kmod_list: add helper function to merge two lists

This helper function will append the second list in the first one, so
they become one single list.

diff --git a/libkmod/libkmod-list.c b/libkmod/libkmod-list.c
index 2b7fc54..a297853 100644 (file)
--- a/libkmod/libkmod-list.c
+++ b/libkmod/libkmod-list.c
@@ -99,6 +99,26 @@ static inline void list_node_insert_before(struct list_node *list,
        list->prev = node;
 }
 
+static inline void list_node_append_list(struct list_node *list1,
+                                                       struct list_node *list2)
+{
+       struct list_node *list1_last;
+
+       if (list1 == NULL) {
+               list_node_init(list2);
+               return;
+       }
+
+       list1->prev->next = list2;
+       list2->prev->next = list1;
+
+       /* cache the last, because we will lose the pointer */
+       list1_last = list1->prev;
+
+       list1->prev = list2->prev;
+       list2->prev = list1_last;
+}
+
 struct kmod_list *kmod_list_append(struct kmod_list *list, const void *data)
 {
        struct kmod_list *new;
@@ -147,6 +167,17 @@ struct kmod_list *kmod_list_insert_before(struct kmod_list *list, const void *da
        return new;
 }
 
+struct kmod_list *kmod_list_append_list(struct kmod_list *list1,
+                                               struct kmod_list *list2)
+{
+       if (list1 == NULL)
+               return list2;
+
+       list_node_append_list(&list1->node, &list2->node);
+
+       return list1;
+}
+
 struct kmod_list *kmod_list_prepend(struct kmod_list *list, const void *data)
 {
        struct kmod_list *new;

diff --git a/libkmod/libkmod-private.h b/libkmod/libkmod-private.h
index 8e9e540..5479cc9 100644 (file)
--- a/libkmod/libkmod-private.h
+++ b/libkmod/libkmod-private.h
@@ -55,6 +55,7 @@ struct kmod_list *kmod_list_remove_n_latest(struct kmod_list *list,
                                                unsigned int n) __must_check;
 struct kmod_list *kmod_list_insert_after(struct kmod_list *list, const void *data) __attribute__((nonnull(2)));
 struct kmod_list *kmod_list_insert_before(struct kmod_list *list, const void *data) __attribute__((nonnull(2)));
+struct kmod_list *kmod_list_append_list(struct kmod_list *list1, struct kmod_list *list2) __must_check;
 
 #undef kmod_list_foreach
 #define kmod_list_foreach(list_entry, first_entry) \