--- HeaderBlockReaderORIG.java	Wed Apr 30 07:38:58 2003
+++ HeaderBlockReader.java	Wed Oct 29 10:43:11 2003
@@ -105,6 +105,22 @@
     {
         _data = new byte[ POIFSConstants.BIG_BLOCK_SIZE ];
         int byte_count = stream.read(_data);
+        /// XXX Patch 
+        // The read() of java.io.InputStream does not guarantee to provide
+        // the full amount of requested bytes. It is necessary to repeat the reading
+        // until the full block is read or eof occured. 
+        // The original source worked fine up to the point of reading Excel-files 
+        // contained in a ZIP-file.
+        while (byte_count!=-1 && byte_count < POIFSConstants.BIG_BLOCK_SIZE) {
+        	int k = stream.read(_data, byte_count, POIFSConstants.BIG_BLOCK_SIZE-byte_count);
+        	if (k==-1) {
+        		break;
+        	} else {
+        		byte_count += k;
+        	}
+        }
+        /// XXX Patch         
+        
 
         if (byte_count != POIFSConstants.BIG_BLOCK_SIZE)
         {