add linked list code

Makefile

@@ -0,0 +1,15 @@
+CFLAGS := -ggdb3 -O2 -Wall -I.
+
+
+LIBIFUPDOWN_SRC = \
+	libifupdown/list.c
+LIBIFUPDOWN_OBJ = ${LIBIFUPDOWN_SRC:.c=.o}
+
+
+libifupdown.a: ${LIBIFUPDOWN_OBJ}
+	ar -rcs $@ ${LIBIFUPDOWN_OBJ}
+
+all: libifupdown.a
+
+clean:
+	rm -f ${LIBIFUPDOWN_OBJ}

libifupdown/libifupdown.h

@@ -0,0 +1,21 @@
+/*
+ * libifupdown/libifupdown.h
+ * Purpose: main header file for libifupdown
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#ifndef LIBIFUPDOWN_LIBIFUPDOWN_H__GUARD
+#define LIBIFUPDOWN_LIBIFUPDOWN_H__GUARD
+
+#include "libifupdown/list.h"
+
+#endif

libifupdown/list.c

@@ -0,0 +1,99 @@
+/*
+ * libifupdown/list.c
+ * Purpose: linked lists
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <stdint.h>
+#include "libifupdown/list.h"
+
+#if 0
+
+struct lif_node {
+	struct lif_node *prev, *next;
+	void *data;
+};
+
+struct lif_list {
+	struct lif_node *head, *tail;
+	size_t length;
+};
+
+#define LIF_LIST_FOREACH(iter, head) \
+	for ((iter) = (head); (iter) != NULL; (iter) = (iter)->next)
+
+#define LIF_LIST_FOREACH_SAFE(iter, iter_next, head) \
+	for ((iter) = (head); (iter) != NULL; (iter) = (iter_next), (iter_next) = (iter) != NULL ? (iter)->next : NULL)
+
+#endif
+
+void
+lif_node_insert(struct lif_node *node, void *data, struct lif_list *list)
+{
+	struct lif_node *tnode;
+
+	node->data = data;
+
+	if (list->head == NULL)
+	{
+		list->head = list->tail = node;
+		list->length = 1;
+		return;
+	}
+
+	tnode = list->head;
+
+	node->next = tnode;
+	tnode->prev = node;
+
+	list->head = node;
+	list->length++;
+}
+
+void
+lif_node_insert_tail(struct lif_node *node, void *data, struct lif_list *list)
+{
+	struct lif_node *tnode;
+
+	node->data = data;
+
+	if (list->tail == NULL)
+	{
+		list->head = list->tail = node;
+		list->length = 1;
+		return;
+	}
+
+	tnode = list->tail;
+
+	node->prev = tnode;
+	tnode->next = node;
+
+	list->tail = node;
+	list->length++;
+}
+
+void
+lif_node_delete(struct lif_node *node, struct lif_list *list)
+{
+	list->length--;
+
+	if (node->prev == NULL)
+		list->head = node->next;
+	else
+		node->prev->next = node->next;
+
+	if (node->next == NULL)
+		list->tail = node->prev;
+	else
+		node->next->prev = node->prev;
+}

libifupdown/list.h

@@ -0,0 +1,42 @@
+/*
+ * libifupdown/list.h
+ * Purpose: linked lists
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#ifndef LIBIFUPDOWN_LIST_H__GUARD
+#define LIBIFUPDOWN_LIST_H__GUARD
+
+#include <stddef.h>
+#include <stdint.h>
+
+struct lif_node {
+	struct lif_node *prev, *next;
+	void *data;
+};
+
+struct lif_list {
+	struct lif_node *head, *tail;
+	size_t length;
+};
+
+extern void lif_node_insert(struct lif_node *node, void *data, struct lif_list *list);
+extern void lif_node_insert_tail(struct lif_node *node, void *data, struct lif_list *list);
+extern void lif_node_delete(struct lif_node *node, struct lif_list *list);
+
+#define LIF_LIST_FOREACH(iter, head) \
+	for ((iter) = (head); (iter) != NULL; (iter) = (iter)->next)
+
+#define LIF_LIST_FOREACH_SAFE(iter, iter_next, head) \
+	for ((iter) = (head); (iter) != NULL; (iter) = (iter_next), (iter_next) = (iter) != NULL ? (iter)->next : NULL)
+
+#endif