/*--------------- 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 t C m d ( ) ---------------
PURPOSE
Accept a command from the keyboard.
INPUT PARAMETERS
cmdStream -- the stream from which commands are to be read
pwlFcn -- the pwlFcn list.
RETURN VALUE
The command letter.
*/
string GetCmd(istream &cmdStream, DblLinkedList &pwlFcn)
{
// Display the current point before accepting each command.
if (!pwlFcn.AtEnd()/* && cmdStream == cin*/)
{
// Display the current item.
cout << "\nCURRENT ITEM" << endl;
cout << pwlFcn.CurrentItem() << endl;
}
// Prompt for a new command.
cout << "\n>";
string cmdLine; // Command line
// Quit at end of a command file.
if (cmdStream.peek() == EOF)
{
cmdLine = QuitCmd;
if (cmdStream != cin)
cout << cmdLine << endl;
return cmdLine;
}
// Get the next command and return it.
getline(cmdStream, cmdLine);
if (cmdStream != cin)
cout << cmdLine << endl;
return cmdLine;
}
/*--------------- 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
}
/*--------------- 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;
}
/*--------------- 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);
}