1 files changed, 57 insertions, 0 deletions
diff --git a/src/MPIutils.cc b/src/MPIutils.cc
new file mode 100644
index 0000000..6f2c83e
--- /dev/null
+++ b/src/MPIutils.cc
@@ -0,0 +1,57 @@
+#include "MPIutils.hh"
+
+
+void MPIbuffer::attach(int size){
+  bufsize=size;
+  char *mybuf = new char[bufsize];
+  MPI_Buffer_attach(mybuf,bufsize);
+}
+void MPIbuffer::detach(){
+  char *tmp;
+  int size;
+  MPI_Buffer_detach(&tmp,&size);
+  if(tmp==mybuf) delete tmp;
+  else MPI_Buffer_attach(tmp,size); // wasn't my buffer
+}
+
+MPIbuffer::MPIbuffer(int size):mybuf(0),bufsize(size){
+  attach(size);
+}
+MPIbuffer::~MPIbuffer() {detach();}
+void MPIbuffer::resize(int size){
+  // check for pending requests using the buffer detach 
+  // actually done by MPI_Buffer_detach() itself
+  detach();
+  attach(size);
+}
+void MPIbuffer::grow(int size){
+  if(bufsize<size)
+    resize(size);
+}
+void MPIbuffer::check(){ // make sure the buffersize is what we thought it was..
+  char *tmp;
+  int size;
+  MPI_Buffer_detach(&tmp,&size);
+  if(!tmp || tmp!=mybuf) 
+    attach(bufsize);
+  else if(tmp!=mybuf){
+    if(size>=bufsize)
+      MPI_Buffer_attach(tmp,size); // reattach
+    else {
+      delete tmp;
+      attach(bufsize);
+    }
+  }
+  else
+    MPI_Buffer_attach(tmp,size); // reattach
+  /* fails if existing buffer was too small and
+     the source process deallocates the buffer without getting
+     a handle to it.
+     Can also fail if malloc != new on that architecture.
+  */
+}
+
+
+// Must watch buffer attachment from external processes
+MPIbuffer *MPIcomm::buffer;
+MPI_Status MPIcomm::defstat;