fanf 00/09/08 23:13:51
Modified: src/include ap_ring.h
Log:
some improvements to the commentary
Revision Changes Path
1.5 +9 -6 apache-2.0/src/include/ap_ring.h
Index: ap_ring.h
===================================================================
RCS file: /home/cvs/apache-2.0/src/include/ap_ring.h,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -u -r1.4 -r1.5
--- ap_ring.h 2000/09/09 01:11:14 1.4
+++ ap_ring.h 2000/09/09 06:13:50 1.5
@@ -71,7 +71,8 @@
#include <stddef.h>
/*
- * A ring is a kind of doubly-linked list.
+ * A ring is a kind of doubly-linked list that can be manipulated
+ * without knowing where its head is.
*/
/*
@@ -119,9 +120,9 @@
* elements in the ring, computed from the address of the ring's head.
*
* Note that for strict C standards compliance you should put the
- * AP_RING_ENTRY first in struct elem_tag unless the head is always
- * part of a larger object with enough earlier fields to accommodate
- * the offsetof() computed below. You can usually ignore this caveat.
+ * AP_RING_ENTRY first in struct elem unless the head is always part
+ * of a larger object with enough earlier fields to accommodate the
+ * offsetof() computed below. You can usually ignore this caveat.
*/
#define AP_RING_SENTINEL(hp, elem, link) \
(struct elem *)((char *)(hp) - offsetof(struct elem, link))
@@ -175,6 +176,10 @@
#define AP_RING_INSERT_AFTER(lep, nep, link) \
AP_RING_SPLICE_AFTER((lep), (nep), (nep), link)
+/*
+ * These macros work when the ring is empty: inserting before the head
+ * or after the tail of an empty ring using the macros above doesn't work.
+ */
#define AP_RING_SPLICE_HEAD(hp, ep1, epN, elem, link)
\
AP_RING_SPLICE_AFTER(AP_RING_SENTINEL((hp), elem, link), \
(ep1), (epN), link)
@@ -191,8 +196,6 @@
/*
* Concatenating ring h2 onto the end of ring h1 leaves h2 empty.
- *
- * Doing this without asking for the element type is ugly.
*/
#define AP_RING_CONCAT(h1, h2, elem, link) do {
\
if (!AP_RING_EMPTY((h2), elem, link)) { \
