]> source.dussan.org Git - poi.git/commitdiff
Fix for bug 46156 - improved POI's number rendering to more closely match Excel's
authorJosh Micich <josh@apache.org>
Mon, 1 Dec 2008 23:24:23 +0000 (23:24 +0000)
committerJosh Micich <josh@apache.org>
Mon, 1 Dec 2008 23:24:23 +0000 (23:24 +0000)
git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@722284 13f79535-47bb-0310-9956-ffa450edef68

15 files changed:
src/documentation/content/xdocs/changes.xml
src/documentation/content/xdocs/status.xml
src/java/org/apache/poi/hssf/record/formula/NumberPtg.java
src/java/org/apache/poi/hssf/record/formula/eval/NumberEval.java
src/java/org/apache/poi/ss/util/NumberToTextConverter.java [new file with mode: 0644]
src/java/org/apache/poi/util/LittleEndian.java
src/testcases/org/apache/poi/hssf/HSSFTests.java
src/testcases/org/apache/poi/hssf/model/TestFormulaParser.java
src/testcases/org/apache/poi/hssf/record/formula/functions/TestNper.java
src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java
src/testcases/org/apache/poi/hssf/usermodel/TestFormulaEvaluatorBugs.java
src/testcases/org/apache/poi/ss/util/AllSSUtilTests.java [new file with mode: 0644]
src/testcases/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java [new file with mode: 0644]
src/testcases/org/apache/poi/ss/util/NumberToTextConversionExamples.java [new file with mode: 0644]
src/testcases/org/apache/poi/ss/util/TestNumberToTextConverter.java [new file with mode: 0644]

index 80a6e8cee56f63f2def4fb1415b18cd92d7ea5b1..1e11f2a4bc5617a65bbc4a36ea2c5a3c5a5f5574 100644 (file)
@@ -37,6 +37,7 @@
 
                <!-- Don't forget to update status.xml too! -->
         <release version="3.5-beta5" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="add">46156 - Improved number to text conversion to be closer to that of Excel</action>
            <action dev="POI-DEVELOPERS" type="fix">46312 - Fixed ValueRecordsAggregate to handle removal of new empty row</action>
            <action dev="POI-DEVELOPERS" type="add">46269 - Improved error message when attempting to read BIFF2 file</action>
            <action dev="POI-DEVELOPERS" type="fix">46206 - Fixed Sheet to tolerate missing DIMENSION records</action>
index 8763adc0a033199e8775fe88887ed0175df7166f..d1d819ad44b9228ac7bbcc2ef86ace8a3224d346 100644 (file)
@@ -34,6 +34,7 @@
        <!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.5-beta5" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="add">46156 - Improved number to text conversion to be closer to that of Excel</action>
            <action dev="POI-DEVELOPERS" type="fix">46312 - Fixed ValueRecordsAggregate to handle removal of new empty row</action>
            <action dev="POI-DEVELOPERS" type="add">46269 - Improved error message when attempting to read BIFF2 file</action>
            <action dev="POI-DEVELOPERS" type="fix">46206 - Fixed Sheet to tolerate missing DIMENSION records</action>
index 5bd8b08453ac2f0e34d8471e28915c3dc19c3994..244c09fe5ff933c8c016e13bdc257dc68fa7b236 100644 (file)
@@ -17,6 +17,7 @@
 
 package org.apache.poi.hssf.record.formula;
 
+import org.apache.poi.ss.util.NumberToTextConverter;
 import org.apache.poi.util.LittleEndianInput;
 import org.apache.poi.util.LittleEndianOutput;
 
@@ -65,7 +66,6 @@ public final class NumberPtg extends ScalarConstantPtg {
        }
 
        public String toFormulaString() {
-               // TODO - java's rendering of double values is not quite same as excel's
-               return String.valueOf(field_1_value);
+               return NumberToTextConverter.toText(field_1_value);
        }
 }
index e22957bd4ab14642d18ac44264ce4001f60f6082..33aff2a49303fd60e1612cf226dbdd29e84ed647 100644 (file)
@@ -23,51 +23,45 @@ package org.apache.poi.hssf.record.formula.eval;
 import org.apache.poi.hssf.record.formula.IntPtg;
 import org.apache.poi.hssf.record.formula.NumberPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.ss.util.NumberToTextConverter;
 
 /**
  * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
  *  
  */
-public class NumberEval implements NumericValueEval, StringValueEval {
+public final class NumberEval implements NumericValueEval, StringValueEval {
     
     public static final NumberEval ZERO = new NumberEval(0);
 
-    private double value;
-    private String stringValue;
+    private final double _value;
+    private String _stringValue;
 
     public NumberEval(Ptg ptg) {
-        if (ptg instanceof IntPtg) {
-            this.value = ((IntPtg) ptg).getValue();
+        if (ptg == null) {
+            throw new IllegalArgumentException("ptg must not be null");
         }
-        else if (ptg instanceof NumberPtg) {
-            this.value = ((NumberPtg) ptg).getValue();
+        if (ptg instanceof IntPtg) {
+            _value = ((IntPtg) ptg).getValue();
+        } else if (ptg instanceof NumberPtg) {
+            _value = ((NumberPtg) ptg).getValue();
+        } else {
+            throw new IllegalArgumentException("bad argument type (" + ptg.getClass().getName() + ")");
         }
     }
 
     public NumberEval(double value) {
-        this.value = value;
+        _value = value;
     }
 
     public double getNumberValue() {
-        return value;
+        return _value;
     }
 
-    public String getStringValue() { // TODO: limit to 15 decimal places
-        if (stringValue == null)
-            makeString();
-        return stringValue;
-    }
-    
-    protected void makeString() {
-        if (!Double.isNaN(value)) {
-            long lvalue = Math.round(value);
-            if (lvalue == value) {
-                stringValue = String.valueOf(lvalue);
-            }
-            else {
-                stringValue = String.valueOf(value);
-            }
+    public String getStringValue() {
+        if (_stringValue == null) {
+            _stringValue = NumberToTextConverter.toText(_value);
         }
+        return _stringValue;
     }
     public final String toString() {
         StringBuffer sb = new StringBuffer(64);
diff --git a/src/java/org/apache/poi/ss/util/NumberToTextConverter.java b/src/java/org/apache/poi/ss/util/NumberToTextConverter.java
new file mode 100644 (file)
index 0000000..1d7a901
--- /dev/null
@@ -0,0 +1,405 @@
+/* ====================================================================
+   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.util;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * Excel converts numbers to text with different rules to those of java, so
+ *  <code>Double.toString(value)</tt> won't do.
+ * <ul>
+ * <li>No more than 15 significant figures are output (java does 18).</li>
+ * <li>The sign char for the exponent is included even if positive</li>
+ * <li>Special values (<tt>NaN</tt> and <tt>Infinity</tt>) get rendered like the ordinary 
+ * number that the bit pattern represents.</li>
+ * <li>Denormalised values (between &plusmn;2<sup>-1074</sup> and &plusmn;2<sup>-1022</sup>
+ *  are displayed as "0"</sup>
+ * </ul>
+ * IEEE 64-bit Double Rendering Comparison
+ * 
+ * <table border="1" cellpadding="2" cellspacing="0" summary="IEEE 64-bit Double Rendering Comparison">
+ * <tr><th>Raw bits</th><th>Java</th><th>Excel</th></tr>
+ * 
+ * <tr><td>0x0000000000000000L</td><td>0.0</td><td>0</td></tr>
+ * <tr><td>0x3FF0000000000000L</td><td>1.0</td><td>1</td></tr>
+ * <tr><td>0x3FF00068DB8BAC71L</td><td>1.0001</td><td>1.0001</td></tr>
+ * <tr><td>0x4087A00000000000L</td><td>756.0</td><td>756</td></tr>
+ * <tr><td>0x401E3D70A3D70A3DL</td><td>7.56</td><td>7.56</td></tr>
+ * <tr><td>0x405EDD3C07FB4C99L</td><td>123.45678901234568</td><td>123.456789012346</td></tr>
+ * <tr><td>0x4132D687E3DF2180L</td><td>1234567.8901234567</td><td>1234567.89012346</td></tr>
+ * <tr><td>0x3EE9E409302678BAL</td><td>1.2345678901234568E-5</td><td>1.23456789012346E-05</td></tr>
+ * <tr><td>0x3F202E85BE180B74L</td><td>1.2345678901234567E-4</td><td>0.000123456789012346</td></tr>
+ * <tr><td>0x3F543A272D9E0E51L</td><td>0.0012345678901234567</td><td>0.00123456789012346</td></tr>
+ * <tr><td>0x3F8948B0F90591E6L</td><td>0.012345678901234568</td><td>0.0123456789012346</td></tr>
+ * <tr><td>0x3EE9E409301B5A02L</td><td>1.23456789E-5</td><td>0.0000123456789</td></tr>
+ * <tr><td>0x3E6E7D05BDABDE50L</td><td>5.6789012345E-8</td><td>0.000000056789012345</td></tr>
+ * <tr><td>0x3E6E7D05BDAD407EL</td><td>5.67890123456E-8</td><td>5.67890123456E-08</td></tr>
+ * <tr><td>0x3E6E7D06029F18BEL</td><td>5.678902E-8</td><td>0.00000005678902</td></tr>
+ * <tr><td>0x2BCB5733CB32AE6EL</td><td>9.999999999999123E-98</td><td>9.99999999999912E-98</td></tr>
+ * <tr><td>0x2B617F7D4ED8C59EL</td><td>1.0000000000001235E-99</td><td>1.0000000000001E-99</td></tr>
+ * <tr><td>0x0036319916D67853L</td><td>1.2345678901234578E-307</td><td>1.2345678901235E-307</td></tr>
+ * <tr><td>0x359DEE7A4AD4B81FL</td><td>2.0E-50</td><td>2E-50</td></tr>
+ * <tr><td>0x41678C29DCD6E9E0L</td><td>1.2345678901234567E7</td><td>12345678.9012346</td></tr>
+ * <tr><td>0x42A674E79C5FE523L</td><td>1.2345678901234568E13</td><td>12345678901234.6</td></tr>
+ * <tr><td>0x42DC12218377DE6BL</td><td>1.2345678901234567E14</td><td>123456789012346</td></tr>
+ * <tr><td>0x43118B54F22AEB03L</td><td>1.2345678901234568E15</td><td>1234567890123460</td></tr>
+ * <tr><td>0x43E56A95319D63E1L</td><td>1.2345678901234567E19</td><td>12345678901234600000</td></tr>
+ * <tr><td>0x441AC53A7E04BCDAL</td><td>1.2345678901234568E20</td><td>1.23456789012346E+20</td></tr>
+ * <tr><td>0xC3E56A95319D63E1L</td><td>-1.2345678901234567E19</td><td>-12345678901234600000</td></tr>
+ * <tr><td>0xC41AC53A7E04BCDAL</td><td>-1.2345678901234568E20</td><td>-1.23456789012346E+20</td></tr>
+ * <tr><td>0x54820FE0BA17F46DL</td><td>1.2345678901234577E99</td><td>1.2345678901235E+99</td></tr>
+ * <tr><td>0x54B693D8E89DF188L</td><td>1.2345678901234576E100</td><td>1.2345678901235E+100</td></tr>
+ * <tr><td>0x4A611B0EC57E649AL</td><td>2.0E50</td><td>2E+50</td></tr>
+ * <tr><td>0x7FEFFFFFFFFFFFFFL</td><td>1.7976931348623157E308</td><td>1.7976931348623E+308</td></tr>
+ * <tr><td>0x0010000000000000L</td><td>2.2250738585072014E-308</td><td>2.2250738585072E-308</td></tr>
+ * <tr><td>0x000FFFFFFFFFFFFFL</td><td>2.225073858507201E-308</td><td>0</td></tr>
+ * <tr><td>0x0000000000000001L</td><td>4.9E-324</td><td>0</td></tr>
+ * <tr><td>0x7FF0000000000000L</td><td>Infinity</td><td>1.7976931348623E+308</td></tr>
+ * <tr><td>0xFFF0000000000000L</td><td>-Infinity</td><td>1.7976931348623E+308</td></tr>
+ * <tr><td>0x441AC7A08EAD02F2L</td><td>1.234999999999999E20</td><td>1.235E+20</td></tr>
+ * <tr><td>0x40FE26BFFFFFFFF9L</td><td>123499.9999999999</td><td>123500</td></tr>
+ * <tr><td>0x3E4A857BFB2F2809L</td><td>1.234999999999999E-8</td><td>0.00000001235</td></tr>
+ * <tr><td>0x3BCD291DEF868C89L</td><td>1.234999999999999E-20</td><td>1.235E-20</td></tr>
+ * <tr><td>0x444B1AE4D6E2EF4FL</td><td>9.999999999999999E20</td><td>1E+21</td></tr>
+ * <tr><td>0x412E847FFFFFFFFFL</td><td>999999.9999999999</td><td>1000000</td></tr>
+ * <tr><td>0x3E45798EE2308C39L</td><td>9.999999999999999E-9</td><td>0.00000001</td></tr>
+ * <tr><td>0x3C32725DD1D243ABL</td><td>9.999999999999999E-19</td><td>0.000000000000000001</td></tr>
+ * <tr><td>0x3BFD83C94FB6D2ABL</td><td>9.999999999999999E-20</td><td>1E-19</td></tr>
+ * <tr><td>0xC44B1AE4D6E2EF4FL</td><td>-9.999999999999999E20</td><td>-1E+21</td></tr>
+ * <tr><td>0xC12E847FFFFFFFFFL</td><td>-999999.9999999999</td><td>-1000000</td></tr>
+ * <tr><td>0xBE45798EE2308C39L</td><td>-9.999999999999999E-9</td><td>-0.00000001</td></tr>
+ * <tr><td>0xBC32725DD1D243ABL</td><td>-9.999999999999999E-19</td><td>-0.000000000000000001</td></tr>
+ * <tr><td>0xBBFD83C94FB6D2ABL</td><td>-9.999999999999999E-20</td><td>-1E-19</td></tr>
+ * <tr><td>0xFFFF0420003C0000L</td><td>NaN</td><td>3.484840871308E+308</td></tr>
+ * <tr><td>0x7FF8000000000000L</td><td>NaN</td><td>2.6965397022935E+308</td></tr>
+ * <tr><td>0x7FFF0420003C0000L</td><td>NaN</td><td>3.484840871308E+308</td></tr>
+ * <tr><td>0xFFF8000000000000L</td><td>NaN</td><td>2.6965397022935E+308</td></tr>
+ * <tr><td>0xFFFF0AAAAAAAAAAAL</td><td>NaN</td><td>3.4877119413344E+308</td></tr>
+ * <tr><td>0x7FF80AAAAAAAAAAAL</td><td>NaN</td><td>2.7012211948322E+308</td></tr>
+ * <tr><td>0xFFFFFFFFFFFFFFFFL</td><td>NaN</td><td>3.5953862697246E+308</td></tr>
+ * <tr><td>0x7FFFFFFFFFFFFFFFL</td><td>NaN</td><td>3.5953862697246E+308</td></tr>
+ * <tr><td>0xFFF7FFFFFFFFFFFFL</td><td>NaN</td><td>2.6965397022935E+308</td></tr>
+ * </table>
+ * 
+ * <b>Note</b>:  
+ * Excel has inconsistent rules for the following numeric operations:
+ * <ul>
+ * <li>Conversion to string (as handled here)</li>
+ * <li>Rendering numerical quantities in the cell grid.</li>
+ * <li>Conversion from text</li>
+ * <li>General arithmetic</li>
+ * </ul>
+ * Excel's text to number conversion is not a true <i>inverse</i> of this operation.  The 
+ * allowable ranges are different.  Some numbers that don't correctly convert to text actually
+ * <b>do</b> get handled properly when used in arithmetic evaluations.
+ * 
+ * @author Josh Micich
+ */
+public final class NumberToTextConverter {
+
+       private static final long expMask  = 0x7FF0000000000000L;
+       private static final long FRAC_MASK= 0x000FFFFFFFFFFFFFL;
+       private static final int  EXPONENT_SHIFT = 52;
+       private static final int  FRAC_BITS_WIDTH = EXPONENT_SHIFT;
+       private static final int  EXPONENT_BIAS  = 1023;
+       private static final long FRAC_ASSUMED_HIGH_BIT = ( 1L<<EXPONENT_SHIFT );
+       
+       private static final long EXCEL_NAN_BITS = 0xFFFF0420003C0000L;
+       private static final int MAX_TEXT_LEN = 20;
+       
+       private static final int DEFAULT_COUNT_SIGNIFICANT_DIGITS = 15;
+       private static final int MAX_EXTRA_ZEROS = MAX_TEXT_LEN - DEFAULT_COUNT_SIGNIFICANT_DIGITS;
+       private static final float LOG2_10 = 3.32F;
+       
+
+       private NumberToTextConverter() {
+               // no instances of this class
+       }
+
+       /**
+        * Converts the supplied <tt>value</tt> 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.<br/>
+        * Note - the results from this method differ slightly from those of <tt>Double.toString()</tt>
+        * 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;
+               }
+               
+               int biasedExponent = (int) ((rawBits & expMask) >> EXPONENT_SHIFT);
+               if (biasedExponent == 0) {
+                       // value is 'denormalised' which means it is less than 2^-1022
+                       // excel displays all these numbers as zero, even though calculations work OK
+                       return "0";
+               }
+               
+               int exponent = biasedExponent - EXPONENT_BIAS; 
+               
+               long fracBits = FRAC_ASSUMED_HIGH_BIT | rawBits & FRAC_MASK;
+               
+               
+               // Start by converting double value to BigDecimal
+               BigDecimal bd;
+               if (biasedExponent == 0x07FF) {
+                       // Special number NaN /Infinity
+                       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
+               }
+               bd = convertToBigDecimal(exponent, fracBits);
+               
+               return formatBigInteger(isNegative, bd.unscaledValue(), bd.scale());
+       }
+
+       private static BigDecimal convertToBigDecimal(int exponent, long fracBits) {
+               byte[] joob = {
+                               (byte) (fracBits >> 48),        
+                               (byte) (fracBits >> 40),        
+                               (byte) (fracBits >> 32),        
+                               (byte) (fracBits >> 24),        
+                               (byte) (fracBits >> 16),        
+                               (byte) (fracBits >>  8),        
+                               (byte) (fracBits >>  0),        
+               };
+               
+               BigInteger bigInt = new BigInteger(joob);
+               int lastSigBitIndex = exponent-FRAC_BITS_WIDTH;
+               if(lastSigBitIndex < 0) {
+                       BigInteger shifto = new BigInteger("1").shiftLeft(-lastSigBitIndex);
+                       int scale = 1 -(int) (lastSigBitIndex/LOG2_10); 
+                       BigDecimal bd1 = new BigDecimal(bigInt);
+                       BigDecimal bdShifto = new BigDecimal(shifto);
+                       return bd1.divide(bdShifto, scale, BigDecimal.ROUND_HALF_UP);
+               }
+               BigInteger sl = bigInt.shiftLeft(lastSigBitIndex);
+               return new BigDecimal(sl);
+       }
+
+       private static String formatBigInteger(boolean isNegative, BigInteger unscaledValue, int scale) {
+
+               if (scale < 0) {
+                       throw new RuntimeException("negative scale");
+               }
+               
+               StringBuffer sb = new StringBuffer(unscaledValue.toString());
+               int numberOfLeadingZeros = -1;
+               
+               int unscaledLength = sb.length();
+               if (scale > 0 && scale >= unscaledLength) {
+                       // less than one
+                       numberOfLeadingZeros = scale-unscaledLength;
+                       formatLessThanOne(sb, numberOfLeadingZeros+1);
+               } else {
+                       int decimalPointIndex = unscaledLength - scale;
+                       formatGreaterThanOne(sb, decimalPointIndex);
+               }
+               if(isNegative) {
+                       sb.insert(0, '-');
+               }
+               return sb.toString();
+       }
+       
+       private static int getNumberOfSignificantFiguresDisplayed(int exponent) {
+               int nLostDigits; // number of significand digits lost due big exponents
+               if(exponent > 99) {
+                       // any exponent greater than 99 has 3 digits instead of 2
+                       nLostDigits = 1;
+               } else if (exponent < -98) {
+                       // For some weird reason on the negative side
+                       // step is occurs from -98 to -99 (not from -99 to -100)
+                       nLostDigits = 1;
+               } else {
+                       nLostDigits = 0;
+               }
+               return DEFAULT_COUNT_SIGNIFICANT_DIGITS - nLostDigits;
+       }
+       
+       private static boolean needsScientificNotation(int nDigits) {
+               return nDigits > MAX_TEXT_LEN;
+       }
+
+       private static void formatGreaterThanOne(StringBuffer sb, int nIntegerDigits) {
+               
+               int maxSigFigs = getNumberOfSignificantFiguresDisplayed(nIntegerDigits);
+               int decimalPointIndex = nIntegerDigits;
+               boolean roundCausedCarry = performRound(sb, 0, maxSigFigs);
+
+               int endIx = Math.min(maxSigFigs, sb.length()-1);
+               
+               int nSigFigures;
+               if(roundCausedCarry) {
+                       sb.insert(0, '1');
+                       decimalPointIndex++;
+                       nSigFigures = 1;
+               } else {
+                       nSigFigures = countSignifantDigits(sb, endIx);
+               }
+
+               if(needsScientificNotation(decimalPointIndex)) {
+                       sb.setLength(nSigFigures);
+                       if (nSigFigures > 1) {
+                               sb.insert(1, '.');
+                       }
+                       sb.append("E+");
+                       appendExp(sb, decimalPointIndex-1);
+                       return;
+               }
+               if(isAllZeros(sb, decimalPointIndex, maxSigFigs)) {
+                       sb.setLength(decimalPointIndex);
+                       return;
+               }
+               // else some sig-digits after the decimal point
+               sb.setLength(nSigFigures);
+               sb.insert(decimalPointIndex, '.');
+       }
+
+       /**
+        * @param sb initially contains just the significant digits
+        * @param pAbsExponent to be inserted (after "0.") at the start of the number
+        */
+       private static void formatLessThanOne(StringBuffer sb, int pAbsExponent) {
+               if (sb.charAt(0) == 0) {
+                       throw new IllegalArgumentException("First digit of significand should be non-zero");
+               }
+               if (pAbsExponent < 1) {
+                       throw new IllegalArgumentException("abs(exponent) must be positive");
+               }
+               
+               int numberOfLeadingZeros = pAbsExponent-1;
+               int absExponent = pAbsExponent; 
+               int maxSigFigs = getNumberOfSignificantFiguresDisplayed(-absExponent); 
+               
+               boolean roundCausedCarry = performRound(sb, 0, maxSigFigs);
+               int nRemainingSigFigs;
+               if(roundCausedCarry) {
+                       absExponent--;
+                       numberOfLeadingZeros--;
+                       nRemainingSigFigs = 1;
+                       sb.setLength(0);
+                       sb.append("1");
+               } else {
+                       nRemainingSigFigs = countSignifantDigits(sb, 0 + maxSigFigs);
+                       sb.setLength(nRemainingSigFigs);
+               }
+               
+               int normalLength = 2 + numberOfLeadingZeros + nRemainingSigFigs; // 2 == "0.".length()
+               
+               if (needsScientificNotation(normalLength)) {
+                       if (sb.length()>1) {
+                               sb.insert(1, '.');
+                       }
+                       sb.append('E');
+                       sb.append('-');
+                       appendExp(sb, absExponent);
+               } else { 
+                       sb.insert(0, "0.");
+                       for(int i=numberOfLeadingZeros; i>0; i--) {
+                               sb.insert(2, '0');
+                       }
+               }
+       }
+
+       private static int countSignifantDigits(StringBuffer sb, int startIx) {
+               int result=startIx;
+               while(sb.charAt(result) == '0') {
+                       result--;
+                       if(result < 0) {
+                               throw new RuntimeException("No non-zero digits found");
+                       }
+               }
+               return result + 1;
+       }
+
+       private static void appendExp(StringBuffer sb, int val) {
+               if(val < 10) {
+                       sb.append('0');
+                       sb.append((char)('0' + val));
+                       return;
+               }
+               sb.append(val);
+               
+       }
+
+
+       private static boolean isAllZeros(StringBuffer sb, int startIx, int endIx) {
+               for(int i=startIx; i<=endIx && i<sb.length(); i++) {
+                       if(sb.charAt(i) != '0') {
+                               return false;
+                       }
+               }
+               return true;
+       }
+
+       /**
+        * @return <code>true</code> if carry (out of the MS digit) occurred
+        */
+       private static boolean performRound(StringBuffer sb, int firstSigFigIx, int nSigFigs) {
+               int nextDigitIx = firstSigFigIx + nSigFigs;
+               if(nextDigitIx == sb.length()) {
+                       return false; // nothing to do - digit to be rounded is at the end of the buffer
+               }
+               if(nextDigitIx > sb.length()) {
+                       throw new RuntimeException("Buffer too small to fit all significant digits");
+               }
+               boolean hadCarryOutOfFirstDigit;
+               if(sb.charAt(nextDigitIx) < '5') {
+                       // change to digit
+                       hadCarryOutOfFirstDigit = false;
+               } else {
+                       hadCarryOutOfFirstDigit = roundAndCarry(sb, nextDigitIx);
+               }
+               // clear out the rest of the digits after the rounded digit
+               // (at least the nearby digits)
+               int endIx = Math.min(nextDigitIx + MAX_EXTRA_ZEROS, sb.length());
+               for(int i = nextDigitIx; i<endIx; i++) {
+                       sb.setCharAt(i, '0');
+               }
+               return hadCarryOutOfFirstDigit;
+       }
+
+       private static boolean roundAndCarry(StringBuffer sb, int nextDigitIx) {
+
+               int changeDigitIx = nextDigitIx - 1;
+               while(sb.charAt(changeDigitIx) == '9') {
+                       sb.setCharAt(changeDigitIx, '0');
+                       changeDigitIx--;
+                       // All nines, rounded up.  Notify caller 
+                       if(changeDigitIx < 0) {
+                               return true;
+                       }
+               }
+               // no more '9's to round up.  
+               // Last digit to be changed is still inside sb
+               char prevDigit = sb.charAt(changeDigitIx);
+               sb.setCharAt(changeDigitIx, (char) (prevDigit + 1));
+               return false;
+       }
+}
index 69a68c8b31c2f5fab552a1412c1afa438ed80853..abc494c3dc3dc067c830e7c1718544a47b441746 100644 (file)
@@ -264,12 +264,7 @@ public class LittleEndian implements LittleEndianConsts {
      *@param  value   the double (64-bit) value
      */
     public static void putDouble(byte[] data, int offset, double value) {
-        // Excel likes NaN to be a specific value.
-        if (Double.isNaN(value)) {
-            putLong(data, offset, -276939487313920L);
-        } else {
-            putLong(data, offset, Double.doubleToLongBits(value));
-        }
+        putLong(data, offset, Double.doubleToLongBits(value));
     }
 
 
index d5a491099dff41a8e2942056e634456891bb964a..fac6e0db308362be5ba2116c4452dd978459a40b 100644 (file)
@@ -29,6 +29,7 @@ import org.apache.poi.hssf.record.AllRecordTests;
 import org.apache.poi.hssf.usermodel.AllUserModelTests;
 import org.apache.poi.hssf.util.AllHSSFUtilTests;
 import org.apache.poi.ss.formula.AllSSFormulaTests;
+import org.apache.poi.ss.util.AllSSUtilTests;
 
 /**
  * Test Suite for all sub-packages of org.apache.poi.hssf<br/>
@@ -54,6 +55,7 @@ public final class HSSFTests {
         suite.addTest(new TestSuite(TestEventRecordFactory.class));
         suite.addTest(new TestSuite(TestModelFactory.class));
         suite.addTest(AllSSFormulaTests.suite());
+        suite.addTest(AllSSUtilTests.suite());
         return suite;
     }
 }
index fe248ca8b50f366bb76e044de4db32068ee86a03..c8a46a8ddecd81d56da8f0709d2618fb93fa047b 100644 (file)
@@ -283,63 +283,63 @@ public final class TestFormulaParser extends TestCase {
 
                cell.setCellFormula("1.3E21/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1.3E21/3", formula);
+               assertEquals("Exponential formula string", "1.3E+21/3", formula);
 
                cell.setCellFormula("-1.3E21/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.3E21/3", formula);
+               assertEquals("Exponential formula string", "-1.3E+21/3", formula);
 
                cell.setCellFormula("1322E21/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1.322E24/3", formula);
+               assertEquals("Exponential formula string", "1.322E+24/3", formula);
 
                cell.setCellFormula("-1322E21/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.322E24/3", formula);
+               assertEquals("Exponential formula string", "-1.322E+24/3", formula);
 
                cell.setCellFormula("1.3E1/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "13.0/3", formula);
+               assertEquals("Exponential formula string", "13/3", formula);
 
                cell.setCellFormula("-1.3E1/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-13.0/3", formula);
+               assertEquals("Exponential formula string", "-13/3", formula);
 
                cell.setCellFormula("1.3E-4/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1.3E-4/3", formula);
+               assertEquals("Exponential formula string", "0.00013/3", formula);
 
                cell.setCellFormula("-1.3E-4/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.3E-4/3", formula);
+               assertEquals("Exponential formula string", "-0.00013/3", formula);
 
                cell.setCellFormula("13E-15/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1.3E-14/3", formula);
+        assertEquals("Exponential formula string", "0.000000000000013/3", formula);
 
                cell.setCellFormula("-13E-15/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.3E-14/3", formula);
+        assertEquals("Exponential formula string", "-0.000000000000013/3", formula);
 
                cell.setCellFormula("1.3E3/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1300.0/3", formula);
+        assertEquals("Exponential formula string", "1300/3", formula);
 
                cell.setCellFormula("-1.3E3/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1300.0/3", formula);
+        assertEquals("Exponential formula string", "-1300/3", formula);
 
                cell.setCellFormula("1300000000000000/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "1.3E15/3", formula);
+        assertEquals("Exponential formula string", "1300000000000000/3", formula);
 
                cell.setCellFormula("-1300000000000000/3");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.3E15/3", formula);
+        assertEquals("Exponential formula string", "-1300000000000000/3", formula);
 
                cell.setCellFormula("-10E-1/3.1E2*4E3/3E4");
                formula = cell.getCellFormula();
-               assertEquals("Exponential formula string", "-1.0/310.0*4000.0/30000.0", formula);
+        assertEquals("Exponential formula string", "-1/310*4000/30000", formula);
        }
 
        public void testNumbers() {
@@ -370,15 +370,15 @@ public final class TestFormulaParser extends TestCase {
 
                cell.setCellFormula("10E1");
                formula = cell.getCellFormula();
-               assertEquals("100.0", formula);
+        assertEquals("100", formula);
 
                cell.setCellFormula("10E+1");
                formula = cell.getCellFormula();
-               assertEquals("100.0", formula);
+        assertEquals("100", formula);
 
                cell.setCellFormula("10E-1");
                formula = cell.getCellFormula();
-               assertEquals("1.0", formula);
+        assertEquals("1", formula);
        }
 
        public void testRanges() {
index a2bb0f6adb0581dcf683fdefbf56532fcde779d4..a919c35af488c10a8c38b72d5c66d2e8d5a8aa38 100644 (file)
 
 package org.apache.poi.hssf.record.formula.functions;
 
+import junit.framework.TestCase;
+
 import org.apache.poi.hssf.record.formula.eval.Eval;
 import org.apache.poi.hssf.record.formula.eval.NumberEval;
 import org.apache.poi.hssf.usermodel.HSSFCell;
 import org.apache.poi.hssf.usermodel.HSSFErrorConstants;
-import org.apache.poi.hssf.usermodel.HSSFFont;
 import org.apache.poi.hssf.usermodel.HSSFFormulaEvaluator;
 import org.apache.poi.hssf.usermodel.HSSFSheet;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 
-import junit.framework.AssertionFailedError;
-import junit.framework.TestCase;
-
 /**
+ * Tests for {@link FinanceFunction#NPER}
  * 
  * @author Josh Micich
  */
 public final class TestNper extends TestCase {
        public void testSimpleEvaluate() {
-               
+
                Eval[] args = {
                        new NumberEval(0.05),
                        new NumberEval(250),
                        new NumberEval(-1000),
                };
                Eval result = FinanceFunction.NPER.evaluate(args, 0, (short)0);
-               
+
                assertEquals(NumberEval.class, result.getClass());
                assertEquals(4.57353557, ((NumberEval)result).getNumberValue(), 0.00000001);
        }
-       
+
        public void testEvaluate_bug_45732() {
                HSSFWorkbook wb = new HSSFWorkbook();
                HSSFSheet sheet = wb.createSheet("Sheet1");
                HSSFCell cell = sheet.createRow(0).createCell(0);
-               
+
                cell.setCellFormula("NPER(12,4500,100000,100000)");
                cell.setCellValue(15.0);
-               assertEquals("NPER(12,4500,100000.0,100000.0)", cell.getCellFormula());
+               assertEquals("NPER(12,4500,100000,100000)", cell.getCellFormula());
                assertEquals(HSSFCell.CELL_TYPE_NUMERIC, cell.getCachedFormulaResultType());
                assertEquals(15.0, cell.getNumericCellValue(), 0.0);
-               
+
                HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
                fe.evaluateFormulaCell(cell);
                assertEquals(HSSFCell.CELL_TYPE_ERROR, cell.getCachedFormulaResultType());
                assertEquals(HSSFErrorConstants.ERROR_NUM, cell.getErrorCellValue());
        }
-       
 }
index 402ee797a91976cee5d9b0a20bd04efb4ef296fe..2c28be65016d2c92b93c0a6c553a2a94cf127a23 100644 (file)
@@ -419,7 +419,7 @@ public final class TestBugs extends TestCase {
           if (name.isFunctionName()) {
               continue;
           }
-          name.getReference();
+          name.getRefersToFormula();
         }
     }
 
@@ -1070,8 +1070,8 @@ public final class TestBugs extends TestCase {
         HSSFSheet s = wb.createSheet();
         s.createRow(0);
         s.createRow(1);
-        HSSFCell c1 = s.getRow(0).createCell(0);
-        HSSFCell c2 = s.getRow(1).createCell(0);
+        s.getRow(0).createCell(0);
+        s.getRow(1).createCell(0);
 
         assertEquals(4, wb.getNumberOfFonts());
 
@@ -1162,7 +1162,7 @@ public final class TestBugs extends TestCase {
         c3.setCellFormula("\"90210\"");
 
         // Check the formulas
-        assertEquals("70164.0", c1.getCellFormula());
+        assertEquals("70164", c1.getCellFormula());
         assertEquals("\"70164\"", c2.getCellFormula());
 
         // And check the values - blank
@@ -1415,67 +1415,67 @@ public final class TestBugs extends TestCase {
         assertFalse(nwb.isSheetHidden(2));
         assertTrue(nwb.isSheetVeryHidden(2));
     }
-    
+
     /**
      * header / footer text too long
      */
     public void test45777() {
-       HSSFWorkbook wb = new HSSFWorkbook();
-       HSSFSheet s = wb.createSheet();
-       
-       String s248 = "";
-       for(int i=0; i<248; i++) {
-               s248 += "x";
-       }
-       String s249 = s248 + "1";
-       String s250 = s248 + "12";
-       String s251 = s248 + "123";
-       assertEquals(248, s248.length());
-       assertEquals(249, s249.length());
-       assertEquals(250, s250.length());
-       assertEquals(251, s251.length());
-       
-       
-       // Try on headers
-       s.getHeader().setCenter(s248);
-       assertEquals(254, s.getHeader().getRawHeader().length());
-       writeOutAndReadBack(wb);
-       
-       s.getHeader().setCenter(s249);
-       assertEquals(255, s.getHeader().getRawHeader().length());
-       writeOutAndReadBack(wb);
-       
-       try {
-               s.getHeader().setCenter(s250); // 256
-               fail();
-       } catch(IllegalArgumentException e) {}
-       
-       try {
-               s.getHeader().setCenter(s251); // 257
-               fail();
-       } catch(IllegalArgumentException e) {}
-       
-       
-       // Now try on footers
-       s.getFooter().setCenter(s248);
-       assertEquals(254, s.getFooter().getRawFooter().length());
-       writeOutAndReadBack(wb);
-       
-       s.getFooter().setCenter(s249);
-       assertEquals(255, s.getFooter().getRawFooter().length());
-       writeOutAndReadBack(wb);
-       
-       try {
-               s.getFooter().setCenter(s250); // 256
-               fail();
-       } catch(IllegalArgumentException e) {}
-       
-       try {
-               s.getFooter().setCenter(s251); // 257
-               fail();
-       } catch(IllegalArgumentException e) {}
-    }
-    
+        HSSFWorkbook wb = new HSSFWorkbook();
+        HSSFSheet s = wb.createSheet();
+
+        String s248 = "";
+        for(int i=0; i<248; i++) {
+            s248 += "x";
+        }
+        String s249 = s248 + "1";
+        String s250 = s248 + "12";
+        String s251 = s248 + "123";
+        assertEquals(248, s248.length());
+        assertEquals(249, s249.length());
+        assertEquals(250, s250.length());
+        assertEquals(251, s251.length());
+
+
+        // Try on headers
+        s.getHeader().setCenter(s248);
+        assertEquals(254, s.getHeader().getRawHeader().length());
+        writeOutAndReadBack(wb);
+
+        s.getHeader().setCenter(s249);
+        assertEquals(255, s.getHeader().getRawHeader().length());
+        writeOutAndReadBack(wb);
+
+        try {
+            s.getHeader().setCenter(s250); // 256
+            fail();
+        } catch(IllegalArgumentException e) {}
+
+        try {
+            s.getHeader().setCenter(s251); // 257
+            fail();
+        } catch(IllegalArgumentException e) {}
+
+
+        // Now try on footers
+        s.getFooter().setCenter(s248);
+        assertEquals(254, s.getFooter().getRawFooter().length());
+        writeOutAndReadBack(wb);
+
+        s.getFooter().setCenter(s249);
+        assertEquals(255, s.getFooter().getRawFooter().length());
+        writeOutAndReadBack(wb);
+
+        try {
+            s.getFooter().setCenter(s250); // 256
+            fail();
+        } catch(IllegalArgumentException e) {}
+
+        try {
+            s.getFooter().setCenter(s251); // 257
+            fail();
+        } catch(IllegalArgumentException e) {}
+    }
+
     /**
      * Charts with long titles
      */
@@ -1485,43 +1485,43 @@ public final class TestBugs extends TestCase {
         assertEquals(1, wb.getNumberOfSheets());
         wb = HSSFTestDataSamples.writeOutAndReadBack(wb);
     }
-    
+
    /**
      * Cell background colours
      */
     public void test45492() {
-       HSSFWorkbook wb = openSample("45492.xls");
-       HSSFSheet s = wb.getSheetAt(0);
-       HSSFRow r = s.getRow(0);
-       HSSFPalette p = wb.getCustomPalette();
-       
-       HSSFCell auto = r.getCell(0);
-       HSSFCell grey = r.getCell(1);
-       HSSFCell red = r.getCell(2);
-       HSSFCell blue = r.getCell(3);
-       HSSFCell green = r.getCell(4);
-       
-       assertEquals(64, auto.getCellStyle().getFillForegroundColor());
-       assertEquals(64, auto.getCellStyle().getFillBackgroundColor());
-       assertEquals("0:0:0", p.getColor(64).getHexString());
-       
-       assertEquals(22, grey.getCellStyle().getFillForegroundColor());
-       assertEquals(64, grey.getCellStyle().getFillBackgroundColor());
-       assertEquals("C0C0:C0C0:C0C0", p.getColor(22).getHexString());
-       
-       assertEquals(10, red.getCellStyle().getFillForegroundColor());
-       assertEquals(64, red.getCellStyle().getFillBackgroundColor());
-       assertEquals("FFFF:0:0", p.getColor(10).getHexString());
-       
-       assertEquals(12, blue.getCellStyle().getFillForegroundColor());
-       assertEquals(64, blue.getCellStyle().getFillBackgroundColor());
-       assertEquals("0:0:FFFF", p.getColor(12).getHexString());
-       
-       assertEquals(11, green.getCellStyle().getFillForegroundColor());
-       assertEquals(64, green.getCellStyle().getFillBackgroundColor());
-       assertEquals("0:FFFF:0", p.getColor(11).getHexString());
-    }
-    
+        HSSFWorkbook wb = openSample("45492.xls");
+        HSSFSheet s = wb.getSheetAt(0);
+        HSSFRow r = s.getRow(0);
+        HSSFPalette p = wb.getCustomPalette();
+
+        HSSFCell auto = r.getCell(0);
+        HSSFCell grey = r.getCell(1);
+        HSSFCell red = r.getCell(2);
+        HSSFCell blue = r.getCell(3);
+        HSSFCell green = r.getCell(4);
+
+        assertEquals(64, auto.getCellStyle().getFillForegroundColor());
+        assertEquals(64, auto.getCellStyle().getFillBackgroundColor());
+        assertEquals("0:0:0", p.getColor(64).getHexString());
+
+        assertEquals(22, grey.getCellStyle().getFillForegroundColor());
+        assertEquals(64, grey.getCellStyle().getFillBackgroundColor());
+        assertEquals("C0C0:C0C0:C0C0", p.getColor(22).getHexString());
+
+        assertEquals(10, red.getCellStyle().getFillForegroundColor());
+        assertEquals(64, red.getCellStyle().getFillBackgroundColor());
+        assertEquals("FFFF:0:0", p.getColor(10).getHexString());
+
+        assertEquals(12, blue.getCellStyle().getFillForegroundColor());
+        assertEquals(64, blue.getCellStyle().getFillBackgroundColor());
+        assertEquals("0:0:FFFF", p.getColor(12).getHexString());
+
+        assertEquals(11, green.getCellStyle().getFillForegroundColor());
+        assertEquals(64, green.getCellStyle().getFillBackgroundColor());
+        assertEquals("0:FFFF:0", p.getColor(11).getHexString());
+    }
+
     /**
      * ContinueRecord after EOF
      */
@@ -1531,7 +1531,7 @@ public final class TestBugs extends TestCase {
         assertEquals(7, wb.getNumberOfSheets());
         wb = HSSFTestDataSamples.writeOutAndReadBack(wb);
     }
-    
+
     /**
      * Odd POIFS blocks issue:
      * block[ 44 ] already removed from org.apache.poi.poifs.storage.BlockListImpl.remove
index ce57c28594f18a84c77a532d96c217df46f35758..ba791bf58a4e9099e19864ec405194449012178c 100644 (file)
@@ -151,7 +151,7 @@ public final class TestFormulaEvaluatorBugs extends TestCase {
 
                row = sheet.getRow(8);
                cell = row.getCell(0);
-               assertEquals("327680.0/32768", cell.getCellFormula());
+               assertEquals("327680/32768", cell.getCellFormula());
                assertEquals(10, eva.evaluate(cell).getNumberValue(), 0);
 
                row = sheet.getRow(9);
@@ -166,15 +166,9 @@ public final class TestFormulaEvaluatorBugs extends TestCase {
 
                row = sheet.getRow(11);
                cell = row.getCell(0);
-               assertEquals("-1000000.0-3000000.0", cell.getCellFormula());
+               assertEquals("-1000000-3000000", cell.getCellFormula());
                assertEquals(-4000000, eva.evaluate(cell).getNumberValue(), 0);
        }
-//     public static void main(String[] args) {
-//             new TestFormulaEvaluatorBugs().test44410();
-//             new TestFormulaEvaluatorBugs().testSlowEvaluate45376();
-//             new HSSFWorkbook();
-//             System.out.println("done");
-//     }
 
        /**
         * Bug 44410: SUM(C:C) is valid in excel, and means a sum
diff --git a/src/testcases/org/apache/poi/ss/util/AllSSUtilTests.java b/src/testcases/org/apache/poi/ss/util/AllSSUtilTests.java
new file mode 100644 (file)
index 0000000..9da4c2c
--- /dev/null
@@ -0,0 +1,35 @@
+/* ====================================================================
+   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.util;
+
+import junit.framework.Test;
+import junit.framework.TestSuite;
+/**
+ * Test suite for <tt>org.apache.poi.ss.util</tt>
+ * 
+ * @author Josh Micich
+ */
+public final class AllSSUtilTests {
+    public static Test suite() {
+               TestSuite result = new TestSuite(AllSSUtilTests.class.getName());
+               result.addTestSuite(TestCellReference.class);
+               result.addTestSuite(TestNumberToTextConverter.class);
+               result.addTestSuite(TestRegion.class);
+               return result;
+       }
+}
diff --git a/src/testcases/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java b/src/testcases/org/apache/poi/ss/util/NumberRenderingSpreadsheetGenerator.java
new file mode 100644 (file)
index 0000000..a03bfb0
--- /dev/null
@@ -0,0 +1,251 @@
+/* ====================================================================
+   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.util;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.poi.hssf.usermodel.HSSFCell;
+import org.apache.poi.hssf.usermodel.HSSFCellStyle;
+import org.apache.poi.hssf.usermodel.HSSFFont;
+import org.apache.poi.hssf.usermodel.HSSFRichTextString;
+import org.apache.poi.hssf.usermodel.HSSFRow;
+import org.apache.poi.hssf.usermodel.HSSFSheet;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.util.NumberToTextConversionExamples.ExampleConversion;
+import org.apache.poi.util.HexDump;
+import org.apache.poi.util.HexRead;
+
+/**
+ * Creates a spreadsheet that demonstrates Excel's rendering of various IEEE double values.
+ * 
+ * @author Josh Micich
+ */
+public class NumberRenderingSpreadsheetGenerator {
+
+       private static final class SheetWriter {
+
+               private final HSSFSheet _sheet;
+               private int _rowIndex;
+               private final List<Long> _replacementNaNs;
+
+               public SheetWriter(HSSFWorkbook wb) {
+                       HSSFSheet sheet = wb.createSheet("Sheet1");
+
+                       writeHeaderRow(wb, sheet);
+                       _sheet = sheet;
+                       _rowIndex = 1;
+                       _replacementNaNs = new ArrayList<Long>();
+               }
+
+               public void addTestRow(long rawBits, String expectedExcelRendering) {
+                       writeDataRow(_sheet, _rowIndex++, rawBits, expectedExcelRendering);
+                       if(Double.isNaN(Double.longBitsToDouble(rawBits))) {
+                               _replacementNaNs.add(new Long(rawBits));
+                       }
+               }
+
+               public long[] getReplacementNaNs() {
+                       int nRepls = _replacementNaNs.size();
+                       long[] result = new long[nRepls];
+                       for (int i = 0; i < nRepls; i++) {
+                               result[i] = _replacementNaNs.get(i).longValue();
+                       }
+                       return result;
+               }
+
+       }
+       /** 0x7ff8000000000000 encoded in little endian order */
+       private static final byte[] JAVA_NAN_BYTES = HexRead.readFromString("00 00 00 00 00 00 F8 7F");
+       
+       private static void writeHeaderCell(HSSFRow row, int i, String text, HSSFCellStyle style) {
+               HSSFCell cell = row.createCell(i);
+               cell.setCellValue(new HSSFRichTextString(text));
+               cell.setCellStyle(style);
+       }
+       static void writeHeaderRow(HSSFWorkbook wb, HSSFSheet sheet) {
+               sheet.setColumnWidth(0, 3000);
+               sheet.setColumnWidth(1, 6000);
+               sheet.setColumnWidth(2, 6000);
+               sheet.setColumnWidth(3, 6000);
+               sheet.setColumnWidth(4, 6000);
+               sheet.setColumnWidth(5, 1600);
+               sheet.setColumnWidth(6, 20000);
+               HSSFRow row = sheet.createRow(0);
+               HSSFCellStyle style = wb.createCellStyle();
+               HSSFFont font = wb.createFont();
+               font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
+               style.setFont(font);
+               writeHeaderCell(row, 0, "Value", style);
+               writeHeaderCell(row, 1, "Raw Long Bits", style);
+               writeHeaderCell(row, 2, "JDK Double Rendering", style);
+               writeHeaderCell(row, 3, "Actual Rendering", style);
+               writeHeaderCell(row, 4, "Expected Rendering", style);
+               writeHeaderCell(row, 5, "Match", style);  
+               writeHeaderCell(row, 6, "Java Metadata", style);
+       }
+       static void writeDataRow(HSSFSheet sheet, int rowIx, long rawLongBits, String expectedExcelRendering) {
+               double d = Double.longBitsToDouble(rawLongBits);
+               HSSFRow row = sheet.createRow(rowIx);
+               
+               int rowNum = rowIx + 1;
+               String cel0ref = "A" + rowNum;
+               String rawBitsText = formatLongAsHex(rawLongBits);
+               String jmExpr = "'ec(" + rawBitsText + ", ''\" & C" + rowNum + " & \"'', ''\" & D" + rowNum + " & \"''),'";
+               
+               // The 'Match' column will contain 'OK' if the metadata (from NumberToTextConversionExamples)
+               // matches Excel's rendering.
+               String matchExpr = "if(D" + rowNum + "=E" + rowNum + ", \"OK\", \"ERROR\")";
+               
+               row.createCell(0).setCellValue(d);
+               row.createCell(1).setCellValue(new HSSFRichTextString(rawBitsText));
+               row.createCell(2).setCellValue(new HSSFRichTextString(Double.toString(d)));
+               row.createCell(3).setCellFormula("\"\" & " + cel0ref);
+               row.createCell(4).setCellValue(new HSSFRichTextString(expectedExcelRendering));
+               row.createCell(5).setCellFormula(matchExpr);
+               row.createCell(6).setCellFormula(jmExpr.replaceAll("'", "\""));
+
+               if (false) {
+                       // for observing arithmetic near numeric range boundaries
+                       row.createCell(7).setCellFormula(cel0ref + " * 1.0001");
+                       row.createCell(8).setCellFormula(cel0ref + " / 1.0001");
+               }
+       }
+       
+       private static String formatLongAsHex(long l) {
+               StringBuilder sb = new StringBuilder(20);
+               sb.append(HexDump.longToHex(l)).append('L');
+               return sb.toString();
+       }
+
+       public static void main(String[] args) {
+               writeJavaDoc();
+               
+               HSSFWorkbook wb = new HSSFWorkbook();
+               SheetWriter sw = new SheetWriter(wb);
+               
+               ExampleConversion[] exampleValues = NumberToTextConversionExamples.getExampleConversions();
+               for (int i = 0; i < exampleValues.length; i++) {
+                       ExampleConversion example = exampleValues[i];
+                       sw.addTestRow(example.getRawDoubleBits(), example.getExcelRendering());
+               }
+               
+               ByteArrayOutputStream baos = new ByteArrayOutputStream();
+               try {
+                       wb.write(baos);
+               } catch (IOException e) {
+                       throw new RuntimeException(e);
+               }
+               byte[] fileContent = baos.toByteArray();
+               replaceNaNs(fileContent, sw.getReplacementNaNs());
+               
+               
+               File outputFile = new File("ExcelNumberRendering.xls");
+               
+               try {
+                       FileOutputStream os = new FileOutputStream(outputFile);
+                       os.write(fileContent);
+                       os.close();
+               } catch (IOException e) {
+                       throw new RuntimeException(e);
+               }
+               System.out.println("Finished writing '" + outputFile.getAbsolutePath() + "'");
+       }
+
+       public static void writeJavaDoc() {
+               
+               ExampleConversion[] exampleConversions = NumberToTextConversionExamples.getExampleConversions();
+               for (int i = 0; i < exampleConversions.length; i++) {
+                       ExampleConversion ec = exampleConversions[i];
+                       String line =   " * <tr><td>" 
+                               + formatLongAsHex(ec.getRawDoubleBits())
+                               + "</td><td>" + Double.toString(ec.getDoubleValue()) 
+                               + "</td><td>" + ec.getExcelRendering() + "</td></tr>";
+                       
+                       System.out.println(line);
+               }
+       }
+
+       
+       
+       private static void replaceNaNs(byte[] fileContent, long[] replacementNaNs) {
+               int countFound = 0;
+               for(int i=0; i<fileContent.length; i++) {
+                       if(isNaNBytes(fileContent, i)) {
+                               writeLong(fileContent, i, replacementNaNs[countFound]);
+                               countFound++;
+                       }
+               }
+               if (countFound < replacementNaNs.length) {
+                       throw new RuntimeException("wrong repl count");
+               }
+               
+       }
+
+       private static void writeLong(byte[] bb, int i, long val) {
+               String oldVal = interpretLong(bb, i);
+               bb[i+7] = (byte) (val >> 56);
+               bb[i+6] = (byte) (val >> 48);
+               bb[i+5] = (byte) (val >> 40);
+               bb[i+4] = (byte) (val >> 32);
+               bb[i+3] = (byte) (val >> 24);
+               bb[i+2] = (byte) (val >> 16);
+               bb[i+1] = (byte) (val >>  8);
+               bb[i+0] = (byte) (val >>  0);
+               if (false) {
+                       String newVal = interpretLong(bb, i);
+                       System.out.println("changed offset " + i + " from " + oldVal + " to " + newVal);
+               }
+               
+       }
+
+       private static String interpretLong(byte[] fileContent, int offset) {
+               InputStream is = new ByteArrayInputStream(fileContent, offset, 8);
+               long l;
+               try {
+                       l = new DataInputStream(is).readLong();
+               } catch (IOException e) {
+                       throw new RuntimeException(e);
+               }
+               return "0x" + Long.toHexString(l).toUpperCase();
+       }
+
+       private static boolean isNaNBytes(byte[] fileContent, int offset) {
+               if(offset + JAVA_NAN_BYTES.length > fileContent.length) {
+                       return false;
+               }
+               // excel NaN bits: 0xFFFF0420003C0000L
+               // java NaN bits :0x7ff8000000000000L
+               return areArraySectionsEqual(fileContent, offset, JAVA_NAN_BYTES);
+       }
+       private static boolean areArraySectionsEqual(byte[] bb, int off, byte[] section) {
+               for (int i=section.length-1; i>=0; i--) {
+                       if (bb[off+i] != section[i]){
+                               return false;
+                       }
+               }
+               return true;
+       }
+}
diff --git a/src/testcases/org/apache/poi/ss/util/NumberToTextConversionExamples.java b/src/testcases/org/apache/poi/ss/util/NumberToTextConversionExamples.java
new file mode 100644 (file)
index 0000000..59cc560
--- /dev/null
@@ -0,0 +1,183 @@
+/* ====================================================================
+   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.util;
+/**
+ * Contains specific examples of <tt>double</tt> values and their rendering in Excel.
+ * 
+ * @author Josh Micich
+ */
+final class NumberToTextConversionExamples {
+
+       private NumberToTextConversionExamples() {
+               // no instances of this class
+       }
+
+       public static final class ExampleConversion {
+               private final String _javaRendering;
+               private final String _excelRendering;
+               private final double _doubleValue;
+               private final long _rawDoubleBits;
+
+               ExampleConversion(long rawDoubleBits, String javaRendering, String excelRendering) {
+                       double d = Double.longBitsToDouble(rawDoubleBits);
+                       if ("NaN".equals(javaRendering)) {
+                               if (!Double.isNaN(d)) {
+                                       throw new IllegalArgumentException("value must be NaN");
+                               }
+                       } else {
+                               if (Double.isNaN(d)) {
+                                       throw new IllegalArgumentException("value must not be NaN");
+                               }
+                               // just to be dead sure test conversion in java both ways
+                               boolean javaToStringOk = javaRendering.equals(Double.toString(d));
+                               boolean javaParseOk = Double.parseDouble(javaRendering) == d;
+                               if(!javaToStringOk || !javaParseOk) {
+                                       String msgA = "Specified rawDoubleBits " + doubleToHexString(d) + " encodes to double '" + d + "'.";
+                                       String msgB = "Specified javaRendering '" + javaRendering+ "' parses as double with rawDoubleBits "
+                                               + doubleToHexString(Double.parseDouble(javaRendering));
+                                       System.err.println(msgA);
+                                       System.err.println(msgB);
+
+                                       throw new RuntimeException(msgA + msgB);
+                               }
+                       }
+                       _rawDoubleBits = rawDoubleBits;
+                       _javaRendering = javaRendering;
+                       _excelRendering = excelRendering;
+                       _doubleValue = d;
+               }
+               private static String doubleToHexString(double d) {
+                       return "0x" + Long.toHexString(Double.doubleToLongBits(d)).toUpperCase() + "L";
+               }
+               public String getJavaRendering() {
+                       return _javaRendering;
+               }
+               public String getExcelRendering() {
+                       return _excelRendering;
+               }
+               public double getDoubleValue() {
+                       return _doubleValue;
+               }
+               public boolean isNaN() {
+                       return Double.isNaN(_doubleValue);
+               }
+               public long getRawDoubleBits() {
+                       return _rawDoubleBits;
+               }
+       }
+
+       
+       private static final ExampleConversion[] examples = {
+               // basic numbers
+               ec(0x0000000000000000L, "0.0", "0"),
+               ec(0x3FF0000000000000L, "1.0", "1"),
+               ec(0x3FF00068DB8BAC71L, "1.0001", "1.0001"),
+               ec(0x4087A00000000000L, "756.0", "756"),
+               ec(0x401E3D70A3D70A3DL, "7.56", "7.56"),
+               
+               ec(0x405EDD3C07FB4C99L, "123.45678901234568", "123.456789012346"),
+               ec(0x4132D687E3DF2180L, "1234567.8901234567", "1234567.89012346"),
+               
+               // small numbers
+               ec(0x3EE9E409302678BAL, "1.2345678901234568E-5", "1.23456789012346E-05"),
+               ec(0x3F202E85BE180B74L, "1.2345678901234567E-4", "0.000123456789012346"),
+               ec(0x3F543A272D9E0E51L, "0.0012345678901234567", "0.00123456789012346"),
+               ec(0x3F8948B0F90591E6L, "0.012345678901234568", "0.0123456789012346"),
+
+               ec(0x3EE9E409301B5A02L, "1.23456789E-5", "0.0000123456789"),
+               
+               ec(0x3E6E7D05BDABDE50L, "5.6789012345E-8", "0.000000056789012345"),
+               ec(0x3E6E7D05BDAD407EL, "5.67890123456E-8", "5.67890123456E-08"),
+               ec(0x3E6E7D06029F18BEL, "5.678902E-8", "0.00000005678902"),
+
+               ec(0x2BCB5733CB32AE6EL, "9.999999999999123E-98",  "9.99999999999912E-98"),
+               ec(0x2B617F7D4ED8C59EL, "1.0000000000001235E-99", "1.0000000000001E-99"),
+               ec(0x0036319916D67853L, "1.2345678901234578E-307", "1.2345678901235E-307"),
+
+               ec(0x359DEE7A4AD4B81FL, "2.0E-50", "2E-50"),
+
+               // large numbers
+               ec(0x41678C29DCD6E9E0L, "1.2345678901234567E7", "12345678.9012346"),
+               ec(0x42A674E79C5FE523L, "1.2345678901234568E13", "12345678901234.6"),
+               ec(0x42DC12218377DE6BL, "1.2345678901234567E14", "123456789012346"),
+               ec(0x43118B54F22AEB03L, "1.2345678901234568E15", "1234567890123460"),
+               ec(0x43E56A95319D63E1L, "1.2345678901234567E19", "12345678901234600000"),
+               ec(0x441AC53A7E04BCDAL, "1.2345678901234568E20", "1.23456789012346E+20"),
+               ec(0xC3E56A95319D63E1L, "-1.2345678901234567E19", "-12345678901234600000"),
+               ec(0xC41AC53A7E04BCDAL, "-1.2345678901234568E20", "-1.23456789012346E+20"),
+
+               ec(0x54820FE0BA17F46DL, "1.2345678901234577E99", "1.2345678901235E+99"),
+               ec(0x54B693D8E89DF188L, "1.2345678901234576E100", "1.2345678901235E+100"),
+               
+               ec(0x4A611B0EC57E649AL, "2.0E50", "2E+50"),
+               
+               // range extremities
+               ec(0x7FEFFFFFFFFFFFFFL, "1.7976931348623157E308", "1.7976931348623E+308"),
+               ec(0x0010000000000000L, "2.2250738585072014E-308", "2.2250738585072E-308"),
+               ec(0x000FFFFFFFFFFFFFL, "2.225073858507201E-308", "0"),
+               ec(0x0000000000000001L, "4.9E-324", "0"),
+               
+               // infinity
+               ec(0x7FF0000000000000L, "Infinity", "1.7976931348623E+308"),
+               ec(0xFFF0000000000000L, "-Infinity", "1.7976931348623E+308"),
+
+               // shortening due to rounding
+               ec(0x441AC7A08EAD02F2L, "1.234999999999999E20", "1.235E+20"),
+               ec(0x40FE26BFFFFFFFF9L, "123499.9999999999", "123500"),
+               ec(0x3E4A857BFB2F2809L, "1.234999999999999E-8", "0.00000001235"),
+               ec(0x3BCD291DEF868C89L, "1.234999999999999E-20", "1.235E-20"),
+
+               // carry up due to rounding
+               // For clarity these tests choose values that don't round in java,
+               // but will round in excel. In some cases there is almost no difference
+               // between excel and java (e.g. 9.9..9E-8)
+               ec(0x444B1AE4D6E2EF4FL, "9.999999999999999E20", "1E+21"),
+               ec(0x412E847FFFFFFFFFL, "999999.9999999999", "1000000"),
+               ec(0x3E45798EE2308C39L, "9.999999999999999E-9", "0.00000001"),
+               ec(0x3C32725DD1D243ABL, "9.999999999999999E-19", "0.000000000000000001"),
+               ec(0x3BFD83C94FB6D2ABL, "9.999999999999999E-20", "1E-19"),
+
+               ec(0xC44B1AE4D6E2EF4FL, "-9.999999999999999E20", "-1E+21"),
+               ec(0xC12E847FFFFFFFFFL, "-999999.9999999999", "-1000000"),
+               ec(0xBE45798EE2308C39L, "-9.999999999999999E-9", "-0.00000001"),
+               ec(0xBC32725DD1D243ABL, "-9.999999999999999E-19", "-0.000000000000000001"),
+               ec(0xBBFD83C94FB6D2ABL, "-9.999999999999999E-20", "-1E-19"),
+
+               
+               // NaNs
+               // Currently these test cases are not critical, since other limitations prevent any variety in
+               // or control of the bit patterns used to encode NaNs in evaluations.
+               ec(0xFFFF0420003C0000L, "NaN", "3.484840871308E+308"),
+               ec(0x7FF8000000000000L, "NaN", "2.6965397022935E+308"),
+               ec(0x7FFF0420003C0000L, "NaN", "3.484840871308E+308"),
+               ec(0xFFF8000000000000L, "NaN", "2.6965397022935E+308"),
+               ec(0xFFFF0AAAAAAAAAAAL, "NaN", "3.4877119413344E+308"),
+               ec(0x7FF80AAAAAAAAAAAL, "NaN", "2.7012211948322E+308"),
+               ec(0xFFFFFFFFFFFFFFFFL, "NaN", "3.5953862697246E+308"),
+               ec(0x7FFFFFFFFFFFFFFFL, "NaN", "3.5953862697246E+308"),
+               ec(0xFFF7FFFFFFFFFFFFL, "NaN", "2.6965397022935E+308"),
+       };
+       
+       private static ExampleConversion ec(long rawDoubleBits, String javaRendering, String excelRendering) {
+               return new ExampleConversion(rawDoubleBits, javaRendering, excelRendering);
+       }
+       
+       public static ExampleConversion[] getExampleConversions() {
+               return examples.clone();
+       }
+}
diff --git a/src/testcases/org/apache/poi/ss/util/TestNumberToTextConverter.java b/src/testcases/org/apache/poi/ss/util/TestNumberToTextConverter.java
new file mode 100644 (file)
index 0000000..9fa5aa1
--- /dev/null
@@ -0,0 +1,128 @@
+/* ====================================================================
+   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.util;
+
+import junit.framework.AssertionFailedError;
+import junit.framework.ComparisonFailure;
+import junit.framework.TestCase;
+
+import org.apache.poi.hssf.biff2.record.BIFF2RecordFactory.NumberRecord;
+import org.apache.poi.hssf.record.FormulaRecord;
+import org.apache.poi.hssf.record.constant.ConstantValueParser;
+import org.apache.poi.hssf.record.formula.NumberPtg;
+import org.apache.poi.ss.util.NumberToTextConverter;
+import org.apache.poi.ss.util.NumberToTextConversionExamples.ExampleConversion;
+/**
+ * Tests for {@link NumberToTextConverter}
+ * 
+ * @author Josh Micich
+ */
+public final class TestNumberToTextConverter extends TestCase {
+       
+
+       /**
+        * Confirms that <tt>ExcelNumberToTextConverter.toText(d)</tt> produces the right results.
+        * As part of preparing this test class, the <tt>ExampleConversion</tt> instances should be set
+        * up to contain the rendering as produced by Excel.
+        */
+       public void testAll() {
+               int failureCount = 0;
+               
+               ExampleConversion[] examples = NumberToTextConversionExamples.getExampleConversions();
+
+               for (int i = 0; i < examples.length; i++) {
+                       ExampleConversion example = examples[i];
+                       try {
+                               if (example.isNaN()) {
+                                       confirmNaN(example.getRawDoubleBits(), example.getExcelRendering());
+                                       continue;
+                               }
+                               String actual = NumberToTextConverter.toText(example.getDoubleValue());
+                               if (!example.getExcelRendering().equals(actual)) {
+                                       failureCount++;
+                                       String msg = "Error rendering for examples[" + i + "] "
+                                                       + formatExample(example) + " "
+                                                       + " bad-result='" + actual + "' "
+                                                       + new ComparisonFailure(null, example.getExcelRendering(), actual).getMessage();
+                                       System.err.println(msg);
+                                       continue;
+                               }
+                       } catch (RuntimeException e) {
+                               failureCount++;
+                               System.err.println("Error in excel rendering for examples[" + i + "] "
+                                               + formatExample(example) + "':" + e.getMessage());
+                               e.printStackTrace();
+                       }
+               }
+               if (failureCount > 0) {
+                       throw new AssertionFailedError(failureCount 
+                                       + " error(s) in excel number to text conversion (see std-err)");
+               }
+       }
+
+       private static String formatExample(ExampleConversion example) {
+               String hexLong = Long.toHexString(example.getRawDoubleBits()).toUpperCase();
+               String longRep = "0x" + "0000000000000000".substring(hexLong.length()) + hexLong+ "L";  
+               return "ec(" + longRep + ", \"" + example.getJavaRendering() + "\", \"" + example.getExcelRendering() + "\")";
+       }
+
+       /**
+        * Excel's abnormal rendering of NaNs is both difficult to test and even reproduce in java. In
+        * general, Excel does not attempt to use raw NaN in the IEEE sense. In {@link FormulaRecord}s,
+        * Excel uses the NaN bit pattern to flag non-numeric (text, boolean, error) cached results.
+        * If the formula result actually evaluates to raw NaN, Excel transforms it to <i>#NUM!</i>.
+        * In other places (e.g. {@link NumberRecord}, {@link NumberPtg}, array items (via {@link 
+        * ConstantValueParser}), there seems to be no special NaN translation scheme.  If a NaN bit 
+        * pattern is somehow encoded into any of these places Excel actually attempts to render the 
+        * values as a plain number. That is the unusual functionality that this method is testing.<p/>   
+        * 
+        * There are multiple encodings (bit patterns) for NaN, and CPUs and applications can convert
+        * to a preferred NaN encoding  (Java prefers <tt>0x7FF8000000000000L</tt>).  Besides the 
+        * special encoding in {@link FormulaRecord.SpecialCachedValue}, it is not known how/whether 
+        * Excel attempts to encode NaN values.
+        * 
+        * Observed NaN behaviour on HotSpot/Windows:
+        * <tt>Double.longBitsToDouble()</tt> will set one bit 51 (the NaN signaling flag) if it isn't
+        *  already. <tt>Double.doubleToLongBits()</tt> will return a double with bit pattern 
+        *  <tt>0x7FF8000000000000L</tt> for any NaN bit pattern supplied.<br/>
+        * Differences are likely to be observed with other architectures.<p/>
+        *  
+        * <p/>
+        * The few test case examples calling this method represent functionality which may not be 
+        * important for POI to support.
+        */
+       private void confirmNaN(long l, String excelRep) {
+               double d = Double.longBitsToDouble(l);
+               assertEquals("NaN", Double.toString(d));
+               
+               String strExcel = NumberToTextConverter.rawDoubleBitsToText(l);
+               
+               assertEquals(excelRep, strExcel);
+       }
+       
+       public void testSimpleRendering_bug56156() {
+               double dResult = 0.05+0.01; // values chosen to produce rounding anomaly
+               String actualText = NumberToTextConverter.toText(dResult);
+               String jdkText = Double.toString(dResult);
+               if (jdkText.equals(actualText)) {
+                       // "0.060000000000000005"
+                       throw new AssertionFailedError("Should not use default JDK IEEE double rendering");
+               }
+               assertEquals("0.06", actualText);
+       }
+}