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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*****************************************************************************
*
* list_sort() adapted from linux kernel.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*****************************************************************************/
#include <assert.h>
#include "list.h"
/* list sort from Mark J Roberts (mjr@znex.org) */
void
__list_sort(
struct list_head *head,
int member_offset,
int (*cmp)(void * a, void * b))
{
struct list_head *p, *q, *e, *list, *tail, *oldhead;
int insize, nmerges, psize, qsize, i;
list = head->next;
list_del(head);
insize = 1;
for (;;) {
p = oldhead = list;
list = tail = NULL;
nmerges = 0;
while (p) {
nmerges++;
q = p;
psize = 0;
for (i = 0; i < insize; i++) {
psize++;
q = q->next == oldhead ? NULL : q->next;
if (!q)
break;
}
qsize = insize;
while (psize > 0 || (qsize > 0 && q)) {
if (!psize) {
e = q;
q = q->next;
qsize--;
if (q == oldhead)
q = NULL;
} else if (!qsize || !q) {
e = p;
p = p->next;
psize--;
if (p == oldhead)
p = NULL;
} else if (cmp((void *)p - member_offset, (void *)q - member_offset) <= 0) {
e = p;
p = p->next;
psize--;
if (p == oldhead)
p = NULL;
} else {
e = q;
q = q->next;
qsize--;
if (q == oldhead)
q = NULL;
}
if (tail)
tail->next = e;
else
list = e;
e->prev = tail;
tail = e;
}
p = q;
}
tail->next = list;
list->prev = tail;
if (nmerges <= 1)
break;
insize *= 2;
}
head->next = list;
head->prev = list->prev;
list->prev->next = head;
list->prev = head;
}
struct test_list_el {
int value;
struct list_head test_list_node;
};
int test_list_sort_comparator(struct test_list_el * e1, struct test_list_el * e2)
{
return e1->value - e2->value;
}
void test_list_sort(void)
{
struct list_head test_list;
struct test_list_el *el, *next;
struct test_list_el te1 = {.value = 1};
struct test_list_el te2 = {.value = 2};
struct test_list_el te3 = {.value = 3};
struct test_list_el te4 = {.value = 4};
struct test_list_el te5 = {.value = 5};
struct test_list_el te6 = {.value = 6};
struct test_list_el te7 = {.value = 7};
const int expected[] = {1, 2, 3, 4, 5, 6, 7};
int i;
INIT_LIST_HEAD(&test_list);
list_add_tail(&te2.test_list_node, &test_list);
list_add_tail(&te6.test_list_node, &test_list);
list_add_tail(&te4.test_list_node, &test_list);
list_add_tail(&te5.test_list_node, &test_list);
list_add_tail(&te7.test_list_node, &test_list);
list_add_tail(&te1.test_list_node, &test_list);
list_add_tail(&te3.test_list_node, &test_list);
list_sort(&test_list, struct test_list_el, test_list_node, test_list_sort_comparator);
i = 0;
list_for_each_entry_safe(el, next, &test_list, test_list_node) {
assert(el->value == expected[i]);
i++;
}
}
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