1 files changed, 173 insertions, 0 deletions
diff --git a/include/ocl/net/modem.hpp b/include/ocl/net/modem.hpp
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+++ b/include/ocl/net/modem.hpp
@@ -0,0 +1,173 @@
+/*
+ * File: net/modem.hpp
+ * Purpose: Modem concept in modern C++
+ * Author: Amlal El Mahrouss (amlal@nekernel.org)
+ * Copyright 2025, Amlal El Mahrouss, licensed under the Boost Software License.
+ */
+
+#pragma once
+
+#include <tests/hpptest.hpp>
+
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <string>
+#include <cstddef>
+
+#define OCL_MODEM_INTERFACE : public ocl::net::modem
+
+#ifdef _WIN32
+#error !!! "Windows is not supported yet for <modem>" !!!
+#endif // _WIN32
+
+namespace ocl::net
+{
+	class modem;
+
+	/// =============================================================================
+	/// @brief Modem container concept, a container to read and write on a network stream.
+	/// =============================================================================
+	class modem final
+	{
+	public:
+		using socket_type	 = int64_t;
+		using error_type	 = bool;
+		using condition_type = bool;
+
+	private:
+		socket_type	   fd_{};
+		condition_type is_server_{false};
+		error_type	   bad_{true};
+
+	public:
+		const error_type& bad{bad_};
+
+		explicit modem() = default;
+
+		~modem()
+		{
+			this->destroy();
+		}
+
+		modem& operator=(const modem&) = delete;
+		modem(const modem&)			   = delete;
+
+		static constexpr auto		local_address_ip4 = "127.0.0.1";
+		static constexpr auto		local_address_ip6 = "::1";
+		static constexpr const auto backlog_count	  = 5U;
+
+		/// =============================================================================
+		/// @brief Check if the modem is valid.
+		/// @return true if valid, false otherwise.
+		/// =============================================================================
+
+		bool is_valid() const noexcept
+		{
+			return this->fd_ != -1 && !this->bad_;
+		}
+
+		template <typename ptr_type>
+		bool receive(ptr_type& out, std::size_t len) noexcept
+		{
+			static_assert(std::is_pointer<ptr_type>::value, "ptr_type is not a pointer!");
+
+			if (!out)
+				return false;
+
+			if (!len)
+				return false;
+
+			socket_type cl_{fd_};
+
+			if (this->is_server_)
+				cl_ = ::accept(fd_, nullptr, nullptr);
+
+			auto ret = ::recv(cl_, out, len, 0);
+
+			return ret > 0L;
+		}
+
+		template <typename ptr_type>
+		bool transmit(ptr_type& out, std::size_t len) noexcept
+		{
+			static_assert(std::is_pointer<ptr_type>::value, "ptr_type is not a pointer!");
+
+			if (!out)
+				return false;
+
+			if (!len)
+				return false;
+
+			auto ret = ::send(fd_, out, len, 0);
+
+			bad_ = !(ret >= 0L);
+
+			return ret >= 0L;
+		}
+
+		template <typename char_type>
+		bool transmit(const std::basic_string<char_type>& out) noexcept
+		{
+			if (out.empty())
+				return false;
+
+			auto ret = ::send(fd_, out.data(), out.size(), 0);
+
+			bad_ = !(ret >= 0L);
+
+			return ret >= 0L;
+		}
+
+		template <int32_t af, int32_t kind, int32_t port>
+		bool construct(const char* addr = modem::local_address_ip4, const bool& is_server = false) noexcept
+		{
+			static_assert(af != 0, "Address family is zero");
+			static_assert(kind != 0, "Kind is zero");
+
+			must_pass<af == AF_INET || af == AF_INET6>();
+			must_pass<kind == SOCK_STREAM || kind == SOCK_DGRAM>();
+			must_pass<(port > 0) && (port < 65536)>();
+
+			fd_		   = ::socket(af, kind, 0);
+			is_server_ = is_server;
+
+			if (fd_ == -1)
+				return false;
+
+			struct sockaddr_in addr_;
+			std::memset(&addr_, 0, sizeof(struct sockaddr_in));
+
+			addr_.sin_addr.s_addr = ::inet_addr(addr);
+			addr_.sin_port		  = htons(port);
+			addr_.sin_family	  = af;
+
+			if (!is_server)
+			{
+				const auto ret = ::connect(fd_, reinterpret_cast<struct sockaddr*>(&addr_), sizeof(addr_));
+				return ret == 0L;
+			}
+
+			int ret = ::bind(fd_, (struct sockaddr*)&addr_, sizeof(addr_));
+
+			bad_ = ret == -1;
+
+			::listen(fd_, modem::backlog_count);
+
+			return bad_ == false;
+		}
+
+		bool destroy() noexcept
+		{
+			if (!fd_)
+				return false;
+
+			::shutdown(fd_, SHUT_RDWR);
+			::close(fd_);
+
+			fd_ = 0L;
+
+			return true;
+		}
+	};
+} // namespace ocl::net