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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.ss.util;
/**
* Excel converts numbers to text with different rules to those of java, so
* Double.toString(value) won't do.
*
* - No more than 15 significant figures are output (java does 18).
* - The sign char for the exponent is included even if positive
* - Special values (NaN and Infinity) get rendered like the ordinary
* number that the bit pattern represents.
* - Denormalised values (between ±2-1074 and ±2-1022
* are displayed as "0"
*
* IEEE 64-bit Double Rendering Comparison
*
*
* Raw bits Java Excel 0x0000000000000000L 0.0 0 0x3FF0000000000000L 1.0 1 0x3FF00068DB8BAC71L 1.0001 1.0001 0x4087A00000000000L 756.0 756 0x401E3D70A3D70A3DL 7.56 7.56 0x405EDD3C07FB4C99L 123.45678901234568 123.456789012346 0x4132D687E3DF2180L 1234567.8901234567 1234567.89012346 0x3EE9E409302678BAL 1.2345678901234568E-5 1.23456789012346E-05 0x3F202E85BE180B74L 1.2345678901234567E-4 0.000123456789012346 0x3F543A272D9E0E51L 0.0012345678901234567 0.00123456789012346 0x3F8948B0F90591E6L 0.012345678901234568 0.0123456789012346 0x3EE9E409301B5A02L 1.23456789E-5 0.0000123456789 0x3E6E7D05BDABDE50L 5.6789012345E-8 0.000000056789012345 0x3E6E7D05BDAD407EL 5.67890123456E-8 5.67890123456E-08 0x3E6E7D06029F18BEL 5.678902E-8 0.00000005678902 0x2BCB5733CB32AE6EL 9.999999999999123E-98 9.99999999999912E-98 0x2B617F7D4ED8C59EL 1.0000000000001235E-99 1.0000000000001E-99 0x0036319916D67853L 1.2345678901234578E-307 1.2345678901235E-307 0x359DEE7A4AD4B81FL 2.0E-50 2E-50 0x41678C29DCD6E9E0L 1.2345678901234567E7 12345678.9012346 0x42A674E79C5FE523L 1.2345678901234568E13 12345678901234.6 0x42DC12218377DE6BL 1.2345678901234567E14 123456789012346 0x43118B54F22AEB03L 1.2345678901234568E15 1234567890123460 0x43E56A95319D63E1L 1.2345678901234567E19 12345678901234600000 0x441AC53A7E04BCDAL 1.2345678901234568E20 1.23456789012346E+20 0xC3E56A95319D63E1L -1.2345678901234567E19 -12345678901234600000 0xC41AC53A7E04BCDAL -1.2345678901234568E20 -1.23456789012346E+20 0x54820FE0BA17F46DL 1.2345678901234577E99 1.2345678901235E+99 0x54B693D8E89DF188L 1.2345678901234576E100 1.2345678901235E+100 0x4A611B0EC57E649AL 2.0E50 2E+50 0x7FEFFFFFFFFFFFFFL 1.7976931348623157E308 1.7976931348623E+308 0x0010000000000000L 2.2250738585072014E-308 2.2250738585072E-308 0x000FFFFFFFFFFFFFL 2.225073858507201E-308 0 0x0000000000000001L 4.9E-324 0 0x7FF0000000000000L Infinity 1.7976931348623E+308 0xFFF0000000000000L -Infinity 1.7976931348623E+308 0x441AC7A08EAD02F2L 1.234999999999999E20 1.235E+20 0x40FE26BFFFFFFFF9L 123499.9999999999 123500 0x3E4A857BFB2F2809L 1.234999999999999E-8 0.00000001235 0x3BCD291DEF868C89L 1.234999999999999E-20 1.235E-20 0x444B1AE4D6E2EF4FL 9.999999999999999E20 1E+21 0x412E847FFFFFFFFFL 999999.9999999999 1000000 0x3E45798EE2308C39L 9.999999999999999E-9 0.00000001 0x3C32725DD1D243ABL 9.999999999999999E-19 0.000000000000000001 0x3BFD83C94FB6D2ABL 9.999999999999999E-20 1E-19 0xC44B1AE4D6E2EF4FL -9.999999999999999E20 -1E+21 0xC12E847FFFFFFFFFL -999999.9999999999 -1000000 0xBE45798EE2308C39L -9.999999999999999E-9 -0.00000001 0xBC32725DD1D243ABL -9.999999999999999E-19 -0.000000000000000001 0xBBFD83C94FB6D2ABL -9.999999999999999E-20 -1E-19 0xFFFF0420003C0000L NaN 3.484840871308E+308 0x7FF8000000000000L NaN 2.6965397022935E+308 0x7FFF0420003C0000L NaN 3.484840871308E+308 0xFFF8000000000000L NaN 2.6965397022935E+308 0xFFFF0AAAAAAAAAAAL NaN 3.4877119413344E+308 0x7FF80AAAAAAAAAAAL NaN 2.7012211948322E+308 0xFFFFFFFFFFFFFFFFL NaN 3.5953862697246E+308 0x7FFFFFFFFFFFFFFFL NaN 3.5953862697246E+308 0xFFF7FFFFFFFFFFFFL NaN 2.6965397022935E+308
*
* Note:
* Excel has inconsistent rules for the following numeric operations:
*
* - Conversion to string (as handled here)
* - Rendering numerical quantities in the cell grid.
* - Conversion from text
* - General arithmetic
*
* Excel's text to number conversion is not a true inverse of this operation. The
* allowable ranges are different. Some numbers that don't correctly convert to text actually
* do get handled properly when used in arithmetic evaluations.
*
* @author Josh Micich
*/
public final class NumberToTextConverter {
private static final long EXCEL_NAN_BITS = 0xFFFF0420003C0000L;
private static final int MAX_TEXT_LEN = 20;
private NumberToTextConverter() {
// no instances of this class
}
/**
* Converts the supplied value to the text representation that Excel would give if
* the value were to appear in an unformatted cell, or as a literal number in a formula.
* Note - the results from this method differ slightly from those of Double.toString()
* In some special cases Excel behaves quite differently. This function attempts to reproduce
* those results.
*/
public static String toText(double value) {
return rawDoubleBitsToText(Double.doubleToLongBits(value));
}
/* package */ static String rawDoubleBitsToText(long pRawBits) {
long rawBits = pRawBits;
boolean isNegative = rawBits < 0; // sign bit is in the same place for long and double
if (isNegative) {
rawBits &= 0x7FFFFFFFFFFFFFFFL;
}
if (rawBits == 0) {
return isNegative ? "-0" : "0";
}
ExpandedDouble ed = new ExpandedDouble(rawBits);
if (ed.getBinaryExponent() < -1022) {
// value is 'denormalised' which means it is less than 2^-1022
// excel displays all these numbers as zero, even though calculations work OK
return isNegative ? "-0" : "0";
}
if (ed.getBinaryExponent() == 1024) {
// Special number NaN /Infinity
// Normally one would not create HybridDecimal objects from these values
// except in these cases Excel really tries to render them as if they were normal numbers
if(rawBits == EXCEL_NAN_BITS) {
return "3.484840871308E+308";
}
// This is where excel really gets it wrong
// Special numbers like Infinity and NaN are interpreted according to
// the standard rules below.
isNegative = false; // except that the sign bit is ignored
}
NormalisedDecimal nd = ed.normaliseBaseTen();
StringBuilder sb = new StringBuilder(MAX_TEXT_LEN+1);
if (isNegative) {
sb.append('-');
}
convertToText(sb, nd);
return sb.toString();
}
private static void convertToText(StringBuilder sb, NormalisedDecimal pnd) {
NormalisedDecimal rnd = pnd.roundUnits();
int decExponent = rnd.getDecimalExponent();
String decimalDigits;
if (Math.abs(decExponent)>98) {
decimalDigits = rnd.getSignificantDecimalDigitsLastDigitRounded();
if (decimalDigits.length() == 16) {
// rounding caused carry
decExponent++;
}
} else {
decimalDigits = rnd.getSignificantDecimalDigits();
}
int countSigDigits = countSignifantDigits(decimalDigits);
if (decExponent < 0) {
formatLessThanOne(sb, decimalDigits, decExponent, countSigDigits);
} else {
formatGreaterThanOne(sb, decimalDigits, decExponent, countSigDigits);
}
}
private static void formatLessThanOne(StringBuilder sb, String decimalDigits, int decExponent,
int countSigDigits) {
int nLeadingZeros = -decExponent - 1;
int normalLength = 2 + nLeadingZeros + countSigDigits; // 2 == "0.".length()
if (needsScientificNotation(normalLength)) {
sb.append(decimalDigits.charAt(0));
if (countSigDigits > 1) {
sb.append('.');
sb.append(decimalDigits.subSequence(1, countSigDigits));
}
sb.append("E-");
appendExp(sb, -decExponent);
return;
}
sb.append("0.");
for (int i=nLeadingZeros; i>0; i--) {
sb.append('0');
}
sb.append(decimalDigits.subSequence(0, countSigDigits));
}
private static void formatGreaterThanOne(StringBuilder sb, String decimalDigits, int decExponent, int countSigDigits) {
if (decExponent > 19) {
// scientific notation
sb.append(decimalDigits.charAt(0));
if (countSigDigits>1) {
sb.append('.');
sb.append(decimalDigits.subSequence(1, countSigDigits));
}
sb.append("E+");
appendExp(sb, decExponent);
return;
}
int nFractionalDigits = countSigDigits - decExponent-1;
if (nFractionalDigits > 0) {
sb.append(decimalDigits.subSequence(0, decExponent+1));
sb.append('.');
sb.append(decimalDigits.subSequence(decExponent+1, countSigDigits));
return;
}
sb.append(decimalDigits.subSequence(0, countSigDigits));
for (int i=-nFractionalDigits; i>0; i--) {
sb.append('0');
}
}
private static boolean needsScientificNotation(int nDigits) {
return nDigits > MAX_TEXT_LEN;
}
private static int countSignifantDigits(String sb) {
int result=sb.length()-1;
while(sb.charAt(result) == '0') {
result--;
if(result < 0) {
throw new RuntimeException("No non-zero digits found");
}
}
return result + 1;
}
private static void appendExp(StringBuilder sb, int val) {
if(val < 10) {
sb.append('0');
sb.append((char)('0' + val));
return;
}
sb.append(val);
}
}