org.apache.poi.hssf.view.SVFractionalFormat Maven / Gradle / Ivy
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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
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See the License for the specific language governing permissions and
limitations under the License.
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package org.apache.poi.hssf.view;
import java.text.*;
/**
* This class is used to format cells into their fractional format.
*
* I cant be 100% sure that the same fractional value will be displayed as in
* excel but then again it is a lossy formating mode anyway
*
* @author Jason Height
* @since 15 July 2002
*/
public class SVFractionalFormat extends Format {
private short ONE_DIGIT = 1;
private short TWO_DIGIT = 2;
private short THREE_DIGIT = 3;
private short UNITS = 4;
private int units = 1;
private short mode = -1;
/** Constructs a new FractionalFormatter
*
* The formatStr defines how the number will be formatted
* # ?/? Up to one digit
* # ??/?? Up to two digits
* # ???/??? Up to three digits
* # ?/2 In halves
* # ?/4 In quarters
* # ?/8 In eighths
* # ?/16 In sixteenths
* # ?/10 In tenths
* # ?/100 In hundredths
*/
public SVFractionalFormat(String formatStr) {
if ("# ?/?".equals(formatStr))
mode = ONE_DIGIT;
else if ("# ??/??".equals(formatStr))
mode = TWO_DIGIT;
else if ("# ???/???".equals(formatStr))
mode = THREE_DIGIT;
else if ("# ?/2".equals(formatStr)) {
mode = UNITS;
units = 2;
} else if ("# ?/4".equals(formatStr)) {
mode = UNITS;
units = 4;
} else if ("# ?/8".equals(formatStr)) {
mode = UNITS;
units = 8;
} else if ("# ?/16".equals(formatStr)) {
mode = UNITS;
units = 16;
} else if ("# ?/10".equals(formatStr)) {
mode = UNITS;
units = 10;
} else if ("# ?/100".equals(formatStr)) {
mode = UNITS;
units = 100;
}
}
/**
* Returns a fractional string representation of a double to a maximum denominator size
*
* This code has been translated to java from the following web page.
* http://www.codeproject.com/cpp/fraction.asp
* Originally coded in c++ By Dean Wyant [email protected]
* The code on the web page is freely available.
*
* @param f Description of the Parameter
* @param MaxDen Description of the Parameter
* @return Description of the Return Value
*/
private String format(final double f, final int MaxDen) {
long Whole = (long)f;
int sign = 1;
if (f < 0) {
sign = -1;
}
double Precision = 0.00001;
double AllowedError = Precision;
double d = Math.abs(f);
d -= Whole;
double Frac = d;
double Diff = Frac;
long Num = 1;
long Den = 0;
long A = 0;
long B = 0;
long i = 0;
if (Frac > Precision) {
while (true) {
d = 1.0 / d;
i = (long) (d + Precision);
d -= i;
if (A > 0) {
Num = i * Num + B;
}
Den = (long) (Num / Frac + 0.5);
Diff = Math.abs((double) Num / Den - Frac);
if (Den > MaxDen) {
if (A > 0) {
Num = A;
Den = (long) (Num / Frac + 0.5);
Diff = Math.abs((double) Num / Den - Frac);
} else {
Den = MaxDen;
Num = 1;
Diff = Math.abs((double) Num / Den - Frac);
if (Diff > Frac) {
Num = 0;
Den = 1;
// Keeps final check below from adding 1 and keeps Den from being 0
Diff = Frac;
}
}
break;
}
if ((Diff <= AllowedError) || (d < Precision)) {
break;
}
Precision = AllowedError / Diff;
// This calcualtion of Precision does not always provide results within
// Allowed Error. It compensates for loss of significant digits that occurs.
// It helps to round the inprecise reciprocal values to i.
B = A;
A = Num;
}
}
if (Num == Den) {
Whole++;
Num = 0;
Den = 0;
} else if (Den == 0) {
Num = 0;
}
if (sign < 0) {
if (Whole == 0) {
Num = -Num;
} else {
Whole = -Whole;
}
}
return new StringBuffer().append(Whole).append(" ").append(Num).append("/").append(Den).toString();
}
/** This method formats the double in the units specified.
* The usints could be any number but in this current implementation it is
* halves (2), quaters (4), eigths (8) etc
*/
private String formatUnit(double f, int units) {
long Whole = (long)f;
f -= Whole;
long Num = Math.round(f * units);
return new StringBuffer().append(Whole).append(" ").append(Num).append("/").append(units).toString();
}
public final String format(double val) {
if (mode == ONE_DIGIT) {
return format(val, 9);
} else if (mode == TWO_DIGIT) {
return format(val, 99);
} else if (mode == THREE_DIGIT) {
return format(val, 999);
} else if (mode == UNITS) {
return formatUnit(val , units);
}
throw new RuntimeException("Unexpected Case");
}
@Override
public StringBuffer format(Object obj,
StringBuffer toAppendTo,
FieldPosition pos) {
if (obj instanceof Number) {
toAppendTo.append(format(((Number)obj).doubleValue()));
return toAppendTo;
}
throw new IllegalArgumentException("Can only handle Numbers");
}
@Override
public Object parseObject(String source,
ParsePosition status) {
//JMH TBD
return null;
}
@Override
public Object parseObject(String source)
throws ParseException {
//JMH TBD
return null;
}
@Override
public Object clone() {
//JMH TBD
return null;
}
}