Fix an issue with the datatype engine where if the left over from

the previous pack was larger than the allowed space in the pack buffer
bad things happened. Thanks to Yuki MATSUMOTO and Takahiro Kawashima
for the bug report and the patch.

This commit was SVN r25488.

opal/datatype/opal_datatype_pack.c

@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2009 The University of Tennessee and The University
+ * Copyright (c) 2004-2011 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2006 High Performance Computing Center Stuttgart,
@@ -194,7 +194,9 @@ opal_pack_homogeneous_contig_with_gaps_function( opal_convertor_t* pConv,
 
             packed_buffer = (unsigned char *) iov[iov_count].iov_base;
             done = pConv->bConverted - i * pData->size;  /* partial data from last pack */
-            if( done != 0 ) {  /* still some data to copy from the last time */
+            /* data left from last round and enough space in the buffer */
+            if( (done + max_allowed) >= pData->size ) {
+                /* copy the partial left-over from the previous round */
                 done = pData->size - done;
                 OPAL_DATATYPE_SAFEGUARD_POINTER( user_memory, done, pConv->pBaseBuf, pData, pConv->count );
                 MEMCPY_CSUM( packed_buffer, user_memory, done, pConv );
@@ -202,18 +204,20 @@ opal_pack_homogeneous_contig_with_gaps_function( opal_convertor_t* pConv,
                 max_allowed -= done;
                 total_bytes_converted += done;
                 user_memory += (extent - pData->size + done);
+
+                /* copy entire types */
+                counter = (uint32_t)(max_allowed / pData->size);
+                if( counter > pConv->count ) counter = pConv->count;
+                for( i = 0; i < counter; i++ ) {
+                    OPAL_DATATYPE_SAFEGUARD_POINTER( user_memory, pData->size, pConv->pBaseBuf, pData, pConv->count );
+                    MEMCPY_CSUM( packed_buffer, user_memory, pData->size, pConv );
+                    packed_buffer+= pData->size;
+                    user_memory += extent;
+                }
+                done = (counter * pData->size);
+                max_allowed -= done;
+                total_bytes_converted += done;
             }
-            counter = (uint32_t)(max_allowed / pData->size);
-            if( counter > pConv->count ) counter = pConv->count;
-            for( i = 0; i < counter; i++ ) {
-                OPAL_DATATYPE_SAFEGUARD_POINTER( user_memory, pData->size, pConv->pBaseBuf, pData, pConv->count );
-                MEMCPY_CSUM( packed_buffer, user_memory, pData->size, pConv );
-                packed_buffer+= pData->size;
-                user_memory += extent;
-            }
-            done = (counter * pData->size);
-            max_allowed -= done;
-            total_bytes_converted += done;
             /* If there is anything pending ... */
             if( 0 != max_allowed ) {
                 done = max_allowed;