[augeas-devel] [PATCH 1 of 4] Add list_reverse and list_tail_cons

[David Lutterkort]

1 file changed, 30 insertions(+)
src/list.h |   30 ++++++++++++++++++++++++++++++


# HG changeset patch
# User David Lutterkort <dlutter at redhat.com>
# Date 1218235118 25200
# Node ID 30fe26d31d9e9f7bd24539870f47727a8677ddd2
# Parent  10f6354c863e1feba41daa86e9d475c25007c0c2
Add list_reverse and list_tail_cons

list_reverse reverses a list in place. list_tail_cons appends to a list in
constant time, since it is given a pointer to the tail of the list.

diff -r 10f6354c863e -r 30fe26d31d9e src/list.h
--- a/src/list.h	Thu Aug 07 18:06:22 2008 -0700
+++ b/src/list.h	Fri Aug 08 15:38:38 2008 -0700
@@ -94,6 +94,36 @@
         (list) = _e;                                                    \
     } while(0)
 
+#define list_reverse(list)                                              \
+    do {                                                                \
+        typeof(list) _head = (list);                                    \
+        typeof(list) _prev = NULL;                                      \
+        while (_head != NULL) {                                         \
+            typeof(list) _next = _head->next;                           \
+            _head->next = _prev;                                        \
+            _prev = _head;                                              \
+            _head = _next;                                              \
+        }                                                               \
+        (list) = _prev;                                                 \
+    } while (0)
+
+/* Append ELT to the end of LIST. TAIL must be NULL or a pointer to
+   the last element of LIST
+*/
+#define list_tail_cons(list, tail, elt)                                 \
+    do {                                                                \
+        if ((list) == NULL) {                                           \
+            (list) = (elt);                                             \
+            (tail) = (list);                                            \
+        } else {                                                        \
+            if ((tail) == NULL)                                         \
+                for ((tail) = (list); (tail)->next != NULL;             \
+                     (tail) = (tail)->next);                            \
+            (tail)->next = (elt);                                       \
+            (tail) = (elt);                                             \
+        }                                                               \
+    } while(0)
+
 /*
  * Local variables:
  *  indent-tabs-mode: nil