Add HasClassRegistry static method deregisterType.

This clears registration of that class under any name or alias.

Author: pavoljuhas

src/diffpy/HasClassRegistry.hpp

@@ -55,12 +55,17 @@ class HasClassRegistry
 
         // methods provided by HasClassRegistry
 
-        /// Add a prototype of this instance to the registry
+        /// Add a prototype of this instance to the registry.
         virtual bool registerThisType() const;
 
-        /// Make registered type tp available under a different alias
+        /// Make registered type tp available under a different alias.
         static bool aliasType(const std::string& tp, const std::string& al);
 
+        /// Clear registration of the specified type under its standard name
+        /// or any alias.  Return the number of unset names and aliases or
+        /// 0 if the specifed string type was not registered.
+        static int deregisterType(const std::string& tp);
+
         /// Create new instance of a specified string type.
         static SharedPtr createByType(const std::string& tp);
 

src/diffpy/HasClassRegistry.ipp

@@ -77,6 +77,27 @@ bool HasClassRegistry<TBase>::aliasType(const std::string& tp,
 }
 
 
+template <class TBase>
+int HasClassRegistry<TBase>::deregisterType(const std::string& tp)
+{
+    RegistryStorage& reg = getRegistry();
+    typename RegistryStorage::iterator ii = reg.find(tp);
+    if (ii == reg.end())  return 0;
+    SharedPtr p = ii->second;
+    int rv = 0;
+    for (ii = reg.begin(); ii != reg.end();)
+    {
+        typename RegistryStorage::iterator jj = ii++;
+        if (jj->second == p)
+        {
+            reg.erase(jj);
+            ++rv;
+        }
+    }
+    return rv;
+}
+
+
 template <class TBase>
 typename HasClassRegistry<TBase>::SharedPtr
 HasClassRegistry<TBase>::createByType(const std::string& tp)

src/tests/TestHasClassRegistry.hpp

@@ -43,6 +43,25 @@ class TestHasClassRegistry : public CxxTest::TestSuite
             mpreg = msftb.get();
         }
 
+        void tearDown()
+        {
+            // restore SFTXray registration if removed in some test.
+            msftb->registerThisType();
+            TS_ASSERT(ScatteringFactorTable::isRegisteredType("X"));
+            TS_ASSERT(ScatteringFactorTable::isRegisteredType("xray"));
+        }
+
+
+        void test_deregisterType()
+        {
+            TS_ASSERT_EQUALS(0,
+                    ScatteringFactorTable::deregisterType("invalid"));
+            TS_ASSERT_EQUALS(2,
+                    ScatteringFactorTable::deregisterType("X"));
+            TS_ASSERT(!(mpreg->isRegisteredType("xray")));
+            TS_ASSERT(!(mpreg->isRegisteredType("X")));
+        }
+
 
         void test_isRegisteredType()
         {