;
}
#endif
else {
es = sizeof(Py_ssize_t);
log2_bytes = log2_size + 2;
}

#if PyDict_MAXFREELIST > 0
Expand All @@ -595,7 +598,7 @@ new_keys_object(uint8_t log2_size)
#endif
{
dk = PyObject_Malloc(sizeof(PyDictKeysObject)
+ (es<<log2_size)
+ ((size_t)1 << log2_bytes)
+ sizeof(PyDictKeyEntry) * usable);
if (dk == NULL) {
PyErr_NoMemory();
Expand All @@ -607,11 +610,12 @@ new_keys_object(uint8_t log2_size)
#endif
dk->dk_refcnt = 1;
dk->dk_log2_size = log2_size;
dk->dk_log2_index_bytes = log2_bytes;
dk->dk_kind = DICT_KEYS_UNICODE;
dk->dk_nentries = 0;
dk->dk_usable = usable;
dk->dk_version = 0;
memset(&dk->dk_indices[0], 0xff, es<<log2_size);
memset(&dk->dk_indices[0], 0xff, ((size_t)1 << log2_bytes));
memset(DK_ENTRIES(dk), 0, sizeof(PyDictKeyEntry) * usable);
return dk;
}
Expand Down