[svn-r19092] Description:

	Bring "shape same" changes from LBL branch to trunk.  These changes
allow shapes that are the same, but projected into dataspaces with different
ranks to be detected correctly, and also contains code to project a dataspace
into greater/lesser number of dimensions, so the I/O can proceed in a faster
way.

	These changes also contain several bug fixes and _lots_ of code
cleanups to the MPI datatype creation code.

	Many other misc. code cleanup are included as well...

Tested on:
        FreeBSD/32 6.3 (duty) in debug mode
        FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode
        Linux/32 2.6 (jam) w/PGI compilers, w/default API=1.8.x,
                w/C++ & FORTRAN, w/threadsafe, in debug mode
        Linux/64-amd64 2.6 (amani) w/Intel compilers, w/default API=1.6.x,
                w/C++ & FORTRAN, in production mode
        Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
                w/szip filter, in production mode
        Linux/64-ia64 2.6 (cobalt) w/Intel compilers, w/C++ & FORTRAN,
                in production mode
        Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in debug mode
        Mac OS X/32 10.6.3 (amazon) in debug mode
        Mac OS X/32 10.6.3 (amazon) w/C++ & FORTRAN, w/threadsafe,
                in production mode

1 files changed, 605 insertions, 135 deletions

diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index a419131..af3c9f9 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -27,6 +27,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5FLprivate.h"	/* Free Lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"        /* Memory management                    */
 #include "H5Spkg.h"		/* Dataspaces 				*/
 #include "H5Vprivate.h"		/* Vector and array functions		*/
 #include "H5WBprivate.h"        /* Wrapped Buffers                      */
@@ -108,7 +109,7 @@ H5S_select_copy (H5S_t *dst, const H5S_t *src, hbool_t share_selection)
 {
     herr_t ret_value;     /* return value */
 
-    FUNC_ENTER_NOAPI(H5S_select_copy, FAIL);
+    FUNC_ENTER_NOAPI(H5S_select_copy, FAIL)
 
     /* Check args */
     assert(dst);
@@ -119,10 +120,10 @@ H5S_select_copy (H5S_t *dst, const H5S_t *src, hbool_t share_selection)
 
     /* Perform correct type of copy based on the type of selection */
     if((ret_value=(*src->select.type->copy)(dst,src,share_selection))<0)
-        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "can't copy selection specific information");
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "can't copy selection specific information")
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_copy() */
 
 
@@ -149,14 +150,14 @@ H5S_select_release(H5S_t *ds)
 {
     herr_t ret_value;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_release);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_release)
 
     assert(ds);
 
     /* Call the selection type's release function */
     ret_value=(*ds->select.type->release)(ds);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5S_select_release() */
 
 
@@ -186,14 +187,14 @@ H5S_select_get_seq_list(const H5S_t *space, unsigned flags,
 {
     herr_t ret_value;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_get_seq_list);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_get_seq_list)
 
     assert(space);
 
     /* Call the selection type's get_seq_list function */
     ret_value=(*space->select.type->get_seq_list)(space,flags,iter,maxseq,maxbytes,nseq,nbytes,off,len);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5S_select_get_seq_list() */
 
 
@@ -221,14 +222,14 @@ H5S_select_serial_size(const H5S_t *space)
 {
     hssize_t ret_value;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_serial_size);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_serial_size)
 
     assert(space);
 
     /* Call the selection type's serial_size function */
     ret_value=(*space->select.type->serial_size)(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5S_select_serial_size() */
 
 
@@ -259,7 +260,7 @@ H5S_select_serialize(const H5S_t *space, uint8_t *buf)
 {
     herr_t ret_value=SUCCEED;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_serialize);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_serialize)
 
     assert(space);
     assert(buf);
@@ -267,7 +268,7 @@ H5S_select_serialize(const H5S_t *space, uint8_t *buf)
     /* Call the selection type's serialize function */
     ret_value=(*space->select.type->serialize)(space,buf);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5S_select_serialize() */
 
 
@@ -410,13 +411,13 @@ H5S_select_valid(const H5S_t *space)
 {
     htri_t ret_value;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_valid);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_valid)
 
     assert(space);
 
     ret_value = (*space->select.type->is_valid)(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_valid() */
 
 
@@ -449,7 +450,7 @@ H5S_select_deserialize (H5S_t *space, const uint8_t *buf)
     uint32_t sel_type;       /* Pointer to the selection type */
     herr_t ret_value=FAIL;  /* return value */
 
-    FUNC_ENTER_NOAPI(H5S_select_deserialize, FAIL);
+    FUNC_ENTER_NOAPI(H5S_select_deserialize, FAIL)
 
     assert(space);
 
@@ -476,10 +477,10 @@ H5S_select_deserialize (H5S_t *space, const uint8_t *buf)
             break;
     }
     if(ret_value<0)
-        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTLOAD, FAIL, "can't deserialize selection");
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTLOAD, FAIL, "can't deserialize selection")
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_deserialize() */
 
 
@@ -567,7 +568,7 @@ H5S_get_select_bounds(const H5S_t *space, hsize_t *start, hsize_t *end)
 {
     herr_t ret_value;        /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_get_select_bounds);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_get_select_bounds)
 
     /* Check args */
     assert(space);
@@ -576,7 +577,7 @@ H5S_get_select_bounds(const H5S_t *space, hsize_t *start, hsize_t *end)
 
     ret_value = (*space->select.type->bounds)(space,start,end);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_get_select_bounds() */
 
 
@@ -646,14 +647,14 @@ H5S_select_is_contiguous(const H5S_t *space)
 {
     herr_t ret_value;        /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_contiguous);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_contiguous)
 
     /* Check args */
     assert(space);
 
     ret_value = (*space->select.type->is_contiguous)(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_is_contiguous() */
 
 
@@ -683,14 +684,14 @@ H5S_select_is_single(const H5S_t *space)
 {
     herr_t ret_value;        /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_single);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_single)
 
     /* Check args */
     assert(space);
 
     ret_value = (*space->select.type->is_single)(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_is_single() */
 
 
@@ -720,14 +721,14 @@ H5S_select_is_regular(const H5S_t *space)
 {
     herr_t ret_value;        /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_regular);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_is_regular)
 
     /* Check args */
     assert(space);
 
     ret_value = (*space->select.type->is_regular)(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_is_regular() */
 
 
@@ -770,6 +771,86 @@ H5S_select_adjust_u(H5S_t *space, const hsize_t *offset)
 
 /*--------------------------------------------------------------------------
  NAME
+    H5S_select_project_scalar
+ PURPOSE
+    Project a single element selection for a scalar dataspace
+ USAGE
+    herr_t H5S_select_project_scalar(space, offset)
+        const H5S_t *space;             IN: Pointer to dataspace to project
+        hsize_t *offset;                IN/OUT: Offset of projected point
+ RETURNS
+    Non-negative on success, negative on failure
+ DESCRIPTION
+    Projects a selection of a single element into a scalar dataspace, computing
+    the offset of the element in the original selection.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine participates in the "Inlining C function pointers"
+        pattern, don't call it directly, use the appropriate macro
+        defined in H5Sprivate.h.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5S_select_project_scalar(const H5S_t *space, hsize_t *offset)
+{
+    herr_t ret_value;        /* Return value */
+
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_project_scalar)
+
+    /* Check args */
+    HDassert(space);
+    HDassert(offset);
+
+    ret_value = (*space->select.type->project_scalar)(space, offset);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* H5S_select_project_scalar() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5S_select_project_simple
+ PURPOSE
+    Project a selection onto/into a dataspace of different rank
+ USAGE
+    herr_t H5S_select_project_simple(space, new_space, offset)
+        const H5S_t *space;             IN: Pointer to dataspace to project
+        H5S_t *new_space;               IN/OUT: Pointer to dataspace projected onto
+        hsize_t *offset;                IN/OUT: Offset of projected point
+ RETURNS
+    Non-negative on success, negative on failure
+ DESCRIPTION
+    Projects a selection onto/into a simple dataspace, computing
+    the offset of the first element in the original selection.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    This routine participates in the "Inlining C function pointers"
+        pattern, don't call it directly, use the appropriate macro
+        defined in H5Sprivate.h.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5S_select_project_simple(const H5S_t *space, H5S_t *new_space, hsize_t *offset)
+{
+    herr_t ret_value;        /* Return value */
+
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_project_simple)
+
+    /* Check args */
+    HDassert(space);
+    HDassert(new_space);
+    HDassert(offset);
+
+    ret_value = (*space->select.type->project_simple)(space, new_space, offset);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* H5S_select_project_simple() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
     H5S_select_iter_init
  PURPOSE
     Initializes iteration information for a selection.
@@ -790,7 +871,7 @@ H5S_select_iter_init(H5S_sel_iter_t *sel_iter, const H5S_t *space, size_t elmt_s
 {
     herr_t ret_value;   /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_init);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_init)
 
     /* Check args */
     assert(sel_iter);
@@ -813,7 +894,7 @@ H5S_select_iter_init(H5S_sel_iter_t *sel_iter, const H5S_t *space, size_t elmt_s
     /* Call initialization routine for selection type */
     ret_value= (*space->select.type->iter_init)(sel_iter, space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_init() */
 
 
@@ -844,7 +925,7 @@ H5S_select_iter_coords (const H5S_sel_iter_t *sel_iter, hsize_t *coords)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_coords);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_coords)
 
     /* Check args */
     assert(sel_iter);
@@ -853,7 +934,7 @@ H5S_select_iter_coords (const H5S_sel_iter_t *sel_iter, hsize_t *coords)
     /* Call iter_coords routine for selection type */
     ret_value = (*sel_iter->type->iter_coords)(sel_iter,coords);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_coords() */
 
 #ifdef LATER
@@ -886,7 +967,7 @@ H5S_select_iter_block (const H5S_sel_iter_t *iter, hsize_t *start, hsize_t *end)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_block);
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_block)
 
     /* Check args */
     assert(iter);
@@ -896,7 +977,7 @@ H5S_select_iter_block (const H5S_sel_iter_t *iter, hsize_t *start, hsize_t *end)
     /* Call iter_block routine for selection type */
     ret_value = (*iter->type->iter_block)(iter,start,end);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_block() */
 #endif /* LATER */
 
@@ -926,7 +1007,7 @@ H5S_select_iter_nelmts (const H5S_sel_iter_t *sel_iter)
 {
     hsize_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_nelmts);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_nelmts)
 
     /* Check args */
     assert(sel_iter);
@@ -934,7 +1015,7 @@ H5S_select_iter_nelmts (const H5S_sel_iter_t *sel_iter)
     /* Call iter_nelmts routine for selection type */
     ret_value = (*sel_iter->type->iter_nelmts)(sel_iter);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_nelmts() */
 
 #ifdef LATER
@@ -965,7 +1046,7 @@ H5S_select_iter_has_next_block (const H5S_sel_iter_t *iter)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_has_next_block);
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_has_next_block)
 
     /* Check args */
     assert(iter);
@@ -973,7 +1054,7 @@ H5S_select_iter_has_next_block (const H5S_sel_iter_t *iter)
     /* Call iter_has_next_block routine for selection type */
     ret_value = (*iter->type->iter_has_next_block)(iter);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_has_next_block() */
 #endif /* LATER */
 
@@ -1005,7 +1086,7 @@ H5S_select_iter_next(H5S_sel_iter_t *iter, size_t nelem)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_next);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_next)
 
     /* Check args */
     assert(iter);
@@ -1017,7 +1098,7 @@ H5S_select_iter_next(H5S_sel_iter_t *iter, size_t nelem)
     /* Decrement the number of elements left in selection */
     iter->elmt_left-=nelem;
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_next() */
 
 #ifdef LATER
@@ -1050,7 +1131,7 @@ H5S_select_iter_next_block(H5S_sel_iter_t *iter)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_next_block);
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_select_iter_next_block)
 
     /* Check args */
     assert(iter);
@@ -1058,7 +1139,7 @@ H5S_select_iter_next_block(H5S_sel_iter_t *iter)
     /* Call iter_next_block routine for selection type */
     ret_value = (*iter->type->iter_next_block)(iter);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_next_block() */
 #endif /* LATER */
 
@@ -1088,7 +1169,7 @@ H5S_select_iter_release(H5S_sel_iter_t *sel_iter)
 {
     herr_t ret_value;         /* return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_release);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_select_iter_release)
 
     /* Check args */
     assert(sel_iter);
@@ -1096,7 +1177,7 @@ H5S_select_iter_release(H5S_sel_iter_t *sel_iter)
     /* Call selection type-specific release routine */
     ret_value = (*sel_iter->type->iter_release)(sel_iter);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5S_select_iter_release() */
 
 
@@ -1154,7 +1235,7 @@ H5S_select_iterate(void *buf, hid_t type_id, const H5S_t *space, H5D_operator_t
     herr_t user_ret=0;          /* User's return value */
     herr_t ret_value=SUCCEED;   /* Return value */
 
-    FUNC_ENTER_NOAPI(H5S_select_iterate, FAIL);
+    FUNC_ENTER_NOAPI(H5S_select_iterate, FAIL)
 
     /* Check args */
     HDassert(buf);
@@ -1302,7 +1383,7 @@ H5S_get_select_type(const H5S_t *space)
 {
     H5S_sel_type        ret_value;       /* Return value */
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5S_get_select_type);
+    FUNC_ENTER_NOAPI_NOFUNC(H5S_get_select_type)
 
     /* Check args */
     assert(space);
@@ -1310,7 +1391,7 @@ H5S_get_select_type(const H5S_t *space)
     /* Set return value */
     ret_value=H5S_GET_SELECT_TYPE(space);
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(ret_value)
 }   /* end H5S_get_select_type() */
 
 
@@ -1334,16 +1415,17 @@ H5S_get_select_type(const H5S_t *space)
     Assumes that there is only a single "block" for hyperslab selections.
  EXAMPLES
  REVISION LOG
+    Modified function to view identical shapes with different dimensions 
+    as being the same under some circumstances.
 --------------------------------------------------------------------------*/
 htri_t
 H5S_select_shape_same(const H5S_t *space1, const H5S_t *space2)
 {
-    H5S_sel_iter_t iter1;               /* Selection #1 iteration info */
-    H5S_sel_iter_t iter2;               /* Selection #2 iteration info */
-    hbool_t iter1_init = 0;             /* Selection #1 iteration info has been initialized */
-    hbool_t iter2_init = 0;             /* Selection #2 iteration info has been initialized */
-    unsigned u;                         /* Index variable */
-    htri_t ret_value = TRUE;            /* Return value */
+    H5S_sel_iter_t iter_a;    /* Selection a iteration info */
+    H5S_sel_iter_t iter_b;    /* Selection b iteration info */
+    hbool_t iter_a_init = 0;  /* Selection a iteration info has been initialized */
+    hbool_t iter_b_init = 0;  /* Selection b iteration info has been initialized */
+    htri_t ret_value = TRUE; /* Return value */
 
     FUNC_ENTER_NOAPI(H5S_select_shape_same, FAIL)
 
@@ -1358,139 +1440,527 @@ H5S_select_shape_same(const H5S_t *space1, const H5S_t *space2)
             HGOTO_DONE(FALSE)
     } /* end if */
     else {
-        /* Check for different dimensionality */
-        if(space1->extent.rank != space2->extent.rank)
-            HGOTO_DONE(FALSE)
+        const H5S_t *space_a;           /* Dataspace with larger rank */
+        const H5S_t *space_b;           /* Dataspace with smaller rank */
+        unsigned space_a_rank;          /* Number of dimensions of dataspace A */
+        unsigned space_b_rank;          /* Number of dimensions of dataspace B */
+
+        /* need to be able to handle spaces of different rank:
+         *
+         * To simplify logic, let space_a point to the element of the set
+         * {space1, space2} with the largest rank or space1 if the ranks 
+         * are identical.
+         *
+         * Similarly, let space_b point to the element of {space1, space2}
+         * with the smallest rank, or space2 if they are identical.
+         *
+         * Let:  space_a_rank be the rank of space_a, 
+         *       space_b_rank be the rank of space_b,
+         *       delta_rank = space_a_rank - space_b_rank.
+         *
+         * Set all this up below.
+         */
+        if(space1->extent.rank >= space2->extent.rank) {
+            space_a = space1;
+            space_a_rank = space_a->extent.rank;
+
+            space_b = space2;
+            space_b_rank = space_b->extent.rank;
+        } /* end if */
+        else {
+            space_a = space2;
+            space_a_rank = space_a->extent.rank;
+
+            space_b = space1;
+            space_b_rank = space_b->extent.rank;
+        } /* end else */
+        HDassert(space_a_rank >= space_b_rank);
+        HDassert(space_b_rank > 0);
 
         /* Check for different number of elements selected */
-        if(H5S_GET_SELECT_NPOINTS(space1) != H5S_GET_SELECT_NPOINTS(space2))
+        if(H5S_GET_SELECT_NPOINTS(space_a) != H5S_GET_SELECT_NPOINTS(space_b))
             HGOTO_DONE(FALSE)
 
         /* Check for "easy" cases before getting into generalized block iteration code */
-        if(H5S_GET_SELECT_TYPE(space1)==H5S_SEL_ALL && H5S_GET_SELECT_TYPE(space2)==H5S_SEL_ALL) {
-            hsize_t dims1[H5O_LAYOUT_NDIMS];             /* End point of selection block in dataspace #1 */
-            hsize_t dims2[H5O_LAYOUT_NDIMS];             /* End point of selection block in dataspace #2 */
-
-            if(H5S_get_simple_extent_dims(space1, dims1, NULL)<0)
-                HGOTO_ERROR (H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get dimensionality");
-            if(H5S_get_simple_extent_dims(space2, dims2, NULL)<0)
-                HGOTO_ERROR (H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get dimensionality");
-
-            /* Check that the sizes are the same */
-            for (u=0; u<space1->extent.rank; u++)
-                if(dims1[u]!=dims2[u])
-                    HGOTO_DONE(FALSE);
+        if((H5S_GET_SELECT_TYPE(space_a) == H5S_SEL_ALL) && (H5S_GET_SELECT_TYPE(space_b) == H5S_SEL_ALL)) {
+            hsize_t dims1[H5O_LAYOUT_NDIMS];    /* End point of selection block in dataspace #1 */
+            hsize_t dims2[H5O_LAYOUT_NDIMS];    /* End point of selection block in dataspace #2 */
+            int space_a_dim;                /* Current dimension in dataspace A */
+            int space_b_dim;                /* Current dimension in dataspace B */
+
+            if(H5S_get_simple_extent_dims(space_a, dims1, NULL) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get dimensionality")
+            if(H5S_get_simple_extent_dims(space_b, dims2, NULL) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get dimensionality")
+
+            space_a_dim = (int)space_a_rank - 1;
+            space_b_dim = (int)space_b_rank - 1;
+
+            /* recall that space_a_rank >= space_b_rank. 
+             *
+             * In the following while loop, we test to see if space_a and space_b
+             * have identical size in all dimensions they have in common.
+             */
+            while(space_b_dim >= 0) {
+                if(dims1[space_a_dim] != dims2[space_b_dim])
+                    HGOTO_DONE(FALSE)
+
+                space_a_dim--;
+                space_b_dim--;
+            } /* end while */
+
+            /* Since we are selecting the entire spaces, we must also verify that space_a 
+             * has size 1 in all dimensions that it does not share with space_b.
+             */
+            while(space_a_dim >= 0) {
+                if(dims1[space_a_dim] != 1)
+                    HGOTO_DONE(FALSE)
+
+                space_a_dim--;
+            } /* end while */
         } /* end if */
-        else if(H5S_GET_SELECT_TYPE(space1)==H5S_SEL_NONE || H5S_GET_SELECT_TYPE(space2)==H5S_SEL_NONE) {
-            HGOTO_DONE(TRUE);
+        else if((H5S_GET_SELECT_TYPE(space1) == H5S_SEL_NONE) || (H5S_GET_SELECT_TYPE(space2) == H5S_SEL_NONE)) {
+            HGOTO_DONE(TRUE)
         } /* end if */
-        else if((H5S_GET_SELECT_TYPE(space1)==H5S_SEL_HYPERSLABS && space1->select.sel_info.hslab->diminfo_valid)
-                && (H5S_GET_SELECT_TYPE(space2)==H5S_SEL_HYPERSLABS && space2->select.sel_info.hslab->diminfo_valid)) {
-
-            /* Check that the shapes are the same */
-            for (u=0; u<space1->extent.rank; u++) {
-                if(space1->select.sel_info.hslab->opt_diminfo[u].stride!=space2->select.sel_info.hslab->opt_diminfo[u].stride)
-                    HGOTO_DONE(FALSE);
-                if(space1->select.sel_info.hslab->opt_diminfo[u].count!=space2->select.sel_info.hslab->opt_diminfo[u].count)
-                    HGOTO_DONE(FALSE);
-                if(space1->select.sel_info.hslab->opt_diminfo[u].block!=space2->select.sel_info.hslab->opt_diminfo[u].block)
-                    HGOTO_DONE(FALSE);
-            } /* end for */
+        else if((H5S_GET_SELECT_TYPE(space_a) == H5S_SEL_HYPERSLABS && space_a->select.sel_info.hslab->diminfo_valid)
+                && (H5S_GET_SELECT_TYPE(space_b) == H5S_SEL_HYPERSLABS && space_b->select.sel_info.hslab->diminfo_valid)) {
+            int space_a_dim;                /* Current dimension in dataspace A */
+            int space_b_dim;                /* Current dimension in dataspace B */
+
+            space_a_dim = (int)space_a_rank - 1;
+            space_b_dim = (int)space_b_rank - 1;
+
+            /* check that the shapes are the same in the common dimensions, and that
+             * block == 1 in all dimensions that appear only in space_a.
+             */
+            while(space_b_dim >= 0) {
+                if(space_a->select.sel_info.hslab->opt_diminfo[space_a_dim].stride != 
+                        space_b->select.sel_info.hslab->opt_diminfo[space_b_dim].stride)
+                    HGOTO_DONE(FALSE)
+
+                if(space_a->select.sel_info.hslab->opt_diminfo[space_a_dim].count !=
+                        space_b->select.sel_info.hslab->opt_diminfo[space_b_dim].count)
+                    HGOTO_DONE(FALSE)
+
+                if(space_a->select.sel_info.hslab->opt_diminfo[space_a_dim].block != 
+                        space_b->select.sel_info.hslab->opt_diminfo[space_b_dim].block)
+                    HGOTO_DONE(FALSE)
+
+                space_a_dim--;
+                space_b_dim--;
+            } /* end while */
+
+            while(space_a_dim >= 0) {
+                if(space_a->select.sel_info.hslab->opt_diminfo[space_a_dim].block != 1)
+                    HGOTO_DONE(FALSE)
+
+                space_a_dim--;
+            } /* end while */
         } /* end if */
         /* Iterate through all the blocks in the selection */
         else {
-            hsize_t start1[H5O_LAYOUT_NDIMS];      /* Start point of selection block in dataspace #1 */
-            hsize_t start2[H5O_LAYOUT_NDIMS];      /* Start point of selection block in dataspace #2 */
-            hsize_t end1[H5O_LAYOUT_NDIMS];        /* End point of selection block in dataspace #1 */
-            hsize_t end2[H5O_LAYOUT_NDIMS];        /* End point of selection block in dataspace #2 */
-            hsize_t off1[H5O_LAYOUT_NDIMS];        /* Offset of selection #1 blocks */
-            hsize_t off2[H5O_LAYOUT_NDIMS];        /* Offset of selection #2 blocks */
-            htri_t status1,status2;         /* Status from next block checks */
-            unsigned first_block=1;         /* Flag to indicate the first block */
+            hsize_t start_a[H5O_LAYOUT_NDIMS]; /* Start point of selection block in dataspace a */
+            hsize_t start_b[H5O_LAYOUT_NDIMS]; /* Start point of selection block in dataspace b */
+            hsize_t end_a[H5O_LAYOUT_NDIMS];   /* End point of selection block in dataspace a */
+            hsize_t end_b[H5O_LAYOUT_NDIMS];   /* End point of selection block in dataspace b */
+            hsize_t off_a[H5O_LAYOUT_NDIMS];   /* Offset of selection a blocks */
+            hsize_t off_b[H5O_LAYOUT_NDIMS];   /* Offset of selection b blocks */
+            hbool_t first_block = TRUE;        /* Flag to indicate the first block */
 
             /* Initialize iterator for each dataspace selection
              * Use '0' for element size instead of actual element size to indicate
              * that the selection iterator shouldn't be "flattened", since we
              * aren't actually going to be doing I/O with the iterators.
              */
-            if(H5S_select_iter_init(&iter1, space1, (size_t)0) < 0)
-                HGOTO_ERROR (H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator");
-            iter1_init = 1;
-            if(H5S_select_iter_init(&iter2, space2, (size_t)0) < 0)
-                HGOTO_ERROR (H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator");
-            iter2_init = 1;
+            if(H5S_select_iter_init(&iter_a, space_a, (size_t)0) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator a")
+            iter_a_init = 1;
+            if(H5S_select_iter_init(&iter_b, space_b, (size_t)0) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator b")
+            iter_b_init = 1;
 
             /* Iterate over all the blocks in each selection */
             while(1) {
+                int space_a_dim;                /* Current dimension in dataspace A */
+                int space_b_dim;                /* Current dimension in dataspace B */
+                htri_t status_a, status_b;      /* Status from next block checks */
+
                 /* Get the current block for each selection iterator */
-                if(H5S_SELECT_ITER_BLOCK(&iter1,start1,end1)<0)
-                    HGOTO_ERROR (H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get iterator block");
-                if(H5S_SELECT_ITER_BLOCK(&iter2,start2,end2)<0)
-                    HGOTO_ERROR (H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get iterator block");
+                if(H5S_SELECT_ITER_BLOCK(&iter_a, start_a, end_a) < 0)
+                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get iterator block a")
+                if(H5S_SELECT_ITER_BLOCK(&iter_b, start_b, end_b) < 0)
+                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get iterator block b")
 
-                /* The first block only compares the sizes and sets the relative offsets for later blocks */
+                space_a_dim = (int)space_a_rank - 1;
+                space_b_dim = (int)space_b_rank - 1;
+
+                /* The first block only compares the sizes and sets the 
+                 * relative offsets for later blocks 
+                 */
                 if(first_block) {
-                    /* If the block sizes from each selection doesn't match, get out */
-                    for (u=0; u<space1->extent.rank; u++) {
-                        if((end1[u]-start1[u])!=(end2[u]-start2[u]))
-                            HGOTO_DONE(FALSE);
+                    /* If the block sizes in the common dimensions from 
+                     * each selection don't match, get out
+                     */
+                    while(space_b_dim >= 0) {
+                        if((end_a[space_a_dim] - start_a[space_a_dim]) !=
+                                (end_b[space_b_dim] - start_b[space_b_dim]))
+                            HGOTO_DONE(FALSE)
+
+                        /* Set the relative locations of the selections */
+                        off_a[space_a_dim] = start_a[space_a_dim];
+                        off_b[space_b_dim] = start_b[space_b_dim];
+
+                        space_a_dim--;
+                        space_b_dim--;
+                    } /* end while */
+
+                    /* similarly, if the block size in any dimension that appears only
+                     * in space_a is not equal to 1, get out.
+                     */
+                    while(space_a_dim >= 0) {
+                        if((end_a[space_a_dim] - start_a[space_a_dim]) != 0)
+                            HGOTO_DONE(FALSE)
 
                         /* Set the relative locations of the selections */
-                        off1[u]=start1[u];
-                        off2[u]=start2[u];
-                    } /* end for */
+                        off_a[space_a_dim] = start_a[space_a_dim];
+
+                        space_a_dim--;
+                    } /* end while */
 
                     /* Reset "first block" flag */
-                    first_block=0;
+                    first_block = FALSE;
                 } /* end if */
+                /* Check over the blocks for each selection */
                 else {
-                    /* Check over the blocks for each selection */
-                    for (u=0; u<space1->extent.rank; u++) {
+                    /* for dimensions that space_a and space_b have in common: */
+                    while(space_b_dim >= 0) {
                         /* Check if the blocks are in the same relative location */
-                        if((start1[u]-off1[u])!=(start2[u]-off2[u]))
-                            HGOTO_DONE(FALSE);
+                        if((start_a[space_a_dim] - off_a[space_a_dim]) !=
+                                (start_b[space_b_dim] - off_b[space_b_dim]))
+                            HGOTO_DONE(FALSE)
 
                         /* If the block sizes from each selection doesn't match, get out */
-                        if((end1[u]-start1[u])!=(end2[u]-start2[u]))
-                            HGOTO_DONE(FALSE);
-                    } /* end for */
+                        if((end_a[space_a_dim] - start_a[space_a_dim]) !=
+                                (end_b[space_b_dim] - start_b[space_b_dim]))
+                            HGOTO_DONE(FALSE)
+
+                        space_a_dim--;
+                        space_b_dim--;
+                    } /* end while */
+
+                    /* For dimensions that appear only in space_a: */
+                    while(space_a_dim >= 0) {
+                        /* If the block size isn't 1, get out */
+                        if((end_a[space_a_dim] - start_a[space_a_dim]) != 0)
+                            HGOTO_DONE(FALSE)
+
+                        space_a_dim--;
+                    } /* end while */
                 } /* end else */
 
                 /* Check if we are able to advance to the next selection block */
-                if((status1=H5S_SELECT_ITER_HAS_NEXT_BLOCK(&iter1))<0)
-                    HGOTO_ERROR (H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to check iterator block");
-                if((status2=H5S_SELECT_ITER_HAS_NEXT_BLOCK(&iter2))<0)
-                    HGOTO_ERROR (H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to check iterator block");
+                if((status_a = H5S_SELECT_ITER_HAS_NEXT_BLOCK(&iter_a)) < 0)
+                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to check iterator block a")
+
+                if((status_b = H5S_SELECT_ITER_HAS_NEXT_BLOCK(&iter_b)) < 0)
+                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to check iterator block b")
 
                 /* Did we run out of blocks at the same time? */
-                if(status1==FALSE && status2==FALSE)
+                if((status_a == FALSE) && (status_b == FALSE))
                     break;
-                else if(status1!=status2) {
-                    HGOTO_DONE(FALSE);
-                } /* end if */
+                else if(status_a != status_b)
+                    HGOTO_DONE(FALSE)
                 else {
                     /* Advance to next block in selection iterators */
-                    if(H5S_SELECT_ITER_NEXT_BLOCK(&iter1)<0)
-                        HGOTO_ERROR (H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to advance to next iterator block");
-                    if(H5S_SELECT_ITER_NEXT_BLOCK(&iter2)<0)
-                        HGOTO_ERROR (H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to advance to next iterator block");
+                    if(H5S_SELECT_ITER_NEXT_BLOCK(&iter_a) < 0)
+                        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to advance to next iterator block a")
+
+                    if(H5S_SELECT_ITER_NEXT_BLOCK(&iter_b) < 0)
+                        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "unable to advance to next iterator block b")
                 } /* end else */
             } /* end while */
         } /* end else */
     } /* end else */
 
 done:
-    if(iter1_init) {
-        if (H5S_SELECT_ITER_RELEASE(&iter1)<0)
-            HDONE_ERROR (H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator");
+    if(iter_a_init)
+        if(H5S_SELECT_ITER_RELEASE(&iter_a) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator a")
+    if(iter_b_init)
+        if(H5S_SELECT_ITER_RELEASE(&iter_b) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator b")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* H5S_select_shape_same() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5S_select_construct_projection
+
+ PURPOSE
+    Given a dataspace a of rank n with some selection, construct a new
+    dataspace b of rank m (m != n), with the selection in a being 
+    topologically identical to that in b (as verified by 
+    H5S_select_shape_same().
+
+    This function exists, as some I/O code chokes of topologically 
+    identical selections with different ranks.  At least to begin 
+    with, we will deal with the issue by constructing projections
+    of the memory dataspace with ranks equaling those of the file 
+    dataspace.
+
+    Note that if m > n, it is possible that the starting point in the 
+    buffer associated with the memory dataspace will have to be 
+    adjusted to match the projected dataspace.  If the buf parameter
+    is not NULL, the function must return an adjusted buffer base
+    address in *adj_buf_ptr.
+
+ USAGE
+    htri_t H5S_select_construct_projection(base_space, 
+                                           new_space_ptr,
+                                           new_space_rank,
+                                           buf,
+                                           adj_buf_ptr)
+        const H5S_t *base_space;     IN: Ptr to Dataspace to project
+        H5S_t ** new_space_ptr;     OUT: Ptr to location in which to return
+					 the address of the projected space
+        int new_space_rank;	     IN: Rank of the projected space.
+        const void * buf;            IN: Base address of the buffer 
+					 associated with the base space.
+					 May be NULL.
+        void ** adj_buf_ptr;        OUT: If buf != NULL, store the base
+					 address of the section of buf 
+					 that is described by *new_space_ptr
+					 in *adj_buf_ptr.
+					 
+ RETURNS
+    Non-negative on success/Negative on failure.
+
+ DESCRIPTION
+    Construct a new dataspace and associated selection which is a 
+    projection of the supplied dataspace and associated selection into 
+    the specified rank.  Return it in *new_space_ptr.
+
+    If buf is supplied, computes the base address of the projected 
+    selection in buf, and stores the base address in *adj_buf_ptr.
+    
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    The selection in the supplied base_space has thickness 1 in all 
+    dimensions greater than new_space_rank.  Note that here we count
+    dimensions from the fastest changing coordinate to the slowest 
+    changing changing coordinate.
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5S_select_construct_projection(const H5S_t *base_space, H5S_t **new_space_ptr,
+    unsigned new_space_rank, const void *buf, void **adj_buf_ptr, hsize_t element_size)
+{
+    H5S_t * new_space = NULL;           /* New dataspace constructed */
+    hsize_t base_space_dims[H5S_MAX_RANK];      /* Current dimensions of base dataspace */
+    hsize_t base_space_maxdims[H5S_MAX_RANK];   /* Maximum dimensions of base dataspace */
+    int sbase_space_rank;               /* Signed # of dimensions of base dataspace */
+    unsigned base_space_rank;           /* # of dimensions of base dataspace */
+    hsize_t projected_space_element_offset = 0; /* Offset of selected element in projected buffer */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(H5S_select_construct_projection, FAIL)
+
+    /* Sanity checks */
+    HDassert(base_space != NULL);
+    HDassert((H5S_GET_EXTENT_TYPE(base_space) == H5S_SCALAR) || (H5S_GET_EXTENT_TYPE(base_space) == H5S_SIMPLE));
+    HDassert(new_space_ptr != NULL);
+    HDassert((new_space_rank != 0) || (H5S_GET_SELECT_NPOINTS(base_space) <= 1));
+    HDassert(new_space_rank <= H5S_MAX_RANK);
+    HDassert((buf == NULL) || (adj_buf_ptr != NULL));
+    HDassert(element_size > 0 );
+
+    /* Get the extent info for the base dataspace */
+    if((sbase_space_rank = H5S_get_simple_extent_dims(base_space, base_space_dims, base_space_maxdims)) < 0)
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get dimensionality of base space")
+    base_space_rank = (unsigned)sbase_space_rank;
+    HDassert(base_space_rank != new_space_rank);
+
+    /* Check if projected space is scalar */
+    if(new_space_rank == 0) {
+        hssize_t npoints;               /* Number of points selected */
+
+        /* Retreve the number of elements selected */
+        if((npoints = (hssize_t)H5S_GET_SELECT_NPOINTS(base_space)) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get number of points selected")
+        HDassert(npoints <= 1);
+
+        /* Create new scalar dataspace */
+        if(NULL == (new_space = H5S_create(H5S_SCALAR)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "unable to create scalar dataspace")
+    
+        /* No need to register the dataspace(i.e. get an ID) as
+         * we will just be discarding it shortly.
+         */
+
+        /* Selection for the new space will be either all or 
+         * none, depending on whether the base space has 0 or
+         * 1 elements selected.
+         *
+         * Observe that the base space can't have more than 
+         * one selected element, since its selection has the
+         * same shape as the file dataspace, and that data 
+         * space is scalar.
+         */
+        if(1 == npoints) {
+            /* Assuming that the selection in the base dataspace is not
+             * empty, we must compute the offset of the selected item in 
+             * the buffer associated with the base dataspace.
+             *
+             * Since the new space rank is zero, we know that the 
+             * the base space must have rank at least 1 -- and 
+             * hence it is a simple dataspace.  However, the 
+             * selection, may be either point, hyperspace, or all.
+             *
+             */
+            if(H5S_SELECT_PROJECT_SCALAR(base_space, &projected_space_element_offset) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "unable to project scalar selection")
+        } /* end if */
+        else {
+            HDassert(0 == npoints);
+
+            if(H5S_select_none(new_space) < 0)
+                 HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't delete default selection")
+        } /* end else */
+    } /* end if */
+    else { /* projected space must be simple */
+        hsize_t new_space_dims[H5S_MAX_RANK];   /* Current dimensions for new dataspace */
+        hsize_t new_space_maxdims[H5S_MAX_RANK];/* Maximum dimensions for new dataspace */
+        unsigned rank_diff;             /* Difference in ranks */
+    
+        /* Set up the dimensions of the new, projected dataspace.
+         *
+         * How we do this depends on whether we are projecting up into 
+         * increased dimensions, or down into a reduced number of 
+         * dimensions.
+         *
+         * If we are projecting up (the first half of the following 
+         * if statement), we copy the dimensions of the base data 
+         * space into the fastest changing dimensions of the new 
+         * projected dataspace, and set the remaining dimensions to
+         * one.
+         *
+         * If we are projecting down (the second half of the following
+         * if statement), we just copy the dimensions with the most 
+         * quickly changing dimensions into the dims for the projected
+         * data set.
+         *
+         * This works, because H5S_select_shape_same() will return 
+         * true on selections of different rank iff:
+         *
+         * 1) the selection in the lower rank dataspace matches that
+         *    in the dimensions with the fastest changing indicies in
+         *    the larger rank dataspace, and
+         *
+         * 2) the selection has thickness 1 in all ranks that appear
+         *    only in the higher rank dataspace (i.e. those with 
+         *    more slowly changing indicies).
+         */ 
+        if(new_space_rank > base_space_rank) {
+            hsize_t tmp_dim_size = 1;   /* Temporary dimension value, for filling arrays */
+
+            /* we must copy the dimensions of the base space into 
+             * the fastest changing dimensions of the new space,
+             * and set the remaining dimensions to 1
+             */
+            rank_diff = new_space_rank - base_space_rank;
+            H5V_array_fill(new_space_dims, &tmp_dim_size, sizeof(tmp_dim_size), rank_diff);
+            H5V_array_fill(new_space_maxdims, &tmp_dim_size, sizeof(tmp_dim_size), rank_diff);
+            HDmemcpy(&new_space_dims[rank_diff], base_space_dims, sizeof(new_space_dims[0]) * base_space_rank);
+            HDmemcpy(&new_space_maxdims[rank_diff], base_space_maxdims, sizeof(new_space_maxdims[0]) * base_space_rank);
+        } /* end if */
+        else { /* new_space_rank < base_space_rank */
+            /* we must copy the fastest changing dimension of the 
+             * base space into the dimensions of the new space.
+             */
+            rank_diff = base_space_rank - new_space_rank;
+            HDmemcpy(new_space_dims, &base_space_dims[rank_diff], sizeof(new_space_dims[0]) * new_space_rank);
+            HDmemcpy(new_space_maxdims, &base_space_maxdims[rank_diff], sizeof(new_space_maxdims[0]) * new_space_rank);
+        } /* end else */
+
+        /* now have the new space rank and dimensions set up -- 
+         * so we can create the new simple dataspace.
+         */
+        if(NULL == (new_space = H5S_create_simple(new_space_rank, new_space_dims, new_space_maxdims)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create simple dataspace")
+    
+        /* No need to register the dataspace(i.e. get an ID) as
+         * we will just be discarding it shortly.
+         */
+
+        /* If we get this far, we have successfully created the projected
+         * dataspace.  We must now project the selection in the base
+         * dataspace into the projected dataspace.
+         */
+        if(H5S_SELECT_PROJECT_SIMPLE(base_space, new_space, &projected_space_element_offset) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "unable to project simple selection")
+    
+        /* If we get this far, we have created the new dataspace, and projected
+         * the selection in the base dataspace into the new dataspace.
+         *
+         * If the base dataspace is simple, check to see if the 
+         * offset_changed flag on the base selection has been set -- if so, 
+         * project the offset into the new dataspace and set the 
+         * offset_changed flag.
+         */
+        if(H5S_GET_EXTENT_TYPE(base_space) == H5S_SIMPLE && base_space->select.offset_changed) {
+            if(new_space_rank > base_space_rank) {
+                HDmemset(new_space->select.offset, 0, sizeof(new_space->select.offset[0]) * rank_diff);
+                HDmemcpy(&new_space->select.offset[rank_diff], base_space->select.offset, sizeof(new_space->select.offset[0]) * base_space_rank);
+            } /* end if */
+            else
+                HDmemcpy(new_space->select.offset, &base_space->select.offset[rank_diff], sizeof(new_space->select.offset[0]) * new_space_rank);
+
+            /* Propagate the offset changed flag into the new dataspace. */
+            new_space->select.offset_changed = TRUE;
+        } /* end if */
+    } /* end else */
+
+    /* If we have done the projection correctly, the following assertion
+     * should hold.
+     */
+    HDassert(TRUE == H5S_select_shape_same(base_space, new_space));
+
+    /* load the address of the new space into *new_space_ptr */
+    *new_space_ptr = new_space;
+
+    /* now adjust the buffer if required */
+    if(buf != NULL) {
+        if(new_space_rank < base_space_rank) {
+            /* a bit of pointer magic here:
+             *
+             * Since we can't do pointer arithmetic on void pointers, we first
+             * cast buf to a pointer to byte -- i.e. uint8_t.
+             *
+             * We then multiply the projected space element offset we 
+             * calculated earlier by the supplied element size, add this 
+             * value to the type cast buf pointer, cast the result back 
+             * to a pointer to void, and assign the result to *adj_buf_ptr.
+             */
+            *adj_buf_ptr = (void *)(((const uint8_t *)buf) + 
+                    ((size_t)(projected_space_element_offset * element_size)));
+        } /* end if */
+        else
+            /* No adjustment necessary */
+            *adj_buf_ptr = buf;
     } /* end if */
-    if(iter2_init) {
-        if (H5S_SELECT_ITER_RELEASE(&iter2)<0)
-            HDONE_ERROR (H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator");
+
+done:
+    /* Cleanup on error */
+    if(ret_value < 0) {
+        if(new_space && H5S_close(new_space) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release dataspace")
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* H5S_select_shape_same() */
+}   /* H5S_select_construct_projection() */
 
 
 /*--------------------------------------------------------------------------
@@ -1536,7 +2006,7 @@ H5S_select_fill(const void *fill, size_t fill_size, const H5S_t *space, void *_b
 
     /* Initialize iterator */
     if(H5S_select_iter_init(&iter, space, fill_size) < 0)
-        HGOTO_ERROR (H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
     iter_init = 1;	/* Selection iteration info has been initialized */
 
     /* Get the number of elements in selection */
@@ -1556,7 +2026,7 @@ H5S_select_fill(const void *fill, size_t fill_size, const H5S_t *space, void *_b
 
         /* Get the sequences of bytes */
         if(H5S_SELECT_GET_SEQ_LIST(space, 0, &iter, (size_t)H5D_IO_VECTOR_SIZE, max_elem, &nseq, &nelem, off, len) < 0)
-            HGOTO_ERROR (H5E_INTERNAL, H5E_UNSUPPORTED, FAIL, "sequence length generation failed")
+            HGOTO_ERROR(H5E_INTERNAL, H5E_UNSUPPORTED, FAIL, "sequence length generation failed")
 
         /* Loop over sequences */
         for(curr_seq = 0; curr_seq < nseq; curr_seq++) {