/*******************************************************************************
* Copyright (c) 2001-2005 Sasa Markovic and Ciaran Treanor.
* Copyright (c) 2011 The OpenNMS Group, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*******************************************************************************/
package org.jrobin.graph;
class ValueScaler {
static final String UNIT_UNKNOWN = "?";
static final String UNIT_SYMBOLS[] = {
"a", "f", "p", "n", "u", "m", " ", "k", "M", "G", "T", "P", "E"
};
static final int SYMB_CENTER = 6;
private final double base;
private double magfact = -1; // nothing scaled before, rescale
private String unit;
ValueScaler(double base) {
this.base = base;
}
Scaled scale(double value, boolean mustRescale) {
Scaled scaled;
if (mustRescale) {
scaled = rescale(value);
}
else if (magfact >= 0) {
// already scaled, need not rescale
scaled = new Scaled(value / magfact, unit);
}
else {
// scaling not requested, but never scaled before - must rescale anyway
scaled = rescale(value);
// if zero, scale again on the next try
if (scaled.value == 0.0 || Double.isNaN(scaled.value)) {
magfact = -1.0;
}
}
return scaled;
}
private Scaled rescale(double value) {
int sindex;
if (value == 0.0 || Double.isNaN(value)) {
sindex = 0;
magfact = 1.0;
}
else {
sindex = (int) (Math.floor(Math.log(Math.abs(value)) / Math.log(base)));
magfact = Math.pow(base, sindex);
}
if (sindex <= SYMB_CENTER && sindex >= -SYMB_CENTER) {
unit = UNIT_SYMBOLS[sindex + SYMB_CENTER];
}
else {
unit = UNIT_UNKNOWN;
}
return new Scaled(value / magfact, unit);
}
static class Scaled {
double value;
String unit;
public Scaled(double value, String unit) {
this.value = value;
this.unit = unit;
}
void dump() {
System.out.println("[" + value + unit + "]");
}
}
}