Fix bug 44898 - Correctly handle short last blocks in POIFS

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@658285 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/changes.xml

@@ -37,7 +37,7 @@
 
 		<!-- Don't forget to update status.xml too! -->
         <release version="3.1-final" date="2008-06-??">
-          <action dev="POI-DEVELOPERS" type="add"><!-- to keep XML validator quiet  --></action>
+           <action dev="POI-DEVELOPERS" type="fix">44898 - Correctly handle short last blocks in POIFS</action>
         </release>  
         <release version="3.1-beta2" date="2008-05-26">
            <action dev="POI-DEVELOPERS" type="fix">44306 - fixed reading/writing of AttrPtg(type=choose) and method toFormulaString() for CHOOSE formulas</action>

src/documentation/content/xdocs/status.xml

@@ -34,6 +34,7 @@
 	<!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.1-final" date="2008-06-??">
+           <action dev="POI-DEVELOPERS" type="fix">44898 - Correctly handle short last blocks in POIFS</action>
         </release>  
         <release version="3.1-beta2" date="2008-05-26">
            <action dev="POI-DEVELOPERS" type="fix">44306 - fixed reading/writing of AttrPtg(type=choose) and method toFormulaString() for CHOOSE formulas</action>

src/java/org/apache/poi/poifs/storage/RawDataBlock.java

@@ -37,6 +37,7 @@ public class RawDataBlock
 {
     private byte[]  _data;
     private boolean _eof;
+    private boolean _hasData;
     private static POILogger log = POILogFactory.getLogger(RawDataBlock.class);
 
     /**
@@ -66,6 +67,7 @@ public class RawDataBlock
     		throws IOException {
         _data = new byte[ blockSize ];
         int count = IOUtils.readFully(stream, _data);
+        _hasData = (count > 0);
 
         if (count == -1) {
             _eof = true;
@@ -94,16 +96,21 @@ public class RawDataBlock
     /**
      * When we read the data, did we hit end of file?
      *
-     * @return true if no data was read because we were at the end of
+     * @return true if the EoF was hit during this block, or
-     *         the file, else false
+     *  false if not. If you have a dodgy short last block, then
-     *
+     *  it's possible to both have data, and also hit EoF...
-     * @exception IOException
      */
-    public boolean eof()
+    public boolean eof() {
-        throws IOException
-    {
         return _eof;
     }
+    /**
+     * Did we actually find any data to read? It's possible,
+     *  in the event of a short last block, to both have hit
+     *  the EoF, but also to have data
+     */
+    public boolean hasData() {
+    	return _hasData;
+    }
 
     /* ********** START implementation of ListManagedBlock ********** */
 
@@ -117,7 +124,7 @@ public class RawDataBlock
     public byte [] getData()
         throws IOException
     {
-        if (eof())
+        if (! hasData())
         {
             throw new IOException("Cannot return empty data");
         }

src/java/org/apache/poi/poifs/storage/RawDataBlockList.java

@@ -51,12 +51,16 @@ public class RawDataBlockList
         while (true)
         {
             RawDataBlock block = new RawDataBlock(stream, bigBlockSize);
+            
+            // If there was data, add the block to the list
+            if(block.hasData()) {
+            	blocks.add(block);
+            }
 
-            if (block.eof())
+            // If the stream is now at the End Of File, we're done
-            {
+            if (block.eof()) {
                 break;
             }
-            blocks.add(block);
         }
         setBlocks(( RawDataBlock [] ) blocks.toArray(new RawDataBlock[ 0 ]));
     }

src/testcases/org/apache/poi/poifs/filesystem/TestPOIFSFileSystem.java

@@ -130,7 +130,7 @@ public final class TestPOIFSFileSystem extends TestCase {
 	 * The other is to fix the handling of the last block in
 	 *  POIFS, since it seems to be slight wrong
 	 */
-	public void DISABLEDtestShortLastBlock() throws Exception {
+	public void testShortLastBlock() throws Exception {
 		String[] files = new String[] {
 			"ShortLastBlock.qwp", "ShortLastBlock.wps"	
 		};