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

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>

tests/utiltest.c

@@ -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
 mymain(void)
@@ -162,6 +200,7 @@ mymain(void)
     DO_TEST(IndexToDiskName);
     DO_TEST(DiskNameToIndex);
     DO_TEST(ParseVersionString);
+    DO_TEST(RoundValueToPowerOfTwo);
 
     return result == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }