Handle amend of mapping values at PFW level

BZ: 24271

Amend mechanism can be used by various plugins, right now it is
implemented in alsa one.

Move this implementation in the PFW for all plugin to benefit
from this mechanism.

Change-Id: I3f193a732b00586c52303390f353fea00f4ce8ec
Signed-off-by: Guillaume Denneulin <guillaumex.denneulin@intel.com>
Reviewed-on: http://android.intel.com:8080/35905
Reviewed-by: Barthes, FabienX <fabienx.barthes@intel.com>
Tested-by: Barthes, FabienX <fabienx.barthes@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>
diff --git a/parameter/SubsystemObject.h b/parameter/SubsystemObject.h
index 711d9d1..d08f3c4 100644
--- a/parameter/SubsystemObject.h
+++ b/parameter/SubsystemObject.h
@@ -34,6 +34,7 @@
 #include <stdint.h>
 
 class CInstanceConfigurableElement;
+class CMappingContext;
 
 class CSubsystemObject : public ISyncer
 {
@@ -63,6 +64,9 @@
     void blackboardWrite(const void* pvData, uint32_t uiSize);
     // Logging
     void log(const string& strMessage, ...) const;
+    // Mapping formatting
+    static string formatMappingValue(const string& strMappingValue, uint32_t uiFirstAmendKey, uint32_t uiNbAmendKeys, const CMappingContext& context);
+
 private:
     // Instance element to sync from/to
     CInstanceConfigurableElement* _pInstanceConfigurableElement;