// Automatically generated C++ file on Mon May 18 07:21:37 2026
//
// To build with Digital Mars C++ Compiler:
//
//    dmc -mn -WD -o classd.cpp kernel32.lib

#include <malloc.h>
#include <math.h>

// Uncomment if any of these are desired
//  extern "C" __declspec(dllexport) void (*Display)(const char *format, ...)       = 0; // works like printf()
//  extern "C" __declspec(dllexport) void (*EXIT)(const char *format, ...)          = 0; // print message like printf() but exit(0) afterward
//  extern "C" __declspec(dllexport) const double *DegreesC                         = 0; // pointer to current circuit temperature
//  extern "C" __declspec(dllexport) const int *StepNumber                          = 0; // pointer to current step number
//  extern "C" __declspec(dllexport) const int *NumberSteps                         = 0; // pointer to estimated number of steps
//  extern "C" __declspec(dllexport) const char* const *InstanceName                = 0; // pointer to address of instance name
//  extern "C" __declspec(dllexport) const char *QUX                                = 0; // path to QUX.exe
//  extern "C" __declspec(dllexport) const bool *ForKeeps                           = 0; // pointer to whether being evaluated non-hypothetically
//  extern "C" __declspec(dllexport) const bool *HoldICs                            = 0; // pointer to whether instance initial conditions are being held
//  extern "C" __declspec(dllexport) const void *GUI_HWND                           = 0; // pointer to Window handle of QUX.exe
//  extern "C" __declspec(dllexport) const double *CKTtime                          = 0;
//  extern "C" __declspec(dllexport) const double *CKTdelta                         = 0;
//  extern "C" __declspec(dllexport) const int *IntegrationOrder                    = 0;
//  extern "C" __declspec(dllexport) const char *InstallDirectory                   = 0;
//  extern "C" __declspec(dllexport) double (*EngAtof)(const char **string)         = 0;
//  extern "C" __declspec(dllexport) const char *(*BinaryFormat)(unsigned int data)                          = 0; // BinaryFormat(0x1C) returns "0b00011100"
//  extern "C" __declspec(dllexport) const char *(*EngFormat   )(double x, const char *units, int numDgts)   = 0; // EngFormat(1e-6, "s", 6) returns "1µs"
//  extern "C" __declspec(dllexport) int (*DFFT)(struct sComplex *u, bool inv, unsigned int N, double scale) = 0; // Discrete Fast Fourier Transform
//  extern "C" __declspec(dllexport) void (*bzero)(void *ptr, unsigned int count)   = 0;

union uData
{
   bool b;
   char c;
   unsigned char uc;
   short s;
   unsigned short us;
   int i;
   unsigned int ui;
   float f;
   double d;
   long long int i64;
   unsigned long long int ui64;
   char *str;
   unsigned char *bytes;
};

int __stdcall DllMain(void *module, unsigned int reason, void *reserved) { return 1; }

struct sCLASSD
{
   bool PHI1, PHI2, direction;
   double maxstep;
};

double compress(double V)
{
   if(V < -1.) return -1. + tanh(V + 1.);
   if(V >  1.) return  1. + tanh(V - 1.);
   return V;
}

extern "C" __declspec(dllexport) void classd(struct sCLASSD **opaque, double t, union uData *data)
{
   const double IN   = compress(data[0].d); // input, compressed
   const double CLK  = data[1].d; // input parameter
   double      &PHI1 = data[2].d; // output
   double      &PHI2 = data[3].d; // output
   if(!*opaque)
   {
      *opaque           = (struct sCLASSD *) calloc(1, sizeof(struct sCLASSD));
     (*opaque)->maxstep = .05 / double(CLK); // so it doesn't accidentally step over a CLK period
   }
   struct sCLASSD *inst  = *opaque;
   const double Tstart   = CLK * t - floor(t * CLK);
   const double triangle = 8. * ((inst->direction = Tstart < .5) ? Tstart : 1. - Tstart) - 2.; // triangle wave from -2V to +2V
   PHI1 = inst->PHI1     = triangle >  IN;
   PHI2 = inst->PHI2     = triangle > -IN;
}

extern "C" __declspec(dllexport) double MaxExtStepSize(struct sCLASSD *inst, double t)
{
   return inst->maxstep;
}

extern "C" __declspec(dllexport) void Trunc(struct sCLASSD *inst, double t, union uData *data, double *timestep)
{
   const double ttol = 1e-11;
   if(*timestep > ttol)
   {
      struct sCLASSD tmp = *inst;
      classd(&(&tmp), t, data);
      if((tmp.PHI1 != inst->PHI1) || (tmp.PHI2 != inst->PHI2) || (tmp.direction != inst->direction))
         *timestep = ttol;
   }
}

extern "C" __declspec(dllexport) void Destroy(struct sCLASSD *inst)
{
   free(inst);
}