Hdf5 1 8 22 (#281)

* Restores maintainer mode in the autotools (#200)

Maintainer mode should be enabled in development branches.

Also adds helpful commenting.

Add bin/switch_maint_mode
Disable maintainer mode for release.
Fix incomplete merge for stub functions in H5Fdhdfs.c

* Update configure for Restores maintainer mode in the autotools (#200).

* Update MANIFEST for switch_maint_mode script.

* Update so numbers for 1.8.22 release.

* Add so numbers changes in Makefile.ins for 1.8.22 release.

* Update pkgconfig settings with version - #218 (#223)

* Add notice of final HDFF5 1.8 release.
Add solaris 64bit alignment issue to "Known Problems".

* Update 1.8 final release notice.

* Update CMake/HDF5Examples version in bin/release

* Fixed typo in an error message. (#227)

* Remove duplicate setting (#239)

* RELEASE.txt cleanup.

* Add macOS Big Sur to tested machines, also missing entries for macOS 10.13 and 10.14.

* )Update version.

* Reverts lock/unlock callback signature to 1.8.21 version (#254)

* Reverts lock/unlock callback signature to 1.8.21 version

This callback is unused in 1.8. The ros3 and hdfs VFDs are the only VFDs
that have the lock callback implemented and that is just as no-op stubs.
These stubs were removed so the callbacks are now NULL pointers, like
the other VFDs in 1.8.

* Trivial whitespace fix

* Update version to 1.8.22-14.

* Update version in H5public.h

* Set version 1.8.22 for release.

* dd RELEASE.txt entry for HDFFV-10741.

* Improve performance of multiple calls to H5Sget_select_elem_pointlist (#270) (#277)

* Cache the pointer to the next point to process after the last call to
H5S__get_select_elem_pointlist.  This allows the normal process of
iterating over the points in batches to be much more efficient, as the
library does not need to traverse the entirety of the preceding points
every time the funciton is re-entered.

* Update RELEASE.txt for point selection iteration performance fix.

Co-authored-by: Dana Robinson <[email protected]>
Co-authored-by: Allen Byrne <[email protected]>
Co-authored-by: bmribler <[email protected]>
Co-authored-by: Neil Fortner <[email protected]>

release_docs/RELEASE.txt

@@ -329,6 +329,15 @@ New Features
 
     Library
     -------
+    - Improved performance of H5Sget_select_elem_pointlist
+
+      Modified library to cache the point after the last block of points
+      retrieved by H5Sget_select_elem_pointlist, so a subsequent call to the
+      same function to retrieve the next block of points from the list can
+      proceed immediately without needing to iterate over the point list.
+
+      (NAF - 2021/01/19)
+
     - Added S3 and HDFS Virtual File Drivers (VFDs) to HDF5
 
       These new VFDs have been added in HDF5-1.8.22.  Instructions to

src/H5Spkg.h

@@ -95,6 +95,11 @@ struct H5S_pnt_node_t {
 /* Information about point selection list */
 typedef struct {
     H5S_pnt_node_t *head; /* Pointer to head of point list */
+
+    hsize_t last_idx;     /* Index of the point after the last returned from H5S__get_select_elem_pointlist() */
+    H5S_pnt_node_t *last_idx_pnt; /* Point after the last returned from H5S__get_select_elem_pointlist().
+        * If we ever add a way to remove points or add points in the middle of
+        * the pointlist we will need to invalidate these fields. */
 } H5S_pnt_list_t;
 
 /* Information about new-style hyperslab spans */

src/H5Spoint.c

@@ -618,6 +618,10 @@ H5S_point_copy(H5S_t *dst, const H5S_t *src, hbool_t H5_ATTR_UNUSED share_select
         curr = curr->next;
     } /* end while */
 
+    /* Clear cached iteration point */
+    dst->select.sel_info.pnt_lst->last_idx = 0;
+    dst->select.sel_info.pnt_lst->last_idx_pnt = NULL;
+
 done:
     if (ret_value < 0 && dst->select.sel_info.pnt_lst) {
         /* Traverse the (incomplete?) dst list, freeing all memory */
@@ -956,6 +960,7 @@ H5S_point_deserialize(H5S_t *space, const uint8_t *buf)
 static herr_t
 H5S_get_select_elem_pointlist(H5S_t *space, hsize_t startpoint, hsize_t numpoints, hsize_t *buf)
 {
+    const hsize_t   endpoint = startpoint + numpoints; /* Index of last point in iteration */
     H5S_pnt_node_t *node; /* Point node */
     unsigned        rank; /* Dataspace rank */
 
@@ -967,14 +972,20 @@ H5S_get_select_elem_pointlist(H5S_t *space, hsize_t startpoint, hsize_t numpoint
     /* Get the dataspace extent rank */
     rank = space->extent.rank;
 
-    /* Get the head of the point list */
-    node = space->select.sel_info.pnt_lst->head;
+    /* Check for cached point at the correct index */
+    if(space->select.sel_info.pnt_lst->last_idx_pnt
+            && startpoint == space->select.sel_info.pnt_lst->last_idx)
+        node = space->select.sel_info.pnt_lst->last_idx_pnt;
+    else {
+        /* Get the head of the point list */
+        node = space->select.sel_info.pnt_lst->head;
 
-    /* Iterate to the first point to return */
-    while (node != NULL && startpoint > 0) {
-        startpoint--;
-        node = node->next;
-    } /* end while */
+        /* Iterate to the first point to return */
+        while (node != NULL && startpoint > 0) {
+            startpoint--;
+            node = node->next;
+        } /* end while */
+    } /* end else */
 
     /* Iterate through the node, copying each point's information */
     while (node != NULL && numpoints > 0) {
@@ -984,6 +995,10 @@ H5S_get_select_elem_pointlist(H5S_t *space, hsize_t startpoint, hsize_t numpoint
         node = node->next;
     } /* end while */
 
+    /* Cached next point in iteration */
+    space->select.sel_info.pnt_lst->last_idx = endpoint;
+    space->select.sel_info.pnt_lst->last_idx_pnt = node;
+
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5S_get_select_elem_pointlist() */
 
@@ -1494,6 +1509,10 @@ H5S_point_project_simple(const H5S_t *base_space, H5S_t *new_space, hsize_t *off
         } /* end while */
     }     /* end else */
 
+    /* Clear cached iteration point */
+    new_space->select.sel_info.pnt_lst->last_idx = 0;
+    new_space->select.sel_info.pnt_lst->last_idx_pnt = NULL;
+
     /* Number of elements selected will be the same */
     new_space->select.num_elem = base_space->select.num_elem;