utility functions to reverse and rotate linklists.

2 files changed, 41 insertions, 1 deletions

diff --git a/source/blender/blenlib/BLI_listbase.h b/source/blender/blenlib/BLI_listbase.h
index 41968f1ebd6..767f61b29dd 100644
--- a/source/blender/blenlib/BLI_listbase.h
+++ b/source/blender/blenlib/BLI_listbase.h
@@ -71,6 +71,8 @@ void BLI_freelinkN(struct ListBase *listbase, void *vlink);
 
 void BLI_movelisttolist(struct ListBase *dst, struct ListBase *src);
 void BLI_duplicatelist(struct ListBase *dst, const struct ListBase *src);
+void BLI_reverselist(struct ListBase *lb);
+void BLI_rotatelist(struct ListBase *lb, LinkData *vlink);
 
 /* create a generic list node containing link to provided data */
 struct LinkData *BLI_genericNodeN(void *data);
diff --git a/source/blender/blenlib/intern/listbase.c b/source/blender/blenlib/intern/listbase.c
index 00b2d3bee74..f5f67ba3645 100644
--- a/source/blender/blenlib/intern/listbase.c
+++ b/source/blender/blenlib/intern/listbase.c
@@ -543,8 +543,10 @@ int BLI_findstringindex(const ListBase *listbase, const char *id, const int offs
 	return -1;
 }
 
+/**
+ * Sets dst to a duplicate of the entire contents of src. dst may be the same as src.
+ */
 void BLI_duplicatelist(ListBase *dst, const ListBase *src)
-/* sets dst to a duplicate of the entire contents of src. dst may be the same as src. */
 {
 	struct Link *dst_link, *src_link;
 
@@ -560,6 +562,42 @@ void BLI_duplicatelist(ListBase *dst, const ListBase *src)
 	}
 }
 
+void BLI_reverselist(ListBase *lb)
+{
+	struct Link *curr = lb->first;
+	struct Link *prev = NULL;
+	struct Link *next = NULL;
+	while(curr) {
+		next = curr->next;
+		curr->next = prev;
+		curr->prev = next;
+		prev = curr;
+		curr = next;
+	}
+
+	/* swap first/last */
+	curr = lb->first;
+	lb->first = lb->last;
+	lb->last = curr;
+}
+
+/**
+ * \param vlink Link to make first.
+ */
+void BLI_rotatelist(ListBase *lb, LinkData *vlink)
+{
+	/* make circular */
+	((LinkData *)lb->first)->prev = lb->last;
+	((LinkData *)lb->last)->next = lb->first;
+
+	lb->first = vlink;
+	lb->last = vlink->prev;
+
+	((LinkData *)lb->first)->prev = NULL;
+	((LinkData *)lb->last)->next = NULL;
+}
+
+
 /* create a generic list node containing link to provided data */
 LinkData *BLI_genericNodeN(void *data)
 {