text: /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Copyright by The HDF Group.                                               *
   * Copyright by the Board of Trustees of the University of Illinois.         *
   * All rights reserved.                                                      *
   *                                                                           *
   * This file is part of HDF5.  The full HDF5 copyright notice, including     *
   * terms governing use, modification, and redistribution, is contained in    *
   * the COPYING file, which can be found at the root of the source code       *
   * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
   * If you do not have access to either file, you may request a copy from     *
   * help@hdfgroup.org.                                                        *
   * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  /* Programmer:  Quincey Koziol
   *              Friday, May 29, 1998
   *
   * Purpose:	Dataspace selection functions.
   */
  
  /****************/
  /* Module Setup */
  /****************/
  
  #include "H5Smodule.h"          /* This source code file is part of the H5S module */
  
  
  /***********/
  /* Headers */
  /***********/
  #include "H5private.h"		/* Generic Functions			*/
  #include "H5Dprivate.h"		/* Datasets				*/
  #include "H5Eprivate.h"		/* Error handling		  	*/
  #include "H5FLprivate.h"	/* Free Lists                           */
  #include "H5Iprivate.h"		/* IDs			  		*/
  #include "H5MMprivate.h"        /* Memory management                    */
  #include "H5Spkg.h"		/* Dataspaces 				*/
  #include "H5VMprivate.h"	/* Vector and array functions		*/
  
  
  /****************/
  /* Local Macros */
  /****************/
  
  /* All the valid public flags to H5Ssel_iter_create() */
  #define H5S_SEL_ITER_ALL_PUBLIC_FLAGS (H5S_SEL_ITER_GET_SEQ_LIST_SORTED | \
                  H5S_SEL_ITER_SHARE_WITH_DATASPACE)
  
  
  /******************/
  /* Local Typedefs */
  /******************/
  
  
  /********************/
  /* Local Prototypes */
  /********************/
  
  #ifdef LATER
  static herr_t H5S_select_iter_block(const H5S_sel_iter_t *iter, hsize_t *start, hsize_t *end);
  static htri_t H5S_select_iter_has_next_block(const H5S_sel_iter_t *iter);
  static herr_t H5S_select_iter_next_block(H5S_sel_iter_t *iter);
  #endif /* LATER */
  
  
  /*****************************/
  /* Library Private Variables */
  /*****************************/
  
  
  /*********************/
  /* Package Variables */
  /*********************/
  
  /* Declare a free list to manage the H5S_sel_iter_t struct */
  H5FL_DEFINE(H5S_sel_iter_t);
  
  /* Declare extern free list to manage sequences of size_t */
  H5FL_SEQ_EXTERN(size_t);
  
  /* Declare extern free list to manage sequences of hsize_t */
  H5FL_SEQ_EXTERN(hsize_t);
  
  
  /*******************/
  /* Local Variables */
  /*******************/
  
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_offset
   PURPOSE
      Set the selection offset for a datapace
   USAGE
      herr_t H5S_select_offset(space, offset)
          H5S_t *space;	        IN/OUT: Dataspace object to set selection offset
          const hssize_t *offset; IN: Offset to position the selection at
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Sets the selection offset for the dataspace
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
      Only works for simple dataspaces currently
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_offset(H5S_t *space, const hssize_t *offset)
  {
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(0 < space->extent.rank && space->extent.rank <= H5S_MAX_RANK);
      HDassert(offset);
  
      /* Copy the offset over */
      H5MM_memcpy(space->select.offset, offset, sizeof(hssize_t) * space->extent.rank);
  
      /* Indicate that the offset was changed */
      space->select.offset_changed = TRUE;
  
      FUNC_LEAVE_NOAPI(SUCCEED)
  } /* end H5S_select_offset() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Soffset_simple
   PURPOSE
      Changes the offset of a selection within a simple dataspace extent
   USAGE
      herr_t H5Soffset_simple(space_id, offset)
          hid_t space_id;	        IN: Dataspace object to reset
          const hssize_t *offset; IN: Offset to position the selection at
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
  	This function creates an offset for the selection within an extent, allowing
      the same shaped selection to be moved to different locations within a
      dataspace without requiring it to be re-defined.
  --------------------------------------------------------------------------*/
  herr_t
  H5Soffset_simple(hid_t space_id, const hssize_t *offset)
  {
      H5S_t *space;                   /* Dataspace to modify */
      herr_t ret_value = SUCCEED;     /* Return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE2("e", "i*Hs", space_id, offset);
  
      /* Check args */
      if(NULL == (space = (H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "not a dataspace")
      if(space->extent.rank == 0 || (H5S_GET_EXTENT_TYPE(space) == H5S_SCALAR
              || H5S_GET_EXTENT_TYPE(space) == H5S_NULL))
          HGOTO_ERROR(H5E_ATOM, H5E_UNSUPPORTED, FAIL, "can't set offset on scalar or null dataspace")
      if(offset == NULL)
          HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no offset specified")
  
      /* Set the selection offset */
      if(H5S_select_offset(space, offset) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't set offset")
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Soffset_simple() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_copy
   PURPOSE
      Copy a selection from one dataspace to another
   USAGE
      herr_t H5Sselect_copy(dst, src)
          hid_t   dst;              OUT: ID of the destination dataspace
          hid_t   src;              IN:  ID of the source dataspace
  
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Copies all the selection information (including offset) from the source
      dataspace to the destination dataspace.
  
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5Sselect_copy(hid_t dst_id, hid_t src_id)
  {
      H5S_t  *src;
      H5S_t  *dst;
      herr_t  ret_value = SUCCEED;
  
      FUNC_ENTER_API(FAIL)
      H5TRACE2("e", "ii", dst_id, src_id);
  
      /* Check args */
      if(NULL == (src = (H5S_t *)H5I_object_verify(src_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == (dst = (H5S_t *)H5I_object_verify(dst_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
  
      /* Copy */
      if(H5S_select_copy(dst, src, FALSE) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "can't copy selection")
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_copy() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_copy
   PURPOSE
      Copy a selection from one dataspace to another
   USAGE
      herr_t H5S_select_copy(dst, src, share_selection)
          H5S_t *dst;  OUT: Pointer to the destination dataspace
          H5S_t *src;  IN: Pointer to the source dataspace
          hbool_t;     IN: Whether to share the selection between the dataspaces
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Copies all the selection information (include offset) from the source
      dataspace to the destination dataspace.
  
      If the SHARE_SELECTION flag is set, then the selection can be shared
      between the source and destination dataspaces.  (This should only occur in
      situations where the destination dataspace will immediately change to a new
      selection)
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_copy(H5S_t *dst, const H5S_t *src, hbool_t share_selection)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(dst);
      HDassert(src);
  
      /* Release the current selection */
      if(H5S_SELECT_RELEASE(dst) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection")
  
      /* Copy regular fields */
      dst->select = src->select;
  
      /* 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")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_copy() */
  
  
  /*-------------------------------------------------------------------------
   * Function:	H5S_select_release
   *
   * Purpose:	Releases all memory associated with a dataspace selection.
   *
   * Return:	Non-negative on success/Negative on failure
   *
   * Programmer:	Quincey Koziol
   *		Friday, May 30, 2003
   *
   * Note: This routine participates in the "Inlining C function pointers"
   *      pattern, don't call it directly, use the appropriate macro
   *      defined in H5Sprivate.h.
   *
   *-------------------------------------------------------------------------
   */
  herr_t
  H5S_select_release(H5S_t *ds)
  {
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT
  
      HDassert(ds);
  
      /* Call the selection type's release function */
      if((ds->select.type) && ((ret_value = (*ds->select.type->release)(ds)) < 0))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_release() */
  
  
  /*-------------------------------------------------------------------------
   * Function:	H5S_select_serial_size
   *
   * Purpose:	Determines the number of bytes required to store the current
   *              selection
   *
   * Return:	Non-negative on success/Negative on failure
   *
   * Programmer:	Quincey Koziol
   *		Tuesday, May 18, 2004
   *
   * Note: This routine participates in the "Inlining C function pointers"
   *      pattern, don't call it directly, use the appropriate macro
   *      defined in H5Sprivate.h.
   *
   *-------------------------------------------------------------------------
   */
  hssize_t
  H5S_select_serial_size(const H5S_t *space)
  {
      hssize_t ret_value = -1;   /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      HDassert(space);
  
      /* Call the selection type's serial_size function */
      ret_value = (*space->select.type->serial_size)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_serial_size() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_serialize
   PURPOSE
      Serialize the selection for a dataspace into a buffer
   USAGE
      herr_t H5S_select_serialize(space, p)
          const H5S_t *space;     IN: Dataspace with selection to serialize
          uint8_t **p;            OUT: Pointer to buffer to put serialized
                                  selection.  Will be advanced to end of
                                  serialized selection.
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Calls the appropriate dataspace selection callback to serialize the
      current selection into a buffer.
   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_serialize(const H5S_t *space, uint8_t **p)
  {
      herr_t ret_value = SUCCEED;   /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      HDassert(space);
      HDassert(p);
  
      /* Call the selection type's serialize function */
      ret_value = (*space->select.type->serialize)(space, p);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_serialize() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sget_select_npoints
   PURPOSE
      Get the number of elements in current selection
   USAGE
      hssize_t H5Sget_select_npoints(dsid)
          hid_t dsid;             IN: Dataspace ID of selection to query
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Returns the number of elements in current selection for dataspace.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  hssize_t
  H5Sget_select_npoints(hid_t spaceid)
  {
      H5S_t *space;               /* Dataspace to modify selection of */
      hssize_t ret_value;         /* return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE1("Hs", "i", spaceid);
  
      /* Check args */
      if(NULL == (space = (H5S_t *)H5I_object_verify(spaceid, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
  
      ret_value = (hssize_t)H5S_GET_SELECT_NPOINTS(space);
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* H5Sget_select_npoints() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_npoints
   PURPOSE
      Get the number of elements in current selection
   USAGE
      hssize_t H5Sget_select_npoints(space)
          H5S_t *space;             IN: Dataspace of selection to query
   RETURNS
      The number of elements in selection on success, 0 on failure
   DESCRIPTION
      Returns the number of elements in current selection for dataspace.
   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
  --------------------------------------------------------------------------*/
  H5_ATTR_PURE hsize_t
  H5S_get_select_npoints(const H5S_t *space)
  {
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      FUNC_LEAVE_NOAPI(space->select.num_elem)
  } /* end H5S_get_select_npoints() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_valid
   PURPOSE
      Check whether the selection fits within the extent, with the current
      offset defined.
   USAGE
      htri_t H5Sselect_void(dsid)
          hid_t dsid;             IN: Dataspace ID to query
   RETURNS
      TRUE if the selection fits within the extent, FALSE if it does not and
          Negative on an error.
   DESCRIPTION
      Determines if the current selection at the current offset fits within the
      extent for the dataspace.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  htri_t
  H5Sselect_valid(hid_t spaceid)
  {
      H5S_t *space;       /* Dataspace to modify selection of */
      htri_t ret_value;   /* return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE1("t", "i", spaceid);
  
      /* Check args */
      if(NULL == (space = (H5S_t *)H5I_object_verify(spaceid, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
  
      ret_value = H5S_SELECT_VALID(space);
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_valid() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_valid
   PURPOSE
      Check whether the selection fits within the extent, with the current
      offset defined.
   USAGE
      htri_t H5S_select_void(space)
          H5S_t *space;           IN: Dataspace to query
   RETURNS
      TRUE if the selection fits within the extent, FALSE if it does not and
          Negative on an error.
   DESCRIPTION
      Determines if the current selection at the current offset fits within the
      extent for the dataspace.
   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
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_valid(const H5S_t *space)
  {
      htri_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      HDassert(space);
  
      ret_value = (*space->select.type->is_valid)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_valid() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_deserialize
   PURPOSE
      Deserialize the current selection from a user-provided buffer into a real
          selection in the dataspace.
   USAGE
      herr_t H5S_select_deserialize(space, p)
          H5S_t **space;          IN/OUT: Dataspace pointer to place
                                  selection into.  Will be allocated if not
                                  provided.
          uint8 **p;              OUT: Pointer to buffer holding serialized
                                  selection.  Will be advanced to end of
                                  serialized selection.
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Deserializes the current selection into a buffer.  (Primarily for retrieving
      from disk).  This routine just hands off to the appropriate routine for each
      type of selection.  The format of the serialized information is shown in
      the H5S_select_serialize() header.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_deserialize(H5S_t **space, const uint8_t **p)
  {
      uint32_t sel_type;          /* Pointer to the selection type */
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      HDassert(space);
  
      /* Selection-type specific coding is moved to the callbacks. */
  
      /* Decode selection type */
      UINT32DECODE(*p, sel_type);
  
      /* Make routine for selection type */
      switch(sel_type) {
          case H5S_SEL_POINTS:         /* Sequence of points selected */
              ret_value = (*H5S_sel_point->deserialize)(space, p);
              break;
  
          case H5S_SEL_HYPERSLABS:     /* Hyperslab selection defined */
              ret_value = (*H5S_sel_hyper->deserialize)(space, p);
              break;
  
          case H5S_SEL_ALL:            /* Entire extent selected */
              ret_value = (*H5S_sel_all->deserialize)(space, p);
              break;
  
          case H5S_SEL_NONE:           /* Nothing selected */
              ret_value = (*H5S_sel_none->deserialize)(space, p);
              break;
  
          default:
              break;
      }
  
      if(ret_value < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTLOAD, FAIL, "can't deserialize selection")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_deserialize() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sget_select_bounds
   PURPOSE
      Gets the bounding box containing the selection.
   USAGE
      herr_t H5S_get_select_bounds(space, start, end)
          hid_t dsid;             IN: Dataspace ID of selection to query
          hsize_t start[];        OUT: Starting coordinate of bounding box
          hsize_t end[];          OUT: Opposite coordinate of bounding box
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Retrieves the bounding box containing the current selection and places
      it into the user's buffers.  The start and end buffers must be large
      enough to hold the dataspace rank number of coordinates.  The bounding box
      exactly contains the selection, ie. if a 2-D element selection is currently
      defined with the following points: (4,5), (6,8) (10,7), the bounding box
      with be (4, 5), (10, 8).  Calling this function on a "none" selection
      returns fail.
          The bounding box calculations _does_ include the current offset of the
      selection within the dataspace extent.
   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
  H5Sget_select_bounds(hid_t spaceid, hsize_t start[], hsize_t end[])
  {
      H5S_t *space;       /* Dataspace to modify selection of */
      herr_t ret_value;   /* return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE3("e", "i*h*h", spaceid, start, end);
  
      /* Check args */
      if(start == NULL || end == NULL)
          HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid pointer")
      if(NULL == (space = (H5S_t *)H5I_object_verify(spaceid, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
  
      ret_value = H5S_SELECT_BOUNDS(space, start, end);
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sget_select_bounds() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_bounds
   PURPOSE
      Gets the bounding box containing the selection.
   USAGE
      herr_t H5S_get_select_bounds(space, start, end)
          H5S_t *space;           IN: Dataspace ID of selection to query
          hsize_t *start;         OUT: Starting coordinate of bounding box
          hsize_t *end;           OUT: Opposite coordinate of bounding box
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Retrieves the bounding box containing the current selection and places
      it into the user's buffers.  The start and end buffers must be large
      enough to hold the dataspace rank number of coordinates.  The bounding box
      exactly contains the selection, ie. if a 2-D element selection is currently
      defined with the following points: (4,5), (6,8) (10,7), the bounding box
      with be (4, 5), (10, 8).  Calling this function on a "none" selection
      returns fail.
          The bounding box calculations _does_ include the current offset of the
      selection within the dataspace extent.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_get_select_bounds(const H5S_t *space, hsize_t *start, hsize_t *end)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(start);
      HDassert(end);
  
      ret_value = (*space->select.type->bounds)(space, start, end);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_get_select_bounds() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_offset
   PURPOSE
      Gets the linear offset of the first element for the selection.
   USAGE
      herr_t H5S_get_select_offset(space, offset)
          const H5S_t *space;     IN: Dataspace pointer of selection to query
          hsize_t *offset;        OUT: Linear offset of first element in selection
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Retrieves the linear offset (in "units" of elements) of the first element
      selected within the dataspace.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
          The offset calculation _does_ include the current offset of the
      selection within the dataspace extent.
  
          Calling this function on a "none" selection returns fail.
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_get_select_offset(const H5S_t *space, hsize_t *offset)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(offset);
  
      ret_value = (*space->select.type->offset)(space, offset);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_get_select_offset() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_unlim_dim
   PURPOSE
      Gets the unlimited dimension in the selection, or -1 if there is no
      unlimited dimension.
   USAGE
      int H5S_get_select_unlim_dim(space)
          const H5S_t *space;     IN: Dataspace pointer of selection to query
   RETURNS
      Unlimited dimension in the selection, or -1 if there is no unlimited
      dimension (never fails)
   DESCRIPTION
      Gets the unlimited dimension in the selection, or -1 if there is no
      unlimited dimension.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
          Currently only implemented for hyperslab selections, all others
          simply return -1.
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  int
  H5S_get_select_unlim_dim(const H5S_t *space)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      ret_value = (*space->select.type->unlim_dim)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_get_select_unlim_dim() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_num_elem_non_unlim
   PURPOSE
      Gets the number of elements in the non-unlimited dimensions
   USAGE
      herr_t H5S_get_select_num_elem_non_unlim(space,num_elem_non_unlim)
          H5S_t *space;           IN: Dataspace pointer to check
          hsize_t *num_elem_non_unlim; OUT: Number of elements in the non-unlimited dimensions
   RETURNS
      Non-negative on success/Negative on failure
   DESCRIPTION
      Returns the number of elements in a slice through the non-unlimited
      dimensions of the selection.  Fails if the selection has no unlimited
      dimension.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_get_select_num_elem_non_unlim(const H5S_t *space,
      hsize_t *num_elem_non_unlim)
  {
      herr_t ret_value = SUCCEED; /* return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(space);
      HDassert(num_elem_non_unlim);
  
      /* Check for selection callback */
      if(!space->select.type->num_elem_non_unlim)
          HGOTO_ERROR(H5E_DATASPACE, H5E_UNSUPPORTED, FAIL, "selection type has no num_elem_non_unlim callback")
  
      /* Make selection callback */
      if((*space->select.type->num_elem_non_unlim)(space, num_elem_non_unlim) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't get number of elements in non-unlimited dimension")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_get_select_unlim_dim() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_is_contiguous
   PURPOSE
      Determines if a selection is contiguous in the dataspace
   USAGE
      htri_t H5S_select_is_contiguous(space)
          const H5S_t *space;             IN: Dataspace of selection to query
   RETURNS
      Non-negative (TRUE/FALSE) on success, negative on failure
   DESCRIPTION
      Checks the selection to determine if the points to iterated over will be
      contiguous in the particular dataspace.
   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
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_is_contiguous(const H5S_t *space)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      ret_value = (*space->select.type->is_contiguous)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_is_contiguous() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_is_single
   PURPOSE
      Determines if a selection is a single block in the dataspace
   USAGE
      htri_t H5S_select_is_single(space)
          const H5S_t *space;             IN: Dataspace of selection to query
   RETURNS
      Non-negative (TRUE/FALSE) on success, negative on failure
   DESCRIPTION
      Checks the selection to determine if it occupies a single block in the
      particular dataspace.
   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
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_is_single(const H5S_t *space)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      ret_value = (*space->select.type->is_single)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_is_single() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_is_regular
   PURPOSE
      Determines if a selection is "regular"  in the dataspace
   USAGE
      htri_t H5S_select_is_regular(space)
          const H5S_t *space;             IN: Dataspace of selection to query
   RETURNS
      Non-negative (TRUE/FALSE) on success, negative on failure
   DESCRIPTION
      Checks the selection to determine if it is "regular" (i.e. a single
      block or a strided pattern) in the particular dataspace.
   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
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_is_regular(const H5S_t *space)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      ret_value = (*space->select.type->is_regular)(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_is_regular() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_adjust_u
   PURPOSE
      Adjust a selection by subtracting an offset
   USAGE
      herr_t H5S_select_adjust_u(space, offset)
          H5S_t *space;           IN/OUT: Pointer to dataspace to adjust
          const hsize_t *offset; IN: Offset to subtract
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Moves a selection by subtracting an offset from it.
   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_adjust_u(H5S_t *space, const hsize_t *offset)
  {
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(offset);
  
      /* Perform operation */
      ret_value = (*space->select.type->adjust_u)(space, offset);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_adjust_u() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_adjust_s
   PURPOSE
      Adjust a selection by subtracting an offset
   USAGE
      herr_t H5S_select_adjust_u(space, offset)
          H5S_t *space;           IN/OUT: Pointer to dataspace to adjust
          const hssize_t *offset; IN: Offset to subtract
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Moves a selection by subtracting an offset from it.
   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_adjust_s(H5S_t *space, const hssize_t *offset)
  {
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(offset);
  
      /* Perform operation */
      ret_value = (*space->select.type->adjust_s)(space, offset);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_adjust_s() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_adjust
   PURPOSE
      Adjust a selection by subtracting an offset
   USAGE
      herr_t H5Sselect_adjust_u(space_id, offset)
          hid_t space_id;        IN: ID of dataspace to adjust
          const hsize_t *offset; IN: Offset to subtract
   RETURNS
      Non-negative on success, negative on failure
   DESCRIPTION
      Moves a selection by subtracting an offset from it.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5Sselect_adjust(hid_t space_id, const hssize_t *offset)
  {
      H5S_t *space;
      hsize_t low_bounds[H5S_MAX_RANK];
      hsize_t high_bounds[H5S_MAX_RANK];
      unsigned u;
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE2("e", "i*Hs", space_id, offset);
  
      if(NULL == (space = (H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == offset)
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "NULL offset pointer")
  
      /* Check bounds */
      if(H5S_SELECT_BOUNDS(space, low_bounds, high_bounds) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get selection bounds")
      for(u = 0; u < space->extent.rank; u++)
          if(offset[u] > (hssize_t)low_bounds[u])
              HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "adjustment would move selection below zero offset")
  
      if(H5S_select_adjust_s(space, offset) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "can't adjust selection")
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_adjust() */
  
  
  /*--------------------------------------------------------------------------
   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 = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
      HDassert(offset);
  
      ret_value = (*space->select.type->project_scalar)(space, offset);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end 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 = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* 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)
  } /* end H5S_select_project_simple() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_init
   PURPOSE
      Initializes iteration information for a selection.
   USAGE
      herr_t H5S_select_iter_init(sel_iter, space, elmt_size, flags)
          H5S_sel_iter_t *sel_iter; OUT: Selection iterator to initialize.
          H5S_t *space;           IN: Dataspace object containing selection to
                                      iterate over
          size_t elmt_size;       IN: Size of elements in the selection
          unsigned flags;         IN: Flags to control iteration behavior
   RETURNS
       Non-negative on success, negative on failure.
   DESCRIPTION
      Initialize the selection iterator object to point to the first element
      in the dataspace's selection.
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_iter_init(H5S_sel_iter_t *sel_iter, const H5S_t *space,
      size_t elmt_size, unsigned flags)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(sel_iter);
      HDassert(space);
  
      /* Initialize common information */
  
      /* Save the dataspace's rank */
      sel_iter->rank = space->extent.rank;
  
      /* If dims > 0, copy the dataspace dimensions & selection offset */
      if(sel_iter->rank > 0) {
          H5MM_memcpy(sel_iter->dims, space->extent.size, sizeof(hsize_t) * space->extent.rank);
          H5MM_memcpy(sel_iter->sel_off, space->select.offset, sizeof(hsize_t) * space->extent.rank);
      }
  
      /* Save the element size */
      sel_iter->elmt_size = elmt_size;
  
      /* Initialize the number of elements to iterate over */
      sel_iter->elmt_left = space->select.num_elem;
  
      /* Set the flags for the iterator */
      sel_iter->flags = flags;
  
      /* Call initialization routine for selection type */
      ret_value = (*space->select.type->iter_init)(space, sel_iter);
      HDassert(sel_iter->type);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_init() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_coords
   PURPOSE
      Get the coordinates of the current iterator position
   USAGE
      herr_t H5S_select_iter_coords(sel_iter,coords)
          H5S_sel_iter_t *sel_iter; IN: Selection iterator to query
          hsize_t *coords;         OUT: Array to place iterator coordinates in
   RETURNS
      Non-negative on success, negative on failure.
   DESCRIPTION
      The current location of the iterator within the selection is placed in
      the COORDS array.
   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_iter_coords(const H5S_sel_iter_t *sel_iter, hsize_t *coords)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(sel_iter);
      HDassert(coords);
  
      /* Call iter_coords routine for selection type */
      ret_value = (*sel_iter->type->iter_coords)(sel_iter, coords);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_coords() */
  
  #ifdef LATER
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_block
   PURPOSE
      Get the block of the current iterator position
   USAGE
      herr_t H5S_select_iter_block(sel_iter,start,end)
          const H5S_sel_iter_t *sel_iter; IN: Selection iterator to query
          hsize_t *start;    OUT: Array to place iterator start block coordinates
          hsize_t *end;      OUT: Array to place iterator end block coordinates
   RETURNS
      Non-negative on success, negative on failure.
   DESCRIPTION
      The current location of the iterator within the selection is placed in
      the COORDS array.
   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
  --------------------------------------------------------------------------*/
  static herr_t
  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_NOERR
  
      /* Check args */
      HDassert(iter);
      HDassert(start);
      HDassert(end);
  
      /* Call iter_block routine for selection type */
      ret_value = (*iter->type->iter_block)(iter, start, end);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_block() */
  #endif /* LATER */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_nelmts
   PURPOSE
      Get the number of elements left to iterate over in selection
   USAGE
      hssize_t H5S_select_iter_nelmts(sel_iter)
          H5S_sel_iter_t *sel_iter; IN: Selection iterator to query
   RETURNS
      The number of elements in selection on success, 0 on failure
   DESCRIPTION
      Returns the number of elements in current selection for dataspace.
   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
  --------------------------------------------------------------------------*/
  hsize_t
  H5S_select_iter_nelmts(const H5S_sel_iter_t *sel_iter)
  {
      hsize_t ret_value = 0;      /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(sel_iter);
  
      /* Call iter_nelmts routine for selection type */
      ret_value = (*sel_iter->type->iter_nelmts)(sel_iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_nelmts() */
  
  #ifdef LATER
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_has_next_block
   PURPOSE
      Check if there is another block available in the selection iterator
   USAGE
      htri_t H5S_select_iter_has_next_block(sel_iter)
          const H5S_sel_iter_t *sel_iter; IN: Selection iterator to query
   RETURNS
      Non-negative on success, negative on failure.
   DESCRIPTION
      Check if there is another block available to advance to in the selection
      iterator.
   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
  --------------------------------------------------------------------------*/
  static htri_t
  H5S_select_iter_has_next_block(const H5S_sel_iter_t *iter)
  {
      herr_t ret_value;         /* return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(iter);
  
      /* Call iter_has_next_block routine for selection type */
      ret_value = (*iter->type->iter_has_next_block)(iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_has_next_block() */
  #endif /* LATER */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_next
   PURPOSE
      Advance selection iterator to next element
   USAGE
      herr_t H5S_select_iter_next(iter, nelem)
          H5S_sel_iter_t *iter;   IN/OUT: Selection iterator to change
          size_t nelem;           IN: Number of elements to advance by
   RETURNS
      Non-negative on success, negative on failure.
   DESCRIPTION
      Move the current element for the selection iterator to the NELEM'th next
      element in the 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_iter_next(H5S_sel_iter_t *iter, size_t nelem)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(iter);
      HDassert(nelem>0);
  
      /* Call iter_next routine for selection type */
      ret_value = (*iter->type->iter_next)(iter, nelem);
  
      /* Decrement the number of elements left in selection */
      iter->elmt_left-=nelem;
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_next() */
  
  #ifdef LATER
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_next_block
   PURPOSE
      Advance selection iterator to next block
   USAGE
      herr_t H5S_select_iter_next_block(iter)
          H5S_sel_iter_t *iter;   IN/OUT: Selection iterator to change
   RETURNS
      Non-negative on success, negative on failure.
   DESCRIPTION
      Move the current element for the selection iterator to the next
      block in the selection.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
      Doesn't maintain the 'elmt_left' field of the selection iterator.
  
      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
  --------------------------------------------------------------------------*/
  static herr_t
  H5S_select_iter_next_block(H5S_sel_iter_t *iter)
  {
      herr_t ret_value;         /* return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(iter);
  
      /* Call iter_next_block routine for selection type */
      ret_value = (*iter->type->iter_next_block)(iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_next_block() */
  #endif /* LATER */
  
  
  /*-------------------------------------------------------------------------
   * Function:	H5S_select_iter_get_seq_list
   *
   * Purpose:	Retrieves the next sequence of offset/length pairs for an
   *              iterator on a dataspace
   *
   * Return:	Non-negative on success/Negative on failure
   *
   * Programmer:	Quincey Koziol
   *		Tuesday, May 18, 2004
   *
   * Note: This routine participates in the "Inlining C function pointers"
   *      pattern, don't call it directly, use the appropriate macro
   *      defined in H5Sprivate.h.
   *
   *-------------------------------------------------------------------------
   */
  herr_t
  H5S_select_iter_get_seq_list(H5S_sel_iter_t *iter, size_t maxseq, size_t maxelmts,
      size_t *nseq, size_t *nelmts, hsize_t *off, size_t *len)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT
  
      /* Sanity check */
      HDassert(iter);
  
      /* Call the selection type's get_seq_list function */
      if((ret_value = (*iter->type->iter_get_seq_list)(iter, maxseq, maxelmts, nseq, nelmts, off, len)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "unable to get selection sequence list")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_get_seq_list() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iter_release
   PURPOSE
      Release a selection iterator's resources.
   USAGE
      herr_t H5S_select_iter_release(sel_iter)
          H5S_sel_iter_t *sel_iter; IN: Selection iterator to query
   RETURNS
      The number of elements in selection on success, 0 on failure
   DESCRIPTION
      Returns the number of elements in current selection for dataspace.
   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_iter_release(H5S_sel_iter_t *sel_iter)
  {
      herr_t ret_value = FAIL;    /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(sel_iter);
  
      /* Call selection type-specific release routine */
      ret_value = (*sel_iter->type->iter_release)(sel_iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iter_release() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_iterate
   PURPOSE
      Iterate over the selected elements in a memory buffer.
   USAGE
      herr_t H5S_select_iterate(buf, type, space, operator, operator_data)
          void *buf;      IN/OUT: Buffer containing elements to iterate over
          H5T_t *type;    IN: Datatype of BUF array.
          H5S_t *space;   IN: Dataspace object containing selection to iterate over
          H5D_operator_t op; IN: Function pointer to the routine to be
                                  called for each element in BUF iterated over.
          void *operator_data;    IN/OUT: Pointer to any user-defined data
                                  associated with the operation.
   RETURNS
      Returns the return value of the last operator if it was non-zero, or zero
      if all elements were processed. Otherwise returns a negative value.
   DESCRIPTION
      Iterates over the selected elements in a memory buffer, calling the user's
      callback function for each element.  The selection in the dataspace is
      modified so that any elements already iterated over are removed from the
      selection if the iteration is interrupted (by the H5D_operator_t function
      returning non-zero) in the "middle" of the iteration and may be re-started
      by the user where it left off.
  
      NOTE: Until "subtracting" elements from a selection is implemented,
          the selection is not modified.
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_iterate(void *buf, const H5T_t *type, const H5S_t *space,
      const H5S_sel_iter_op_t *op, void *op_data)
  {
      H5S_sel_iter_t *iter = NULL; /* Selection iteration info */
      hbool_t iter_init = FALSE;  /* Selection iteration info has been initialized */
      hsize_t *off = NULL;        /* Array to store sequence offsets */
      size_t *len = NULL;         /* Array to store sequence lengths */
      hssize_t nelmts;            /* Number of elements in selection */
      hsize_t space_size[H5S_MAX_RANK]; /* Dataspace size */
      size_t max_elem;            /* Maximum number of elements allowed in sequences */
      size_t elmt_size;           /* Datatype size */
      unsigned ndims;             /* Number of dimensions in dataspace */
      herr_t user_ret = 0;        /* User's return value */
      herr_t ret_value = SUCCEED; /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(buf);
      HDassert(type);
      HDassert(space);
      HDassert(op);
  
      /* Get the datatype size */
      if(0 == (elmt_size = H5T_get_size(type)))
          HGOTO_ERROR(H5E_DATATYPE, H5E_BADSIZE, FAIL, "datatype size invalid")
  
      /* Allocate the selection iterator */
      if(NULL == (iter = H5FL_MALLOC(H5S_sel_iter_t)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
  
      /* Initialize iterator */
      if(H5S_select_iter_init(iter, space, elmt_size, 0) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
      iter_init = TRUE;	/* Selection iteration info has been initialized */
  
      /* Get the number of elements in selection */
      if((nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(space)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't get number of elements selected")
  
      /* Get the rank of the dataspace */
      ndims = space->extent.rank;
  
      if(ndims > 0) {
  	/* Copy the size of the space */
  	HDassert(space->extent.size);
  	H5MM_memcpy(space_size, space->extent.size, ndims * sizeof(hsize_t));
      } /* end if */
      space_size[ndims] = elmt_size;
  
      /* Compute the maximum number of bytes required */
      H5_CHECKED_ASSIGN(max_elem, size_t, nelmts, hssize_t);
  
      /* Allocate the offset & length arrays */
      if(NULL == (len = H5FL_SEQ_MALLOC(size_t, H5D_IO_VECTOR_SIZE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate length vector array")
      if(NULL == (off = H5FL_SEQ_MALLOC(hsize_t, H5D_IO_VECTOR_SIZE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate offset vector array")
  
      /* Loop, while elements left in selection */
      while(max_elem > 0 && user_ret == 0) {
          size_t nelem;               /* Number of elements used in sequences */
          size_t nseq;                /* Number of sequences generated */
          size_t curr_seq;            /* Current sequence being worked on */
  
          /* Get the sequences of bytes */
          if(H5S_SELECT_ITER_GET_SEQ_LIST(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")
  
          /* Loop, while sequences left to process */
          for(curr_seq = 0; curr_seq < nseq && user_ret == 0; curr_seq++) {
              hsize_t curr_off;           /* Current offset within sequence */
              size_t curr_len;            /* Length of bytes left to process in sequence */
  
              /* Get the current offset */
              curr_off = off[curr_seq];
  
              /* Get the number of bytes in sequence */
              curr_len = len[curr_seq];
  
              /* Loop, while bytes left in sequence */
              while(curr_len > 0 && user_ret == 0) {
                  hsize_t coords[H5S_MAX_RANK];  /* Coordinates of element in dataspace */
                  hsize_t tmp_off;        /* Temporary offset within sequence */
                  uint8_t *loc;           /* Current element location in buffer */
                  int i;			/* Local Index variable */
  
                  /* Compute the coordinate from the offset */
                  for(i = (int)ndims, tmp_off = curr_off; i >= 0; i--) {
                      coords[i] = tmp_off % space_size[i];
                      tmp_off /= space_size[i];
                  } /* end for */
  
                  /* Get the location within the user's buffer */
                  loc = (unsigned char *)buf + curr_off;
  
                  /* Check which type of callback to make */
                  switch(op->op_type) {
                      case H5S_SEL_ITER_OP_APP:
                          /* Make the application callback */
                          user_ret = (op->u.app_op.op)(loc, op->u.app_op.type_id, ndims, coords, op_data);
                      break;
  
                      case H5S_SEL_ITER_OP_LIB:
                          /* Call the library's callback */
                          user_ret = (op->u.lib_op)(loc, type, ndims, coords, op_data);
                      break;
  
                      default:
                          HGOTO_ERROR(H5E_DATASPACE, H5E_UNSUPPORTED, FAIL, "unsupported op type")
                  } /* end switch */
  
                  /* Check for error return from iterator */
                  if(user_ret < 0)
                      HERROR(H5E_DATASPACE, H5E_CANTNEXT, "iteration operator failed");
  
                  /* Increment offset in dataspace */
                  curr_off += elmt_size;
  
                  /* Decrement number of bytes left in sequence */
                  curr_len -= elmt_size;
              } /* end while */
          } /* end for */
  
          /* Decrement number of elements left to process */
          max_elem -= nelem;
      } /* end while */
  
      /* Set return value */
      ret_value = user_ret;
  
  done:
      /* Release resources, if allocated */
      if(len)
          len = H5FL_SEQ_FREE(size_t, len);
      if(off)
          off = H5FL_SEQ_FREE(hsize_t, off);
  
      /* Release selection iterator */
      if(iter_init && H5S_SELECT_ITER_RELEASE(iter) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator")
      if(iter)
          iter = H5FL_FREE(H5S_sel_iter_t, iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_iterate() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sget_select_type
   PURPOSE
      Retrieve the type of selection in a dataspace
   USAGE
      H5S_sel_type H5Sget_select_type(space_id)
          hid_t space_id;	        IN: Dataspace object to query
   RETURNS
      Non-negative on success/Negative on failure.  Return value is from the
      set of values in the H5S_sel_type enumerated type.
   DESCRIPTION
  	This function retrieves the type of selection currently defined for
      a dataspace.
  --------------------------------------------------------------------------*/
  H5S_sel_type
  H5Sget_select_type(hid_t space_id)
  {
      H5S_t *space;	        /* dataspace to modify */
      H5S_sel_type ret_value;     /* Return value */
  
      FUNC_ENTER_API(H5S_SEL_ERROR)
      H5TRACE1("St", "i", space_id);
  
      /* Check args */
      if(NULL == (space = (H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, H5S_SEL_ERROR, "not a dataspace")
  
      /* Set return value */
      ret_value = H5S_GET_SELECT_TYPE(space);
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sget_select_type() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_get_select_type
   PURPOSE
      Retrieve the type of selection in a dataspace
   USAGE
      H5S_sel_type H5Sget_select_type(space)
          const H5S_t *space;	        IN: Dataspace object to query
   RETURNS
      Non-negative on success/Negative on failure.  Return value is from the
      set of values in the H5S_sel_type enumerated type.
   DESCRIPTION
  	This function retrieves the type of selection currently defined for
      a dataspace.
   COMMENTS
       This routine participates in the "Inlining C function pointers"
          pattern, don't call it directly, use the appropriate macro
          defined in H5Sprivate.h.
  --------------------------------------------------------------------------*/
  H5_ATTR_PURE H5S_sel_type
  H5S_get_select_type(const H5S_t *space)
  {
      H5S_sel_type        ret_value = H5S_SEL_ERROR;      /* Return value */
  
      FUNC_ENTER_NOAPI_NOINIT_NOERR
  
      /* Check args */
      HDassert(space);
  
      /* Set return value */
      ret_value = H5S_GET_SELECT_TYPE(space);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_get_select_type() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_shape_same
   PURPOSE
      Check if two selections are the same shape
   USAGE
      htri_t H5S_select_shape_same(space1, space2)
          const H5S_t *space1;         IN: 1st Dataspace pointer to compare
          const H5S_t *space2;         IN: 2nd Dataspace pointer to compare
   RETURNS
      TRUE/FALSE/FAIL
   DESCRIPTION
      Checks to see if the current selection in the dataspaces are the same
      dimensionality and shape.
  
      This is primarily used for reading the entire selection in one swoop.
   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
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_shape_same(const H5S_t *space1, const H5S_t *space2)
  {
      H5S_sel_iter_t *iter_a = NULL;  /* Selection a iteration info */
      H5S_sel_iter_t *iter_b = NULL;  /* Selection b iteration info */
      hbool_t iter_a_init = FALSE;    /* Selection a iteration info has been initialized */
      hbool_t iter_b_init = FALSE;    /* Selection b iteration info has been initialized */
      htri_t ret_value = TRUE;        /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(space1);
      HDassert(space2);
  
      /* Check for different number of elements selected */
      if(H5S_GET_SELECT_NPOINTS(space1) != H5S_GET_SELECT_NPOINTS(space2))
          HGOTO_DONE(FALSE)
  
      /* Check special cases if both dataspaces aren't scalar */
      /* (If only one is, the number of selected points check is sufficient) */
      if(space1->extent.rank > 0 && space2->extent.rank > 0) {
          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 */
          int space_a_dim;                /* Current dimension in dataspace A */
          int space_b_dim;                /* Current dimension in dataspace B */
          H5S_sel_type sel_a_type;        /* Selection type for dataspace A */
          H5S_sel_type sel_b_type;        /* Selection type for 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,
           *
           * Set all this up here.
           */
          if(space1->extent.rank >= space2->extent.rank) {
              space_a = space1;
              space_b = space2;
          } /* end if */
          else {
              space_a = space2;
              space_b = space1;
          } /* end else */
          space_a_rank = space_a->extent.rank;
          space_b_rank = space_b->extent.rank;
          HDassert(space_a_rank >= space_b_rank);
          HDassert(space_b_rank > 0);
  
          /* Get selection type for both dataspaces */
          sel_a_type = H5S_GET_SELECT_TYPE(space_a);
          sel_b_type = H5S_GET_SELECT_TYPE(space_b);
  
          /* If selections aren't "none", compare their bounds */
          if(sel_a_type != H5S_SEL_NONE && sel_b_type != H5S_SEL_NONE) {
              hsize_t low_a[H5S_MAX_RANK];    /* Low bound of selection in dataspace a */
              hsize_t low_b[H5S_MAX_RANK];    /* Low bound of selection in dataspace b */
              hsize_t high_a[H5S_MAX_RANK];   /* High bound of selection in dataspace a */
              hsize_t high_b[H5S_MAX_RANK];   /* High bound of selection in dataspace b */
  
              /* Get low & high bounds for both dataspaces */
              if(H5S_SELECT_BOUNDS(space_a, low_a, high_a) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get selection bounds for first dataspace")
              if(H5S_SELECT_BOUNDS(space_b, low_b, high_b) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get selection bounds for second dataspace")
  
              /* Check that the range between the low & high bounds are the same */
              space_a_dim = (int)space_a_rank - 1;
              space_b_dim = (int)space_b_rank - 1;
              while(space_b_dim >= 0) {
                  /* Sanity check */
                  HDassert(low_a[space_a_dim] <= high_a[space_a_dim]);
                  HDassert(low_a[space_b_dim] <= high_a[space_b_dim]);
  
                  /* Verify that the ranges are the same */
                  if((high_a[space_a_dim] - low_a[space_a_dim])
                          != (high_b[space_b_dim] - low_b[space_b_dim]))
                      HGOTO_DONE(FALSE)
  
                  /* Go to next dimension */
                  space_a_dim--;
                  space_b_dim--;
              } /* end while */
  
              /* Check that the rest of the ranges in space a are "flat" */
              while(space_a_dim >= 0) {
                  /* Sanity check */
                  HDassert(low_a[space_a_dim] <= high_a[space_a_dim]);
  
                  /* This range should be flat to be the same in a lower dimension */
                  if(low_a[space_a_dim] != high_a[space_a_dim])
                      HGOTO_DONE(FALSE)
  
                  space_a_dim--;
              } /* end while */
  
              /* Check for a single block in each selection */
              if(H5S_SELECT_IS_SINGLE(space_a) && H5S_SELECT_IS_SINGLE(space_b)) {
                  /* If both selections are a single block and their bounds are
                   * the same, then the selections are the same, even if the
                   * selection types are different.
                   */
                  HGOTO_DONE(TRUE)
              } /* end if */
          } /* end if */
  
          /* If the dataspaces have the same selection type, use the selection's
           * shape_same operator.
           */
          if(sel_a_type == sel_b_type)
              ret_value = (*space_a->select.type->shape_same)(space_a, space_b);
          /* Otherwise, iterate through all the blocks in the selection */
          else {
              hsize_t start_a[H5S_MAX_RANK];      /* Start point of selection block in dataspace a */
              hsize_t start_b[H5S_MAX_RANK];      /* Start point of selection block in dataspace b */
              hsize_t end_a[H5S_MAX_RANK];        /* End point of selection block in dataspace a */
              hsize_t end_b[H5S_MAX_RANK];        /* End point of selection block in dataspace b */
              hssize_t offset[H5S_MAX_RANK];      /* Offset of selection b blocks relative to selection a blocks */
              hbool_t first_block = TRUE;         /* Flag to indicate the first block */
  
              /* Allocate the selection iterators */
              if(NULL == (iter_a = H5FL_MALLOC(H5S_sel_iter_t)))
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
              if(NULL == (iter_b = H5FL_MALLOC(H5S_sel_iter_t)))
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
  
              /* 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(iter_a, space_a, (size_t)0, 0) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator a")
              iter_a_init = TRUE;
              if(H5S_select_iter_init(iter_b, space_b, (size_t)0, 0) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator b")
              iter_b_init = TRUE;
  
              /* Iterate over all the blocks in each selection */
              while(1) {
                  htri_t status_a, status_b;      /* Status from next block checks */
  
                  /* Get the current block for each selection iterator */
                  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")
  
                  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 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 */
                          offset[space_a_dim] = (hssize_t)start_b[space_b_dim] - (hssize_t)start_a[space_a_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(start_a[space_a_dim] != end_a[space_a_dim])
                              HGOTO_DONE(FALSE)
  
                          space_a_dim--;
                      } /* end while */
  
                      /* Reset "first block" flag */
                      first_block = FALSE;
                  } /* end if */
                  /* Check over the blocks for each selection */
                  else {
                      /* 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((hsize_t)((hssize_t)start_a[space_a_dim] + offset[space_a_dim]) != start_b[space_b_dim])
                              HGOTO_DONE(FALSE)
  
                          /* If the block sizes from each selection doesn't match, get out */
                          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(start_a[space_a_dim] != end_a[space_a_dim])
                              HGOTO_DONE(FALSE)
  
                          space_a_dim--;
                      } /* end while */
                  } /* end else */
  
                  /* Check if we are able to advance to the next selection 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((status_a == FALSE) && (status_b == FALSE))
                      break;
                  else if(status_a != status_b)
                      HGOTO_DONE(FALSE)
                  else {
                      /* Advance to next block in selection iterators */
                      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 if */
  
  done:
      if(iter_a_init && H5S_SELECT_ITER_RELEASE(iter_a) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator a")
      if(iter_a)
          iter_a = H5FL_FREE(H5S_sel_iter_t, iter_a);
      if(iter_b_init && H5S_SELECT_ITER_RELEASE(iter_b) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator b")
      if(iter_b)
          iter_b = H5FL_FREE(H5S_sel_iter_t, iter_b);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_shape_same() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_shape_same
   PURPOSE
      Check if two selections are the same shape
   USAGE
      htri_t H5Sselect_shape_same(space1_id, space2_id)
          hid_t space1_id;         IN: ID of 1st Dataspace pointer to compare
          hid_t space2_id;         IN: ID of 2nd Dataspace pointer to compare
   RETURNS
      TRUE/FALSE/FAIL
   DESCRIPTION
      Checks to see if the current selection in the dataspaces are the same
      dimensionality and shape.
      This is primarily used for reading the entire selection in one swoop.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  htri_t
  H5Sselect_shape_same(hid_t space1_id, hid_t space2_id)
  {
      H5S_t *space1, *space2;     /* Dataspaces to compare */
      htri_t ret_value;           /* Return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE2("t", "ii", space1_id, space2_id);
  
      if(NULL == (space1 = (H5S_t *)H5I_object_verify(space1_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == (space2 = (H5S_t *)H5I_object_verify(space2_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
  
      if((ret_value = H5S_select_shape_same(space1, space2)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOMPARE, FAIL, "can't compare selections")
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_shape_same() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_intersect_block
   PURPOSE
      Check if current selection intersects with a block
   USAGE
      htri_t H5S_select_intersect_block(space, start, end)
          const H5S_t *space;      IN: Dataspace to compare
          const hsize_t *start;    IN: Starting coordinate of block
          const hsize_t *end;      IN: Opposite ("ending") coordinate of block
   RETURNS
      TRUE / FALSE / FAIL
   DESCRIPTION
      Checks to see if the current selection in the dataspace intersects with
      the block given.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
      Assumes that start & end block bounds are _inclusive_, so start == end
      value OK.
  
      This routine participates in the "Inlining C function pointers" pattern,
      don't call it directly, use the appropriate macro defined in H5Sprivate.h.
  --------------------------------------------------------------------------*/
  htri_t
  H5S_select_intersect_block(const H5S_t *space, const hsize_t *start,
      const hsize_t *end)
  {
      htri_t ret_value = TRUE;        /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(space);
      HDassert(start);
      HDassert(end);
  
      /* If selections aren't "none", compare their bounds */
      if(H5S_SEL_NONE != H5S_GET_SELECT_TYPE(space)) {
          hsize_t low[H5S_MAX_RANK];      /* Low bound of selection in dataspace */
          hsize_t high[H5S_MAX_RANK];     /* High bound of selection in dataspace */
          unsigned u;                     /* Local index variable */
  
          /* Get low & high bounds for dataspace selection */
          if(H5S_SELECT_BOUNDS(space, low, high) < 0)
              HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get selection bounds for dataspace")
  
          /* Loop over selection bounds and block, checking for overlap */
          for(u = 0; u < space->extent.rank; u++)
              /* If selection bounds & block don't overlap, can leave now */
              if(!H5S_RANGE_OVERLAP(low[u], high[u], start[u], end[u]))
                  HGOTO_DONE(FALSE)
      } /* end if */
  
      /* Call selection type's intersect routine */
      if((ret_value = (*space->select.type->intersect_block)(space, start, end)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOMPARE, FAIL, "can't intersect block with selection")
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_intersect_block() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_intersect_block
   PURPOSE
      Check if current selection intersects with a block
   USAGE
      htri_t H5Sselect_intersect_block(space_id, start, end)
          hid_t space1_id;         IN: ID of dataspace pointer to compare
          const hsize_t *start;    IN: Starting coordinate of block
          const hsize_t *end;      IN: Opposite ("ending") coordinate of block
   RETURNS
      TRUE / FALSE / FAIL
   DESCRIPTION
      Checks to see if the current selection in the dataspace intersects with
      the block given.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
      Assumes that start & end block bounds are _inclusive_, so start == end
      value OK.
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  htri_t
  H5Sselect_intersect_block(hid_t space_id, const hsize_t *start, const hsize_t *end)
  {
      H5S_t *space;                       /* Dataspace to query */
      unsigned u;                         /* Local index value */
      htri_t ret_value = FAIL;            /* Return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE3("t", "i*h*h", space_id, start, end);
  
      /* Check arguments */
      if(NULL == (space = (H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == start)
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "block start array pointer is NULL")
      if(NULL == end)
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "block end array pointer is NULL")
  
      /* Range check start & end values */
      for(u = 0; u < space->extent.rank; u++)
          if(start[u] > end[u])
              HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "block start[%u] (%llu) > end[%u] (%llu)", u, (unsigned long long)start[u], u, (unsigned long long)end[u])
  
      /* Call internal routine to do comparison */
      if((ret_value = H5S_select_intersect_block(space, start, end)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOMPARE, FAIL, "can't compare selection and block")
  
  done:
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_intersect_block() */
  
  
  /*--------------------------------------------------------------------------
   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 on 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 const **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(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;
              H5VM_array_fill(new_space_dims, &tmp_dim_size, sizeof(tmp_dim_size), rank_diff);
              H5VM_array_fill(new_space_maxdims, &tmp_dim_size, sizeof(tmp_dim_size), rank_diff);
              H5MM_memcpy(&new_space_dims[rank_diff], base_space_dims, sizeof(new_space_dims[0]) * base_space_rank);
              H5MM_memcpy(&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;
              H5MM_memcpy(new_space_dims, &base_space_dims[rank_diff], sizeof(new_space_dims[0]) * new_space_rank);
              H5MM_memcpy(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);
                  H5MM_memcpy(&new_space->select.offset[rank_diff], base_space->select.offset, sizeof(new_space->select.offset[0]) * base_space_rank);
              } /* end if */
              else
                  H5MM_memcpy(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 = (const 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 */
  
  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")
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_construct_projection() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_fill
   PURPOSE
      Fill a selection in memory with a value
   USAGE
      herr_t H5S_select_fill(fill,fill_size,space,buf)
          const void *fill;       IN: Pointer to fill value to use
          size_t fill_size;       IN: Size of elements in memory buffer & size of
                                      fill value
          H5S_t *space;           IN: Dataspace describing memory buffer &
                                      containing selection to use.
          void *buf;              IN/OUT: Memory buffer to fill selection in
   RETURNS
      Non-negative on success/Negative on failure.
   DESCRIPTION
      Use the selection in the dataspace to fill elements in a memory buffer.
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
      The memory buffer elements are assumed to have the same datatype as the
      fill value being placed into them.
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_fill(const void *fill, size_t fill_size, const H5S_t *space, void *_buf)
  {
      H5S_sel_iter_t *iter = NULL; /* Selection iteration info */
      hbool_t iter_init = FALSE;  /* Selection iteration info has been initialized */
      hsize_t *off = NULL;        /* Array to store sequence offsets */
      size_t *len = NULL;         /* Array to store sequence lengths */
      hssize_t nelmts;            /* Number of elements in selection */
      size_t max_elem;            /* Total number of elements in selection */
      herr_t ret_value = SUCCEED; /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Check args */
      HDassert(fill);
      HDassert(fill_size > 0);
      HDassert(space);
      HDassert(_buf);
  
      /* Allocate the selection iterator */
      if(NULL == (iter = H5FL_MALLOC(H5S_sel_iter_t)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
  
      /* Initialize iterator */
      if(H5S_select_iter_init(iter, space, fill_size, 0) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
      iter_init = TRUE;	/* Selection iteration info has been initialized */
  
      /* Get the number of elements in selection */
      if((nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(space)) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't get number of elements selected")
  
      /* Compute the number of bytes to process */
      H5_CHECKED_ASSIGN(max_elem, size_t, nelmts, hssize_t);
  
      /* Allocate the offset & length arrays */
      if(NULL == (len = H5FL_SEQ_MALLOC(size_t, H5D_IO_VECTOR_SIZE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate length vector array")
      if(NULL == (off = H5FL_SEQ_MALLOC(hsize_t, H5D_IO_VECTOR_SIZE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate offset vector array")
  
      /* Loop, while elements left in selection */
      while(max_elem > 0) {
          size_t nseq;                /* Number of sequences generated */
          size_t curr_seq;            /* Current sequnce being worked on */
          size_t nelem;               /* Number of elements used in sequences */
  
          /* Get the sequences of bytes */
          if(H5S_SELECT_ITER_GET_SEQ_LIST(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")
  
          /* Loop over sequences */
          for(curr_seq = 0; curr_seq < nseq; curr_seq++) {
              uint8_t *buf;               /* Current location in buffer */
  
              /* Get offset in memory buffer */
              buf = (uint8_t *)_buf + off[curr_seq];
  
              /* Fill each sequence in memory with fill value */
              HDassert((len[curr_seq] % fill_size) == 0);
              H5VM_array_fill(buf, fill, fill_size, (len[curr_seq] / fill_size));
          } /* end for */
  
          /* Decrement number of elements left to process */
          max_elem -= nelem;
      } /* end while */
  
  done:
      /* Release resources, if allocated */
      if(len)
          len = H5FL_SEQ_FREE(size_t, len);
      if(off)
          off = H5FL_SEQ_FREE(hsize_t, off);
  
      /* Release selection iterator */
      if(iter_init && H5S_SELECT_ITER_RELEASE(iter) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator")
      if(iter)
          iter = H5FL_FREE(H5S_sel_iter_t, iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_fill() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_project_intersection
  
   PURPOSE
      Projects the intersection of of the selections of src_space and
      src_intersect_space within the selection of src_space as a selection
      within the selection of dst_space
  
   USAGE
      herr_t H5S_select_project_intersection(src_space,dst_space,src_intersect_space,proj_space,share_selection)
          H5S_t *src_space;       IN: Selection that is mapped to dst_space, and intersected with src_intersect_space
          H5S_t *dst_space;       IN: Selection that is mapped to src_space
          H5S_t *src_intersect_space; IN: Selection whose intersection with src_space is projected to dst_space to obtain the result
          H5S_t **new_space_ptr;  OUT: Will contain the result (intersection of src_intersect_space and src_space projected from src_space to dst_space) after the operation
          hbool_t share_selection; IN: Whether we are allowed to share structures inside dst_space with proj_space
  
   RETURNS
      Non-negative on success/Negative on failure.
  
   DESCRIPTION
      Projects the intersection of of the selections of src_space and
      src_intersect_space within the selection of src_space as a selection
      within the selection of dst_space.  The result is placed in the
      selection of new_space_ptr.
  
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_project_intersection(const H5S_t *src_space, const H5S_t *dst_space,
      const H5S_t *src_intersect_space, H5S_t **new_space_ptr,
      hbool_t share_selection)
  {
      H5S_t *new_space = NULL;            /* New dataspace constructed */
      H5S_t *tmp_src_intersect_space = NULL; /* Temporary SIS converted from points->hyperslabs */
      H5S_sel_iter_t *ss_iter = NULL;     /* Selection iterator for src_space */
      hbool_t ss_iter_init = FALSE;       /* Whether ss_iter has been initialized */
      H5S_sel_iter_t *ds_iter = NULL;     /* Selection iterator for dst_space */
      hbool_t ds_iter_init = FALSE;       /* Whether ds_iter has been initialized */
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Sanity checks */
      HDassert(src_space);
      HDassert(dst_space);
      HDassert(src_intersect_space);
      HDassert(new_space_ptr);
      HDassert(H5S_GET_SELECT_NPOINTS(src_space) == H5S_GET_SELECT_NPOINTS(dst_space));
      HDassert(H5S_GET_EXTENT_NDIMS(src_space) == H5S_GET_EXTENT_NDIMS(src_intersect_space));
  
      if(NULL == (ss_iter = H5FL_CALLOC(H5S_sel_iter_t)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
      if(NULL == (ds_iter = H5FL_CALLOC(H5S_sel_iter_t)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate selection iterator")
  
      /* Create new space, using dst extent.  Start with "all" selection. */
      if(NULL == (new_space = H5S_create(H5S_SIMPLE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "unable to create output dataspace")
      if(H5S__extent_copy_real(&new_space->extent, &dst_space->extent, TRUE) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "unable to copy destination space extent")
  
      /* If the intersecting space is "all", the intersection must be equal to the
       * source space and the projection must be equal to the destination space */
      if(H5S_GET_SELECT_TYPE(src_intersect_space) == H5S_SEL_ALL) {
          /* Copy the destination selection. */
          if(H5S_select_copy(new_space, dst_space, FALSE) < 0)
              HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "can't copy destination space selection")
      } /* end if */
      /* If any of the selections contain no elements, the projection must be
       * "none" */
      else if((H5S_GET_SELECT_NPOINTS(src_intersect_space) == 0)
              || (H5S_GET_SELECT_NPOINTS(src_space) == 0)
              || (H5S_GET_SELECT_NPOINTS(dst_space) == 0)) {
          /* Change to "none" selection */
          if(H5S_select_none(new_space) < 0)
              HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
      } /* end if */
      else {
          /* Handle scalar dataspaces.  It should not be possible for the source
           * intersect space or the source space to be scalar since scalar spaces
           * only support all or none selections, and both of those cases are
           * covered above, and the source intersect space must have the same
           * rank, so it also cannot be scalar, as scalar dataspaces have a rank
           * of 0. */
          HDassert(H5S_GET_EXTENT_TYPE(src_space) != H5S_SCALAR);
          HDassert(H5S_GET_EXTENT_TYPE(src_intersect_space) != H5S_SCALAR);
  
          /* Check for scalar dst_space.  In this case we simply check if the
           * (single) point selected in src_space intersects src_intersect_space,
           * if so select all in new_space, otherwise select none. */
          if(H5S_GET_EXTENT_TYPE(dst_space) == H5S_SCALAR) {
              hsize_t coords_start[H5S_MAX_RANK];
              hsize_t coords_end[H5S_MAX_RANK];
              htri_t intersect;
  
              /* Get source space bounds.  Should be a single point. */
              if(H5S_SELECT_BOUNDS(src_space, coords_start, coords_end) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get source space bounds")
              HDassert(0 == HDmemcmp(coords_start, coords_end, H5S_GET_EXTENT_NDIMS(src_space) * sizeof(coords_start[0])));
  
              /* Check for intersection */
              if((intersect = H5S_SELECT_INTERSECT_BLOCK(src_intersect_space, coords_start, coords_end)) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOMPARE, FAIL, "can't check for intersection")
  
              /* Select all or none as appropriate */
              if(intersect) {
                  if(H5S_select_all(new_space, TRUE) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "can't select all")
              } /* end if */
              else
                  if(H5S_select_none(new_space) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
          } /* end if */
          else {
              /* If the source intersect space is a point selection, convert it to a
               * hyperslab (discarding ordering).  We can get away with this because
               * the order does not matter for the source intersect space */
              /* Maybe we should just leave it as a point selection for the point by
               * point algorithm?  The search through the selection in
               * H5S_SELECT_INTERSECT_BLOCK will likely be O(N) either way.  -NAF */
              if(H5S_GET_SELECT_TYPE(src_intersect_space) == H5S_SEL_POINTS) {
                  H5S_pnt_node_t *curr_pnt = src_intersect_space->select.sel_info.pnt_lst->head;
  
                  /* Create dataspace and copy extent */
                  if(NULL == (tmp_src_intersect_space = H5S_create(H5S_SIMPLE)))
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "unable to create temporary source intersect dataspace")
                  if(H5S__extent_copy_real(&tmp_src_intersect_space->extent, &src_intersect_space->extent, FALSE) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, FAIL, "unable to copy source intersect space extent")
  
                  /* Iterate over points */
                  for(curr_pnt = src_intersect_space->select.sel_info.pnt_lst->head; curr_pnt; curr_pnt = curr_pnt->next)
                      /* Add point to hyperslab selection */
                      if(H5S_hyper_add_span_element(tmp_src_intersect_space, src_intersect_space->extent.rank, curr_pnt->pnt) < 0)
                          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSELECT, FAIL, "can't add point to temporary dataspace selection")
  
                  /* Redirect local src_intersect_space pointer (will not affect
                   * calling function) */
                  src_intersect_space = tmp_src_intersect_space;
              } /* end for */
  
              /* By this point, src_intersect_space must be a hyperslab selection */
              HDassert(H5S_GET_SELECT_TYPE(src_intersect_space) == H5S_SEL_HYPERSLABS);
  
              /* If either the source space or the destination space is a point
               * selection, iterate element by element */
              if((H5S_GET_SELECT_TYPE(src_space) == H5S_SEL_POINTS)
                      || (H5S_GET_SELECT_TYPE(dst_space) == H5S_SEL_POINTS)) {
                  hsize_t coords[H5S_MAX_RANK];
                  htri_t intersect;
  
                  /* Start with "none" selection */
                  if(H5S_select_none(new_space) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
  
                  /* Initialize iterators */
                  if(H5S_select_iter_init(ss_iter, src_space, 1, H5S_SEL_ITER_SHARE_WITH_DATASPACE) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't initialize source space selection iterator")
                  ss_iter_init = TRUE;
                  if(H5S_select_iter_init(ds_iter, dst_space, 1, H5S_SEL_ITER_SHARE_WITH_DATASPACE) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't initialize destination space selection iterator")
                  ds_iter_init = TRUE;
  
                  /* Iterate over points */
                  do {
                      HDassert(ss_iter->elmt_left > 0);
                      HDassert(ss_iter->elmt_left > 0);
  
                      /* Get SS coords */
                      if(H5S_SELECT_ITER_COORDS(ss_iter, coords) < 0)
                          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get source selection coordinates")
  
                      /* Check for intersection */
                      if((intersect = H5S_SELECT_INTERSECT_BLOCK(src_intersect_space, coords, coords)) < 0)
                          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOMPARE, FAIL, "can't check for intersection")
  
                      /* Add point if it intersects */
                      if(intersect) {
                          /* Get DS coords */
                          if(H5S_SELECT_ITER_COORDS(ds_iter, coords) < 0)
                              HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get destination selection coordinates")
  
                          /* Add point to new_space */
                          if(H5S_select_elements(new_space, H5S_SELECT_APPEND, 1, coords) < 0)
                              HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSELECT, FAIL, "can't add point to new selection")
                      } /* end if */
  
                      /* Advance iterators */
                      if(H5S_SELECT_ITER_NEXT(ss_iter, 1) < 0)
                          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "can't advacne source selection iterator")
                      ss_iter->elmt_left--;
                      if(H5S_SELECT_ITER_NEXT(ds_iter, 1) < 0)
                          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTNEXT, FAIL, "can't advacne destination selection iterator")
                      ds_iter->elmt_left--;
                  } while(ss_iter->elmt_left > 0);
                  HDassert(H5S_SELECT_ITER_NELMTS(ds_iter) == 0);
              } /* end if */
              else {
                  HDassert(H5S_GET_SELECT_TYPE(src_space) != H5S_SEL_NONE);
                  HDassert(H5S_GET_SELECT_TYPE(dst_space) != H5S_SEL_NONE);
  
                  /* Source and destination selections are all or hyperslab,
                   * intersecting selection is hyperslab.  Call the hyperslab routine
                   * to project to another hyperslab selection. */
                  if(H5S__hyper_project_intersection(src_space, dst_space, src_intersect_space, new_space, share_selection) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCLIP, FAIL, "can't project hyperslab onto destination selection")
              } /* end else */
          } /* end else */
      } /* end else */
  
      /* load the address of the new space into *new_space_ptr */
      *new_space_ptr = new_space;
  
  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")
  
      /* General cleanup */
      if(tmp_src_intersect_space && H5S_close(tmp_src_intersect_space) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release temporary dataspace")
      if(ss_iter_init && H5S_SELECT_ITER_RELEASE(ss_iter) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release source selection iterator")
      if(ds_iter_init && H5S_SELECT_ITER_RELEASE(ds_iter) < 0)
          HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release destination selection iterator")
  
      ss_iter = H5FL_FREE(H5S_sel_iter_t, ss_iter);
      ds_iter = H5FL_FREE(H5S_sel_iter_t, ds_iter);
  
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_project_intersection() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5Sselect_project_intersection
  
   PURPOSE
      Projects the intersection of of the selections of src_space_id and
      src_intersect_space_id within the selection of src_space_id as a
      selection within the selection of dst_space_id.
  
   USAGE
      hid_t H5Sselect_project_intersection(src_space_id,dst_space_d,src_intersect_space_id)
          hid_t src_space_id;         IN: Selection that is mapped to dst_space_id, and intersected with src_intersect_space_id
          hid_t dst_space_id;         IN: Selection that is mapped to src_space_id
          hid_t src_intersect_space_id; IN: Selection whose intersection with src_space_id is projected to dst_space_id to obtain the result
  
   RETURNS
      A dataspace with a selection equal to the intersection of
      src_intersect_space_id and src_space_id projected from src_space to
      dst_space on success, negative on failure.
  
   DESCRIPTION
      Projects the intersection of of the selections of src_space and
      src_intersect_space within the selection of src_space as a selection
      within the selection of dst_space.  The result is placed in the
      selection of new_space_ptr.
  
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  hid_t
  H5Sselect_project_intersection(hid_t src_space_id, hid_t dst_space_id,
      hid_t src_intersect_space_id)
  {
      H5S_t *src_space, *dst_space, *src_intersect_space; /* Input dataspaces */
      H5S_t *proj_space = NULL;  /* Output dataspace */
      hid_t ret_value;           /* Return value */
  
      FUNC_ENTER_API(FAIL)
      H5TRACE3("i", "iii", src_space_id, dst_space_id, src_intersect_space_id);
  
      /* Check args */
      if(NULL == (src_space = (H5S_t *)H5I_object_verify(src_space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == (dst_space = (H5S_t *)H5I_object_verify(dst_space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
      if(NULL == (src_intersect_space = (H5S_t *)H5I_object_verify(src_intersect_space_id, H5I_DATASPACE)))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "not a dataspace")
  
      /* Check numbers of points selected matches in source and destination */
      if(H5S_GET_SELECT_NPOINTS(src_space) != H5S_GET_SELECT_NPOINTS(dst_space))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "number of points selected in source space does not match that in destination space")
  
      /* Check numbers of dimensions matches in source and source intersect spaces
       */
      if(H5S_GET_EXTENT_NDIMS(src_space) != H5S_GET_EXTENT_NDIMS(src_intersect_space))
          HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "rank of source space does not match rank of source intersect space")
  
      /* Perform operation */
      if(H5S_select_project_intersection(src_space, dst_space,
              src_intersect_space, &proj_space, FALSE) < 0)
          HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project dataspace intersection")
  
      /* Atomize */
      if((ret_value = H5I_register(H5I_DATASPACE, proj_space, TRUE)) < 0)
          HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register dataspace atom")
  
  done:
      if(ret_value < 0)
          if(proj_space && H5S_close(proj_space) < 0)
              HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release dataspace")
  
      FUNC_LEAVE_API(ret_value)
  } /* end H5Sselect_project_intersection() */
  
  
  /*--------------------------------------------------------------------------
   NAME
      H5S_select_subtract
  
   PURPOSE
      Subtract one selection from another
  
   USAGE
      herr_t H5S_select_subtract(space,subtract_space)
          H5S_t *space;           IN/OUT: Selection to be operated on
          H5S_t *subtract_space;  IN: Selection that will be subtracted from space
  
   RETURNS
      Non-negative on success/Negative on failure.
  
   DESCRIPTION
      Removes any and all portions of space that are also present in
      subtract_space.  In essence, performs an A_NOT_B operation with the
      two selections.
  
   GLOBAL VARIABLES
   COMMENTS, BUGS, ASSUMPTIONS
   EXAMPLES
   REVISION LOG
  --------------------------------------------------------------------------*/
  herr_t
  H5S_select_subtract(H5S_t *space, H5S_t *subtract_space)
  {
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Sanity checks */
      HDassert(space);
      HDassert(subtract_space);
  
      /* If either space is using the none selection, then we do not need to do
       * anything */
      if((space->select.type->type != H5S_SEL_NONE)
              && (subtract_space->select.type->type != H5S_SEL_NONE)) {
          /* If subtract_space is using the all selection, set space to none */
          if(subtract_space->select.type->type == H5S_SEL_ALL) {
              /* Change to "none" selection */
              if(H5S_select_none(space) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
          } /* end if */
          /* If either selection is a point selection, fail currently */
          else if((subtract_space->select.type->type == H5S_SEL_POINTS) ||
                  (space->select.type->type == H5S_SEL_POINTS)) {
              HGOTO_ERROR(H5E_DATASPACE, H5E_UNSUPPORTED, FAIL, "point selections not currently supported")
          } /* end if */
          else {
              /* Check for all selection in space, convert to hyperslab */
              if(space->select.type->type == H5S_SEL_ALL) {
                  /* Convert current "all" selection to "real" hyperslab selection */
                  /* Then allow operation to proceed */
                  hsize_t tmp_start[H5S_MAX_RANK];        /* Temporary start information */
                  hsize_t tmp_stride[H5S_MAX_RANK];       /* Temporary stride information */
                  hsize_t tmp_count[H5S_MAX_RANK];        /* Temporary count information */
                  hsize_t tmp_block[H5S_MAX_RANK];        /* Temporary block information */
                  unsigned u;                             /* Local index variable */
  
                  /* Fill in temporary information for the dimensions */
                  for(u = 0; u < space->extent.rank; u++) {
                      tmp_start[u] = 0;
                      tmp_stride[u] = 1;
                      tmp_count[u] = 1;
                      tmp_block[u] = space->extent.size[u];
                  } /* end for */
  
                  /* Convert to hyperslab selection */
                  if(H5S_select_hyperslab(space, H5S_SELECT_SET, tmp_start, tmp_stride, tmp_count, tmp_block) < 0)
                      HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSELECT, FAIL, "can't convert selection")
              } /* end if */
  
              HDassert(space->select.type->type == H5S_SEL_HYPERSLABS);
              HDassert(subtract_space->select.type->type == H5S_SEL_HYPERSLABS);
  
              /* Both spaces are now hyperslabs, perform the operation */
              if(H5S__modify_select(space, H5S_SELECT_NOTB, subtract_space) < 0)
                  HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCLIP, FAIL, "can't subtract hyperslab")
          } /* end else */
      } /* end if */
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_select_subtract() */
  
  
  /*-------------------------------------------------------------------------
   * Function:	H5S_sel_iter_close
   *
   * Purpose:	Releases a dataspace selection iterator and its memory.
   *
   * Return:	Non-negative on success / Negative on failure
   *
   * Programmer:	Quincey Koziol
   *		Monday, February 11, 2019
   *
   *-------------------------------------------------------------------------
   */
  herr_t
  H5S_sel_iter_close(H5S_sel_iter_t *sel_iter)
  {
      herr_t ret_value = SUCCEED;         /* Return value */
  
      FUNC_ENTER_NOAPI(FAIL)
  
      /* Sanity check */
      HDassert(sel_iter);
  
      /* Call selection type-specific release routine */
      if(H5S_SELECT_ITER_RELEASE(sel_iter) < 0)
          HGOTO_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "problem releasing a selection iterator's type-specific info")
  
      /* Release the structure */
      sel_iter = H5FL_FREE(H5S_sel_iter_t, sel_iter);
  
  done:
      FUNC_LEAVE_NOAPI(ret_value)
  } /* end H5S_sel_iter_close() */
  
  