first commit

hrmsEjb/org/nfunk/jep/function/Logarithm.java

@@ -0,0 +1,30 @@
+package org.nfunk.jep.function;
+
+import java.util.Stack;
+import org.nfunk.jep.ParseException;
+import org.nfunk.jep.type.Complex;
+
+public class Logarithm extends PostfixMathCommand {
+  private static final double LOG10 = Math.log(10.0D);
+  
+  private static final Complex CLOG10 = new Complex(Math.log(10.0D), 0.0D);
+  
+  public void run(Stack paramStack) throws ParseException {
+    checkStack(paramStack);
+    Object object = paramStack.pop();
+    paramStack.push(log(object));
+  }
+  
+  public Object log(Object paramObject) throws ParseException {
+    if (paramObject instanceof Complex)
+      return ((Complex)paramObject).log().div(CLOG10); 
+    if (paramObject instanceof Number) {
+      double d = ((Number)paramObject).doubleValue();
+      if (d > 0.0D)
+        return new Double(Math.log(d) / LOG10); 
+      Complex complex = new Complex(d);
+      return complex.log().div(CLOG10);
+    } 
+    throw new ParseException("Invalid parameter type");
+  }
+}