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55419 and refactor SimpleFraction

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git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1514123 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Tim Allison 2013-08-15 01:46:25 +00:00
parent 17f3b2cb26
commit a62fcb2fbf
4 changed files with 188 additions and 221 deletions
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124
src/java/org/apache/poi/ss/format/CellNumberFormatter.java
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@ -824,7 +824,7 @@ public class CellNumberFormatter extends CellFormatter {
n = (int) Math.round(fractional);
d = 1;
} else {
Fraction frac = new Fraction(fractional, maxDenominator);
SimpleFraction frac = SimpleFraction.buildFractionMaxDenominator(fractional, maxDenominator);
n = frac.getNumerator();
d = frac.getDenominator();
}
@ -971,128 +971,6 @@ public class CellNumberFormatter extends CellFormatter {
SIMPLE_NUMBER.formatValue(toAppendTo, value);
}
/**
* Based on org.apache.commons.math.fraction.Fraction from Apache Commons-Math.
* YK: The only reason of having this inner class is to avoid dependency on the Commons-Math jar.
*/
private static class Fraction {
/** The denominator. */
private final int denominator;
/** The numerator. */
private final int numerator;
/**
* Create a fraction given the double value and either the maximum error
* allowed or the maximum number of denominator digits.
*
* @param value the double value to convert to a fraction.
* @param epsilon maximum error allowed. The resulting fraction is within
* <code>epsilon</code> of <code>value</code>, in absolute terms.
* @param maxDenominator maximum denominator value allowed.
* @param maxIterations maximum number of convergents
* @throws RuntimeException if the continued fraction failed to
* converge.
*/
private Fraction(double value, double epsilon, int maxDenominator, int maxIterations)
{
long overflow = Integer.MAX_VALUE;
double r0 = value;
long a0 = (long)Math.floor(r0);
if (a0 > overflow) {
throw new IllegalArgumentException("Overflow trying to convert "+value+" to fraction ("+a0+"/"+1l+")");
}
// check for (almost) integer arguments, which should not go
// to iterations.
if (Math.abs(a0 - value) < epsilon) {
this.numerator = (int) a0;
this.denominator = 1;
return;
}
long p0 = 1;
long q0 = 0;
long p1 = a0;
long q1 = 1;
long p2;
long q2;
int n = 0;
boolean stop = false;
do {
++n;
double r1 = 1.0 / (r0 - a0);
long a1 = (long)Math.floor(r1);
p2 = (a1 * p1) + p0;
q2 = (a1 * q1) + q0;
if ((p2 > overflow) || (q2 > overflow)) {
throw new RuntimeException("Overflow trying to convert "+value+" to fraction ("+p2+"/"+q2+")");
}
double convergent = (double)p2 / (double)q2;
if (n < maxIterations && Math.abs(convergent - value) > epsilon && q2 < maxDenominator) {
p0 = p1;
p1 = p2;
q0 = q1;
q1 = q2;
a0 = a1;
r0 = r1;
} else {
stop = true;
}
} while (!stop);
if (n >= maxIterations) {
throw new RuntimeException("Unable to convert "+value+" to fraction after "+maxIterations+" iterations");
}
if (q2 < maxDenominator) {
this.numerator = (int) p2;
this.denominator = (int) q2;
} else {
this.numerator = (int) p1;
this.denominator = (int) q1;
}
}
/**
* Create a fraction given the double value and maximum denominator.
* <p>
* References:
* <ul>
* <li><a href="http://mathworld.wolfram.com/ContinuedFraction.html">
* Continued Fraction</a> equations (11) and (22)-(26)</li>
* </ul>
* </p>
* @param value the double value to convert to a fraction.
* @param maxDenominator The maximum allowed value for denominator
* @throws RuntimeException if the continued fraction failed to
* converge
*/
public Fraction(double value, int maxDenominator)
{
this(value, 0, maxDenominator, 100);
}
/**
* Access the denominator.
* @return the denominator.
*/
public int getDenominator() {
return denominator;
}
/**
* Access the numerator.
* @return the numerator.
*/
public int getNumerator() {
return numerator;
}
}
}

170
src/java/org/apache/poi/ss/format/SimpleFraction.java Normal file
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@ -0,0 +1,170 @@
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.poi.ss.format;
public class SimpleFraction {
/** The denominator. */
private final int denominator;
/** The numerator. */
private final int numerator;
/**
* Create a fraction given a double value and a denominator.
*
* @param val double value of fraction
* @param exactDenom the exact denominator
* @return
*/
public static SimpleFraction buildFractionExactDenominator(double val, int exactDenom){
int num = (int)Math.round(val*(double)exactDenom);
return new SimpleFraction(num,exactDenom);
}
/**
* Create a fraction given the double value and either the maximum error
* allowed or the maximum number of denominator digits.
*
* @param value the double value to convert to a fraction.
* @param maxDenominator maximum denominator value allowed.
*
* @throws RuntimeException if the continued fraction failed to
* converge.
* @throws IllegalArgumentException if value > Integer.MAX_VALUE
*/
public static SimpleFraction buildFractionMaxDenominator(double value, int maxDenominator){
return buildFractionMaxDenominator(value, 0, maxDenominator, 100);
}
/**
* Create a fraction given the double value and either the maximum error
* allowed or the maximum number of denominator digits.
* <p>
* References:
* <ul>
* <li><a href="http://mathworld.wolfram.com/ContinuedFraction.html">
* Continued Fraction</a> equations (11) and (22)-(26)</li>
* </ul>
* </p>
*
* Based on org.apache.commons.math.fraction.Fraction from Apache Commons-Math.
* YK: The only reason of having this class is to avoid dependency on the Commons-Math jar.
*
* @param value the double value to convert to a fraction.
* @param epsilon maximum error allowed. The resulting fraction is within
* <code>epsilon</code> of <code>value</code>, in absolute terms.
* @param maxDenominator maximum denominator value allowed.
* @param maxIterations maximum number of convergents
* @throws RuntimeException if the continued fraction failed to
* converge.
* @throws IllegalArgumentException if value > Integer.MAX_VALUE
*/
private static SimpleFraction buildFractionMaxDenominator(double value, double epsilon, int maxDenominator, int maxIterations)
{
long overflow = Integer.MAX_VALUE;
double r0 = value;
long a0 = (long)Math.floor(r0);
if (a0 > overflow) {
throw new IllegalArgumentException("Overflow trying to convert "+value+" to fraction ("+a0+"/"+1l+")");
}
// check for (almost) integer arguments, which should not go
// to iterations.
if (Math.abs(a0 - value) < epsilon) {
return new SimpleFraction((int)a0, 1);
}
long p0 = 1;
long q0 = 0;
long p1 = a0;
long q1 = 1;
long p2;
long q2;
int n = 0;
boolean stop = false;
do {
++n;
double r1 = 1.0 / (r0 - a0);
long a1 = (long)Math.floor(r1);
p2 = (a1 * p1) + p0;
q2 = (a1 * q1) + q0;
//MATH-996/POI-55419
if (epsilon == 0.0f && maxDenominator > 0 && Math.abs(q2) > maxDenominator &&
Math.abs(q1) < maxDenominator){
return new SimpleFraction((int)p1, (int)q1);
}
if ((p2 > overflow) || (q2 > overflow)) {
throw new RuntimeException("Overflow trying to convert "+value+" to fraction ("+p2+"/"+q2+")");
}
double convergent = (double)p2 / (double)q2;
if (n < maxIterations && Math.abs(convergent - value) > epsilon && q2 < maxDenominator) {
p0 = p1;
p1 = p2;
q0 = q1;
q1 = q2;
a0 = a1;
r0 = r1;
} else {
stop = true;
}
} while (!stop);
if (n >= maxIterations) {
throw new RuntimeException("Unable to convert "+value+" to fraction after "+maxIterations+" iterations");
}
if (q2 < maxDenominator) {
return new SimpleFraction((int) p2, (int)q2);
} else {
return new SimpleFraction((int)p1, (int)q1);
}
}
/**
* Create a fraction given a numerator and denominator.
* @param numerator
* @param denominator maxDenominator The maximum allowed value for denominator
*/
public SimpleFraction(int numerator, int denominator)
{
this.numerator = numerator;
this.denominator = denominator;
}
/**
* Access the denominator.
* @return the denominator.
*/
public int getDenominator() {
return denominator;
}
/**
* Access the numerator.
* @return the numerator.
*/
public int getNumerator() {
return numerator;
}
}

104
src/java/org/apache/poi/ss/usermodel/FractionFormat.java
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@ -22,6 +22,7 @@ import java.text.ParsePosition;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.poi.ss.format.SimpleFraction;
import org.apache.poi.ss.formula.eval.NotImplementedException;
/**
@ -35,7 +36,7 @@ import org.apache.poi.ss.formula.eval.NotImplementedException;
* If further uses for Commons Math are found, we will consider adding it as a dependency.
* For now, we have in-lined the one method to keep things simple.</p>
*/
/* One question remains...is the value of epsilon in calcFractionMaxDenom reasonable? */
@SuppressWarnings("serial")
public class FractionFormat extends Format {
private final static Pattern DENOM_FORMAT_PATTERN = Pattern.compile("(?:(#+)|(\\d+))");
@ -113,7 +114,6 @@ public class FractionFormat extends Format {
}
//this is necessary to prevent overflow in the maxDenom calculation
//stink1
if (wholePart+(int)decPart == wholePart+decPart){
StringBuilder sb = new StringBuilder();
@ -128,11 +128,11 @@ public class FractionFormat extends Format {
try{
//this should be the case because of the constructor
if (exactDenom > 0){
fract = calcFractionExactDenom(decPart, exactDenom);
fract = SimpleFraction.buildFractionExactDenominator(decPart, exactDenom);
} else {
fract = calcFractionMaxDenom(decPart, maxDenom);
fract = SimpleFraction.buildFractionMaxDenominator((double)decPart, maxDenom);
}
} catch (SimpleFractionException e){
} catch (RuntimeException e){
e.printStackTrace();
return Double.toString(doubleValue);
}
@ -175,97 +175,5 @@ public class FractionFormat extends Format {
public Object parseObject(String source, ParsePosition pos) {
throw new NotImplementedException("Reverse parsing not supported");
}
private SimpleFraction calcFractionMaxDenom(double value, int maxDenominator)
throws SimpleFractionException{
/*
* Lifted wholesale from org.apache.math.fraction.Fraction 2.2
*/
double epsilon = 0.000000000001f;
int maxIterations = 100;
long overflow = Integer.MAX_VALUE;
double r0 = value;
long a0 = (long)Math.floor(r0);
if (Math.abs(a0) > overflow) {
throw new SimpleFractionException(
String.format("value > Integer.MAX_VALUE: %d.", a0));
}
// check for (almost) integer arguments, which should not go
// to iterations.
if (Math.abs(a0 - value) < epsilon) {
return new SimpleFraction((int) a0, 1);
}
long p0 = 1;
long q0 = 0;
long p1 = a0;
long q1 = 1;
long p2 = 0;
long q2 = 1;
int n = 0;
boolean stop = false;
do {
++n;
double r1 = 1.0 / (r0 - a0);
long a1 = (long)Math.floor(r1);
p2 = (a1 * p1) + p0;
q2 = (a1 * q1) + q0;
if ((Math.abs(p2) > overflow) || (Math.abs(q2) > overflow)) {
throw new SimpleFractionException(
String.format("Greater than overflow in loop %f, %d, %d", value, p2, q2));
}
double convergent = (double)p2 / (double)q2;
if (n < maxIterations && Math.abs(convergent - value) > epsilon && q2 < maxDenominator) {
p0 = p1;
p1 = p2;
q0 = q1;
q1 = q2;
a0 = a1;
r0 = r1;
} else {
stop = true;
}
} while (!stop);
if (n >= maxIterations) {
throw new SimpleFractionException("n greater than max iterations " + value + " : " + maxIterations);
}
if (q2 < maxDenominator) {
return new SimpleFraction((int) p2, (int) q2);
} else {
return new SimpleFraction((int) p1, (int) q1);
}
}
private SimpleFraction calcFractionExactDenom(double val, int exactDenom){
int num = (int)Math.round(val*(double)exactDenom);
return new SimpleFraction(num,exactDenom);
}
private class SimpleFraction {
private final int num;
private final int denom;
public SimpleFraction(int num, int denom) {
this.num = num;
this.denom = denom;
}
public int getNumerator() {
return num;
}
public int getDenominator() {
return denom;
}
}
private class SimpleFractionException extends Throwable{
private SimpleFractionException(String message){
super(message);
}
}
}

11
src/testcases/org/apache/poi/ss/format/TestCellFormat.java
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@ -825,4 +825,15 @@ public class TestCellFormat extends TestCase {
}
public void testSimpleFractionFormat() {
CellFormat cf1 = CellFormat.getInstance("# ?/?");
// Create a workbook, row and cell to test with
Workbook wb = new HSSFWorkbook();
Sheet sheet = wb.createSheet();
Row row = sheet.createRow(0);
Cell cell = row.createCell(0);
cell.setCellValue(123456.6);
System.out.println(cf1.apply(cell).text);
assertEquals("123456 3/5", cf1.apply(cell).text);
}
}