feat: generic: new `except` module, network model for FIX, and tracked_ptr improvements.

feat: introduce the `must_pass` concept to validate a container.

Signed-off-by: Amlal El Mahrouss <amlal@nekernel.org>

2 files changed, 70 insertions, 12 deletions

diff --git a/dev/lib/fix/network.hpp b/dev/lib/fix/network.hpp
index 0ca0920..637559c 100644
--- a/dev/lib/fix/network.hpp
+++ b/dev/lib/fix/network.hpp
@@ -1,5 +1,5 @@
 /*
-* File: fix/netowrk.hpp
+ * File: fix/netowrk.hpp
  * Purpose: Financial Information Exchange in C++
  * Author: Amlal El Mahrouss (founder@snu.systems)
  * Copyright 2025, Amlal El Mahrouss and SNU Systems Corp all rights reserved.
@@ -11,10 +11,67 @@
 #include <arpa/inet.h>
 #include <sys/socket.h>
 
+#include <cstddef>
+
 namespace snu::fix
 {
-	class network_rx;
-	class network_tx;	
+	class delivery_modem;
+
+	typedef int delivery_type;
+
+	/// @brief a delivery modem is a container which establishes a comm. channel between the FIX session and application.
+	class delivery_modem final
+	{
+	public:
+		explicit delivery_modem() = default;
+		~delivery_modem()		  = default;
+
+		delivery_modem& operator=(const delivery_modem&) = default;
+		delivery_modem(const delivery_modem&)			 = default;
+
+	public:
+		delivery_type fd_{};
+
+		template <typename T>
+		bool receive(T& out, std::size_t len) noexcept
+		{
+			if (!len)
+				return false;
+
+			auto ret = ::recv(fd_, &out, len, 0);
+			return ret > 0;
+		}
+
+		template <typename T>
+		bool transmit(T& out, std::size_t len) noexcept
+		{
+			if (!out)
+				return false;
+			if (!len)
+				return false;
+
+			auto ret = ::send(fd_, out, len, 0);
+			return ret > 0;
+		}
+
+		bool construct() noexcept
+		{
+			fd_ = ::socket(SOCK_STREAM, AF_INET, 0);
+			return fd_ > 0;
+		}
+
+		bool destroy() noexcept
+		{
+			if (!fd_)
+				return false;
+
+			::shutdown(fd_, SHUT_RDWR);
+
+			fd_ = 0U;
+
+			return true;
+		}
+	};
 } // namespace snu::fix
 
 #endif // ifndef _SNU_FIX_NETWORK_HPP
\ No newline at end of file
diff --git a/dev/lib/fix/parser.hpp b/dev/lib/fix/parser.hpp
index e432b6c..e007906 100644
--- a/dev/lib/fix/parser.hpp
+++ b/dev/lib/fix/parser.hpp
@@ -86,9 +86,9 @@ namespace snu::fix
 	class range_data final
 	{
 	public:
-		std::basic_string<char_type>													   msg_magic_;
-		std::size_t																		   msg_body_len_;
-		std::vector<std::pair<std::basic_string<char_type>, std::basic_string<char_type>>> msg_body_;
+		std::basic_string<char_type>													   magic_;
+		std::size_t																		   body_len_;
+		std::vector<std::pair<std::basic_string<char_type>, std::basic_string<char_type>>> body_;
 
 		static inline const char_type* begin = detail::begin_fix<char_type>();
 
@@ -105,19 +105,20 @@ namespace snu::fix
 				return std::basic_string<char_type>{};
 			}
 
-			for (const auto& pair : msg_body_)
+			for (const auto& pair : this->body_)
 			{
 				if (pair.first == key)
 				{
 					return pair.second;
 				}
 			}
+
 			return std::basic_string<char_type>{};
 		}
 
 		bool is_valid()
 		{
-			return msg_magic_.starts_with(range_data<char_type>::begin);
+			return magic_.starts_with(range_data<char_type>::begin);
 		}
 
 		operator bool()
@@ -170,14 +171,14 @@ namespace snu::fix
 					std::basic_string<char_type> key = in_tmp.substr(0, in_tmp.find(visitor::eq));
 					std::basic_string<char_type> val = in_tmp.substr(in_tmp.find(visitor::eq) + 1);
 
-					if (ret.msg_magic_.empty())
+					if (ret.magic_.empty())
 					{
-						ret.msg_magic_ = val;
+						ret.magic_ = val;
 					}
 					else
 					{
-						ret.msg_body_.emplace_back(std::make_pair(key, val));
-						ret.msg_body_len_ += in_tmp.size();
+						ret.body_.emplace_back(std::make_pair(key, val));
+						ret.body_len_ += in_tmp.size();
 					}
 
 					in_tmp.clear();