private double doFunction(int beg, int end) {
int argbeg;
for (argbeg = beg; argbeg <= end && expression.charAt(argbeg) != '('; argbeg++) {;
}
String fncnam = expression.substring(beg, argbeg).trim();
ArgParser fncargs = new ArgParser(argbeg, end);
FunctionHandler fnchdl = null;
try {
if ((fnchdl = pureFunctions.get(fncnam)) != null) {
return fnchdl.evaluateFunction(fncnam, fncargs);
} else if ((fnchdl = impureFunctions.get(fncnam)) != null) {
isConstant = false; // impure functions cannot be guaranteed to be constant
return fnchdl.evaluateFunction(fncnam, fncargs);
}
fncargs = null; // suppress check for too many fncargs
} catch (ArithmeticException thr) {
fncargs = null;
throw thr;
} catch (NoSuchMethodError thr) {
fncargs = null;
throw exception(beg, "Function not supported in this JVM: \"" + fncnam + "\"");
} catch (UnsupportedOperationException thr) {
fncargs = null;
throw exception(beg, thr.getMessage());
} catch (Throwable thr) {
fncargs = null;
throw exception(beg, "Unexpected exception parsing function arguments", thr);
} finally {
if (fncargs != null) {
if (fncargs.hasNext()) {
throw exception(fncargs.getIndex(), "Function has too many arguments");
}
offset = fncargs.getIndex();
}
}
throw exception(beg, "Function \"" + fncnam + "\" not recognized");
}
// To add/remove functions change evaluateOperator() and registration
public double evaluateFunction(String fncnam, ArgParser fncargs) throws ArithmeticException {
switch (Character.toLowerCase(fncnam.charAt(0))) {
case 'a':
{
if (fncnam.equalsIgnoreCase("abs")) {
return Math.abs(fncargs.next());
}
if (fncnam.equalsIgnoreCase("acos")) {
return Math.acos(fncargs.next());
}
if (fncnam.equalsIgnoreCase("asin")) {
return Math.asin(fncargs.next());
}
if (fncnam.equalsIgnoreCase("atan")) {
return Math.atan(fncargs.next());
}
}
break;
case 'c':
{
if (fncnam.equalsIgnoreCase("cbrt")) {
return Math.cbrt(fncargs.next());
}
if (fncnam.equalsIgnoreCase("ceil")) {
return Math.ceil(fncargs.next());
}
if (fncnam.equalsIgnoreCase("cos")) {
return Math.cos(fncargs.next());
}
if (fncnam.equalsIgnoreCase("cosh")) {
return Math.cosh(fncargs.next());
}
}
break;
case 'e':
{
if (fncnam.equalsIgnoreCase("exp")) {
return Math.exp(fncargs.next());
}
if (fncnam.equalsIgnoreCase("expm1")) {
return Math.expm1(fncargs.next());
}
}
break;
case 'f':
{
if (fncnam.equalsIgnoreCase("floor")) {
return Math.floor(fncargs.next());
}
}
break;
case 'g':
{
// if(fncnam.equalsIgnoreCase("getExponent" )) { return
// Math.getExponent(fncargs.next()); } needs Java 6
}
break;
case 'l':
{
if (fncnam.equalsIgnoreCase("log")) {
return Math.log(fncargs.next());
}
if (fncnam.equalsIgnoreCase("log10")) {
return Math.log10(fncargs.next());
}
if (fncnam.equalsIgnoreCase("log1p")) {
return Math.log1p(fncargs.next());
}
}
break;
case 'm':
{
if (fncnam.equalsIgnoreCase("max")) {
return Math.max(fncargs.next(), fncargs.next());
}
if (fncnam.equalsIgnoreCase("min")) {
return Math.min(fncargs.next(), fncargs.next());
}
}
break;
case 'n':
{
// if(fncnam.equalsIgnoreCase("nextUp" )) { return Math.nextUp
// (fncargs.next()); } needs Java 6
}
break;
case 'r':
{
if (fncnam.equalsIgnoreCase("random")) {
return Math.random();
} // impure
if (fncnam.equalsIgnoreCase("round")) {
return Math.round(fncargs.next());
}
if (fncnam.equalsIgnoreCase("roundHE")) {
return Math.rint(fncargs.next());
} // round half-even
}
break;
case 's':
{
if (fncnam.equalsIgnoreCase("signum")) {
return Math.signum(fncargs.next());
}
if (fncnam.equalsIgnoreCase("sin")) {
return Math.sin(fncargs.next());
}
if (fncnam.equalsIgnoreCase("sinh")) {
return Math.sinh(fncargs.next());
}
if (fncnam.equalsIgnoreCase("sqrt")) {
return Math.sqrt(fncargs.next());
}
}
break;
case 't':
{
if (fncnam.equalsIgnoreCase("tan")) {
return Math.tan(fncargs.next());
}
if (fncnam.equalsIgnoreCase("tanh")) {
return Math.tanh(fncargs.next());
}
if (fncnam.equalsIgnoreCase("toDegrees")) {
return Math.toDegrees(fncargs.next());
}
if (fncnam.equalsIgnoreCase("toRadians")) {
return Math.toRadians(fncargs.next());
}
}
break;
case 'u':
{
if (fncnam.equalsIgnoreCase("ulp")) {
return Math.ulp(fncargs.next());
}
}
break;
// no default
}
throw new UnsupportedOperationException(
"MathEval internal function setup is incorrect - internal function \""
+ fncnam
+ "\" not handled");
}