[Libguestfs] [PATCH nbdkit 2/3] common: Introduce round up, down; and divide round up functions.
Richard W.M. Jones
rjones at redhat.com
Mon Sep 17 15:01:24 UTC 2018
These are used at various places in the code already. This
refactoring simply moves them to a common header file and should have
no other effect.
---
common/include/rounding.h | 63 +++++++++++++++++++++++++++++++++++++
filters/cache/Makefile.am | 3 +-
filters/cache/cache.c | 2 +-
filters/cow/Makefile.am | 3 +-
filters/cow/cow.c | 2 +-
filters/truncate/truncate.c | 5 +--
6 files changed, 72 insertions(+), 6 deletions(-)
diff --git a/common/include/rounding.h b/common/include/rounding.h
new file mode 100644
index 0000000..bb07c79
--- /dev/null
+++ b/common/include/rounding.h
@@ -0,0 +1,63 @@
+/* nbdkit
+ * Copyright (C) 2018 Red Hat Inc.
+ * All rights reserved.
+ *
+ * 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 Red Hat 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 RED HAT 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 RED HAT 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 NBDKIT_ROUNDING_H
+#define NBDKIT_ROUNDING_H
+
+#include <stdint.h>
+#include <assert.h>
+
+#include "ispowerof2.h"
+
+/* Round up I to next multiple of N (N must be a power of 2). Note
+ * that I is the name of a variable, and the result is returned in I.
+ */
+#define ROUND_UP(I, N) \
+ do { \
+ assert (is_power_of_2 (N)); \
+ I = (I + (N) - 1) & ~((N) - 1); \
+ } while (0)
+
+/* Round down I to next multiple of N (N must be a power of 2). Note
+ * that I is the name of a variable, and the result is returned in I.
+ */
+#define ROUND_DOWN(I, N) \
+ do { \
+ assert (is_power_of_2 (N)); \
+ I &= ~((N) - 1); \
+ } while (0)
+
+/* Return n / d, rounding the result up to the next integer. */
+#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+
+#endif /* NBDKIT_ROUNDING_H */
diff --git a/filters/cache/Makefile.am b/filters/cache/Makefile.am
index 867812e..827ff17 100644
--- a/filters/cache/Makefile.am
+++ b/filters/cache/Makefile.am
@@ -41,7 +41,8 @@ nbdkit_cache_filter_la_SOURCES = \
$(top_srcdir)/include/nbdkit-filter.h
nbdkit_cache_filter_la_CPPFLAGS = \
- -I$(top_srcdir)/include
+ -I$(top_srcdir)/include \
+ -I$(top_srcdir)/common/include
nbdkit_cache_filter_la_CFLAGS = \
$(WARNINGS_CFLAGS)
nbdkit_cache_filter_la_LDFLAGS = \
diff --git a/filters/cache/cache.c b/filters/cache/cache.c
index 90a0444..6ae6a4a 100644
--- a/filters/cache/cache.c
+++ b/filters/cache/cache.c
@@ -52,7 +52,7 @@
#include <nbdkit-filter.h>
-#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+#include "rounding.h"
/* XXX See design comment in filters/cow/cow.c. */
#define THREAD_MODEL NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS
diff --git a/filters/cow/Makefile.am b/filters/cow/Makefile.am
index 778df1e..c81b41c 100644
--- a/filters/cow/Makefile.am
+++ b/filters/cow/Makefile.am
@@ -41,7 +41,8 @@ nbdkit_cow_filter_la_SOURCES = \
$(top_srcdir)/include/nbdkit-filter.h
nbdkit_cow_filter_la_CPPFLAGS = \
- -I$(top_srcdir)/include
+ -I$(top_srcdir)/include \
+ -I$(top_srcdir)/common/include
nbdkit_cow_filter_la_CFLAGS = \
$(WARNINGS_CFLAGS)
nbdkit_cow_filter_la_LDFLAGS = \
diff --git a/filters/cow/cow.c b/filters/cow/cow.c
index 5df1db2..001d5bf 100644
--- a/filters/cow/cow.c
+++ b/filters/cow/cow.c
@@ -89,7 +89,7 @@
#include <nbdkit-filter.h>
-#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+#include "rounding.h"
/* XXX See design comment above. */
#define THREAD_MODEL NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS
diff --git a/filters/truncate/truncate.c b/filters/truncate/truncate.c
index 185f6cc..94c748b 100644
--- a/filters/truncate/truncate.c
+++ b/filters/truncate/truncate.c
@@ -46,6 +46,7 @@
#include "ispowerof2.h"
#include "iszero.h"
+#include "rounding.h"
#define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL
@@ -157,9 +158,9 @@ truncate_get_size (struct nbdkit_next_ops *next_ops, void *nxdata,
if (truncate_size >= 0)
size = truncate_size;
if (round_up > 0)
- size = (size + round_up - 1) & ~(round_up - 1);
+ ROUND_UP (size, round_up);
if (round_down > 0)
- size &= ~(round_down - 1);
+ ROUND_DOWN (size, round_down);
ret = size;
pthread_mutex_unlock (&lock);
--
2.19.0.rc0
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