view 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);
			}
		}
	}
}