1 files changed, 280 insertions, 169 deletions

diff --git a/src/list.h b/src/list.h
index 3b53fab..92000d5 100644
--- a/src/list.h
+++ b/src/list.h
@@ -21,6 +21,7 @@
  *     SLIST_INIT(&list);
  *
  *     struct item item;
+ *     SLIST_ITEM_INIT(&item);
  *     SLIST_APPEND(&list, &item);
  *
  * Doubly linked lists are similar:
@@ -39,6 +40,7 @@
  *     LIST_INIT(&list);
  *
  *     struct item item;
+ *     LIST_ITEM_INIT(&item);
  *     LIST_APPEND(&list, &item);
  *
  * Items can be on multiple lists at once:
@@ -71,20 +73,25 @@
  *     LIST_INIT(&items.cache);
  *
  *     struct item item;
+ *     SLIST_ITEM_INIT(&item, chain);
  *     SLIST_APPEND(&items.queue, &item, chain);
+ *     LIST_ITEM_INIT(&item, lru);
  *     LIST_APPEND(&items.cache, &item, lru);
  */
 
 #ifndef BFS_LIST_H
 #define BFS_LIST_H
 
+#include "bfs.h"
+#include "diag.h"
+
 #include <stddef.h>
 #include <string.h>
 
 /**
  * Initialize a singly-linked list.
  *
- * @param list
+ * @list
  *         The list to initialize.
  *
  * ---
@@ -94,303 +101,407 @@
  * don't have to.
  */
 #define SLIST_INIT(list) \
-	LIST_BLOCK_(SLIST_INIT_((list)))
+	SLIST_INIT_((list))
 
-#define SLIST_INIT_(list) \
-	list->head = NULL; \
-	list->tail = &list->head;
+/**
+ * Helper for SLIST_INIT().
+ */
+#define SLIST_INIT_(list) LIST_VOID_( \
+	list->head = NULL, \
+	list->tail = &list->head)
 
 /**
- * Wraps a group of statements in a block.
+ * Cast a list of expressions to void.
  */
-#define LIST_BLOCK_(block) do { block } while (0)
+#define LIST_VOID_(...) ((void)(__VA_ARGS__))
 
 /**
- * Insert an item into a singly-linked list.
+ * Initialize a singly-linked list item.
  *
- * @param list
- *         The list to modify.
- * @param cursor
- *         A pointer to the item to insert after, e.g. &list->head or list->tail.
- * @param item
- *         The item to insert.
- * @param node (optional)
+ * @item
+ *         The item to initialize.
+ * @node (optional)
  *         If specified, use item->node.next rather than item->next.
- *
- * ---
- *
- * We play some tricks with variadic macros to handle the optional parameter:
- *
- *     SLIST_INSERT(list, cursor, item) => {
- *             item->next = *cursor;
- *             *cursor = item;
- *             list->tail = item->next ? list->tail : &item->next;
- *     }
- *
- *     SLIST_INSERT(list, cursor, item, node) => {
- *             item->node.next = *cursor;
- *             *cursor = item;
- *             list->tail = item->node.next ? list->tail : &item->node.next;
- *     }
- *
- * The first trick is that
- *
- *     #define SLIST_INSERT(list, item, cursor, ...)
- *
- * won't work because both commas are required (until C23; see N3033). As a
- * workaround, we dispatch to another macro and add a trailing comma.
- *
- *     SLIST_INSERT(list, cursor, item)       => SLIST_INSERT_(list, cursor, item, )
- *     SLIST_INSERT(list, cursor, item, node) => SLIST_INSERT_(list, cursor, item, node, )
  */
-#define SLIST_INSERT(list, cursor, ...) SLIST_INSERT_(list, cursor, __VA_ARGS__, )
+#define SLIST_ITEM_INIT(item, ...) \
+	SLIST_ITEM_INIT_((item), LIST_NEXT_(__VA_ARGS__))
+
+#define SLIST_ITEM_INIT_(item, next) \
+	LIST_VOID_(item->next = NULL)
 
 /**
- * Now we need a way to generate either ->next or ->node.next depending on
- * whether the node parameter was passed.  The approach is based on
- *
- *     #define FOO(...) BAR(__VA_ARGS__, 1, 2, )
- *     #define BAR(x, y, z, ...) z
- *
- *     FOO(a)    => 2
- *     FOO(a, b) => 1
+ * Get the projection for an item's next pointer.
  *
- * The LIST_NEXT_() macro uses this technique:
+ *     LIST_NEXT_()     => next
+ *     LIST_NEXT_(node) => node.next
+ */
+#define LIST_NEXT_(node) \
+	BFS_VA_IF(node)(node.next)(next)
+
+/**
+ * Type-checking macro for singly-linked lists.
+ */
+#define SLIST_CHECK_(list) \
+	(void)sizeof(list->tail - &list->head)
+
+/**
+ * Get the head of a singly-linked list.
  *
- *     LIST_NEXT_()       => LIST_NODE_(next, )
- *     LIST_NEXT_(node, ) => LIST_NODE_(next, node, )
+ * @list
+ *         The list in question.
+ * @return
+ *         The first item in the list.
  */
-#define LIST_NEXT_(...) LIST_NODE_(next, __VA_ARGS__)
+#define SLIST_HEAD(list) \
+	SLIST_HEAD_((list))
+
+#define SLIST_HEAD_(list) \
+	(SLIST_CHECK_(list), list->head)
 
 /**
- * LIST_NODE_() dispatches to yet another macro:
+ * Check if a singly-linked list is empty.
+ */
+#define SLIST_EMPTY(list) \
+	(!SLIST_HEAD(list))
+
+/**
+ * Get the tail of a singly-linked list.
  *
- *     LIST_NODE_(next, )       => LIST_NODE__(next,     , . ,   , )
- *     LIST_NODE_(next, node, ) => LIST_NODE__(next, node,   , . , , )
+ * @list
+ *         The list in question.
+ * @node (optional)
+ *         If specified, use item->node.next rather than item->next.
+ * @return
+ *         The last item in the list.
  */
-#define LIST_NODE_(dir, ...) LIST_NODE__(dir, __VA_ARGS__, . , , )
+#define SLIST_TAIL(list, ...) \
+	SLIST_TAIL_((list), LIST_NEXT_(__VA_ARGS__))
+
+#define SLIST_TAIL_(list, next) \
+	(list->head ? container_of(list->tail, typeof(*list->head), next) : NULL)
 
 /**
- * And finally, LIST_NODE__() adds the node and the dot if necessary.
- *
- *                 dir   node ignored dot
- *                  v     v      v     v
- *     LIST_NODE__(next,     ,   .   ,   , )   => next
- *     LIST_NODE__(next, node,       , . , , ) => node . next
- *                  ^     ^      ^     ^
- *                 dir   node ignored dot
+ * Check if an item is attached to a singly-linked list.
+ *
+ * @list
+ *         The list to check.
+ * @item
+ *         The item to check.
+ * @node (optional)
+ *         If specified, use item->node.next rather than item->next.
+ * @return
+ *         Whether the item is attached to the list.
  */
-#define LIST_NODE__(dir, node, ignored, dot, ...) node dot dir
+#define SLIST_ATTACHED(list, item, ...) \
+	SLIST_ATTACHED_((list), (item), LIST_NEXT_(__VA_ARGS__))
+
+#define SLIST_ATTACHED_(list, item, next) \
+	(item->next || list->tail == &item->next)
 
 /**
- * SLIST_INSERT_() uses LIST_NEXT_() to generate the right name for the list
- * node, and finally delegates to the actual implementation.
+ * Insert an item into a singly-linked list.
+ *
+ * @list
+ *         The list to modify.
+ * @cursor
+ *         A pointer to the item to insert after, e.g. &list->head or list->tail.
+ * @item
+ *         The item to insert.
+ * @node (optional)
+ *         If specified, use item->node.next rather than item->next.
+ * @return
+ *         A cursor for the next item.
  */
-#define SLIST_INSERT_(list, cursor, item, ...) \
-	LIST_BLOCK_(SLIST_INSERT__((list), (cursor), (item), LIST_NEXT_(__VA_ARGS__)))
+#define SLIST_INSERT(list, cursor, item, ...) \
+	SLIST_INSERT_((list), (cursor), (item), LIST_NEXT_(__VA_ARGS__))
 
-#define SLIST_INSERT__(list, cursor, item, next) \
-	item->next = *cursor; \
-	*cursor = item; \
-	list->tail = item->next ? list->tail : &item->next;
+#define SLIST_INSERT_(list, cursor, item, next) \
+	(bfs_assert(!SLIST_ATTACHED_(list, item, next)), \
+	 item->next = *cursor, \
+	 *cursor = item, \
+	 list->tail = item->next ? list->tail : &item->next, \
+	 &item->next)
 
 /**
  * Add an item to the tail of a singly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param item
+ * @item
  *         The item to append.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.next rather than item->next.
  */
-#define SLIST_APPEND(list, ...) SLIST_APPEND_(list, __VA_ARGS__, )
-
-#define SLIST_APPEND_(list, item, ...) \
-	SLIST_INSERT_(list, (list)->tail, item, __VA_ARGS__)
+#define SLIST_APPEND(list, item, ...) \
+	LIST_VOID_(SLIST_INSERT(list, (list)->tail, item, __VA_ARGS__))
 
 /**
  * Add an item to the head of a singly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param item
+ * @item
  *         The item to prepend.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.next rather than item->next.
  */
-#define SLIST_PREPEND(list, ...) SLIST_PREPEND_(list, __VA_ARGS__, )
+#define SLIST_PREPEND(list, item, ...) \
+	LIST_VOID_(SLIST_INSERT(list, &(list)->head, item, __VA_ARGS__))
+
+/**
+ * Splice a singly-linked list into another.
+ *
+ * @dest
+ *         The destination list.
+ * @cursor
+ *         A pointer to the item to splice after, e.g. &list->head or list->tail.
+ * @src
+ *         The source list.
+ */
+#define SLIST_SPLICE(dest, cursor, src) \
+	LIST_VOID_(SLIST_SPLICE_((dest), (cursor), (src)))
 
-#define SLIST_PREPEND_(list, item, ...) \
-	SLIST_INSERT_(list, &(list)->head, item, __VA_ARGS__)
+#define SLIST_SPLICE_(dest, cursor, src) \
+	*src->tail = *cursor, \
+	*cursor = src->head, \
+	dest->tail = *dest->tail ? src->tail : dest->tail, \
+	SLIST_INIT(src)
 
 /**
  * Add an entire singly-linked list to the tail of another.
  *
- * @param dest
+ * @dest
  *         The destination list.
- * @param src
+ * @src
  *         The source list.
  */
 #define SLIST_EXTEND(dest, src) \
-	LIST_BLOCK_(SLIST_EXTEND_((dest), (src)))
-
-#define SLIST_EXTEND_(dest, src) \
-	if (src->head) { \
-		*dest->tail = src->head; \
-		dest->tail = src->tail; \
-		SLIST_INIT(src); \
-	}
+	SLIST_SPLICE(dest, (dest)->tail, src)
 
 /**
  * Remove an item from a singly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param cursor
+ * @cursor
  *         A pointer to the item to remove, either &list->head or &prev->next.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.next rather than item->next.
  * @return
  *         The removed item.
  */
-#define SLIST_REMOVE(list, ...) SLIST_REMOVE_(list, __VA_ARGS__, )
-
-#define SLIST_REMOVE_(list, cursor, ...) \
-	SLIST_REMOVE__((list), (cursor), LIST_NEXT_(__VA_ARGS__))
+#define SLIST_REMOVE(list, cursor, ...) \
+	SLIST_REMOVE_((list), (cursor), LIST_NEXT_(__VA_ARGS__))
 
-#define SLIST_REMOVE__(list, cursor, next) \
+#define SLIST_REMOVE_(list, cursor, next) \
 	(list->tail = (*cursor)->next ? list->tail : cursor, \
-	 slist_remove_impl(*cursor, cursor, &(*cursor)->next, list->tail, sizeof(*cursor)))
+	 (typeof(*cursor))slist_remove_(*cursor, cursor, &(*cursor)->next, sizeof(*cursor)))
 
 // Helper for SLIST_REMOVE()
-static inline void *slist_remove_impl(void *ret, void *cursor, void *next, void *tail, size_t size) {
+static inline void *slist_remove_(void *ret, void *cursor, void *next, size_t size) {
 	// ret = *cursor;
 	// *cursor = ret->next;
 	memcpy(cursor, next, size);
-	// ret->next = *list->tail; (NULL)
-	memcpy(next, tail, size);
+	// ret->next = NULL;
+	memset(next, 0, size);
 	return ret;
 }
 
 /**
  * Pop the head off a singly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use head->node.next rather than head->next.
  * @return
  *         The popped item, or NULL if the list was empty.
  */
-#define SLIST_POP(...) SLIST_POP_(__VA_ARGS__, )
+#define SLIST_POP(list, ...) \
+	((list)->head ? SLIST_REMOVE(list, &(list)->head, __VA_ARGS__) : NULL)
 
-#define SLIST_POP_(list, ...) \
-	((list)->head ? SLIST_REMOVE_(list, &(list)->head, __VA_ARGS__) : NULL)
+/**
+ * Loop over the items in a singly-linked list.
+ *
+ * @type
+ *         The list item type.
+ * @item
+ *         The induction variable name.
+ * @list
+ *         The list to iterate.
+ * @node (optional)
+ *         If specified, use head->node.next rather than head->next.
+ */
+#define for_slist(type, item, list, ...) \
+	for_slist_(type, item, (list), LIST_NEXT_(__VA_ARGS__))
+
+#define for_slist_(type, item, list, next) \
+	for (type *item = SLIST_HEAD(list), *_next; \
+	     item && (_next = item->next, true); \
+	     item = _next)
+
+/**
+ * Loop over a singly-linked list, popping each item.
+ *
+ * @type
+ *         The list item type.
+ * @item
+ *         The induction variable name.
+ * @list
+ *         The list to drain.
+ * @node (optional)
+ *         If specified, use head->node.next rather than head->next.
+ */
+#define drain_slist(type, item, list, ...) \
+	for (type *item; (item = SLIST_POP(list, __VA_ARGS__));)
 
 /**
  * Initialize a doubly-linked list.
  *
- * @param list
+ * @list
  *         The list to initialize.
  */
 #define LIST_INIT(list) \
-	LIST_BLOCK_(LIST_INIT_((list)))
+	LIST_INIT_((list))
 
 #define LIST_INIT_(list) \
-	list->head = list->tail = NULL;
+	LIST_VOID_(list->head = list->tail = NULL)
+
+/**
+ * LIST_PREV_()     => prev
+ * LIST_PREV_(node) => node.prev
+ */
+#define LIST_PREV_(node) \
+	BFS_VA_IF(node)(node.prev)(prev)
+
+/**
+ * Initialize a doubly-linked list item.
+ *
+ * @item
+ *         The item to initialize.
+ * @node (optional)
+ *         If specified, use item->node.next rather than item->next.
+ */
+#define LIST_ITEM_INIT(item, ...) \
+	LIST_ITEM_INIT_((item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__))
+
+#define LIST_ITEM_INIT_(item, prev, next) \
+	LIST_VOID_(item->prev = item->next = NULL)
+
+/**
+ * Type-checking macro for doubly-linked lists.
+ */
+#define LIST_CHECK_(list) \
+	(void)sizeof(list->tail - list->head)
 
 /**
- * LIST_PREV_()       => prev
- * LIST_PREV_(node, ) => node.prev
+ * Check if a doubly-linked list is empty.
  */
-#define LIST_PREV_(...) LIST_NODE_(prev, __VA_ARGS__)
+#define LIST_EMPTY(list) \
+	(LIST_CHECK_(list), !(list)->head)
 
 /**
  * Add an item to the tail of a doubly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param item
+ * @item
  *         The item to append.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
  */
-#define LIST_APPEND(list, ...) LIST_INSERT(list, (list)->tail, __VA_ARGS__)
+#define LIST_APPEND(list, item, ...) \
+	LIST_INSERT(list, (list)->tail, item, __VA_ARGS__)
 
 /**
  * Add an item to the head of a doubly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param item
+ * @item
  *         The item to prepend.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
  */
-#define LIST_PREPEND(list, ...) LIST_INSERT(list, NULL, __VA_ARGS__)
+#define LIST_PREPEND(list, item, ...) \
+	LIST_INSERT(list, NULL, item, __VA_ARGS__)
+
+/**
+ * Check if an item is attached to a doubly-linked list.
+ *
+ * @list
+ *         The list to check.
+ * @item
+ *         The item to check.
+ * @node (optional)
+ *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
+ * @return
+ *         Whether the item is attached to the list.
+ */
+#define LIST_ATTACHED(list, item, ...) \
+	LIST_ATTACHED_((list), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__))
+
+#define LIST_ATTACHED_(list, item, prev, next) \
+	(item->prev || item->next || list->head == item || list->tail == item)
 
 /**
  * Insert into a doubly-linked list after the given cursor.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param cursor
+ * @cursor
  *         Insert after this element.
- * @param item
+ * @item
  *         The item to insert.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
  */
-#define LIST_INSERT(list, cursor, ...) LIST_INSERT_(list, cursor, __VA_ARGS__, )
+#define LIST_INSERT(list, cursor, item, ...) \
+	LIST_INSERT_((list), (cursor), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__))
 
-#define LIST_INSERT_(list, cursor, item, ...) \
-	LIST_BLOCK_(LIST_INSERT__((list), (cursor), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__)))
-
-#define LIST_INSERT__(list, cursor, item, prev, next) \
-	item->prev = cursor; \
-	item->next = cursor ? cursor->next : list->head; \
-	*(item->prev ? &item->prev->next : &list->head) = item; \
-	*(item->next ? &item->next->prev : &list->tail) = item;
+#define LIST_INSERT_(list, cursor, item, prev, next) LIST_VOID_( \
+	bfs_assert(!LIST_ATTACHED_(list, item, prev, next)), \
+	item->prev = cursor, \
+	item->next = cursor ? cursor->next : list->head, \
+	*(item->prev ? &item->prev->next : &list->head) = item, \
+	*(item->next ? &item->next->prev : &list->tail) = item)
 
 /**
  * Remove an item from a doubly-linked list.
  *
- * @param list
+ * @list
  *         The list to modify.
- * @param item
+ * @item
  *         The item to remove.
- * @param node (optional)
+ * @node (optional)
  *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
  */
-#define LIST_REMOVE(list, ...) LIST_REMOVE_(list, __VA_ARGS__, )
-
-#define LIST_REMOVE_(list, item, ...) \
-	LIST_BLOCK_(LIST_REMOVE__((list), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__)))
+#define LIST_REMOVE(list, item, ...) \
+	LIST_REMOVE_((list), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__))
 
-#define LIST_REMOVE__(list, item, prev, next) \
-	*(item->prev ? &item->prev->next : &list->head) = item->next; \
-	*(item->next ? &item->next->prev : &list->tail) = item->prev; \
-	item->prev = item->next = NULL;
+#define LIST_REMOVE_(list, item, prev, next) LIST_VOID_( \
+	*(item->prev ? &item->prev->next : &list->head) = item->next, \
+	*(item->next ? &item->next->prev : &list->tail) = item->prev, \
+	item->prev = item->next = NULL)
 
 /**
- * Check if an item is attached to a doubly-linked list.
- *
- * @param list
- *         The list to check.
- * @param item
- *         The item to check.
- * @param node (optional)
- *         If specified, use item->node.{prev,next} rather than item->{prev,next}.
- * @return
- *         Whether the item is attached to the list.
+ * Loop over the items in a doubly-linked list.
+ *
+ * @type
+ *         The list item type.
+ * @item
+ *         The induction variable name.
+ * @list
+ *         The list to iterate.
+ * @node (optional)
+ *         If specified, use head->node.next rather than head->next.
  */
-#define LIST_ATTACHED(list, ...) LIST_ATTACHED_(list, __VA_ARGS__, )
-
-#define LIST_ATTACHED_(list, item, ...) \
-	LIST_ATTACHED__((list), (item), LIST_PREV_(__VA_ARGS__), LIST_NEXT_(__VA_ARGS__))
+#define for_list(type, item, list, ...) \
+	for_list_(type, item, (list), LIST_NEXT_(__VA_ARGS__))
 
-#define LIST_ATTACHED__(list, item, prev, next) \
-	(item->prev || item->next || list->head == item || list->tail == item)
+#define for_list_(type, item, list, next) \
+	for (type *item = (LIST_CHECK_(list), list->head), *_next; \
+	     item && (_next = item->next, true); \
+	     item = _next)
 
 #endif // BFS_LIST_H