From 5c09b782b970e9fecd192d5f34e56f3add0893ff Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Sun, 4 Feb 2024 20:32:10 -0500
Subject: [PATCH] Added helper file for connect code

---
 includes/connect-helpers.hpp | 86 ++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 includes/connect-helpers.hpp

diff --git a/includes/connect-helpers.hpp b/includes/connect-helpers.hpp
new file mode 100644
index 0000000..f98daca
--- /dev/null
+++ b/includes/connect-helpers.hpp
@@ -0,0 +1,86 @@
+#include <iostream>
+#include <string>
+#include <cstring>
+#include <vector>
+#include <cstdint>
+#include <iomanip>
+namespace code {
+	namespace { /* Since these are internal function, I have wrapped them in an anonymous namespace, to prevent outside access to them */
+
+		 /* Tokenizes a string, based on the given delimiter */
+		std::vector<std::string> tokenize_str(std::string str, std::string delim) {
+			std::vector<std::string> result;
+			char* c_str = str.data();
+			char* c_delim = delim.data();
+
+			char* tok = strtok(c_str, c_delim);
+			while (tok != NULL) {
+				result.push_back(std::string(tok));
+				tok = strtok(NULL, c_delim);
+			}
+
+			return result;
+		}
+
+		/* Convert an IPv4 address from decimal to dotted decimal notation */
+		std::string dec_to_dotted_dec(std::string addr) {
+			uint32_t addr_val = std::stoul(addr); /* 32 bit address */
+			uint8_t addr_1 = (addr_val & (0xFF << 24)) >> 24;   /* First octet (Bitwise AND the address with 255.0.0.0, and shift it to the right to obtain the first octet) */
+			uint8_t addr_2 = (addr_val & (0xFF << 16)) >> 16;
+			uint8_t addr_3 = (addr_val & (0xFF << 8)) >> 8;
+			uint8_t addr_4 = (addr_val & 0xFF);
+
+			std::string ret_val = std::string(std::to_string(addr_1) + "." + std::to_string(addr_2) + "." + std::to_string(addr_3) + "." + std::to_string(addr_4));
+
+			return ret_val;
+		}
+
+		/* Convert an IPv4 address from dotted deecimal to decimal */
+		std::string dotted_dec_to_dec(std::string addr) {
+			std::vector<std::string> octets = tokenize_str(addr, ".");
+			uint32_t addr_val = (std::stoul(octets[0]) << 24) + (std::stoul(octets[1]) << 16) + (std::stoul(octets[2]) << 8) + (std::stoul(octets[3]));
+			return std::to_string(addr_val);
+		}
+
+	}
+
+
+	/* Given an address and a port, return a 'code' which has the address and port encoded in it */
+	std::string encode(std::string address, std::string port) {
+		/* Convert the address to decimal, and convert that to hex */
+		std::string addr_coded = dotted_dec_to_dec(address);
+		std::stringstream stream;
+		stream << std::hex << std::stoul(addr_coded, 0, 10);
+		addr_coded = stream.str();
+
+		stream.str("");
+
+		/* Convert the port to hex */
+		stream << std::hex << std::stoul(port, 0, 10);
+		std::string port_coded = stream.str();
+
+		std::string ret_val = addr_coded + "_" + port_coded;
+
+		return ret_val;
+
+	}
+
+	/* Given a code, decode it and return a vector with the address and port */
+	std::vector<std::string> decode(std::string connect_code) {
+		std::vector<std::string> result = tokenize_str(connect_code, "_"); /* Split the string into address and port */
+		std::string address = result[0]; /* Address (in base 16) */
+		std::string port = result[1]; /* Port (in base 16) */
+
+		/* Base 16 to base 10 - These lines convert the string to a base 10 number, and convert the result back into a string */
+		address = std::to_string(std::stoul(address, 0, 16));
+		port = std::to_string(std::stoul(address, 0, 10));
+
+		/* Convert decimal address to dotted decimal */
+		address = dec_to_dotted_dec(address);
+
+		std::vector<std::string> ret_val;
+		ret_val.push_back(address);
+		ret_val.push_back(port);
+		return ret_val;
+	}
+}