Avoid integer overflow while calculating max values

BZ: 134249

The behavior is undefined in the case of signed integer overflow
for enum and fixed point parameter types.

Modify the behavior to handle correctly the signed integers.

Change-Id: Idbd0798a39f826853ae1afcd05cebd897675b9a8
Signed-off-by: Dmitry Shkurko <Dmitry.V.Shkurko@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/parameter/ParameterType.h b/parameter/ParameterType.h
index d83dbce..ed30ac3 100644
--- a/parameter/ParameterType.h
+++ b/parameter/ParameterType.h
@@ -25,6 +25,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <limits>
 
 #include "TypeElement.h"
 
@@ -87,6 +88,15 @@ protected:
     // Remove all bits set outside available range
     uint32_t makeEncodable(uint32_t uiData) const;
 
+    /** Compute max value according to the parameter type */
+    template <typename type>
+    type getMaxValue() const
+    {
+        return getSize() < sizeof(type) ?
+                    (static_cast<type>(1) << (getSize() * numeric_limits<unsigned char>::digits - 1)) - 1 :
+                    numeric_limits<type>::max();
+    }
+
 private:
     // Instantiation
     virtual CInstanceConfigurableElement* doInstantiate() const;