quickerNES/source/emuInstance.hpp

#pragma once

#include <utils.hpp> 
#include "sha1/sha1.hpp"

#define _LOW_MEM_SIZE 0x800
#define _HIGH_MEM_SIZE 0x2000
#define _NAMETABLES_MEM_SIZE 0x1000

// Size of image generated in graphics buffer
static const uint16_t image_width   = 256;
static const uint16_t image_height  = 240;

class EmuInstance
{
 public:

 typedef uint8_t inputType;

 // Deleting default constructors
 virtual ~EmuInstance() = default;

 // Controller input bits
 // 0 - A / 1
 // 1 - B / 2
 // 2 - Select / 4
 // 3 - Start / 8
 // 4 - Up / 16
 // 5 - Down / 32
 // 6 - Left / 64
 // 7 - Right / 128

 // Move Format:
 // RLDUTSBA
 // ........

 static inline inputType moveStringToCode(const std::string& move)
 {
  inputType moveCode = 0;

  for (size_t i = 0; i < move.size(); i++) switch(move[i])
  {
    case 'U': moveCode |= 0b00010000; break;
    case 'D': moveCode |= 0b00100000; break;
    case 'L': moveCode |= 0b01000000; break;
    case 'R': moveCode |= 0b10000000; break;
    case 'S': moveCode |= 0b00001000; break;
    case 's': moveCode |= 0b00000100; break;
    case 'B': moveCode |= 0b00000010; break;
    case 'A': moveCode |= 0b00000001; break;
    case 'r': break;
    case '.': break;
    case '|': break;
    default: EXIT_WITH_ERROR("Move provided cannot be parsed: '%s', unrecognized character: '%c'\n", move.c_str(), move[i]);
  }

  return moveCode;
 }

 static inline std::string moveCodeToString(const inputType move)
 {
#ifndef _NES_PLAYER_2
  std::string moveString = "|..|";
#else
  std::string moveString = "|..|........|";
#endif

  if (move & 0b00010000) moveString += 'U'; else moveString += '.';
  if (move & 0b00100000) moveString += 'D'; else moveString += '.';
  if (move & 0b01000000) moveString += 'L'; else moveString += '.';
  if (move & 0b10000000) moveString += 'R'; else moveString += '.';
  if (move & 0b00001000) moveString += 'S'; else moveString += '.';
  if (move & 0b00000100) moveString += 's'; else moveString += '.';
  if (move & 0b00000010) moveString += 'B'; else moveString += '.';
  if (move & 0b00000001) moveString += 'A'; else moveString += '.';

  moveString += "|";
  return moveString;
 }
 
 inline void advanceState(const std::string& move)
 {
  if (move.find("r") != std::string::npos) doSoftReset(); 

  advanceStateImpl(moveStringToCode(move), 0);
 }

 inline size_t getStateSize() const { return _stateSize; }
 inline std::string getRomSHA1() const { return _romSHA1String; }

 inline hash_t getStateHash() const
 {
  MetroHash128 hash;

  uint8_t stateData[_stateSize];
  serializeState(stateData);

  hash.Update(getLowMem(), _LOW_MEM_SIZE);
  hash.Update(getHighMem(), _HIGH_MEM_SIZE);
  hash.Update(getNametableMem(), _NAMETABLES_MEM_SIZE);
  hash.Update(getChrMem(), getChrMemSize());

  hash_t result;
  hash.Finalize(reinterpret_cast<uint8_t *>(&result));
  return result;
 }

 inline void enableRendering() { _doRendering = true; };
 inline void disableRendering() { _doRendering = false; };

 inline void loadStateFile(const std::string& stateFilePath) 
 {
  std::string stateData;
  bool status = loadStringFromFile(stateData, stateFilePath);
  if (status == false) EXIT_WITH_ERROR("Could not find/read state file: %s\n", stateFilePath.c_str());
  deserializeState((uint8_t*)stateData.data());
 }

 inline void saveStateFile(const std::string& stateFilePath) const 
 {
  std::string stateData;
  stateData.resize(_stateSize);
  serializeState((uint8_t*)stateData.data());
  saveStringToFile(stateData, stateFilePath.c_str());
 }

inline void loadROMFile(const std::string& romFilePath) 
{
  // Loading ROM data
  bool status = loadStringFromFile(_romData, romFilePath);
  if (status == false) EXIT_WITH_ERROR("Could not find/read ROM file: %s\n", romFilePath.c_str());

  // Calculating ROM hash value
  _romSHA1String = SHA1::GetHash((uint8_t*)_romData.data(), _romData.size());

  // Actually loading rom file
  status = loadROMFileImpl(_romData);
  if (status == false) EXIT_WITH_ERROR("Could not process ROM file: %s\n", romFilePath.c_str());

  // Detecting state size
  _stateSize = getStateSizeImpl();
}

 // Virtual functions

 virtual bool loadROMFileImpl(const std::string& romFilePath) = 0;
 virtual void advanceStateImpl(const inputType controller1, const inputType controller2) = 0;
 virtual uint8_t* getLowMem() const = 0;
 virtual uint8_t* getNametableMem() const = 0;
 virtual uint8_t* getHighMem() const = 0;
 virtual const uint8_t* getChrMem() const = 0;
 virtual size_t getChrMemSize() const = 0;
 virtual void serializeState(uint8_t* state) const = 0;
 virtual void deserializeState(const uint8_t* state) = 0;
 virtual size_t getStateSizeImpl() const = 0;
 virtual void doSoftReset() = 0;
 virtual void doHardReset() = 0;
 virtual std::string getCoreName() const = 0;
 virtual void* getInternalEmulatorPointer() const = 0;
 
 protected:

 EmuInstance() = default;

 // Storage for the state
 size_t _stateSize;

 // Flag to determine whether to enable/disable rendering
 bool _doRendering = true;
 
 private: 

 // Storage for the ROM data
 std::string _romData;

 // SHA1 rom hash 
 std::string _romSHA1String;
};