mpidummy: add MPI_Type_size()

and use it internally, instead of repeated switch statements. I'm intentionally using an if-else chain rather than switch in the implementation, since I want this to work if MPI_Datatype isn't an integer type in the future.
ornladios · May 29, 2019 · b595b2a · b595b2a
1 parent 649753b
commit b595b2a
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Showing 2 changed files with 48 additions and 51 deletions.
diff --git a/source/adios2/helper/mpidummy.cpp b/source/adios2/helper/mpidummy.cpp
@@ -105,57 +105,28 @@ int MPI_Gather(const void *sendbuf, int sendcnt, MPI_Datatype sendtype,
                MPI_Comm comm)
 {
     int ier = MPI_SUCCESS;
-    size_t n = 0, nsent = 0, nrecv = 0;
+    int n;
+    size_t nsent = 0, nrecv = 0;
     if (!sendbuf && !recvbuf)
     {
         return ier;
     }
     if (comm == MPI_COMM_NULL || root)
     {
-        ier = MPI_ERR_COMM;
+        return MPI_ERR_COMM;
     }
 
-    switch (sendtype)
+    ier = MPI_Type_size(sendtype, &n);
+    if (ier != MPI_SUCCESS)
     {
-    case MPI_CHAR:
-        n = sizeof(char);
-        break;
-    case MPI_INT:
-        n = sizeof(int);
-        break;
-    case MPI_UNSIGNED:
-        n = sizeof(unsigned int);
-        break;
-    case MPI_UNSIGNED_LONG:
-        n = sizeof(unsigned long);
-        break;
-    case MPI_UNSIGNED_LONG_LONG:
-        n = sizeof(unsigned long long);
-        break;
-    default:
-        return MPI_ERR_TYPE;
+        return ier;
     }
     nsent = n * sendcnt;
 
-    switch (recvtype)
+    ier = MPI_Type_size(recvtype, &n);
+    if (ier != MPI_SUCCESS)
     {
-    case MPI_CHAR:
-        n = sizeof(char);
-        break;
-    case MPI_INT:
-        n = sizeof(int);
-        break;
-    case MPI_UNSIGNED:
-        n = sizeof(unsigned int);
-        break;
-    case MPI_UNSIGNED_LONG:
-        n = sizeof(unsigned long);
-        break;
-    case MPI_UNSIGNED_LONG_LONG:
-        n = sizeof(unsigned long long);
-        break;
-    default:
-        return MPI_ERR_TYPE;
+        return ier;
     }
     nrecv = n * recvcnt;
 
@@ -206,7 +177,8 @@ int MPI_Scatter(const void *sendbuf, int sendcnt, MPI_Datatype sendtype,
                 MPI_Comm comm)
 {
     int ier = MPI_SUCCESS;
-    size_t n = 0, nsent = 0, nrecv = 0;
+    int n;
+    size_t nsent = 0, nrecv = 0;
     if (!sendbuf || !recvbuf)
     {
         ier = MPI_ERR_BUFFER;
@@ -217,23 +189,17 @@ int MPI_Scatter(const void *sendbuf, int sendcnt, MPI_Datatype sendtype,
         ier = MPI_ERR_COMM;
     }
 
-    switch (sendtype)
+    ier = MPI_Type_size(sendtype, &n);
+    if (ier != MPI_SUCCESS)
     {
-    case MPI_INT:
-        n = sizeof(int);
-        break;
-    default:
-        return MPI_ERR_TYPE;
+        return ier;
     }
     nsent = n * sendcnt;
 
-    switch (recvtype)
+    ier = MPI_Type_size(recvtype, &n);
+    if (ier != MPI_SUCCESS)
     {
-    case MPI_INT:
-        n = sizeof(int);
-        break;
-    default:
-        return MPI_ERR_TYPE;
+        return ier;
     }
     nrecv = n * recvcnt;
 
@@ -467,6 +433,35 @@ int MPI_Allreduce(const void *sendbuf, void *recvbuf, int count,
     return MPI_Reduce(sendbuf, recvbuf, count, datatype, op, 0, comm);
 }
 
+int MPI_Type_size(MPI_Datatype datatype, int *size)
+{
+    if (datatype == MPI_CHAR)
+    {
+        *size = sizeof(char);
+    }
+    else if (datatype == MPI_INT)
+    {
+        *size = sizeof(int);
+    }
+    else if (datatype == MPI_UNSIGNED)
+    {
+        *size = sizeof(unsigned int);
+    }
+    else if (datatype == MPI_UNSIGNED_LONG)
+    {
+        *size = sizeof(unsigned long);
+    }
+    else if (datatype == MPI_UNSIGNED_LONG_LONG)
+    {
+        *size = sizeof(unsigned long long);
+    }
+    else
+    {
+        return MPI_ERR_TYPE;
+    }
+    return MPI_SUCCESS;
+}
+
 } // end namespace mpi
 } // end namespace helper
 } // end namespace adios2
diff --git a/source/adios2/helper/mpidummy.h b/source/adios2/helper/mpidummy.h
@@ -126,6 +126,8 @@ int MPI_Isend(const void *buf, int count, MPI_Datatype datatype, int dest,
 
 int MPI_Wait(MPI_Request *request, MPI_Status *status);
 
+int MPI_Type_size(MPI_Datatype datatype, int *size);
+
 int MPI_File_open(MPI_Comm comm, const char *filename, int amode, MPI_Info info,
                   MPI_File *fh);
 int MPI_File_close(MPI_File *fh);