1 files changed, 62 insertions, 0 deletions
diff --git a/libcr_ipc/_linkedlist.c b/libcr_ipc/_linkedlist.c
new file mode 100644
index 0000000..b27dba8
--- /dev/null
+++ b/libcr_ipc/_linkedlist.c
@@ -0,0 +1,62 @@
+/* libcr_ipc/_linkedlist.c - Common low-level linked lists for use in libcr_ipc
+ *
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <stddef.h> /* for NULL */
+
+#include "_linkedlist.h"
+
+/* singly linked list *********************************************************/
+
+void cr_ipc_sll_push_to_rear(_cr_ipc_sll_root *root, cr_ipc_sll_node *node) {
+	assert(root);
+	node->rear = NULL;
+	if (root->rear)
+		root->rear->rear = node;
+	else
+		root->front = node;
+	root->rear = node;
+}
+
+void cr_ipc_sll_pop_from_front(_cr_ipc_sll_root *root) {
+	assert(root);
+	assert(root->front);
+	root->front = root->front->rear;
+	if (!root->front)
+		root->rear = NULL;
+}
+
+/* doubly linked list *********************************************************/
+
+void cr_ipc_dll_push_to_rear(_cr_ipc_dll_root *root, cr_ipc_dll_node *node) {
+	assert(root);
+	assert(node);
+	node->front = root->rear;
+	node->rear = NULL;
+	if (root->rear)
+		root->rear->rear = node;
+	else
+		root->front = node;
+	root->rear = node;
+}
+
+void cr_ipc_dll_remove(_cr_ipc_dll_root *root, cr_ipc_dll_node *node) {
+	assert(root);
+	assert(node);
+	if (node->front)
+		node->front->rear = node->rear;
+	else
+		root->front = node->rear;
+	if (node->rear)
+		node->rear->front = node->front;
+	else
+		root->rear = node->front;
+}
+
+void cr_ipc_dll_pop_from_front(_cr_ipc_dll_root *root) {
+	assert(root);
+	assert(root->front);
+	cr_ipc_dll_remove(root, root->front);
+}