erts: Segment allocator CircleQ API

1 files changed, 77 insertions, 0 deletions

diff --git a/erts/emulator/sys/common/erl_util_queue.h b/erts/emulator/sys/common/erl_util_queue.h
new file mode 100644
index 0000000000..47925e2264
--- /dev/null
+++ b/erts/emulator/sys/common/erl_util_queue.h
@@ -0,0 +1,77 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2013. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+#ifndef ERL_UTIL_QUEUE_H_
+#define ERL_UTIL_QUEUE_H_
+
+#define erts_circleq_head(Q)     ((Q)->next)
+#define erts_circleq_tail(Q)     ((Q)->prev)
+#define erts_circleq_next(Q)     ((Q)->next)
+#define erts_circleq_prev(Q)     ((Q)->prev)
+#define erts_circleq_is_empty(Q) ((Q)->next == (void *)(Q))
+
+#define erts_circleq_remove(N)        \
+    do {                              \
+        (N)->next->prev = (N)->prev;  \
+        (N)->prev->next = (N)->next;  \
+        (N)->next = (N);              \
+        (N)->prev = (N);              \
+    } while(0)
+
+#define erts_circleq_pop_head(Q, N)   \
+    do {                              \
+	(N) = (Q)->next;              \
+        (N)->next->prev = (N)->prev;  \
+        (N)->prev->next = (N)->next;  \
+        (N)->next = (N);              \
+        (N)->prev = (N);              \
+    } while(0)
+
+#define erts_circleq_pop_tail(Q, N)   \
+    do {                              \
+	(N) = (Q)->prev;              \
+        (N)->next->prev = (N)->prev;  \
+        (N)->prev->next = (N)->next;  \
+        (N)->next = (N);              \
+        (N)->prev = (N);              \
+    } while(0)
+
+#define erts_circleq_push_head(Q, N)  \
+    do {                              \
+        (N)->next = (Q)->next;        \
+        (N)->prev = (void *)(Q);      \
+        (Q)->next->prev = (N);        \
+        (Q)->next = (N);              \
+    } while(0)
+
+#define erts_circleq_push_tail(Q, N)  \
+    do {                              \
+        (N)->prev = (Q)->prev;        \
+        (N)->next = (void *)(Q);      \
+        (Q)->prev->next = (N);        \
+        (Q)->prev = (N);              \
+    } while(0)
+
+#define erts_circleq_foreach(V, Q) \
+    for ((V) = (Q)->next; (V) != (const void *)(Q); (V) = (V)->next)
+
+#define erts_circleq_foreach_reverse(V, Q) \
+    for ((V) = (Q)->prev; (V) != (const void *)(Q); (V) = (V)->prev)
+
+#endif