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snapshot v2/p11; cleanup, still broken

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Gregory Burd 2024-03-26 10:53:24 -04:00
parent 3805123dee
commit acd2db46a9
1 changed files with 21 additions and 16 deletions
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37
include/sl.h
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@ -314,7 +314,7 @@
size_t level = 0; \
double probability = 0.5; \
\
double random_value = (double)rand() / RAND_MAX; /* NOLINT(*-msc50-cpp) */ \
double random_value = (double)(rand() / RAND_MAX); /* NOLINT(*-msc50-cpp) */ \
while (random_value < probability && level < max) { \
level++; \
probability *= 0.5; \
@ -529,7 +529,7 @@
} \
\
/* (d) set duplicate flag */ \
dest->field.sle.next[0] = (decl##_node_t *)is_dup; \
dest->field.sle.next[1] = (decl##_node_t *)is_dup; \
\
/* (e) insert node into slh_pres list at head */ \
if (slist->slh_pres == NULL) \
@ -564,6 +564,7 @@
{ \
int rc = 0, n; \
size_t i; \
decl##_node_t *prev = NULL; \
\
if (path == NULL) \
return 0; \
@ -575,6 +576,10 @@
/* No need to preserve the head or tail sentry nodes. */ \
if (path[i] == slist->slh_head || path[i] == slist->slh_tail) \
continue; \
/* No need to preserve a node more than once. */ \
if (path[i] == prev) \
continue; \
prev = path[i]; \
\
/* When the generation of the node in the path is < the list's \
current generation, we must preserve it. */ \
@ -1131,6 +1136,20 @@
* \
* Restores the Skiplist to generation `gen`. Once you restore `gen` you \
* can no longer access any generations > `gen`. \
* \
* ALGORITHM: \
* iterate over the preserved nodes (slist->slh_pres) \
* a) remove/free nodes with node->gen > gen from slist \
* b) remove/free nodes > gen from slh_pres \
* c) restore nodes == gen by... \
* i) remove node from slh_pres list \
* ii) _insert(node) or \
* _insert_dup() if node->field.sle_next[1] != 0 (clear that) \
* d) set slist's gen to `gen` \
* \
* NOTES: \
* - Starting with slh_pres, the `node->field.sle.next[0]` form a \
* singly-linked list. \
*/ \
decl##_t *prefix##skip_restore_snapshot_##decl(decl##_t *slist, unsigned gen) \
{ \
@ -1143,20 +1162,6 @@
if (gen >= slist->gen || slist->slh_pres == NULL) \
return slist; \
\
/* ALGORITHM: \
* iterate over the preserved nodes (slist->slh_pres) \
* a) remove nodes with node->gen > gen from slist \
* b) remove nodes > gen from slh_pres and _free_node() \
* c) restore nodes == gen by... \
* i) remove node from slh_pres list \
* ii) _insert(node) or \
* _insert_dup() if node->field.sle_next[1] != 0 (clear that) \
* d) set slist's gen to `gen` \
* \
* NOTES: \
* - the `node->field.sle.next[0]` forms a singly-linked list. \
*/ \
\
/* (a) */ \
SKIPLIST_FOREACH_H2T(decl, prefix, slist, node, i) \
{ \