Fix a couple of NPOIFS bugs relating to empty files, empty documents and non-padded stream data

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1085493 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 14 insertions, 3 deletions

diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
index 3a2c286023..484914e54c 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
@@ -24,6 +24,7 @@ import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.List;
 
 import org.apache.poi.poifs.common.POIFSConstants;
 import org.apache.poi.poifs.dev.POIFSViewable;
@@ -106,7 +107,12 @@ public final class NPOIFSDocument implements POIFSViewable {
    }
    
    Iterator<ByteBuffer> getBlockIterator() {
-      return _stream.getBlockIterator();
+      if(getSize() > 0) {
+         return _stream.getBlockIterator();
+      } else {
+         List<ByteBuffer> empty = Collections.emptyList();
+         return empty.iterator();
+      }
    }
 
    /**
diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
index 58d77be69a..b15df9bd4c 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
@@ -103,6 +103,9 @@ public class NPOIFSFileSystem extends BlockStore
         _xbat_blocks     = new ArrayList<BATBlock>();
         _bat_blocks     = new ArrayList<BATBlock>();
         _root           = null;
+        
+        // Data needs to initially hold just the header block 
+        _data           = new ByteArrayBackedDataSource(new byte[bigBlockSize.getBigBlockSize()]);
     }
 
     /**
diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
index 458100950d..5d8d1fa882 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
@@ -102,7 +102,7 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
    public void updateContents(byte[] contents) throws IOException {
       // How many blocks are we going to need?
       int blockSize = blockStore.getBlockStoreBlockSize();
-      int blocks = (int)Math.ceil(contents.length / blockSize);
+      int blocks = (int)Math.ceil( ((double)contents.length) / blockSize );
       
       // Make sure we don't encounter a loop whilst overwriting
       //  the existing blocks
@@ -141,7 +141,9 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
          
          // Write it
          ByteBuffer buffer = blockStore.createBlockIfNeeded(thisBlock);
-         buffer.put(contents, i*blockSize, blockSize);
+         int startAt = i*blockSize;
+         int endAt = Math.min(contents.length - startAt, blockSize);
+         buffer.put(contents, startAt, endAt); 
          
          // Update pointers
          prevBlock = thisBlock;