Fix inverted if branches in `fmpi_domain.c`

src/fmpi_domain.c

@@ -136,10 +136,10 @@ static struct fmpi_data fmpi_halo_1d(
         memcpy(((char *)halo.raw + type_size), data.raw, (data.size + type_size));
     // Right boundary
     } else if(rank == (size_t)(ctx->mpi->size - 1)) {
-        memcpy(halo.raw, ((const char *)(data.raw) - type_size), size);
+        memcpy(halo.raw, ((const char *)(data.raw) - type_size), (data.size + type_size));
     // Middle
     } else {
-        memcpy(halo.raw, ((const char *)(data.raw) - type_size), (data.size + type_size));
+        memcpy(halo.raw, ((const char *)(data.raw) - type_size), size);
     }
     return halo;
 }