/*--------------- D i s p l a y P w l F c n ( ) ---------------
PURPOSE
Display a pwlFcn from beginning to end.
INPUT PARAMETERS
pwlFcn -- the pwlFcn to be displayed.
*/
void DisplayPwlFcn(DblLinkedList &pwlFcn)
{
double x;
double y;
//Check if empty
if(pwlFcn.Empty())
{
cout<<"The pwlFcn is empty."<<endl;
return;
}
//Start at the beginning and print everything
pwlFcn.Rewind();
cout<<"PIECEWISE LINEAR FUNCTION DEFINITION"<<endl;
while(!pwlFcn.AtEnd())
{
x = pwlFcn.CurrentItem().X();
y = pwlFcn.CurrentItem().Y();
cout<<"("<<x<<","<<y<<")"<<endl;
pwlFcn.Forward();
}
//Reset to beginning
pwlFcn.Rewind();
}
/*--------------- W r i t e P w l F c n F i l e ( ) ---------------
PURPOSE
Write out a pwlFcn file.
INPUT PARAMETERS
cmdLine -- the execute command command line.
pwlFcn -- the pwlFcn list.
*/
void WritePwlFcnFile(string cmdLine, DblLinkedList &pwlFcn)
{
ofstream pwlFcnStream; // The output stream
string pwlFcnFile; // The output file name
// Ask for the file name and then open the file.
pwlFcnFile = GetFileName(cmdLine);
if (pwlFcnFile.length() == 0)
return;
pwlFcnStream.open(pwlFcnFile.c_str());
if (!pwlFcnStream.is_open())
{
cout << "*** ERROR: Failed to open file " << pwlFcnFile << endl;
return;
}
// Write out the entire pwlFcn.
pwlFcn.Rewind();
while (!pwlFcn.AtEnd())
{
pwlFcnStream << pwlFcn.CurrentItem().X() <<" " << pwlFcn.CurrentItem().Y() << endl;
pwlFcn.Forward();
}
pwlFcnStream.close();
pwlFcn.Rewind();
}
/*--------------- G e n e r a t e ( ) ---------------
PURPOSE
Generate the periodic function.
INPUT PARAMETERS
cmdLine -- the execute command command line.
pwlFcn -- the pwlFcn list.
*/
void Generate(string cmdLine, DblLinkedList &pwlFcn)
{
// Make sure the function is defined.
if (pwlFcn.Empty())
{
cout << "The pwlFcn is empty." << endl;
return;
}
Point testPoint; // The point to test
const unsigned MinCmdSize = 2; // To check for an empty test command
istringstream cmdStream(cmdLine.erase(0,1)); // Command stream
// Ignore if empty test parameters.
if (cmdLine.length() < MinCmdSize)
return;
// Display the current entry.
cout << "\nCURRENT ENTRY\n" << pwlFcn.CurrentItem() << endl << endl;
// Read the start and stop times and the number of points.
double tStart;
double tEnd;
unsigned numPts;
cmdStream >> tStart >> tEnd >> numPts;
double dt = (tEnd - tStart) / (numPts - 1);
// Generate the waveform starting at t = 0.
double t = tStart;
pwlFcn.Rewind();
for (unsigned i=0; i<numPts; i++)
{
Point pt = Point(t, Interpolate(pwlFcn, t));
cout << pt << endl;
t += dt;
}
pwlFcn.Rewind();
}
/*--------------- R e a d P w l F c n F i l e ( ) ---------------
PURPOSE
Read in a pwlFcn file.
INPUT PARAMETERS
cmdLine -- the execute command command line.
pwlFcn -- the pwlFcn list.
*/
void ReadPwlFcnFile(string cmdLine, DblLinkedList &pwlFcn)
{
ifstream pwlFcnStream; // The input stream
string pwlFcnFile; // The input file name
// Ask for the file name and then open the file.
pwlFcnFile = GetFileName(cmdLine);
if (pwlFcnFile.length() == 0)
return;
pwlFcnStream.open(pwlFcnFile.c_str());
if (!pwlFcnStream.is_open())
{
cout << "*** ERROR: No such file " << pwlFcnFile << endl;
return;
}
// Read in the entire pwlFcn file.
while (pwlFcnStream.peek() != EOF)
{
Point point; // Next input point
pwlFcnStream >> point;
pwlFcn.InsertItem(point);
}
pwlFcnStream.close();
pwlFcn.Rewind();
}
/*--------------- C o u n t P o i n t s ( ) ---------------
PURPOSE
Count the number of points in the pwlFcn.
The list is passed by value to invoke the copy constructor.
The destructor is executed upon return when the parameter is destroyed.
*/
void CountPoints(DblLinkedList pwlFcn)
{
unsigned numPts = 0; // Number of points in the pwlFcn
// Display the current entry.
cout << "\nCURRENT ENTRY\n" << pwlFcn.CurrentItem() << endl << endl;
// Rewind to the beginning.
pwlFcn.Rewind();
// Add 1 point and move forward until reaching the end of the pwlFcn.
while (!pwlFcn.AtEnd())
{
++numPts;
pwlFcn.Forward();
}
// Rewind on the way out.
pwlFcn.Rewind();
// Display the count.
cout << "Number of Points: " << numPts << endl;
}
/*--------------- I n t e r p o l a t e ( ) ---------------
PURPOSE
Determine the value of the waveform at time t by linear interpolation.
INPUT PARAMETERS
pwlFcn -- the pwlFcn list
t -- the time at which the waveform value is to be obtained
*/
double Interpolate(DblLinkedList &pwlFcn, double t)
{
double lowerBound;
double upperBound;
Point low;
Point high;
lowerBound = pwlFcn.FirstItem().X();
upperBound = pwlFcn.LastItem().X();
//modulate t to be in the period of the wave
while(t<lowerBound)
{
t+=upperBound;
}
while(t>upperBound)
{
t-=upperBound;
}
t=fmod(t,upperBound);
//find the upper and lower points to use to interp
pwlFcn.Rewind();
while(!pwlFcn.AtEnd())
{
if(t>pwlFcn.CurrentItem().X())
{
low = pwlFcn.CurrentItem();
}
else
{
high = pwlFcn.CurrentItem();
break;
}
pwlFcn.Forward();
}
//calculate line
double m = (high.Y()-low.Y())/(high.X()-low.X()); //slope
double b = (high.Y())-(m*high.X()); //offset
return (m*t+b); //Compute and return y
}
//------------------- DblLinkedList::DeepCopy() -------------------
// Deep copy source to this object
void DblLinkedList::DeepCopy(DblLinkedList &source)
{
Node *tempNode;
assert(tempNode = new(nothrow) Node());
tempNode = source.current;
//Delete the old list
this->~DblLinkedList();
//Rewind the source list
source.Rewind();
//Copy that linked list.
while (source.current != 0)
{
InsertItem(source.CurrentItem());
source.Forward();
}
source.current = tempNode;
current = tempNode;
tempNode = 0;
delete tempNode;
}
/*--------------- E x e c u t e ( ) ---------------
PURPOSE
Execute a command stream, either from cin of
from a command file
INPUT PARAMETERS
cmdStream -- the stream from which commands are to be read
pwlFcn -- the pwlFcn list.
*/
void Execute(istream &cmdStream, DblLinkedList &pwlFcn)
{
string cmdLine; // The current command line
// Repeatedly get a command from the keyboard and
// execute it.
do
{
cmdLine = GetCmd(cmdStream, pwlFcn);
if (cmdLine.length() != 0)
{
switch (toupper(cmdLine[0]))
{
// Execute a command file.
case ExecuteCmd:
DoExecute(cmdLine, pwlFcn);
break;
// Determine which command to execute.
case InsertCmd: // Insert a new point.
InsertPoint(cmdLine, pwlFcn);
break;
case ClearCmd: // Clear the pwlFcn.
pwlFcn.~DblLinkedList(); // Explicit destructor function call
break;
case DeleteCmd: // Delete the current point.
if (!pwlFcn.AtEnd())
pwlFcn.DeleteItem();
if (pwlFcn.Empty())
cout << "The pwlFcn is empty." << endl;
break;
case PrintCmd: // Display the pwlFcn.
DisplayPwlFcn(pwlFcn);
break;
case OpenCmd: // Read in a pwlFcn file.
ReadPwlFcnFile(cmdLine, pwlFcn);
break;
case SaveAsCmd: // Write out a pwlFcn file.
WritePwlFcnFile(cmdLine, pwlFcn);
break;
case ForwardCmd: // Advance to the next point.
if (!pwlFcn.AtEnd())
pwlFcn.Forward();
if (pwlFcn.AtEnd())
cout << "The pwlFcn is at the end." << endl;
break;
case BackwardCmd: // Go back to the previous point.
pwlFcn.Backward();
break;
case RewindCmd: // Rewind to the first point in the pwlFcn.
pwlFcn.Rewind();
break;
case GenerateCmd: // Generate waveform.
{
DblLinkedList pwlFcnCopy(pwlFcn); // Invokes copy constructor
Generate(cmdLine, pwlFcnCopy);
}
break;
case NumPtsCmd:
{
DblLinkedList pwlFcnCopy; // A copy of the pwlFcn
pwlFcnCopy = pwlFcn; // Invokes overloaded assignment
CountPoints(pwlFcnCopy); // Pass by value invokes the copy constructor.
}
break;
case QuitCmd: // Terminate execution.
break;
default: // Bad command
cout << "*** Error: Unknown Command" << endl;
break;
}
}
}
while (cmdLine.length() > 0 && toupper(cmdLine[0]) != QuitCmd);
}