comparison src/samer/core_/DoubleFormat.java @ 0:bf79fb79ee13

Initial Mercurial check in.

+/*
+ *	DoubleFormat.java	
+ *
+ *	Copyright (c) 2000, Samer Abdallah, King's College London.
+ *	All rights reserved.
+ *
+ *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
+ *	without even the implied warranty of MERCHANTABILITY or 
+ *	FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+package samer.core;
+import  java.text.*;
+
+public class DoubleFormat extends NumberFormat
+{
+	int nfix=2;
+
+	public DoubleFormat(int n) { setDecimals(n); }
+
+	public void   setDecimals(int n) { nfix=n; }
+	public String _format(double x) { return format(x,nfix); }
+	public double _parse(String s) { return Double.valueOf(s).doubleValue(); }
+
+
+	public StringBuffer format( long n, StringBuffer buf, FieldPosition fp) {
+		buf.append(n);
+		return buf;
+	}
+	public StringBuffer format( double x, StringBuffer buf, FieldPosition fp) {
+		buf.append(x);
+		return buf;
+	}
+
+	public Number parse(String s, java.text.ParsePosition pp) {
+		return Double.valueOf(s);
+	}
+	// ...............................................
+
+	public static String format( double x, int nfix)
+	{
+		int nfixPlus1=nfix+1;
+		// quick and dirty hack!
+		String s=Double.toString(x);
+		int	point = s.indexOf('.');
+
+		// no decimals: return as is
+		if (point==-1) return s;
+
+		// look for exponent
+		int	exp = s.indexOf('E',point);
+
+		if (exp==-1) {
+			// no exponent: count decimals
+			if (s.length()-point <= nfixPlus1) return s;
+			else {
+				// chop off excess precision
+				return s.substring(0,point+nfixPlus1);
+			}
+		} else {
+			// count digits up to exponent
+			if (exp-point < nfixPlus1) return s;
+			else {
+				// return truncated mantissa and exponent
+				return s.substring(0,point+nfixPlus1) + s.substring(exp);
+			}
+		}
+	}
+}