Added hashing and string conversion interfaces

utils/include/utility/IHashable.h

@@ -0,0 +1,70 @@
+/* The MIT License (MIT)
+*
+* Copyright (c) 2014 Michael Crawford
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+* SOFTWARE.
+*/
+
+#ifndef IHASHABLE_H_INCLUDED__
+#define IHASHABLE_H_INCLUDED__
+
+#include "prereqs.h"
+
+namespace libutil
+{
+
+/**
+ * Provides an interface for any classes that support hashing.
+ */
+class IHashable
+{
+public:
+  virtual ~IHashable() = default;
+
+  /**
+   * Returns the hash of the object.
+   */
+  virtual std::size_t hash() const = 0;
+};
+
+}
+
+/**
+ * Generates specializations of std::hash and std::equal_to for a hashable 
+ * class, allowing them to be used with STL hashing containers.  There is no 
+ * way to declare a single specialization for these functors since template 
+ * containers are instantiated using the most derived type.
+ */
+#define HASHABLE_STL_HELPER_DECLARATION(hashable) \
+  namespace std { \
+    template<> \
+    struct hash<hashable> { \
+      size_t operator()(const hashable& h) { \
+        return h.hash(); \
+      } \
+    }; \
+    template<> \
+    struct equal_to<hashable> { \
+      bool operator()(const hashable& lhs, const hashable& rhs) { \
+        return lhs.hash() == rhs.hash(); \
+      } \
+    }; \
+  }
+
+#endif

utils/include/utility/IToString.h

@@ -0,0 +1,58 @@
+/* The MIT License (MIT)
+*
+* Copyright (c) 2014 Michael Crawford
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+* SOFTWARE.
+*/
+
+#ifndef ITOSTRING_H_INCLUDED__
+#define ITOSTRING_H_INCLUDED__
+
+#include "prereqs.h"
+#include <string>
+#include <ostream>
+
+namespace libutil
+{
+
+/**
+ * Provides an interface for any classes that are representable as strings.  
+ * Includes a stream insertion overload operator so that implementing classes 
+ * may be used with std::ostreams.
+ */
+class IToString
+{
+public:
+  virtual ~IToString() = default;
+
+  /**
+   * Returns a string representation of the object.
+   */
+  virtual std::string toString() const = 0;
+};
+
+}
+
+std::ostream& operator<<(std::ostream& os, const libutil::IToString& its)
+{
+  os << its.toString();
+  return os;
+}
+
+#endif

utils/utils.vcxproj

@@ -85,6 +85,8 @@
     <ClInclude Include="include\prereqs.h" />
     <ClInclude Include="include\debug.h" />
     <ClInclude Include="include\platform.h" />
+    <ClInclude Include="include\utility\IHashable.h" />
+    <ClInclude Include="include\utility\IToString.h" />
     <ClInclude Include="include\utility\Singleton.h" />
     <ClInclude Include="include\utility\Singularity.h" />
   </ItemGroup>

utils/utils.vcxproj.filters

@@ -62,6 +62,12 @@
     <ClInclude Include="include\log\StreamLogWriter.h">
       <Filter>Header Files\log</Filter>
     </ClInclude>
+    <ClInclude Include="include\utility\IHashable.h">
+      <Filter>Header Files\utility</Filter>
+    </ClInclude>
+    <ClInclude Include="include\utility\IToString.h">
+      <Filter>Header Files\utility</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="src\log\StreamLogWriter.cpp">