From c1b79eb035fa158fb2ac3bc8e559809611070016 Mon Sep 17 00:00:00 2001
From: Yaniv Kamay <ykamay@redhat.com>
Date: Sat, 19 Sep 2009 21:25:46 +0300
Subject: fresh start

---
 common/ipc_ring.h | 135 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 common/ipc_ring.h

(limited to 'common/ipc_ring.h')

diff --git a/common/ipc_ring.h b/common/ipc_ring.h
new file mode 100644
index 00000000..1d9b3e1e
--- /dev/null
+++ b/common/ipc_ring.h
@@ -0,0 +1,135 @@
+/*
+   Copyright (C) 2009 Red Hat, Inc.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in
+         the documentation and/or other materials provided with the
+         distribution.
+       * Neither the name of the copyright holder nor the names of its
+         contributors may be used to endorse or promote products derived
+         from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS
+   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#ifndef _H_RING_
+#define _H_RING_
+
+
+#define MSB_MASK4(x)        \
+    (((x) & 0x8) ? 0x8 :    \
+     ((x) & 0x4) ? 0x4 :    \
+     ((x) & 0x2) ? 0x2 :    \
+     ((x) & 0x1) ? 0x1 : 0)
+
+#define MSB_MASK8(x) \
+    (((x) & 0xf0) ? MSB_MASK4((x) >> 4) << 4 : MSB_MASK4(x))
+
+#define MSB_MASK16(x) \
+    (((x) & 0xff00) ? MSB_MASK8((x) >> 8) << 8 : MSB_MASK8(x))
+
+#define MSB_MASK(x) \
+    (((x) & 0xffff0000) ? MSB_MASK16((x) >> 16) << 16 : MSB_MASK16(x))
+
+#define POWER2_ALIGN(x) MSB_MASK((x) * 2 - 1)
+
+
+#define _TOSHIFT_4(x)      \
+    (((x) & 0x8) ? 3 :     \
+     ((x) & 0x4) ? 2 :     \
+     ((x) & 0x2) ? 1 : 0)
+
+#define _TOSHIFT_8(x) \
+    (((x) & 0xf0) ? _TOSHIFT_4((x) >> 4) + 4 : _TOSHIFT_4(x))
+
+#define _TOSHIFT_16(x) \
+    (((x) & 0xff00) ? _TOSHIFT_8((x) >> 8) + 8 : _TOSHIFT_8(x))
+
+#define PAWER2_TO_SHIFT(x) \
+    (((x) & 0xffff0000) ? _TOSHIFT_16((x) >> 16) + 16 : _TOSHIFT_16(x))
+
+
+
+#define RING_DECLARE(name, el_type, size)               \
+typedef struct ATTR_PACKED name##_ring_el {             \
+    union {                                             \
+        el_type el;                                     \
+        UINT8 data[POWER2_ALIGN(sizeof(el_type))];      \
+    } ;                                                 \
+} name##_ring_el;                                       \
+                                                        \
+typedef struct ATTR_PACKED name {                       \
+    UINT32 num_items;                                   \
+    UINT32 prod;                                        \
+    UINT32 notify_on_prod;                              \
+    UINT32 cons;                                        \
+    UINT32 notify_on_cons;                              \
+    name##_ring_el items[POWER2_ALIGN(size)];           \
+} name;
+
+
+#define RING_INIT(r)                                                \
+    (r)->num_items = sizeof((r)->items) >>                          \
+                        PAWER2_TO_SHIFT(sizeof((r)->items[0]));     \
+    (r)->prod = (r)->cons = 0;                                      \
+    (r)->notify_on_prod = 1;                                        \
+    (r)->notify_on_cons = 0;
+
+
+#define RING_INDEX_MASK(r) ((r)->num_items - 1)
+
+#define RING_IS_PACKED(r) (sizeof((r)->items[0]) == sizeof((r)->items[0]).el)
+
+#define RING_IS_EMPTY(r) ((r)->cons == (r)->prod)
+
+#define RING_IS_FULL(r) (((r)->prod - (r)->cons) == (r)->num_items)
+
+#define RING_PROD_ITEM(r) (&(r)->items[(r)->prod & RING_INDEX_MASK(r)].el)
+
+#define RING_PROD_WAIT(r, wait)                 \
+    if (((wait) = RING_IS_FULL(r))) {           \
+        (r)->notify_on_cons = (r)->cons + 1;    \
+        mb();	                                \
+        (wait) = RING_IS_FULL(r);               \
+    }
+
+#define RING_PUSH(r, notify)                    \
+    (r)->prod++;                                \
+    mb();                                       \
+    (notify) = (r)->prod == (r)->notify_on_prod;
+
+
+#define RING_CONS_ITEM(r) (&(r)->items[(r)->cons & RING_INDEX_MASK(r)].el)
+
+#define RING_CONS_WAIT(r, wait)                 \
+    if (((wait) = RING_IS_EMPTY(r))) {          \
+        (r)->notify_on_prod = (r)->prod + 1;    \
+        mb();                                   \
+        (wait) = RING_IS_EMPTY(r);              \
+    }
+
+#define RING_POP(r, notify)                         \
+    (r)->cons++;                                    \
+    mb();                                           \
+    (notify) = (r)->cons == (r)->notify_on_cons;
+
+
+
+#endif
-- 
cgit