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-rw-r--r--src/llist.c202
-rw-r--r--src/llist.h3
-rw-r--r--src/llist_ts.h2
3 files changed, 148 insertions, 59 deletions
diff --git a/src/llist.c b/src/llist.c
index aca0a9d..04f16a1 100644
--- a/src/llist.c
+++ b/src/llist.c
@@ -109,6 +109,34 @@ llist_item_t *llist_next(llist_item_t * i)
}
/*
+ * Return the predecessor of a list item or, if head, the list item itself,
+ * or if not in the list, NULL.
+ * The list item may be supplied either directly (i) or as a pointer to
+ * the contents (data); the first case takes precedence.
+ */
+static llist_item_t *llist_prev(llist_t *l, llist_item_t *i, void *data)
+{
+ llist_item_t *j;
+
+ if (!i && !data)
+ return NULL;
+
+ if (l->head == i || l->head->data == data)
+ return l->head;
+
+ if (i) {
+ for (j = l->head; j; j = j->next)
+ if (j->next == i)
+ return j;
+ } else {
+ for (j = l->head; j && j->next; j = j->next)
+ if (j->next->data == data)
+ return j;
+ }
+ return NULL;
+}
+
+/*
* Return the successor of a list item if it is matched by some filter
* callback. Return NULL otherwise.
*/
@@ -150,34 +178,94 @@ void llist_add(llist_t * l, void *data)
}
/*
+ * Insert an existing item in a sorted list.
+ */
+static void llist_relink(llist_t *l, llist_item_t *i, llist_fn_cmp_t fn_cmp)
+{
+ llist_item_t *j;
+
+ if (!i)
+ return;
+
+ i->next = NULL;
+ if (!l->head) {
+ l->head = l->tail = i;
+ } else if (fn_cmp(i->data, l->tail->data) >= 0) {
+ l->tail->next = i;
+ l->tail = i;
+ } else if (fn_cmp(i->data, l->head->data) < 0) {
+ i->next = l->head;
+ l->head = i;
+ } else {
+ j = l->head;
+ while (j->next && fn_cmp(i->data, j->next->data) >= 0)
+ j = j->next;
+ i->next = j->next;
+ j->next = i;
+ }
+}
+
+/*
+ * Unlink an item from a list and return it.
+ */
+static llist_item_t *llist_unlink(llist_t *l, llist_item_t *i)
+{
+ llist_item_t *p;
+
+ if (!i)
+ return NULL;
+
+ p = llist_prev(l, i, NULL);
+ if (!p)
+ return NULL;
+
+ if (i == l->tail)
+ l->tail = (i == l->head) ? NULL : p;
+ if (i == l->head)
+ l->head = i->next;
+ else
+ p->next = i->next;
+ i->next = NULL;
+ return i;
+}
+
+/*
+ * Find an item matched by some filter callback; start from a specified item.
+ */
+static llist_item_t *llist_find_from(llist_item_t *i, void *data,
+ llist_fn_match_t fn_match)
+{
+ if (!i)
+ return NULL;
+
+ if (fn_match) {
+ for (; i; i = i->next) {
+ if (fn_match(i->data, data))
+ return i;
+ }
+ } else {
+ for (; i; i = i->next) {
+ if (i->data == data)
+ return i;
+ }
+ }
+
+ return NULL;
+}
+
+/*
* Add an item to a sorted list.
*/
void llist_add_sorted(llist_t * l, void *data, llist_fn_cmp_t fn_cmp)
{
llist_item_t *o = mem_malloc(sizeof(llist_item_t));
- llist_item_t *i;
if (o) {
o->data = data;
o->next = NULL;
-
- if (!l->head) {
- l->head = l->tail = o;
- } else if (fn_cmp(o->data, l->tail->data) >= 0) {
- l->tail->next = o;
- l->tail = o;
- } else if (fn_cmp(o->data, l->head->data) < 0) {
- o->next = l->head;
- l->head = o;
- } else {
- i = l->head;
- while (i->next
- && fn_cmp(o->data, i->next->data) >= 0)
- i = i->next;
- o->next = i->next;
- i->next = o;
- }
}
+
+ llist_relink(l, o, fn_cmp);
}
/*
@@ -209,21 +297,7 @@ void llist_remove(llist_t * l, llist_item_t * i)
llist_item_t *llist_find_first(llist_t * l, void *data,
llist_fn_match_t fn_match)
{
- llist_item_t *i;
-
- if (fn_match) {
- for (i = l->head; i; i = i->next) {
- if (fn_match(i->data, data))
- return i;
- }
- } else {
- for (i = l->head; i; i = i->next) {
- if (i->data == data)
- return i;
- }
- }
-
- return NULL;
+ return l ? llist_find_from(l->head, data, fn_match) : NULL;
}
/*
@@ -232,22 +306,7 @@ llist_item_t *llist_find_first(llist_t * l, void *data,
llist_item_t *llist_find_next(llist_item_t * i, void *data,
llist_fn_match_t fn_match)
{
- if (i) {
- i = i->next;
- if (fn_match) {
- for (; i; i = i->next) {
- if (fn_match(i->data, data))
- return i;
- }
- } else {
- for (; i; i = i->next) {
- if (i->data == data)
- return i;
- }
- }
- }
-
- return NULL;
+ return i ? llist_find_from(i->next, data, fn_match) : NULL;
}
/*
@@ -261,17 +320,42 @@ llist_item_t *llist_find_nth(llist_t * l, int n, void *data,
if (n < 0)
return NULL;
- if (fn_match) {
- for (i = l->head; i; i = i->next) {
- if (fn_match(i->data, data) && (n-- == 0))
- return i;
- }
- } else {
- for (i = l->head; i; i = i->next) {
- if ((i->data == data) && (n-- == 0))
- return i;
- }
+ for (i = l->head; i; i = i->next, n--) {
+ i = llist_find_from(i, data, fn_match);
+ if (!i || !n)
+ return i;
}
return NULL;
}
+
+/*
+ * Reorder a sorted linked list when an item has changed.
+ */
+void llist_reorder(llist_t *l, void *data, llist_fn_cmp_t fn_cmp)
+{
+ llist_item_t *o, *p;
+
+ if (!(p = llist_prev(l, NULL, data)))
+ return;
+
+ /* List head? */
+ if (p->data == data)
+ o = p;
+ else
+ o = p->next;
+
+ /* Sorted already?
+ * Note: p is either the previous element or o itself.
+ */
+ if (o->next &&
+ fn_cmp(p->data, o->data) <= 0 &&
+ fn_cmp(o->data, o->next->data) <= 0)
+ return;
+ if (!o->next &&
+ fn_cmp(p->data, o->data) <= 0)
+ return;
+
+ /* Link manipulation only. */
+ llist_relink(l, llist_unlink(l, o), fn_cmp);
+}
diff --git a/src/llist.h b/src/llist.h
index 9533819..1f7f419 100644
--- a/src/llist.h
+++ b/src/llist.h
@@ -99,8 +99,11 @@ void *llist_get_data(llist_item_t *);
void llist_add(llist_t *, void *);
void llist_add_sorted(llist_t *, void *, llist_fn_cmp_t);
void llist_remove(llist_t *, llist_item_t *);
+void llist_reorder(llist_t *, void *, llist_fn_cmp_t);
#define LLIST_ADD(l, data) llist_add(l, data)
#define LLIST_ADD_SORTED(l, data, fn_cmp) \
llist_add_sorted(l, data, (llist_fn_cmp_t)fn_cmp)
#define LLIST_REMOVE(l, i) llist_remove(l, i)
+#define LLIST_REORDER(l, data, fn_cmp) \
+ llist_reorder(l, data, (llist_fn_cmp_t)fn_cmp)
diff --git a/src/llist_ts.h b/src/llist_ts.h
index 6597cde..1604d3e 100644
--- a/src/llist_ts.h
+++ b/src/llist_ts.h
@@ -90,3 +90,5 @@ struct llist_ts {
#define LLIST_TS_REMOVE(l_ts, i) llist_remove ((llist_t *)l_ts, i)
#define LLIST_TS_ADD_SORTED(l_ts, data, fn_cmp) \
llist_add_sorted ((llist_t *)l_ts, data, (llist_fn_cmp_t)fn_cmp)
+#define LLIST_TS_REORDER(l_ts, data, fn_cmp) \
+ llist_reorder((llist_t *)l_ts, data, (llist_fn_cmp_t)fn_cmp)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-25 21:09:01 +0000