virutil: introduce helper functions for memory limits

The first one is to truncate the memory limit to
VIR_DOMAIN_MEMORY_PARAM_UNLIMITED if the value is greater and the second
one is to decide whether the memory limit is set or not, unlimited means
that it's not set.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

src/libvirt_private.syms

@@ -2270,6 +2270,8 @@ virIsCapableVport;
 virIsDevMapperDevice;
 virIsSUID;
 virManageVport;
+virMemoryLimitIsSet;
+virMemoryLimitTruncate;
 virParseNumber;
 virParseOwnershipIds;
 virParseVersionString;

src/util/virutil.c

@@ -2598,3 +2598,27 @@ long virGetSystemPageSizeKB(void)
         return val;
     return val / 1024;
 }
+
+/**
+ * virMemoryLimitTruncate
+ *
+ * Return truncated memory limit to VIR_DOMAIN_MEMORY_PARAM_UNLIMITED as maximum
+ * which means that the limit is not set => unlimited.
+ */
+unsigned long long
+virMemoryLimitTruncate(unsigned long long value)
+{
+    return value < VIR_DOMAIN_MEMORY_PARAM_UNLIMITED ? value :
+        VIR_DOMAIN_MEMORY_PARAM_UNLIMITED;
+}
+
+/**
+ * virMemoryLimitIsSet
+ *
+ * Returns true if the limit is set and false for unlimited value.
+ */
+bool
+virMemoryLimitIsSet(unsigned long long value)
+{
+    return value < VIR_DOMAIN_MEMORY_PARAM_UNLIMITED;
+}

src/util/virutil.h

@@ -247,4 +247,7 @@ unsigned int virGetListenFDs(void);
 long virGetSystemPageSize(void);
 long virGetSystemPageSizeKB(void);
 
+unsigned long long virMemoryLimitTruncate(unsigned long long value);
+bool virMemoryLimitIsSet(unsigned long long value);
+
 #endif /* __VIR_UTIL_H__ */