libbb: shrink linked list ops (by xmaks AT email.cz)

function                                             old     new   delta
llist_pop                                             33      29      -4
llist_unlink                                          47      28     -19
llist_add_to_end                                      50      31     -19
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-42)             Total: -42 bytes

1 files changed, 18 insertions, 36 deletions

diff --git a/libbb/llist.c b/libbb/llist.c
index 7e78f7cb4..5ba7f6047 100644
--- a/libbb/llist.c
+++ b/libbb/llist.c
@@ -25,56 +25,38 @@ void FAST_FUNC llist_add_to(llist_t **old_head, void *data)
 /* Add data to the end of the linked list.  */
 void FAST_FUNC llist_add_to_end(llist_t **list_head, void *data)
 {
-        llist_t *new_item = xmalloc(sizeof(llist_t));
-
-        new_item->data = data;
-        new_item->link = NULL;
-
-        if (!*list_head)
-                *list_head = new_item;
-        else {
-                llist_t *tail = *list_head;
-
-                while (tail->link)
-                        tail = tail->link;
-                tail->link = new_item;
-        }
+        while (*list_head)
+                list_head = &(*list_head)->link;
+        *list_head = xzalloc(sizeof(llist_t));
+        (*list_head)->data = data;
+        /*(*list_head)->link = NULL;*/
 }
 
 /* Remove first element from the list and return it */
 void* FAST_FUNC llist_pop(llist_t **head)
 {
-        void *data, *next;
-
-        if (!*head)
-                return NULL;
-
-        data = (*head)->data;
-        next = (*head)->link;
-        free(*head);
-        *head = next;
+        void *data = NULL;
+        llist_t *temp = *head;
 
+        if (temp) {
+                data = temp->data;
+                *head = temp->link;
+                free(temp);
+        }
         return data;
 }
 
 /* Unlink arbitrary given element from the list */
 void FAST_FUNC llist_unlink(llist_t **head, llist_t *elm)
 {
-        llist_t *crt;
-
-        if (!(elm && *head))
-                return;
-
-        if (elm == *head) {
-                *head = (*head)->link;
+        if (!elm)
                 return;
-        }
-
-        for (crt = *head; crt; crt = crt->link) {
-                if (crt->link == elm) {
-                        crt->link = elm->link;
-                        return;
+        while (*head) {
+                if (*head == elm) {
+                        *head = (*head)->link;
+                        break;
                 }
+                head = &(*head)->link;
         }
 }