/// <summary>
/// Gets the precedence of operator codes.
/// </summary>
/// <param name="opcode">operater code</param>
/// <returns>value indicating precedence</returns>
private static int OperatorPrecedence(GerberOpcodes opcode)
{
switch (opcode)
{
case GerberOpcodes.Add:
case GerberOpcodes.Subtract:
return(1);
case GerberOpcodes.Multiple:
case GerberOpcodes.Divide:
return(2);
}
return(0);
}
public static ApertureMacro ProcessApertureMacro(GerberLineReader reader)
{
const int MathOperationStackSize = 2;
ApertureMacro apertureMacro = new ApertureMacro();
GerberInstruction instruction;
GerberOpcodes[] mathOperations = new GerberOpcodes[MathOperationStackSize];
char characterRead;
int primitive = 0;
int mathOperationIndex = 0;
int equate = 0;
bool continueLoop = true;
bool comma = false; // Just read an operator (one of '*+X/)
bool isNegative = false; // Negative numbers succeeding ','
bool foundPrimitive = false;
int length = 0;
// Get macro name
apertureMacro.Name = reader.GetStringValue('*');
characterRead = reader.Read(); // skip '*'
// The first instruction in all programs will be NOP.
instruction = new GerberInstruction();
instruction.Opcode = GerberOpcodes.NOP;
apertureMacro.InstructionList.Add(instruction);
while (continueLoop && !reader.EndOfFile)
{
length = 0;
characterRead = reader.Read();
switch (characterRead)
{
case '$':
if (foundPrimitive)
{
instruction = new GerberInstruction();
instruction.Opcode = GerberOpcodes.PushParameter;
apertureMacro.InstructionList.Add(instruction);
apertureMacro.NufPushes++;
instruction.Data.IntValue = reader.GetIntegerValue(ref length);
comma = false;
}
else
{
equate = reader.GetIntegerValue(ref length);
}
break;
case '*':
while (mathOperationIndex != 0)
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
// Check is due to some gerber files has spurious empty lines (eg EagleCad)
if (foundPrimitive)
{
instruction = new GerberInstruction();
if (equate > 0)
{
instruction.Opcode = GerberOpcodes.PopParameter;
instruction.Data.IntValue = equate;
}
else
{
instruction.Opcode = GerberOpcodes.Primative;
instruction.Data.IntValue = primitive;
}
apertureMacro.InstructionList.Add(instruction);
equate = 0;
primitive = 0;
foundPrimitive = false;
}
break;
case '=':
if (equate > 0)
{
foundPrimitive = true;
}
break;
case ',':
if (!foundPrimitive)
{
foundPrimitive = true;
break;
}
while (mathOperationIndex != 0)
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
comma = true;
break;
case '+':
while ((mathOperationIndex != 0) &&
OperatorPrecedence((mathOperationIndex > 0) ? mathOperations[mathOperationIndex - 1] : GerberOpcodes.NOP) >=
(OperatorPrecedence(GerberOpcodes.Add)))
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
mathOperations[mathOperationIndex++] = GerberOpcodes.Add;
comma = true;
break;
case '-':
if (comma)
{
isNegative = true;
comma = false;
break;
}
while ((mathOperationIndex != 0) &&
OperatorPrecedence((mathOperationIndex > 0) ? mathOperations[mathOperationIndex - 1] : GerberOpcodes.NOP) >=
(OperatorPrecedence(GerberOpcodes.Subtract)))
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
mathOperations[mathOperationIndex++] = GerberOpcodes.Subtract;
break;
case '/':
while ((mathOperationIndex != 0) &&
OperatorPrecedence((mathOperationIndex > 0) ? mathOperations[mathOperationIndex - 1] : GerberOpcodes.NOP) >=
(OperatorPrecedence(GerberOpcodes.Divide)))
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
mathOperations[mathOperationIndex++] = GerberOpcodes.Divide;
comma = true;
break;
case 'X':
case 'x':
while ((mathOperationIndex != 0) &&
OperatorPrecedence((mathOperationIndex > 0) ? mathOperations[mathOperationIndex - 1] : GerberOpcodes.NOP) >=
(OperatorPrecedence(GerberOpcodes.Multiple)))
{
instruction = new GerberInstruction();
instruction.Opcode = mathOperations[--mathOperationIndex];
apertureMacro.InstructionList.Add(instruction);
}
mathOperations[mathOperationIndex++] = GerberOpcodes.Multiple;
comma = true;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '.':
// Comments in aperture macros are a definition starting with zero and ends with a '*'
if ((characterRead == '0') && (!foundPrimitive) && (primitive == 0))
{
// Comment continues until next '*', just throw it away.
reader.GetStringValue('*');
characterRead = reader.Read(); // Read the '*'.
break;
}
// First number in an aperture macro describes the primitive as a numerical value
if (!foundPrimitive)
{
primitive = (primitive * 10) + (characterRead - '0');
break;
}
reader.Position--;
instruction = new GerberInstruction();
instruction.Opcode = GerberOpcodes.Push;
apertureMacro.InstructionList.Add(instruction);
apertureMacro.NufPushes++;
instruction.Data.DoubleValue = reader.GetDoubleValue();
if (isNegative)
{
instruction.Data.DoubleValue = -(instruction.Data.DoubleValue);
}
isNegative = false;
comma = false;
break;
case '%':
reader.Position--; // Must return with % first in string since the main parser needs it.
continueLoop = false; // Reached the end of the macro.
break;
default:
// Whitespace.
break;
}
}
if (reader.EndOfFile)
{
return(null);
}
return(apertureMacro);
}