From 32649d6af01092580411bb14a0484b02594a8eea Mon Sep 17 00:00:00 2001
From: Dominik Friedrich <D.Friedrich@bull.de>
Date: Mon, 17 Jun 2013 16:28:24 -0700
Subject: [PATCH] Make the list_sort use a merge sort with is n log n instead
of the n^2 algo we have previously used.
---
src/common/list.c | 101 ++++++++++++++++++++++++++++++++--------------
1 file changed, 70 insertions(+), 31 deletions(-)
diff --git a/src/common/list.c b/src/common/list.c
index a016c414db9..e40b37e53c9 100644
--- a/src/common/list.c
+++ b/src/common/list.c
@@ -529,51 +529,90 @@ list_flush (List l)
return(n);
}
-
void
list_sort (List l, ListCmpF f)
{
-/* Note: Time complexity O(n^2).
- */
- ListNode *pp, *ppPrev, *ppPos, pTmp;
- ListIterator i;
+ ListIterator it;
+
+ ListNode p, q, e, tail, head;
+ int insize, nmerges, psize, qsize, i;
assert(l != NULL);
assert(f != NULL);
list_mutex_lock(&l->mutex);
assert(l->magic == LIST_MAGIC);
+ head = l->head;
if (l->count > 1) {
- ppPrev = &l->head;
- pp = &(*ppPrev)->next;
- while (*pp) {
- if (f((*pp)->data, (*ppPrev)->data) < 0) {
- ppPos = &l->head;
- while (f((*pp)->data, (*ppPos)->data) >= 0)
- ppPos = &(*ppPos)->next;
- pTmp = (*pp)->next;
- (*pp)->next = *ppPos;
- *ppPos = *pp;
- *pp = pTmp;
- if (ppPrev == ppPos)
- ppPrev = &(*ppPrev)->next;
- }
- else {
- ppPrev = pp;
- pp = &(*pp)->next;
- }
- }
- l->tail = pp;
-
- for (i=l->iNext; i; i=i->iNext) {
- assert(i->magic == LIST_MAGIC);
- i->pos = i->list->head;
- i->prev = &i->list->head;
- }
+ insize=1;
+ while(1) {
+ p = head;
+ head = NULL;
+ tail = NULL;
+
+
+ nmerges = 0;
+ while(p) {
+ nmerges++;
+ q = p;
+
+ psize=0;
+ for (i = 0; i < insize; i++) {
+ psize++;
+ q = q->next;
+
+ if (!q) break;
+ }
+ qsize = insize;
+ while (psize > 0 || (qsize > 0 && q)) {
+ if (psize == 0) {
+ e = q;
+ q = q->next;
+ qsize--;
+ } else if (qsize == 0 || !q ) {
+ e = p;
+ p = p->next;
+ psize--;
+ } else if (f(p->data,q->data) < 0) {
+ e = p;
+ p = p->next;
+ psize--;
+ } else {
+ e = q;
+ q = q->next;
+ qsize--;
+ }
+ if (tail) {
+ tail->next = e;
+ } else {
+ head = e;
+ }
+ tail = e;
+ }
+ p = q;
+
+ }
+ tail->next = NULL;
+ if(nmerges <= 1) {
+ l->head = head;
+ l->tail = &tail;
+ for (it=l->iNext; it; it=it->iNext) {
+ assert(it->magic == LIST_MAGIC);
+ it->pos = it->list->head;
+ it->prev = &it->list->head;
+ }
+
+ list_mutex_unlock(&l->mutex);
+ return;
+ }
+ insize *=2;
+ }
}
+
list_mutex_unlock(&l->mutex);
return;
}
+
void *
list_push (List l, void *x)
{
--
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