Revert RTL::LinkedList::RemoveEntryList() routine signature and extend RTL::LinkedList API

xtoskrnl/rtl/llist.cc

@@ -9,6 +9,32 @@
 #include <xtos.hh>
 
 
+/**
+ * Retrieves the first entry from a double-linked list without removing it from the list.
+ *
+ * @param ListHead
+ *        Pointer to a structure that serves as the list header.
+ *
+ * @return This routine returns a pointer to the first entry in the list.
+ *         If the list is empty, the return value points to the list head.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+PLIST_ENTRY
+RTL::LinkedList::GetFirstEntry(IN PLIST_ENTRY ListHead)
+{
+    /* Check if the list is empty */
+    if(ListEmpty(ListHead))
+    {
+        /* Empty list, return NULLPTR */
+        return NULLPTR;
+    }
+
+    /* Return first entry in the list */
+    return ListHead->Flink;
+}
+
 /**
  * This routine initializes a structure representing the head of a double-linked list.
  *
@@ -23,6 +49,7 @@ XTCDECL
 VOID
 RTL::LinkedList::InitializeListHead(IN PLIST_ENTRY ListHead)
 {
+    /* Initialize list head */
     ListHead->Blink = ListHead;
     ListHead->Flink = ListHead;
 }
@@ -41,6 +68,7 @@ XTCDECL
 VOID
 RTL::LinkedList::InitializeListHead32(IN PLIST_ENTRY32 ListHead)
 {
+    /* Initialize list head */
     ListHead->Blink = PtrToUlong(ListHead);
     ListHead->Flink = PtrToUlong(ListHead);
 }
@@ -63,6 +91,7 @@ VOID
 RTL::LinkedList::InsertHeadList(IN OUT PLIST_ENTRY ListHead,
                                 IN PLIST_ENTRY Entry)
 {
+    /* Insert entry at the head of the list */
     Entry->Flink = ListHead->Flink;
     Entry->Blink = ListHead;
     ListHead->Flink->Blink = Entry;
@@ -87,6 +116,7 @@ VOID
 RTL::LinkedList::InsertTailList(IN OUT PLIST_ENTRY ListHead,
                                 IN PLIST_ENTRY Entry)
 {
+    /* Insert entry at the tail of the list */
     Entry->Flink = ListHead;
     Entry->Blink = ListHead->Blink;
     ListHead->Blink->Flink = Entry;
@@ -107,6 +137,7 @@ XTCDECL
 BOOLEAN
 RTL::LinkedList::ListEmpty(IN PLIST_ENTRY ListHead)
 {
+    /* Check if the list is empty */
     return (((ListHead->Flink == NULLPTR) && (ListHead->Blink == NULLPTR)) || (ListHead->Flink == ListHead));
 }
 
@@ -162,18 +193,99 @@ RTL::LinkedList::ListLoop(IN PLIST_ENTRY ListHead)
  * @param Entry
  *        Pointer to the entry that will be removed from the list.
  *
- * @return This routine returns TRUE if the list is empty after removal, or FALSE otherwise.
+ * @return This routine does not return any value.
  *
  * @since XT 1.0
  */
 XTCDECL
-BOOLEAN
+VOID
 RTL::LinkedList::RemoveEntryList(IN PLIST_ENTRY Entry)
 {
     /* Remove entry from the list */
     Entry->Flink->Blink = Entry->Blink;
     Entry->Blink->Flink = Entry->Flink;
-
-    /* Return TRUE if list is empty, or FALSE otherwise */
-    return ListEmpty(Entry);
+}
+
+/**
+ * Splices a doubly linked list at the head of another list. The source list is reinitialized to empty.
+ *
+ * @param ListHead
+ *        Pointer to a structure that represents the head of the list.
+ *
+ * @param SpliceList
+ *        Pointer to a structure that represents the head of the list that will be spliced.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+VOID
+RTL::LinkedList::SpliceHeadList(IN OUT PLIST_ENTRY ListHead,
+                                IN OUT PLIST_ENTRY SpliceList)
+{
+    PLIST_ENTRY FirstEntry, LastEntry;
+
+    /* Check if the list to splice is empty */
+    if(SpliceList->Flink == SpliceList)
+    {
+        /* Nothing to splice, return */
+        return;
+    }
+
+    /* Get first and last entries of the list to splice */
+    FirstEntry = SpliceList->Flink;
+    LastEntry = SpliceList->Blink;
+
+    /* Splice the list at the head of destination */
+    FirstEntry->Blink = ListHead;
+    LastEntry->Flink = ListHead->Flink;
+    ListHead->Flink->Blink = LastEntry;
+    ListHead->Flink = FirstEntry;
+
+    /* Reinitialize the source list to empty */
+    SpliceList->Blink = SpliceList;
+    SpliceList->Flink = SpliceList;
+}
+
+/**
+ * Splices a doubly linked list at the tail of another list. The source list is reinitialized to empty.
+ *
+ * @param ListHead
+ *        Pointer to the head of the destination list.
+ *
+ * @param SpliceList
+ *        Pointer to the head of the list that will be spliced.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+VOID
+RTL::LinkedList::SpliceTailList(IN OUT PLIST_ENTRY ListHead,
+                                IN OUT PLIST_ENTRY SpliceList)
+{
+    PLIST_ENTRY FirstEntry, LastEntry;
+
+    /* Check if the list to splice is empty */
+    if(SpliceList->Flink == SpliceList)
+    {
+        /* Nothing to splice, return */
+        return;
+    }
+
+    /* Get first and last entries of the list to splice */
+    FirstEntry = SpliceList->Flink;
+    LastEntry = SpliceList->Blink;
+
+    /* Splice the list at the tail of destination */
+    FirstEntry->Blink = ListHead->Blink;
+    LastEntry->Flink = ListHead;
+    ListHead->Blink->Flink = FirstEntry;
+    ListHead->Blink = LastEntry;
+
+    /* Reinitialize the source list to empty */
+    SpliceList->Blink = SpliceList;
+    SpliceList->Flink = SpliceList;
 }