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move re-balancing work to branch

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Gregory Burd 2024-04-08 09:28:52 -04:00
parent 0275f505fc
commit 28db528869
1 changed files with 5 additions and 80 deletions
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85
include/sl.h
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@ -600,7 +600,7 @@ void __attribute__((format(printf, 4, 5))) __skip_diag_(const char *file, int li
} \
\
/** \
* -- __skip_adjust_hit_counts_ TODO \
* -- __skip_adjust_hit_counts_ TODO: see gburd/splay-list \
* \
* On delete we check the hit counts across all nodes and next[] pointers \
* and find the smallest counter then subtract that + 1 from all hit \
@ -622,85 +622,10 @@ void __attribute__((format(printf, 4, 5))) __skip_diag_(const char *file, int li
*/ \
static void __skip_rebalance_##decl(decl##_t *slist, size_t len, __skiplist_path_##decl##_t path[]) \
{ \
size_t i, j, u_hits, hits_CHu = 0, hits_CHv = 0, delta_height, new_height, cur_hits, prev_hits; \
double k_threshold, m_total_hits, asc_cond, dsc_cond; \
\
/* return; TODO/WIP */ \
/* Total hits, `k`, accross all nodes. */ \
m_total_hits = slist->slh_head->field.sle_levels[slist->slh_head->field.sle_height].hits; \
\
/* Height of the head node, should be close to floor(log(max_height)). */ \
k_threshold = slist->slh_head->field.sle_height + 1; \
\
/* Moving backwards along the path... \
* - path[0] contains a match, if there was one \
* - path[1..len] will be the nodes traversed along the way \
* - path[len] is where the locate() terminated, just before path[0] \
* if there was a match \
*/ \
for (i = 1; i < len; i++) { \
if (path[i].node == slist->slh_head || path[i].node == slist->slh_tail) \
continue; \
\
__SKIP_SUBTREE_CHu(decl, field, slist, path, i) \
{ \
hits_CHu += elm->field.sle_levels[i].hits; \
} \
__SKIP_SUBTREE_CHv(decl, field, slist, path, i) \
{ \
hits_CHv += elm->field.sle_levels[i].hits; \
} \
u_hits = hits_CHu + hits_CHv; \
\
/* (a) Check the decent condition: \
* u_hits <= m_total_hits / (2 ^ (k_threshold - height of node)) \
* When met should induce: \
* 1) traverse the path backward, and... \
* 2) propagate path[i].level[i] hits backward along path, and... \
* 3) adjust any forward pointers along the way, then... \
* 4) lower the path[i]'s node height by 1 \
*/ \
delta_height = k_threshold - path[i].node->field.sle_height + 1; \
dsc_cond = m_total_hits / pow(2.0, delta_height); \
if (u_hits <= dsc_cond && path[i].node->field.sle_height > 0) { \
if (path[i - 1].node->field.sle_prev != slist->slh_head) { \
/* 1) go backwards along path from where we are until head */ \
j = i; \
cur_hits = path[j].node->field.sle_levels[path[j].in].hits; \
do { \
/* 2) propagate hits */ \
prev_hits = path[j - 1].node->field.sle_levels[path[j - 1].in].hits; \
path[j - 1].node->field.sle_levels[path[j - 1].in].hits += cur_hits; \
cur_hits = prev_hits; \
/* 3) adjust forward pointers */ \
if (path[j - 1].node->field.sle_levels[j].next == path[i].node) \
path[j - 1].node->field.sle_levels[j].next = path[i].node->field.sle_levels[j].next; \
} while (j-- > 1); \
/* 4) reduce height by one */ \
path[i].node->field.sle_height--; \
} \
} \
/* (b) Check the ascent condition: \
* path[i].pu + node_hits > hits total / (2 ^ (height of head - height of node - 1)) \
* When met should induce: \
* 1) check the ascent condition, then iff true ... \
* 2) add a level, and ... \
* 3) set its hits to the prev node at intersection height \
* 4) set prev node hits to 0 and forward to this new level \
*/ \
/* 1) check ascent condition */ \
asc_cond = m_total_hits / pow(2.0, delta_height == 0 ? 0 : delta_height - 1); \
if (path[i - 1].pu > asc_cond && path[i].node->field.sle_height < slist->slh_max_height - 1) { \
/* 2) increase height by one */ \
new_height = path[i].node->field.sle_height++; \
/* 3) update hit counter */ \
path[i].node->field.sle_levels[new_height].hits += path[i - 1].node->field.sle_levels[path[i - 1].in].hits; \
/* 4) reset the prev node hits to 0 */ \
path[i - 1].node->field.sle_levels[path[i - 1].in].hits = 0; \
if (path[i - 1].in != 0) \
path[i - 1].node->field.sle_levels[path[i - 1].in].next->field.sle_levels[path[i - 1].in].next = path[i].node; \
} \
} \
((void)slist); \
((void)len); \
((void)path); \
return; /* TODO: WIP, see branch gburd/splay-list */ \
} \
\
/** \