FairMQ/fairmq/MemoryResourceTools.h
2022-01-24 06:40:24 +01:00

66 lines
2.7 KiB
C++

/********************************************************************************
* Copyright (C) 2018 CERN and copyright holders of ALICE O2 *
* Copyright (C) 2018 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH *
* *
* This software is distributed under the terms of the *
* GNU Lesser General Public Licence (LGPL) version 3, *
* copied verbatim in the file "LICENSE" *
********************************************************************************/
/// @brief Tools for interfacing containers to the transport via polymorphic
/// allocators
///
/// @author Mikolaj Krzewicki, mkrzewic@cern.ch
#include <fairmq/TransportFactory.h>
#include <fairmq/MemoryResources.h>
namespace fair::mq
{
using BytePmrAllocator = pmr::polymorphic_allocator<fair::mq::byte>;
//_________________________________________________________________________________________________
// return the message associated with the container or throw if it is not possible
template<typename ContainerT>
// typename std::enable_if<
// std::is_base_of<
// pmr::polymorphic_allocator<typename
// ContainerT::value_type>,
// typename ContainerT::allocator_type>::value == true,
// MessagePtr>::type
MessagePtr getMessage(ContainerT &&container_, MemoryResource *targetResource = nullptr)
{
auto container = std::move(container_);
auto alloc = container.get_allocator();
auto resource = dynamic_cast<MemoryResource *>(alloc.resource());
if (!resource && !targetResource) {
throw std::runtime_error("Neither the container or target resource specified");
}
size_t containerSizeBytes = container.size() * sizeof(typename ContainerT::value_type);
if ((!targetResource && resource)
|| (resource && targetResource && resource->is_equal(*targetResource))) {
auto message = resource->getMessage(static_cast<void *>(
const_cast<typename std::remove_const<typename ContainerT::value_type>::type *>(
container.data())));
if (message)
{
message->SetUsedSize(containerSizeBytes);
return message;
} else {
//container is not required to allocate (like in std::string small string optimization)
//in case we get no message we fall back to default (copy) behaviour)
targetResource = resource;
}
}
auto message = targetResource->getTransportFactory()->CreateMessage(containerSizeBytes);
std::memcpy(static_cast<fair::mq::byte *>(message->GetData()),
container.data(),
containerSizeBytes);
return message;
}
} // namespace fair::mq