VFD SWMR: sync with develop (#1825)

* bin directory sync

* doxygen changes

* C++ sync with develop

* Fortran sync with develop

* Sync various docs with develop

* Java sync with develop

* More doxygen sync with develop

* tools sync with develop

* h5test.h testing macros get enclosed in do..while loops (#1721)

* Minor examples normalization with develop

* hl sync with develop

* sprintf to snprintf (#1815)

* Misc sync w/ develop

* Brings some selection I/O bits over from develop

* Brings over some const fixes from develop

* Brings over more const bits from develop

* Minor bits missed in early syncs

* Brings over rest of selection I/O

* Sync of mirror VFD changes w/ develop

* Committing clang-format changes

* Adds missing testpar file

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

1 files changed, 28 insertions, 19 deletions

diff --git a/src/H5Dio.c b/src/H5Dio.c
index d87d052..470b245 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -174,21 +174,21 @@ H5D__read(H5D_t *dataset, hid_t mem_type_id, H5S_t *mem_space, H5S_t *file_space
      */
     if (nelmts > 0 && TRUE == H5S_SELECT_SHAPE_SAME(mem_space, file_space) &&
         H5S_GET_EXTENT_NDIMS(mem_space) != H5S_GET_EXTENT_NDIMS(file_space)) {
-        const void *adj_buf = NULL; /* Pointer to the location in buf corresponding  */
-                                    /* to the beginning of the projected mem space.  */
+        ptrdiff_t buf_adj = 0;
 
         /* Attempt to construct projected dataspace for memory dataspace */
         if (H5S_select_construct_projection(mem_space, &projected_mem_space,
-                                            (unsigned)H5S_GET_EXTENT_NDIMS(file_space), buf, &adj_buf,
-                                            type_info.dst_type_size) < 0)
+                                            (unsigned)H5S_GET_EXTENT_NDIMS(file_space),
+                                            type_info.dst_type_size, &buf_adj) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to construct projected memory dataspace")
         HDassert(projected_mem_space);
-        HDassert(adj_buf);
+
+        /* Adjust the buffer by the given amount */
+        buf = (void *)(((uint8_t *)buf) + buf_adj);
 
         /* Switch to using projected memory dataspace & adjusted buffer */
         mem_space = projected_mem_space;
-        buf       = (void *)adj_buf; /* Casting away 'const' OK -QAK */
-    }                                /* end if */
+    } /* end if */
 
     /* Retrieve dataset properties */
     /* <none needed in the general case> */
@@ -407,20 +407,20 @@ H5D__write(H5D_t *dataset, hid_t mem_type_id, H5S_t *mem_space, H5S_t *file_spac
      */
     if (nelmts > 0 && TRUE == H5S_SELECT_SHAPE_SAME(mem_space, file_space) &&
         H5S_GET_EXTENT_NDIMS(mem_space) != H5S_GET_EXTENT_NDIMS(file_space)) {
-        const void *adj_buf = NULL; /* Pointer to the location in buf corresponding  */
-                                    /* to the beginning of the projected mem space.  */
+        ptrdiff_t buf_adj = 0;
 
         /* Attempt to construct projected dataspace for memory dataspace */
         if (H5S_select_construct_projection(mem_space, &projected_mem_space,
-                                            (unsigned)H5S_GET_EXTENT_NDIMS(file_space), buf, &adj_buf,
-                                            type_info.src_type_size) < 0)
+                                            (unsigned)H5S_GET_EXTENT_NDIMS(file_space),
+                                            type_info.src_type_size, &buf_adj) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to construct projected memory dataspace")
         HDassert(projected_mem_space);
-        HDassert(adj_buf);
+
+        /* Adjust the buffer by the given amount */
+        buf = (const void *)(((const uint8_t *)buf) + buf_adj);
 
         /* Switch to using projected memory dataspace & adjusted buffer */
         mem_space = projected_mem_space;
-        buf       = adj_buf;
     } /* end if */
 
     /* Retrieve dataset properties */
@@ -576,6 +576,10 @@ H5D__ioinfo_init(H5D_t *dset, const H5D_type_info_t *type_info, H5D_storage_t *s
         io_info->io_ops.single_write = H5D__scatgath_write;
     } /* end else */
 
+    /* Start with selection I/O off, layout callback will turn it on if
+     * appropriate */
+    io_info->use_select_io = FALSE;
+
 #ifdef H5_HAVE_PARALLEL
     /* Determine if the file was opened with an MPI VFD */
     io_info->using_mpi_vfd = H5F_HAS_FEATURE(dset->oloc.file, H5FD_FEAT_HAS_MPI);
@@ -814,12 +818,17 @@ H5D__ioinfo_adjust(H5D_io_info_t *io_info, const H5D_t *dset, const H5S_t *file_
 
         /* Check if we can use the optimized parallel I/O routines */
         if (opt == TRUE) {
-            /* Override the I/O op pointers to the MPI-specific routines */
-            io_info->io_ops.multi_read   = dset->shared->layout.ops->par_read;
-            io_info->io_ops.multi_write  = dset->shared->layout.ops->par_write;
-            io_info->io_ops.single_read  = H5D__mpio_select_read;
-            io_info->io_ops.single_write = H5D__mpio_select_write;
-        } /* end if */
+            /* Override the I/O op pointers to the MPI-specific routines, unless
+             * selection I/O is to be used - in this case the file driver will
+             * handle collective I/O */
+            /* Check for selection/vector support in file driver? -NAF */
+            if (!io_info->use_select_io) {
+                io_info->io_ops.multi_read   = dset->shared->layout.ops->par_read;
+                io_info->io_ops.multi_write  = dset->shared->layout.ops->par_write;
+                io_info->io_ops.single_read  = H5D__mpio_select_read;
+                io_info->io_ops.single_write = H5D__mpio_select_write;
+            } /* end if */
+        }     /* end if */
         else {
             /* Check if there are any filters in the pipeline. If there are,
              * we cannot break to independent I/O if this is a write operation