Fix bug #50939 - ChartEndObjectRecord is supposed to have 6 bytes at the end, but handle it not

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1082936 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/status.xml

 
     <changes>
         <release version="3.8-beta2" date="2011-??-??">
+           <action dev="poi-developers" type="fix">50939 - ChartEndObjectRecord is supposed to have 6 bytes at the end, but handle it not</action>
            <action dev="poi-developers" type="add">HMEF - New component which supports TNEF (Transport Neutral Encoding Format), aka winmail.dat</action>
            <action dev="poi-developers" type="fix">50313 - support for getting HWPFDocument fields</action>
            <action dev="poi-developers" type="fix">50912 - fixed setting named styles to HSSFCells</action>

src/java/org/apache/poi/hssf/record/chart/ChartEndObjectRecord.java

 	private short rt;
 	private short grbitFrt;
 	private short iObjectKind;
-	private byte[] unused;
+	private byte[] reserved;
 
 	public ChartEndObjectRecord(RecordInputStream in) {
 		rt = in.readShort();
 		grbitFrt = in.readShort();
 		iObjectKind = in.readShort();
 
-		unused = new byte[6];
-		in.readFully(unused);
+		// The spec says that there should be 6 bytes at the
+		//  end, which must be there and must be zero
+		// However, sometimes Excel forgets them...
+		reserved = new byte[6];
+		if(in.available() == 0) {
+		   // They've gone missing...
+		} else {
+		   // Read the reserved bytes 
+		   in.readFully(reserved);
+		}
 	}
 
 	@Override
 		out.writeShort(grbitFrt);
 		out.writeShort(iObjectKind);
 		// 6 bytes unused
-		out.write(unused);
+		out.write(reserved);
 	}
 
 	@Override
 		buffer.append("    .rt         =").append(HexDump.shortToHex(rt)).append('\n');
 		buffer.append("    .grbitFrt   =").append(HexDump.shortToHex(grbitFrt)).append('\n');
 		buffer.append("    .iObjectKind=").append(HexDump.shortToHex(iObjectKind)).append('\n');
-		buffer.append("    .unused     =").append(HexDump.toHex(unused)).append('\n');
+		buffer.append("    .reserved   =").append(HexDump.toHex(reserved)).append('\n');
 		buffer.append("[/ENDOBJECT]\n");
 		return buffer.toString();
 	}

src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java

         writeOutAndReadBack(wb2);
     }
 
+    /**
+     * The spec says that ChartEndObjectRecord has 6 reserved
+     *  bytes on the end, but we sometimes find files without... 
+     */
+    public void test50939() throws Exception {
+       HSSFWorkbook wb = openSample("50939.xls");
+       assertEquals(2, wb.getNumberOfSheets());
+    }
 }