COSC_4P14_Assignment_2/src/main.cpp

/*
 *  Main file containing the program entry point. I really want to name all this all femboy themed
 *  Copyright (C) 2023  Brett Terpstra
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include <blt/parse/argparse.h>
#include <blt/std/string.h>
#include <blt/std/logging.h>
#include <blt/std/memory.h>
#include <blt/std/random.h>
#include <blt/std/time.h>
#include <blt/std/assert.h>
#include <fstream>
#include <iostream>
#include <ios>
#include <cstdint>
#include <memory>
#include <thread>
#include <mutex>
#include <atomic>

constexpr size_t PACKET_SIZE = 512;

class packet
{
    private:
        std::uint8_t* buffer = new std::uint8_t[PACKET_SIZE];
    public:
        size_t used = 0;
        
        packet() = default;
        
        packet(const packet& copy)
        {
            for (size_t i = 0; i < PACKET_SIZE; i++)
                buffer[i] = copy[i];
            used = copy.used;
        }
        
        packet(packet&& move) noexcept
        {
            delete[] buffer;
            buffer = move.buffer;
            used = move.used;
            move.buffer = nullptr;
        }
        
        packet& operator=(const packet& copy)
        {
            if (&copy == this)
                return *this;
            for (size_t i = 0; i < PACKET_SIZE; i++)
                buffer[i] = copy[i];
            used = copy.used;
            return *this;
        }
        
        packet& operator=(packet&& move) noexcept
        {
            delete[] buffer;
            buffer = move.buffer;
            move.buffer = nullptr;
            used = move.used;
            return *this;
        }
        
        std::uint8_t* data()
        {
            return buffer;
        }
        
        std::uint8_t& operator[](size_t index)
        {
            BLT_ASSERT(index < PACKET_SIZE);
            return buffer[index];
        }
        
        [[nodiscard]] const std::uint8_t& operator[](size_t index) const
        {
            BLT_ASSERT(index < PACKET_SIZE);
            return buffer[index];
        }
        
        [[nodiscard]] size_t size() const
        {
            return used;
        }
        
        ~packet()
        {
            delete[] buffer;
        }
};

void mangle(packet& packet)
{
    static std::random_device dev;
    static std::mt19937_64 engine(dev());
    static std::uniform_real_distribution dist(0.0, 1.0);
    static std::uniform_int_distribution randomizer(0, 7);
    
    // 50% chance to mangle 10% of the data.
    if (dist(engine) < 0.5)
    {
        for (size_t i = 0; i < PACKET_SIZE; i++)
            if (dist(engine) < 0.1)
            {
                // this is bad
                auto pos = static_cast<uint8_t>(exp2(randomizer(engine)));
                // flip the bit
                auto bit = ~(packet[i] & pos);
                // extra everything but the bit
                auto data = packet[i] & ~pos;
                // recombine bit
                packet[i] = data | bit;
            }
    }
}

class pipe
{
    private:
        std::random_device dev{};
        std::mt19937_64 engine{dev()};
        std::uniform_real_distribution<double> dist{0.0, 1.0};
        
        packet buffer;
        std::atomic<bool> is_written{false};
    public:
        pipe() = default;
        
        void send(packet packet)
        {
            while (is_written.load(std::memory_order::memory_order_acquire))
                std::this_thread::sleep_for(std::chrono::milliseconds(1));
            
            // 10% chance to drop the packet all together
            if (dist(engine) < 0.1)
                return;
            
            buffer = std::move(packet);
            
            is_written.store(true, std::memory_order::memory_order_release);
        }
        
        void receive(packet& out)
        {
            while (!is_written.load(std::memory_order::memory_order_acquire))
                std::this_thread::sleep_for(std::chrono::milliseconds(1));
            
            out = packet(buffer);
            
            mangle(out);
            
            is_written.store(false, std::memory_order::memory_order_release);
        }
};

void process_packets(const std::vector<packet>& packets)
{

}

int main(int argc, const char** argv)
{
    
    blt::arg_parse parser;
    parser.addArgument(
            blt::arg_builder{"-f", "--file"}.setNArgs(1).setHelp("Specify a file to read from instead of cin").setAction(blt::arg_action_t::STORE)
                                            .build());
    
    auto args = parser.parse_args(argc, argv);
    
    std::vector<packet> packets;
    
    if (args.contains("--file"))
    {
        auto& path = blt::arg_parse::get<std::string>(args.data["file"]);
        
        std::ifstream file(path);
        
        file.seekg(0, std::ifstream::end);
        size_t length = file.tellg();
        file.seekg(0, std::ifstream::beg);
        
        blt::scoped_buffer<std::uint8_t> data(length);
        
        file.read(reinterpret_cast<char*>(data.data()), static_cast<long>(length));
        
        if (file)
            BLT_INFO("All bytes have been read from the file, parsing into packets");
        else
            BLT_WARN("Only read %d characters, expected %d", file.gcount(), length);
        file.close();
        
        size_t rp = 0;
        while (rp < length)
        {
            packet p;
            if (rp + PACKET_SIZE < length)
                p.used = PACKET_SIZE;
            else
                p.used = length - rp;
            std::memcpy(p.data(), &data[rp], p.used);
            rp += PACKET_SIZE;
            packets.push_back(std::move(p));
        }
    } else
    {
        do
        {
            packet p;
            std::cin.read(reinterpret_cast<char*>(p.data()), PACKET_SIZE);
            packets.push_back(std::move(p));
        } while (!std::cin.eof() && !std::cin.fail());
    }
    
    process_packets(packets);
    
    return 0;
}