quickerNES/source/controller.hpp

#pragma once

// Base controller class
// by eien86

#include <cstdint>
#include <string>
#include <sstream>

namespace quickNES
{

class Controller
{
public:

  enum controller_t { none, joypad, fourscore1, fourscore2 };

  typedef uint32_t port_t;

  struct input_t
  {
    bool power = false;
    bool reset = false;
    port_t port1 = 0;
    port_t port2 = 0;
  };

  inline bool parseInputString(const std::string& input, input_t* decoded) const
  {
    // Parse valid flag
    bool isValid = true;

    // Converting input into a stream for parsing
    std::istringstream ss(input);

    // Start separator
    if (ss.get() != '|') isValid = false;

    // Parsing console inputs
    isValid &= parseConsoleInputs(decoded->reset, decoded->power, ss);

    // Parsing controller 1 inputs
    isValid &= parseControllerInputs(_controller1Type, decoded->port1, ss);

    // Parsing controller 1 inputs
    isValid &= parseControllerInputs(_controller2Type, decoded->port2, ss);

    // End separator
    if (ss.get() != '|') isValid = false;

    // If its not the end of the stream, then extra values remain and its invalid
    ss.get();
    if (ss.eof() == false) isValid = false;

    // Returning valid flag
    return isValid;
  };

  inline void setController1Type(const controller_t type) { _controller1Type = type; }
  inline void setController2Type(const controller_t type) { _controller2Type = type; }

  private:

  static bool parseJoyPadInput(uint8_t& code, std::istringstream& ss)
  {
    // Currently read character
    char c;

    // Cleaning code
    code = 0;

    // Up
    c = ss.get();
    if (c != '.' && c != 'U') return false;
    if (c == 'U') code |= 0b00010000;

    // Down
    c = ss.get();
    if (c != '.' && c != 'D') return false;
    if (c == 'D') code |= 0b00100000;

    // Left
    c = ss.get();
    if (c != '.' && c != 'L') return false;
    if (c == 'L') code |= 0b01000000;

    // Right
    c = ss.get();
    if (c != '.' && c != 'R') return false;
    if (c == 'R') code |= 0b10000000;

    // Start
    c = ss.get();
    if (c != '.' && c != 'S') return false;
    if (c == 'S') code |= 0b00001000;

    // Select
    c = ss.get();
    if (c != '.' && c != 's') return false;
    if (c == 's') code |= 0b00000100;

    // B
    c = ss.get();
    if (c != '.' && c != 'B') return false;
    if (c == 'B') code |= 0b00000010;

    // A
    c = ss.get();
    if (c != '.' && c != 'A') return false;
    if (c == 'A') code |= 0b00000001;

    return true;
  }

  static bool parseControllerInputs(const controller_t type, port_t& port, std::istringstream& ss)
  {
    // Parse valid flag
    bool isValid = true; 
 
    // If no controller assigned then, its port is all zeroes.
    if (type == controller_t::none) { port = 0; return true; }

    // Controller separator
    if (ss.get() != '|') isValid = false;

    // If normal joypad, parse its code now
    if (type == controller_t::joypad) 
    {
      // Storage for joypad's code
      uint8_t code = 0;

      // Parsing joypad code
      isValid &= parseJoyPadInput(code, ss);

      // Pushing input code into the port
      port = code;

      // Adding joypad signature
      // Per https://www.nesdev.org/wiki/Standard_controller, the joypad reports 1s after the first 8 bits
      port |= ~0xFF;
    }

    // If its fourscore, its like two joypads separated by a |
    if (type == controller_t::fourscore1 || type == controller_t::fourscore2) 
    {
      // Storage for joypad's code
      uint8_t code1 = 0;
      uint8_t code2 = 0;

      // Parsing joypad code1
      isValid &= parseJoyPadInput(code1, ss);

      // Separator
      if (ss.get() != '|') return false;

      // Parsing joypad code1
      isValid &= parseJoyPadInput(code2, ss);

      // Creating code
      port = code1;
      port |= (uint32_t)0 | code2 << 8;
      if (type == controller_t::fourscore1) port |= (uint32_t)0 | 1 << 19;
      if (type == controller_t::fourscore2) port |= (uint32_t)0 | 1 << 18;
      port |= (uint32_t)0 | 1 << 24;
      port |= (uint32_t)0 | 1 << 25;
      port |= (uint32_t)0 | 1 << 26;
      port |= (uint32_t)0 | 1 << 27;
      port |= (uint32_t)0 | 1 << 28;
      port |= (uint32_t)0 | 1 << 29;
      port |= (uint32_t)0 | 1 << 30;
      port |= (uint32_t)0 | 1 << 31;
    }
    // Return valid flag
    return isValid;
  }

  static bool parseConsoleInputs(bool& reset, bool& power, std::istringstream& ss)
  {
    // Parse valid flag
    bool isValid = true; 

    // Currently read character
    char c;

    // Power trigger
    c = ss.get();
    if (c != '.' && c != 'P') isValid = false;
    if (c == 'P') power = true;
    if (c == '.') power = false;

    // Reset trigger
    c = ss.get();
    if (c != '.' && c != 'r') isValid = false;
    if (c == 'r') reset = true;
    if (c == '.') reset = false;

    // Return valid flag
    return isValid;
  }

  controller_t _controller1Type;
  controller_t _controller2Type;
  
}; // class Controller

} // namespace quickNES