Resources/ResourceKeyTraits.hpp

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//
// Thor C++ Library
// Copyright (c) 2011-2012 Jan Haller
// 
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// 
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would be
//    appreciated but is not required.
// 
// 2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
// 
// 3. This notice may not be removed or altered from any source distribution.
//


#ifndef THOR_RESOURCEKEYTRAITS_HPP
#define THOR_RESOURCEKEYTRAITS_HPP

#include <Thor/Config.hpp>
#include <Thor/Detail/Metaprogramming.hpp>

#include <string>


namespace sf
{

    class Image;
    class Texture;
    class Font;
    class Shader;
    class Music;
    class SoundBuffer;

    class InputStream;

} // namespace sf


namespace thor
{   
namespace Resources
{

    class ImageKey;
    class TextureKey;
    class FontKey;
    class ShaderKey;
    class SoundBufferKey;
    class MusicKey;

} // namespace Resources
} // namespace thor

// ---------------------------------------------------------------------------------------------------------------------------


namespace thor
{


namespace Resources
{

    template <class Resource>
    struct KeyTraits;

} // namespace Resources


#define THOR_MAP_RESOURCEKEY(Resource, ResourceKey)     \
namespace thor                                          \
{                                                       \
namespace Resources                                     \
{                                                       \
    template <>                                         \
    struct KeyTraits< Resource >                        \
    {                                                   \
        typedef ResourceKey Type;                       \
    };                                                  \
}                                                       \
} 


} // namespace thor

// Map SFML resources to built-in keys
THOR_MAP_RESOURCEKEY(sf::Image,         ImageKey)
THOR_MAP_RESOURCEKEY(sf::Texture,       TextureKey)
THOR_MAP_RESOURCEKEY(sf::Font,          FontKey)
THOR_MAP_RESOURCEKEY(sf::Shader,        ShaderKey)
THOR_MAP_RESOURCEKEY(sf::SoundBuffer,   SoundBufferKey)
THOR_MAP_RESOURCEKEY(sf::Music,         MusicKey)

// ---------------------------------------------------------------------------------------------------------------------------


// Helper functions to access key strings
namespace thor
{
namespace detail
{
    // Class to access the strings of resource keys
    struct KeyInfoAccessor
    {
        // Resource key string accessors for built-in keys
        template <class Key>
        static const std::string& Get(const Key& key, Int2Type<true>)
        {
            return key.mKey;
        }

        // Resource key string accessors for other keys
        template <class Key>
        static const std::string& Get(const Key&, Int2Type<false>)
        {
            static const std::string emptyString = "";
            return emptyString;
        }
    };

    // Access the resource key string
    template <class Key>
    const std::string& GetKeyInfo(const Key& key)
    {
        using std::tr1::is_same;

        const bool builtin =
            is_same<Key, Resources::ImageKey>::value
         || is_same<Key, Resources::TextureKey>::value
         || is_same<Key, Resources::FontKey>::value
         || is_same<Key, Resources::ShaderKey>::value
         || is_same<Key, Resources::SoundBufferKey>::value
         || is_same<Key, Resources::MusicKey>::value;

        return KeyInfoAccessor::Get(key, Int2Type<builtin>());
    }

} // namespace detail
} // namespace thor

#endif // THOR_RESOURCEKEYTRAITS_HPP