External/libvirt
1
0
Fork 0
mirror of https://gitlab.com/libvirt/libvirt.git synced 2025-01-22 04:25:18 +00:00
Code Issues Packages Projects Releases Wiki Activity

internal: add macro to round value to the next closest power of 2

Browse Source 
There are two special cases, if the input number is 0 or the number is
larger then 2^31 (for 32bit unsigned int). For the special cases the
return value is 0 because they cannot be rounded.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
This commit is contained in:
Pavel Hrdina 2014-11-18 17:13:38 +01:00
parent 3a04f73997
commit ff28ebf136
3 changed files with 47 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
bootstrap.conf
View File

@ -35,6 +35,7 @@ clock-time
close close
connect connect
configmake configmake
count-leading-zeros
count-one-bits count-one-bits
crypto/md5 crypto/md5
crypto/sha256 crypto/sha256

7
src/internal.h
View File

@ -62,6 +62,7 @@
# include "c-strcase.h" # include "c-strcase.h"
# include "ignore-value.h" # include "ignore-value.h"
# include "count-leading-zeros.h"
/* On architectures which lack these limits, define them (ie. Cygwin). /* On architectures which lack these limits, define them (ie. Cygwin).
* Note that the libvirt code should be robust enough to handle the * Note that the libvirt code should be robust enough to handle the
@ -382,6 +383,12 @@
/* round up value to the closest multiple of size */ /* round up value to the closest multiple of size */
# define VIR_ROUND_UP(value, size) (VIR_DIV_UP(value, size) * (size)) # define VIR_ROUND_UP(value, size) (VIR_DIV_UP(value, size) * (size))
/* Round up to the next closest power of 2. It will return rounded number or 0
* for 0 or number more than 2^31 (for 32bit unsigned int). */
# define VIR_ROUND_UP_POWER_OF_TWO(value) \
((value) > 0 && (value) <= 1U << (sizeof(unsigned int) * 8 - 1) ? \
1U << (sizeof(unsigned int) * 8 - count_leading_zeros((value) - 1)) : 0)
/* Specific error values for use in forwarding programs such as /* Specific error values for use in forwarding programs such as
* virt-login-shell; these values match what GNU env does. */ * virt-login-shell; these values match what GNU env does. */

39
tests/utiltest.c
View File

@ -143,6 +143,44 @@ testParseVersionString(const void *data ATTRIBUTE_UNUSED)
struct testRoundData {
unsigned int input;
unsigned int output;
};
static struct testRoundData roundData[] = {
{ 0, 0 },
{ 1, 1 },
{ 1000, 1024 },
{ 1024, 1024 },
{ 1025, 2048 },
{ UINT_MAX, 0 },
};
static int
testRoundValueToPowerOfTwo(const void *data ATTRIBUTE_UNUSED)
{
unsigned int result;
size_t i;
for (i = 0; i < ARRAY_CARDINALITY(roundData); i++) {
result = VIR_ROUND_UP_POWER_OF_TWO(roundData[i].input);
if (roundData[i].output != result) {
if (virTestGetDebug() > 0) {
fprintf(stderr, "\nInput number [%u]\n", roundData[i].input);
fprintf(stderr, "Expected number [%u]\n", roundData[i].output);
fprintf(stderr, "Actual number [%u]\n", result);
}
return -1;
}
}
return 0;
}
static int static int
mymain(void) mymain(void)
@ -162,6 +200,7 @@ mymain(void)
DO_TEST(IndexToDiskName); DO_TEST(IndexToDiskName);
DO_TEST(DiskNameToIndex); DO_TEST(DiskNameToIndex);
DO_TEST(ParseVersionString); DO_TEST(ParseVersionString);
DO_TEST(RoundValueToPowerOfTwo);
return result == 0 ? EXIT_SUCCESS : EXIT_FAILURE; return result == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
} }