New upstream version 1.18.0 upstream/1.18.0

1 files changed, 209 insertions, 0 deletions

diff --git a/shared/nm-std-aux/c-list-util.c b/shared/nm-std-aux/c-list-util.c
new file mode 100644
index 00000000..44ca26a5
--- /dev/null
+++ b/shared/nm-std-aux/c-list-util.c
@@ -0,0 +1,209 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * (C) Copyright 2017 Red Hat, Inc.
+ */
+
+#include "c-list-util.h"
+
+/*****************************************************************************/
+
+/**
+ * c_list_relink:
+ * @lst: the head list entry
+ *
+ * Takes an invalid list, that has undefined prev pointers.
+ * Only the next pointers are valid, and the tail's next
+ * pointer points to %NULL instead of the head.
+ *
+ * c_list_relink() fixes the list by updating all prev pointers
+ * and close the circular linking by pointing the tails' next
+ * pointer to @lst.
+ *
+ * The use of this function is to do a bulk update, that lets the
+ * list degredate by not updating the prev pointers. At the end,
+ * the list can be fixed by c_list_relink().
+ */
+void
+c_list_relink (CList *lst)
+{
+	CList *ls, *ls_prev;
+
+	ls_prev = lst;
+	ls = lst->next;
+	do {
+		ls->prev = ls_prev;
+		ls_prev = ls;
+		ls = ls->next;
+	} while (ls);
+	ls_prev->next = lst;
+	lst->prev = ls_prev;
+}
+
+/*****************************************************************************/
+
+static CList *
+_c_list_srt_split (CList *ls)
+{
+	CList *ls2;
+
+	ls2 = ls;
+	ls = ls->next;
+	if (!ls)
+		return NULL;
+	do {
+		ls = ls->next;
+		if (!ls)
+			break;
+		ls = ls->next;
+		ls2 = ls2->next;
+	} while (ls);
+	ls = ls2->next;
+	ls2->next = NULL;
+	return ls;
+}
+
+static CList *
+_c_list_srt_merge (CList *ls1,
+                   CList *ls2,
+                   CListSortCmp cmp,
+                   const void *user_data)
+{
+	CList *ls;
+	CList head;
+
+	ls = &head;
+	for (;;) {
+		/* while invoking the @cmp function, the list
+		 * elements are not properly linked. Don't try to access
+		 * their next/prev pointers. */
+		if (cmp (ls1, ls2, user_data) <= 0) {
+			ls->next = ls1;
+			ls = ls1;
+			ls1 = ls1->next;
+			if (!ls1)
+				break;
+		} else {
+			ls->next = ls2;
+			ls = ls2;
+			ls2 = ls2->next;
+			if (!ls2)
+				break;
+		}
+	}
+	ls->next = ls1 ?: ls2;
+
+	return head.next;
+}
+
+typedef struct {
+	CList *ls1;
+	CList *ls2;
+	char ls1_sorted;
+} SortStack;
+
+static CList *
+_c_list_sort (CList *ls,
+              CListSortCmp cmp,
+              const void *user_data)
+{
+	/* reserve a huge stack-size. We need roughly log2(n) entries, hence this
+	 * is much more we will ever need. We don't guard for stack-overflow either. */
+	SortStack stack_arr[70];
+	SortStack *stack_head = stack_arr;
+
+	stack_arr[0].ls1 = ls;
+
+	/* A simple top-down, non-recursive, stable merge-sort.
+	 *
+	 * Maybe natural merge-sort would be better, to do better for
+	 * partially sorted lists. */
+_split:
+	stack_head[0].ls2 = _c_list_srt_split (stack_head[0].ls1);
+	if (stack_head[0].ls2) {
+		stack_head[0].ls1_sorted = 0;
+		stack_head[1].ls1 = stack_head[0].ls1;
+		stack_head++;
+		goto _split;
+	}
+
+_backtrack:
+	if (stack_head == stack_arr)
+		return stack_arr[0].ls1;
+
+	stack_head--;
+	if (!stack_head[0].ls1_sorted) {
+		stack_head[0].ls1 = stack_head[1].ls1;
+		stack_head[0].ls1_sorted = 1;
+		stack_head[1].ls1 = stack_head[0].ls2;
+		stack_head++;
+		goto _split;
+	}
+
+	stack_head[0].ls1 = _c_list_srt_merge (stack_head[0].ls1, stack_head[1].ls1, cmp, user_data);
+	goto _backtrack;
+}
+
+/**
+ * c_list_sort_headless:
+ * @lst: the list.
+ * @cmp: compare function for sorting. While comparing two
+ *   CList elements, their next/prev pointers are in undefined
+ *   state.
+ * @user_data: user data for @cmp.
+ *
+ * Sorts the list @lst according to @cmp. Contrary to
+ * c_list_sort(), @lst is not the list head but a
+ * valid entry as well. This function returns the new
+ * list head.
+ */
+CList *
+c_list_sort_headless (CList *lst,
+                      CListSortCmp cmp,
+                      const void *user_data)
+{
+	if (!c_list_is_empty (lst)) {
+		lst->prev->next = NULL;
+		lst = _c_list_sort (lst, cmp, user_data);
+		c_list_relink (lst);
+	}
+	return lst;
+}
+
+/**
+ * c_list_sort:
+ * @head: the list head.
+ * @cmp: compare function for sorting. While comparing two
+ *   CList elements, their next/prev pointers are in undefined
+ *   state.
+ * @user_data: user data for @cmp.
+ *
+ * Sorts the list @head according to @cmp.
+ */
+void
+c_list_sort (CList *head,
+             CListSortCmp cmp,
+             const void *user_data)
+{
+	if (   !c_list_is_empty (head)
+	    && head->next->next != head) {
+		head->prev->next = NULL;
+		head->next = _c_list_sort (head->next, cmp, user_data);
+		c_list_relink (head);
+	}
+}