[libvirt] [PATCHv3 1/4] bitmap: add virBitmapCountBits
Sometimes it's handy to know how many bits are set.
* src/util/bitmap.h (virBitmapCountBits): New prototype.
(virBitmapNextSetBit): Use correct type.
* src/util/bitmap.c (virBitmapNextSetBit): Likewise.
(virBitmapCountBits): New function.
* src/libvirt_private.syms (bitmap.h): Export it.
* tests/virbitmaptest.c (test2): Test it.
---
src/libvirt_private.syms | 1 +
src/util/bitmap.c | 26 +++++++++++++++++++++++---
src/util/bitmap.h | 6 +++++-
tests/virbitmaptest.c | 7 +++++++
4 files changed, 36 insertions(+), 4 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 699c9a3..7a87f2b 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -9,6 +9,7 @@
virBitmapClearAll;
virBitmapClearBit;
virBitmapCopy;
+virBitmapCountBits;
virBitmapEqual;
virBitmapFormat;
virBitmapFree;
diff --git a/src/util/bitmap.c b/src/util/bitmap.c
index 2797005..9a9152a 100644
--- a/src/util/bitmap.c
+++ b/src/util/bitmap.c
@@ -35,6 +35,7 @@
#include "buf.h"
#include "util.h"
#include "c-ctype.h"
+#include "count-one-bits.h"
struct _virBitmap {
@@ -585,10 +586,10 @@ bool virBitmapIsAllSet(virBitmapPtr bitmap)
*
* returns the position of the found bit, or -1 if no bit found.
*/
-int virBitmapNextSetBit(virBitmapPtr bitmap, int pos)
+ssize_t virBitmapNextSetBit(virBitmapPtr bitmap, ssize_t pos)
{
- int nl;
- int nb;
+ size_t nl;
+ size_t nb;
unsigned long bits;
if (pos < 0)
@@ -613,3 +614,22 @@ int virBitmapNextSetBit(virBitmapPtr bitmap, int pos)
return ffsl(bits) - 1 + nl * VIR_BITMAP_BITS_PER_UNIT;
}
+
+/* Return the number of bits currently set in the map. */
+size_t
+virBitmapCountBits(virBitmapPtr bitmap)
+{
+ size_t i;
+ size_t ret = 0;
+ int tail = bitmap->max_bit % VIR_BITMAP_BITS_PER_UNIT;
+
+ /* Ensure tail bits are clear. */
+ if (tail)
+ bitmap->map[bitmap->map_len - 1] &=
+ -1UL >> (VIR_BITMAP_BITS_PER_UNIT - tail);
+
+ for (i = 0; i < bitmap->map_len; i++)
+ ret += count_one_bits_l(bitmap->map[i]);
+
+ return ret;
+}
diff --git a/src/util/bitmap.h b/src/util/bitmap.h
index 7755a17..346a1fb 100644
--- a/src/util/bitmap.h
+++ b/src/util/bitmap.h
@@ -1,6 +1,7 @@
/*
* bitmap.h: Simple bitmap operations
*
+ * Copyright (C) 2012 Red Hat, Inc.
* Copyright (C) 2010 Novell, Inc.
*
* This library is free software; you can redistribute it and/or
@@ -99,7 +100,10 @@ void virBitmapClearAll(virBitmapPtr bitmap)
bool virBitmapIsAllSet(virBitmapPtr bitmap)
ATTRIBUTE_NONNULL(1);
-int virBitmapNextSetBit(virBitmapPtr bitmap, int pos)
+ssize_t virBitmapNextSetBit(virBitmapPtr bitmap, ssize_t pos)
+ ATTRIBUTE_NONNULL(1);
+
+size_t virBitmapCountBits(virBitmapPtr bitmap)
ATTRIBUTE_NONNULL(1);
#endif
diff --git a/tests/virbitmaptest.c b/tests/virbitmaptest.c
index 0aa28fd..f1eb9d5 100644
--- a/tests/virbitmaptest.c
+++ b/tests/virbitmaptest.c
@@ -99,6 +99,9 @@ static int test2(const void *data ATTRIBUTE_UNUSED)
if (testBit(bitmap, 100, 1020, false) < 0)
goto error;
+ if (virBitmapCountBits(bitmap) != 48)
+ goto error;
+
bitsString2 = virBitmapFormat(bitmap);
if (strcmp(bitsString1, bitsString2))
goto error;
@@ -106,6 +109,8 @@ static int test2(const void *data ATTRIBUTE_UNUSED)
virBitmapSetAll(bitmap);
if (testBit(bitmap, 0, size - 1, true) < 0)
goto error;
+ if (virBitmapCountBits(bitmap) != size)
+ goto error;
if (!virBitmapIsAllSet(bitmap))
goto error;
@@ -113,6 +118,8 @@ static int test2(const void *data ATTRIBUTE_UNUSED)
virBitmapClearAll(bitmap);
if (testBit(bitmap, 0, size - 1, false) < 0)
goto error;
+ if (virBitmapCountBits(bitmap) != 0)
+ goto error;
ret = 0;
--
1.7.11.7