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/*
* Copyright (C) 2010 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef APIClient_h
#define APIClient_h
#include <algorithm>
#include <array>
#include <tuple>
namespace API {
template<typename ClientInterface> struct ClientTraits;
template<typename ClientInterface> class Client {
typedef typename ClientTraits<ClientInterface>::Versions ClientVersions;
static const int latestClientVersion = std::tuple_size<ClientVersions>::value - 1;
typedef typename std::tuple_element<latestClientVersion, ClientVersions>::type LatestClientInterface;
// Helper class that can return an std::array of element sizes in a tuple.
template<typename> struct InterfaceSizes;
template<typename... Interfaces> struct InterfaceSizes<std::tuple<Interfaces...>> {
static std::array<size_t, sizeof...(Interfaces)> sizes()
{
return { { sizeof(Interfaces)... } };
}
};
public:
Client()
{
#if ASSERT_ENABLED
auto interfaceSizes = InterfaceSizes<ClientVersions>::sizes();
ASSERT(std::is_sorted(interfaceSizes.begin(), interfaceSizes.end()));
#endif
initialize(nullptr);
}
void initialize(const ClientInterface* client)
{
if (client && client->version == latestClientVersion) {
m_client = *reinterpret_cast<const LatestClientInterface*>(client);
return;
}
memset(&m_client, 0, sizeof(m_client));
if (client && client->version < latestClientVersion) {
auto interfaceSizes = InterfaceSizes<ClientVersions>::sizes();
memcpy(&m_client, client, interfaceSizes[client->version]);
}
}
const LatestClientInterface& client() const { return m_client; }
protected:
LatestClientInterface m_client;
};
} // namespace API
#endif // APIClient_h
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