Issue 18771: Make it possible to set the number linear probes at compile-time.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 23d624f..ece76bf 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -44,7 +44,9 @@
/* ======= Begin logic for probing the hash table ========================= */
/* This should be >= PySet_MINSIZE - 1 */
+#ifndef LINEAR_PROBES
#define LINEAR_PROBES 9
+#endif
/* This must be >= 1 */
#define PERTURB_SHIFT 5
@@ -55,12 +57,14 @@
setentry *table = so->table;
setentry *freeslot = NULL;
setentry *entry;
- setentry *limit;
size_t perturb = hash;
size_t mask = so->mask;
size_t i = (size_t)hash; /* Unsigned for defined overflow behavior. */
- size_t j;
int cmp;
+#if LINEAR_PROBES
+ setentry *limit;
+ size_t j;
+#endif
entry = &table[i & mask];
if (entry->key == NULL)
@@ -84,6 +88,7 @@
if (entry->key == dummy && freeslot == NULL)
freeslot = entry;
+#if LINEAR_PROBES
limit = &table[mask];
for (j = 0 ; j < LINEAR_PROBES ; j++) {
entry = (entry == limit) ? &table[0] : entry + 1;
@@ -106,13 +111,14 @@
if (entry->key == dummy && freeslot == NULL)
freeslot = entry;
}
+#endif
perturb >>= PERTURB_SHIFT;
i = i * 5 + 1 + perturb;
entry = &table[i & mask];
if (entry->key == NULL)
- break;
+ goto found_null;
}
found_null:
return freeslot == NULL ? entry : freeslot;
@@ -129,11 +135,13 @@
setentry *table = so->table;
setentry *freeslot = NULL;
setentry *entry;
- setentry *limit;
size_t perturb = hash;
size_t mask = so->mask;
size_t i = (size_t)hash;
+#if LINEAR_PROBES
+ setentry *limit;
size_t j;
+#endif
/* Make sure this function doesn't have to handle non-unicode keys,
including subclasses of str; e.g., one reason to subclass
@@ -157,6 +165,7 @@
if (entry->key == dummy && freeslot == NULL)
freeslot = entry;
+#if LINEAR_PROBES
limit = &table[mask];
for (j = 0 ; j < LINEAR_PROBES ; j++) {
entry = (entry == limit) ? &table[0] : entry + 1;
@@ -170,13 +179,14 @@
if (entry->key == dummy && freeslot == NULL)
freeslot = entry;
}
+#endif
perturb >>= PERTURB_SHIFT;
i = i * 5 + 1 + perturb;
entry = &table[i & mask];
if (entry->key == NULL)
- break;
+ goto found_null;
}
found_null:
return freeslot == NULL ? entry : freeslot;
@@ -198,17 +208,21 @@
size_t perturb = hash;
size_t mask = (size_t)so->mask;
size_t i = (size_t)hash;
+#if LINEAR_PROBES
size_t j;
+#endif
while (1) {
entry = &table[i & mask];
if (entry->key == NULL)
goto found_null;
+#if LINEAR_PROBES
for (j = 1 ; j <= LINEAR_PROBES ; j++) {
entry = &table[(i + j) & mask];
if (entry->key == NULL)
goto found_null;
}
+#endif
perturb >>= PERTURB_SHIFT;
i = i * 5 + 1 + perturb;
}