list: add "simple" linked list

include/neo/list.h

@@ -0,0 +1,151 @@
+/** See the end of this file for copyright and license terms. */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "neo/_stddef.h"
+#include "neo/_types.h"
+
+struct _neo_listnode {
+	struct _neo_listnode *_next;
+	struct _neo_listnode *_prev;
+	struct _neo_list *_list;
+};
+/**
+ * List node anchor for embedding into your own structure.
+ */
+typedef struct _neo_listnode listnode_t;
+
+struct _neo_list {
+	struct _neo_listnode _root;
+	NLEN_FIELD(_len);
+};
+typedef struct _neo_list list_t;
+
+/**
+ * Initialize a list.
+ *
+ * @param list: The list
+ */
+void list_init(list_t *list);
+
+/**
+ * When casting out from a `listnode_t` to its supposed containing structure
+ * (in a loop), it is possible that it was in fact the `list_t` that contained
+ * the `listnode_t`.  This macro checks whether that is the case.
+ *
+ * @param casted: `struct *` that the `listnode_t *` was casted out to
+ * @param list: `list_t *` storing the root `listnode_t`
+ * @param member: Name of the `listnode_t` member embedded within the `struct *`
+ */
+#define _neo_list_is_root(casted, list, member) \
+	( &(casted)->member == &(list)->_root )
+
+#define _neo_list_first(list, type, member) ({		\
+	void *__ptr = (list)->_root._next;		\
+	(type)( __ptr - offsetof(type, member) );	\
+})
+
+#define _neo_list_last(list, type, member) ({		\
+	void *__ptr = (list)->_root._prev;		\
+	(type)( __ptr - offsetof(type, member) );	\
+})
+
+#define _neo_list_next(current, member) ({					\
+	void *__next = (current)->member._next;					\
+	(typeof(current))( __next - offsetof(typeof(current), member) );	\
+})
+
+#define _neo_list_prev(current, member) ({					\
+	void *__prev = (current)->member._prev;					\
+	(typeof(current))( __prev - offsetof(typeof(current), member) );	\
+})
+
+/**
+ * Append a new node to the end of a list.
+ *
+ * @param list: List to append to
+ * @param new: New node to append
+ */
+void list_add(list_t *list, listnode_t *new);
+
+/**
+ * Remove a node from a list.
+ *
+ * @param node: Node to remove
+ */
+void list_del(listnode_t *node);
+
+/**
+ * Insert a new node to the beginning of a list.
+ *
+ * @param list: List to insert the node into
+ * @param new: New node to insert
+ */
+void list_add_first(list_t *list, listnode_t *new);
+
+/**
+ * Insert a new node after the specified list node.
+ *
+ * @param pos: List node to insert the new node after
+ * @param new: Node to insert after the specified position
+ */
+void list_insert(listnode_t *pos, listnode_t *new);
+
+/**
+ * Insert a new node before the specified list node.
+ *
+ * @param pos: List node to insert the new node before
+ * @param new: Node to insert before the specified position
+ */
+void list_insert_before(listnode_t *pos, listnode_t *new);
+
+/**
+ * Iterate over each item in a list.
+ *
+ * The current entry can be safely removed from the list.
+ *
+ * @param cursor: `type *` to use as a cursor; may be a declaration
+ * @param list: `list_t *` to iterate over
+ * @param member: Name of the `listnode_t` member embedded within `cursor`
+ */
+#define list_foreach(cursor, list, member)					\
+	for (cursor = _neo_list_first(list, typeof(cursor), member)),		\
+		typeof(cursor) __tmp = _neo_list_next(cursor, member);		\
+	     !_neo_list_is_root(cursor, list, member);				\
+	     cursor = __tmp, __tmp = _neo_list_next(__tmp, member))
+
+/**
+ * Iterate over each item in a list in reverse order.
+ *
+ * The current entry can be safely removed from the list.
+ *
+ * @param cursor: `type *` to use as a cursor; may be a declaration
+ * @param list: `list_t *` to iterate over
+ * @param member: Name of the `listnode_t` member embedded within `cursor`
+ */
+#define list_foreach_reverse(cursor, list, member)				\
+	for (cursor = _neo_list_last(list, typeof(cursor), member)),		\
+		typeof(cursor) __tmp = _neo_list_prev(cursor, member);		\
+	     !_neo_list_is_root(cursor, list, member);				\
+	     cursor = __tmp, __tmp = _neo_list_prev(__tmp, member))
+
+#ifdef __cplusplus
+}; /* extern "C" */
+#endif
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */

src/CMakeLists.txt

@@ -2,7 +2,7 @@
 
 add_library(neo STATIC)
 
-target_link_options(neo INTERFACE -T${CMAKE_SOURCE_DIR}/src/neo.ld)
+target_link_options(neo INTERFACE -T${CMAKE_CURRENT_SOURCE_DIR}/src/neo.ld)
 
 execute_process(COMMAND uname -m OUTPUT_VARIABLE HOST_ARCH OUTPUT_STRIP_TRAILING_WHITESPACE)
 string(TOLOWER "${HOST_ARCH}" HOST_ARCH)

src/list.c

@@ -0,0 +1,72 @@
+/** See the end of this file for copyright and license terms. */
+
+#include "neo/list.h"
+
+void list_init(list_t *list)
+{
+	list->_root._next = &list->_root;
+	list->_root._prev = &list->_root;
+	list->_root._list = list;
+	list->_len = 0;
+}
+
+void list_add(list_t *list, listnode_t *new)
+{
+	list_insert_before(&list->_root, new);
+	new->_list = list;
+	list->_len++;
+}
+
+void list_add_first(list_t *list, listnode_t *new)
+{
+	list_insert(&list->_root, new);
+	new->_list = list;
+	list->_len++;
+}
+
+void list_del(listnode_t *node)
+{
+	node->_prev->_next = node->_next;
+	node->_next->_prev = node->_prev;
+
+	node->_list->_len++;
+
+	/* TODO: find a way to nil the pointers in node w/out breaking list_foreach */
+}
+
+void list_insert(listnode_t *pos, listnode_t *new)
+{
+	new->_next = pos->_next;
+	pos->_next->_prev = new;
+
+	new->_prev = pos;
+	pos->_next = new;
+
+	new->_list = pos->_list;
+	pos->_list->_len++;
+}
+
+void list_insert_before(listnode_t *pos, listnode_t *new)
+{
+	pos->_prev->_next = new;
+	new->_prev = pos->_prev;
+
+	new->_next = pos;
+	pos->_prev = new;
+
+	new->_list = pos->_list;
+	pos->_list->_len++;
+}
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */