diff options
Diffstat (limited to '3rdparty/asio/src/examples/cpp11/allocation/server.cpp')
-rw-r--r-- | 3rdparty/asio/src/examples/cpp11/allocation/server.cpp | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/3rdparty/asio/src/examples/cpp11/allocation/server.cpp b/3rdparty/asio/src/examples/cpp11/allocation/server.cpp new file mode 100644 index 00000000000..4d0d80e6875 --- /dev/null +++ b/3rdparty/asio/src/examples/cpp11/allocation/server.cpp @@ -0,0 +1,255 @@ +// +// server.cpp +// ~~~~~~~~~~ +// +// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#include <array> +#include <cstdlib> +#include <iostream> +#include <memory> +#include <type_traits> +#include <utility> +#include "asio.hpp" + +using asio::ip::tcp; + +// Class to manage the memory to be used for handler-based custom allocation. +// It contains a single block of memory which may be returned for allocation +// requests. If the memory is in use when an allocation request is made, the +// allocator delegates allocation to the global heap. +class handler_memory +{ +public: + handler_memory() + : in_use_(false) + { + } + + handler_memory(const handler_memory&) = delete; + handler_memory& operator=(const handler_memory&) = delete; + + void* allocate(std::size_t size) + { + if (!in_use_ && size < sizeof(storage_)) + { + in_use_ = true; + return &storage_; + } + else + { + return ::operator new(size); + } + } + + void deallocate(void* pointer) + { + if (pointer == &storage_) + { + in_use_ = false; + } + else + { + ::operator delete(pointer); + } + } + +private: + // Storage space used for handler-based custom memory allocation. + typename std::aligned_storage<1024>::type storage_; + + // Whether the handler-based custom allocation storage has been used. + bool in_use_; +}; + +// The allocator to be associated with the handler objects. This allocator only +// needs to satisfy the C++11 minimal allocator requirements. +template <typename T> +class handler_allocator +{ +public: + using value_type = T; + + explicit handler_allocator(handler_memory& mem) + : memory_(mem) + { + } + + template <typename U> + handler_allocator(const handler_allocator<U>& other) noexcept + : memory_(other.memory_) + { + } + + bool operator==(const handler_allocator& other) const noexcept + { + return &memory_ == &other.memory_; + } + + bool operator!=(const handler_allocator& other) const noexcept + { + return &memory_ != &other.memory_; + } + + T* allocate(std::size_t n) const + { + return static_cast<T*>(memory_.allocate(sizeof(T) * n)); + } + + void deallocate(T* p, std::size_t /*n*/) const + { + return memory_.deallocate(p); + } + +private: + template <typename> friend class handler_allocator; + + // The underlying memory. + handler_memory& memory_; +}; + +// Wrapper class template for handler objects to allow handler memory +// allocation to be customised. The allocator_type type and get_allocator() +// member function are used by the asynchronous operations to obtain the +// allocator. Calls to operator() are forwarded to the encapsulated handler. +template <typename Handler> +class custom_alloc_handler +{ +public: + using allocator_type = handler_allocator<Handler>; + + custom_alloc_handler(handler_memory& m, Handler h) + : memory_(m), + handler_(h) + { + } + + allocator_type get_allocator() const noexcept + { + return allocator_type(memory_); + } + + template <typename ...Args> + void operator()(Args&&... args) + { + handler_(std::forward<Args>(args)...); + } + +private: + handler_memory& memory_; + Handler handler_; +}; + +// Helper function to wrap a handler object to add custom allocation. +template <typename Handler> +inline custom_alloc_handler<Handler> make_custom_alloc_handler( + handler_memory& m, Handler h) +{ + return custom_alloc_handler<Handler>(m, h); +} + +class session + : public std::enable_shared_from_this<session> +{ +public: + session(tcp::socket socket) + : socket_(std::move(socket)) + { + } + + void start() + { + do_read(); + } + +private: + void do_read() + { + auto self(shared_from_this()); + socket_.async_read_some(asio::buffer(data_), + make_custom_alloc_handler(handler_memory_, + [this, self](std::error_code ec, std::size_t length) + { + if (!ec) + { + do_write(length); + } + })); + } + + void do_write(std::size_t length) + { + auto self(shared_from_this()); + asio::async_write(socket_, asio::buffer(data_, length), + make_custom_alloc_handler(handler_memory_, + [this, self](std::error_code ec, std::size_t /*length*/) + { + if (!ec) + { + do_read(); + } + })); + } + + // The socket used to communicate with the client. + tcp::socket socket_; + + // Buffer used to store data received from the client. + std::array<char, 1024> data_; + + // The memory to use for handler-based custom memory allocation. + handler_memory handler_memory_; +}; + +class server +{ +public: + server(asio::io_context& io_context, short port) + : acceptor_(io_context, tcp::endpoint(tcp::v4(), port)) + { + do_accept(); + } + +private: + void do_accept() + { + acceptor_.async_accept( + [this](std::error_code ec, tcp::socket socket) + { + if (!ec) + { + std::make_shared<session>(std::move(socket))->start(); + } + + do_accept(); + }); + } + + tcp::acceptor acceptor_; +}; + +int main(int argc, char* argv[]) +{ + try + { + if (argc != 2) + { + std::cerr << "Usage: server <port>\n"; + return 1; + } + + asio::io_context io_context; + server s(io_context, std::atoi(argv[1])); + io_context.run(); + } + catch (std::exception& e) + { + std::cerr << "Exception: " << e.what() << "\n"; + } + + return 0; +} |