Send size of buffer bigendian buffer of eight bytes rather than an int so

avoid problems with MPI maybe/maybenot doing typeconversion when running
between machines with different MPI_INT types.

Tom


git-svn-id: http://svn.cactuscode.org/arrangements/CactusConnect/HTTPD/trunk@103 1faa4e14-9dd3-4be0-9f0e-ffe519881164

1 files changed, 69 insertions, 2 deletions

diff --git a/src/Steer.c b/src/Steer.c
index 2f89e9b..f54bd26 100644
--- a/src/Steer.c
+++ b/src/Steer.c
@@ -47,6 +47,7 @@ CCTK_FILEVERSION(DevThorns_httpd_Steer_c)
 
 static int CommunicateBuffer(void);
 static int SteerParameters(void);
+static void ByteSwap(void *buf,int nelements,int elementsize);
 
 /********************************************************************
  ********************* Other Routine Prototypes *********************
@@ -184,6 +185,7 @@ static int CommunicateBuffer(void)
   int rank;
   int nprocs;
   int buffer_size;
+  CCTK_INT8 transmit_buffer_size;
 
   /* Work out how many processes there are. */
   MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
@@ -206,8 +208,12 @@ static int CommunicateBuffer(void)
         buffer_size++;
       }
 
+      transmit_buffer_size = buffer_size;
+      
+      ByteSwap(&transmit_buffer_size, 1, 8);
+
       /* Tell other procs how much data to receive. */
-      MPI_Bcast(&buffer_size, 1, MPI_INT, 0, MPI_COMM_WORLD);
+      MPI_Bcast(&transmit_buffer_size, 8, MPI_BYTE, 0, MPI_COMM_WORLD);
 
       if(buffer_size > 0)
       {
@@ -220,8 +226,12 @@ static int CommunicateBuffer(void)
       /* Receiving process */
 
       /* Find out how much data to receive. */
-      MPI_Bcast(&buffer_size, 1, MPI_INT, 0, MPI_COMM_WORLD);
+      MPI_Bcast(&transmit_buffer_size, 8, MPI_BYTE, 0, MPI_COMM_WORLD);
 
+      ByteSwap(&transmit_buffer_size, 1, 8);
+
+      buffer_size = transmit_buffer_size;
+      
 #ifdef TEST_HTTP_STEER
       fprintf(stderr, "%d - buffer size %d queuebuffer size %d\n", rank, buffer_size, queuebuffer_size);
 #endif
@@ -330,6 +340,63 @@ static int SteerParameters(void)
   return retval;
 }
 
+ /*@@
+   @routine    ByteSwap
+   @date       Mon Oct 09 2000
+   @author     John Shalf
+   @desc 
+   
+   @enddesc 
+   @calls     
+   @calledby   
+   @history 
+ 
+   @endhistory 
+   @var     buf
+   @vdesc   buffer to byteswap
+   @vtype   void *
+   @vio     inout
+   @vcomment 
+ 
+   @endvar 
+   @var     nelements
+   @vdesc   number of data elements in array
+   @vtype   int
+   @vio     in
+   @vcomment 
+ 
+   @endvar 
+   @var     elementsize
+   @vdesc   size of each element in buffer
+   @vtype   int
+   @vio     in
+   @vcomment 
+ 
+   @endvar 
+
+@@*/
+static void ByteSwap(void *buf,int nelements,int elementsize)
+{
+#ifndef WORDS_BIGENDIAN
+  char *buffer;
+  int i;
+  int s,d;
+
+  buffer=(char *)buf;
+  
+  for(i=0;i<nelements;i++,buffer+=elementsize)
+  {
+    /* do the swap thing on each element */
+    for(s=0,d=elementsize-1;s<d;s++,d--)
+    {
+      char	c=buffer[s]; 
+      buffer[s]=buffer[d]; 
+      buffer[d]=c;
+    }
+  } 
+#endif
+}
+
 #ifdef TEST_HTTP_STEER
 
 int CCTK_ParameterSet(char *parameter, char *thorn, char *value)