lib: add linked list abstraction

kernel-src/include/list.h

@@ -0,0 +1,84 @@
+#ifndef _LIST_H
+#define _LIST_H
+
+#include <stddef.h>
+
+typedef struct _list_node {
+    struct _list_node *prev;
+    struct _list_node *next;
+} list_node_t;
+
+typedef struct {
+    list_node_t *head;
+    list_node_t *tail;
+} list_t;
+
+#define LIST_INIT_VALUE ((list_t){.head = NULL, .tail = NULL})
+
+static inline void list_init(list_t *list) {
+    list->head = NULL;
+    list->tail = NULL;
+}
+
+static inline void list_push_front(list_t *list, list_node_t *node) {
+    node->prev = NULL;
+    node->next = list->head;
+    if (list->head != NULL) {
+        list->head->prev = node;
+    } else {
+        list->tail = node;
+    }
+    list->head = node;
+}
+
+static inline void list_push_back(list_t *list, list_node_t *node) {
+    node->next = NULL;
+    node->prev = list->tail;
+    if (list->tail != NULL) {
+        list->tail->next = node;
+    } else {
+        list->head = node;
+    }
+    list->tail = node;
+}
+
+static inline void list_remove(list_t *list, list_node_t *node) {
+    if (node->prev != NULL) {
+        node->prev->next = node->next;
+    } else {
+        list->head = node->next;
+    }
+    if (node->next != NULL) {
+        node->next->prev = node->prev;
+    } else {
+        list->tail = node->prev;
+    }
+    node->prev = NULL;
+    node->next = NULL;
+}
+
+static inline list_node_t* list_pop_front(list_t *list) {
+    if (list->head == NULL) {
+        return NULL;
+    }
+    list_node_t *node = list->head;
+    list_remove(list, node);
+    return node;
+}
+
+static inline list_node_t* list_pop_back(list_t *list) {
+    if (list->tail == NULL) {
+        return NULL;
+    }
+    list_node_t *node = list->tail;
+    list_remove(list, node);
+    return node;
+}
+
+#define list_for_each(LIST, ITER) \
+    for (list_node_t *ITER = (LIST)->head; ITER != NULL; ITER = ITER->next)
+
+#define list_for_each_safe(LIST, ITER) \
+	for (list_node_t *ITER = (LIST)->head, *_next = (ITER ? ITER->next : NULL); ITER != NULL; ITER = _next, _next = (ITER ? ITER->next : NULL))
+
+#endif