summaryrefslogtreecommitdiffstats
path: root/src/H5Smpio.c
blob: b2d4abb8416055c29c1493a45defb71639962a03 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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 files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  rky 980813
 *
 * Purpose:	Functions to read/write directly between app buffer and file.
 *
 * 		Beware of the ifdef'ed print statements.
 *		I didn't make them portable.
 */

#define H5S_PACKAGE		/*suppress error about including H5Spkg	  */


#include "H5private.h"		/* Generic Functions			*/
#include "H5Dprivate.h"		/* Datasets				*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fprivate.h"		/* File access				*/
#include "H5FDprivate.h"	/* File drivers				*/
#include "H5Iprivate.h"		/* IDs			  		*/
#include "H5MMprivate.h"        /* Memory management                    */
#include "H5Oprivate.h"		/* Object headers		  	*/
#include "H5Pprivate.h"         /* Property lists                       */
#include "H5Spkg.h"		/* Dataspaces 				*/
#include "H5VMprivate.h"		/* Vector and array functions		*/

#ifdef H5_HAVE_PARALLEL

static herr_t H5S_mpio_all_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type);
static herr_t H5S_mpio_none_type(MPI_Datatype *new_type, int *count,
    hbool_t *is_derived_type);
static herr_t H5S_mpio_create_point_datatype(size_t elmt_size, hsize_t num_points, 
    MPI_Aint *disp, MPI_Datatype *new_type);
static herr_t H5S_mpio_point_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type,
    hbool_t do_permute, hsize_t **permute_map, hbool_t *is_permuted);
static herr_t H5S_mpio_permute_type(const H5S_t *space, size_t elmt_size, 
    hsize_t **permute_map, MPI_Datatype *new_type, int *count,
    hbool_t *is_derived_type);
static herr_t H5S_mpio_hyper_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type);
static herr_t H5S_mpio_span_hyper_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type);
static herr_t H5S_obtain_datatype(const hsize_t down[], H5S_hyper_span_t* span,
    const MPI_Datatype *elmt_type, MPI_Datatype *span_type, size_t elmt_size);

#define H5S_MPIO_INITIAL_ALLOC_COUNT    256


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_all_type
 *
 * Purpose:	Translate an HDF5 "all" selection into an MPI type.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:	rky 980813
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_all_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type)
{
    hsize_t	total_bytes;
    hssize_t	snelmts;                /* Total number of elmts	(signed) */
    hsize_t	nelmts;                 /* Total number of elmts	*/
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);

    /* Just treat the entire extent as a block of bytes */
    if((snelmts = (hssize_t)H5S_GET_EXTENT_NPOINTS(space)) < 0)
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "src dataspace has invalid selection")
    H5_ASSIGN_OVERFLOW(nelmts, snelmts, hssize_t, hsize_t);

    total_bytes = (hsize_t)elmt_size * nelmts;

    /* fill in the return values */
    *new_type = MPI_BYTE;
    H5_ASSIGN_OVERFLOW(*count, total_bytes, hsize_t, int);
    *is_derived_type = FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5S_mpio_all_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_none_type
 *
 * Purpose:	Translate an HDF5 "none" selection into an MPI type.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:	Quincey Koziol, October 29, 2002
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_none_type(MPI_Datatype *new_type, int *count, hbool_t *is_derived_type)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* fill in the return values */
    *new_type = MPI_BYTE;
    *count = 0;
    *is_derived_type = FALSE;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* H5S_mpio_none_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_create_point_datatype
 *
 * Purpose:	Create a derived datatype for point selections.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *
 * Programmer:	Mohamad Chaarawi
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5S_mpio_create_point_datatype (size_t elmt_size, hsize_t num_points,
    MPI_Aint *disp, MPI_Datatype *new_type) 
{
    MPI_Datatype   elmt_type;           /* MPI datatype for individual element */
    hbool_t        elmt_type_created = FALSE;   /* Whether the element MPI datatype was created */
    int            mpi_code;            /* MPI error code */
    int            *blocks = NULL;      /* Array of block sizes for MPI hindexed create call */
    hsize_t        u;                   /* Local index variable */
    herr_t	   ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Create an MPI datatype for an element */
    if(MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)elmt_size, MPI_BYTE, &elmt_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
    elmt_type_created = TRUE;
    
    /* Allocate block sizes for MPI datatype call */
    if(NULL == (blocks = (int *)H5MM_malloc(sizeof(int) * num_points)))
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of blocks")

    /* Would be nice to have Create_Hindexed_block to avoid this array of all ones */
    for(u = 0; u < num_points; u++)
        blocks[u] = 1;

    /* Create an MPI datatype for the whole point selection */
    if(MPI_SUCCESS != (mpi_code = MPI_Type_create_hindexed((int)num_points, blocks, disp, elmt_type, new_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_indexed_block failed", mpi_code)

    /* Commit MPI datatype for later use */
    if(MPI_SUCCESS != (mpi_code = MPI_Type_commit(new_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)

done:
    if(elmt_type_created)
        MPI_Type_free(&elmt_type);
    if(blocks)
        H5MM_free(blocks);

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5S_mpio_create_point_datatype() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_point_type
 *
 * Purpose:	Translate an HDF5 "point" selection into an MPI type.
 *              Create a permutation array to handle out-of-order point selections.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *              *permute_map      the permutation of the displacements to create
 *                                the MPI_Datatype
 *              *is_permuted      0 if the displacements are permuted, 1 if not
 *
 * Programmer:	Mohamad Chaarawi
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_point_type(const H5S_t *space, size_t elmt_size, MPI_Datatype *new_type, 
    int *count, hbool_t *is_derived_type, hbool_t do_permute, hsize_t **permute,
    hbool_t *is_permuted)
{
    MPI_Aint *disp = NULL;      /* Datatype displacement for each point*/
    H5S_pnt_node_t *curr = NULL; /* Current point being operated on in from the selection */
    hssize_t snum_points;       /* Signed number of elements in selection */
    hsize_t num_points;         /* Sumber of points in the selection */
    hsize_t u;                  /* Local index variable */
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);

    /* Get the total number of points selected */
    if((snum_points = (hssize_t)H5S_GET_SELECT_NPOINTS(space)) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't get number of elements selected")
    num_points = (hsize_t)snum_points;

    /* Allocate array for element displacements */
    if(NULL == (disp = (MPI_Aint *)H5MM_malloc(sizeof(MPI_Aint) * num_points)))
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of displacements")

    /* Allocate array for element permutation - returned to caller */
    if(do_permute)
        if(NULL == (*permute = (hsize_t *)H5MM_malloc(sizeof(hsize_t) * num_points)))
            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate permutation array")

    /* Iterate through list of elements */
    curr = space->select.sel_info.pnt_lst->head;
    for(u = 0 ; u < num_points ; u++) {
        /* calculate the displacement of the current point */
        disp[u] = H5VM_array_offset(space->extent.rank, space->extent.size, curr->pnt);
        disp[u] *= elmt_size;

        /* This is a File Space used to set the file view, so adjust the displacements 
         * to have them monotonically non-decreasing.
         * Generate the permutation array by indicating at each point being selected, 
         * the position it will shifted in the new displacement. Example: 
         * Suppose 4 points with corresponding are selected 
         * Pt 1: disp=6 ; Pt 2: disp=3 ; Pt 3: disp=0 ; Pt 4: disp=4 
         * The permute map to sort the displacements in order will be:
         * point 1: map[0] = L, indicating that this point is not moved (1st point selected)
         * point 2: map[1] = 0, indicating that this point is moved to the first position, 
         *                      since disp_pt1(6) > disp_pt2(3)
         * point 3: map[2] = 0, move to position 0, bec it has the lowest disp between 
         *                      the points selected so far.
         * point 4: map[3] = 2, move the 2nd position since point 1 has a higher disp, 
         *                      but points 2 and 3 have lower displacements.
         */
        if(do_permute) {
            if(u > 0 && disp[u] < disp[u - 1]) {
                unsigned s = 0, l = u, m = u / 2;

                *is_permuted = TRUE;
                do {
                    if(disp[u] > disp[m])
                        s = m + 1;
                    else if(disp[u] < disp[m])
                        l = m;
                    else
                        break;
                    m = s + ((l - s) / 2);
                } while(s < l);

                if(m < u) {
                    MPI_Aint temp;

                    temp = disp[u];
                    HDmemmove(disp + m + 1, disp + m, (u - m) * sizeof(MPI_Aint));
                    disp[m] = temp;
                } /* end if */
                (*permute)[u] = m;                
            } /* end if */
            else
                (*permute)[u] = num_points;
        } /* end if */
        /* this is a memory space, and no permutation is necessary to create
           the derived datatype */
        else {
            ;/* do nothing */
        } /* end else */

        /* get the next point */
        curr = curr->next;
    } /* end for */

    /* Create the MPI datatype for the set of element displacements */
    if(H5S_mpio_create_point_datatype(elmt_size, num_points, disp, new_type) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't create an MPI Datatype from point selection")

    /* Set values about MPI datatype created */
    *count = 1;
    *is_derived_type = TRUE;

done:
    if(NULL != disp)
        H5MM_free(disp);

    /* Release the permutation buffer, if it wasn't used */
    if(!(*is_permuted) && (*permute)) {
        H5MM_free(*permute);
        *permute = NULL;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5S_mpio_point_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_permute_type
 *
 * Purpose:	Translate an HDF5 "all/hyper/point" selection into an MPI type,
 *              while applying the permutation map. This function is called if
 *              the file space selection is permuted due to out-of-order point
 *              selection and so the memory datatype has to be permuted using the
 *              permutation map created by the file selection.
 *
 * Note:	This routine is called from H5S_mpio_space_type(), which is
 *              called first for the file dataspace and creates
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:	Mohamad Chaarawi
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_permute_type(const H5S_t *space, size_t elmt_size, hsize_t **permute, 
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type)
{
    MPI_Aint *disp = NULL;      /* Datatype displacement for each point*/
    H5S_sel_iter_t sel_iter;    /* Selection iteration info */
    hbool_t sel_iter_init = FALSE;      /* Selection iteration info has been initialized */
    hssize_t snum_points;       /* Signed number of elements in selection */
    hsize_t num_points;         /* Number of points in the selection */
    size_t max_elem;            /* Maximum number of elements allowed in sequences */
    hsize_t u;                  /* Local index variable */
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);

    /* Get the total number of points selected */
    if((snum_points = (hssize_t)H5S_GET_SELECT_NPOINTS(space)) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't get number of elements selected")
    num_points = (hsize_t)snum_points;

    /* Allocate array to store point displacements */
    if(NULL == (disp = (MPI_Aint *)H5MM_malloc(sizeof(MPI_Aint) * num_points)))
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of displacements")

    /* Initialize selection iterator */
    if(H5S_select_iter_init(&sel_iter, space, elmt_size) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
    sel_iter_init = TRUE;	/* Selection iteration info has been initialized */

    /* Set the number of elements to iterate over */
    H5_ASSIGN_OVERFLOW(max_elem, num_points, hsize_t, size_t);

    /* Loop, while elements left in selection */
    u = 0;
    while(max_elem > 0) {
        hsize_t off[H5D_IO_VECTOR_SIZE];        /* Array to store sequence offsets */
        size_t len[H5D_IO_VECTOR_SIZE];         /* Array to store sequence lengths */
        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_GET_SEQ_LIST(space, 0, &sel_iter, (size_t)H5D_IO_VECTOR_SIZE, max_elem, &nseq, &nelem, off, len) < 0)
            HGOTO_ERROR(H5E_DATASPACE, H5E_UNSUPPORTED, FAIL, "sequence length generation failed")

        /* Loop, while sequences left to process */
        for(curr_seq = 0; curr_seq < nseq; 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) {
                /* Set the displacement of the current point */
                disp[u] = curr_off;

                /* This is a memory displacement, so for each point selected, 
                 * apply the map that was generated by the file selection */
                if((*permute)[u] != num_points) {
                    MPI_Aint temp = disp[u];

                    HDmemmove(disp + (*permute)[u] + 1, disp + (*permute)[u], 
                             (u - (*permute)[u]) * sizeof(MPI_Aint));
                    disp[(*permute)[u]] = temp;
                } /* end if */

                /* Advance to next element */
                u++;

                /* 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 */

    /* Create the MPI datatype for the set of element displacements */
    if(H5S_mpio_create_point_datatype(elmt_size, num_points, disp, new_type) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't create an MPI Datatype from point selection")

    /* Set values about MPI datatype created */
    *count = 1;
    *is_derived_type = TRUE;

done:
    /* Release selection iterator */
    if(sel_iter_init)
        if(H5S_SELECT_ITER_RELEASE(&sel_iter) < 0)
            HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator")

    /* Free memory */
    if(disp)
        H5MM_free(disp);
    if(*permute) {
        H5MM_free(*permute);
        *permute = NULL;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5S_mpio_permute_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_hyper_type
 *
 * Purpose:	Translate an HDF5 hyperslab selection into an MPI type.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:	rky 980813
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_hyper_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type)
{
    H5S_sel_iter_t sel_iter;    /* Selection iteration info */
    hbool_t sel_iter_init = FALSE;    /* Selection iteration info has been initialized */

    struct dim {	/* less hassle than malloc/free & ilk */
        hssize_t start;
        hsize_t strid;
        hsize_t block;
        hsize_t xtent;
        hsize_t count;
    } d[H5S_MAX_RANK];

    hsize_t		offset[H5S_MAX_RANK];
    hsize_t		max_xtent[H5S_MAX_RANK];
    H5S_hyper_dim_t	*diminfo;		/* [rank] */
    unsigned		rank;
    int			block_length[3];
    MPI_Datatype	inner_type, outer_type, old_types[3];
    MPI_Aint            extent_len, displacement[3];
    MPI_Aint        lb; /* Needed as an argument for MPI_Type_get_extent */
    unsigned		u;			/* Local index variable */
    int			i;			/* Local index variable */
    int                 mpi_code;               /* MPI return code */
    herr_t		ret_value = SUCCEED;

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);
    HDassert(sizeof(MPI_Aint) >= sizeof(elmt_size));

    /* Initialize selection iterator */
    if(H5S_select_iter_init(&sel_iter, space, elmt_size) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "unable to initialize selection iterator")
    sel_iter_init = TRUE;	/* Selection iteration info has been initialized */

    /* Abbreviate args */
    diminfo = sel_iter.u.hyp.diminfo;
    HDassert(diminfo);

    /* make a local copy of the dimension info so we can operate with them */

    /* Check if this is a "flattened" regular hyperslab selection */
    if(sel_iter.u.hyp.iter_rank != 0 && sel_iter.u.hyp.iter_rank < space->extent.rank) {
        /* Flattened selection */
        rank = sel_iter.u.hyp.iter_rank;
        HDassert(rank <= H5S_MAX_RANK);	/* within array bounds */
#ifdef H5S_DEBUG
  if(H5DEBUG(S))
            HDfprintf(H5DEBUG(S), "%s: Flattened selection\n",FUNC);
#endif
        for(u = 0; u < rank; ++u) {
            H5_CHECK_OVERFLOW(diminfo[u].start, hsize_t, hssize_t)
            d[u].start = (hssize_t)diminfo[u].start + sel_iter.u.hyp.sel_off[u];
            d[u].strid = diminfo[u].stride;
            d[u].block = diminfo[u].block;
            d[u].count = diminfo[u].count;
            d[u].xtent = sel_iter.u.hyp.size[u];
#ifdef H5S_DEBUG
       if(H5DEBUG(S)){
            HDfprintf(H5DEBUG(S), "%s: start=%Hd  stride=%Hu  count=%Hu  block=%Hu  xtent=%Hu",
                FUNC, d[u].start, d[u].strid, d[u].count, d[u].block, d[u].xtent );
            if (u==0)
                HDfprintf(H5DEBUG(S), "  rank=%u\n", rank );
            else
                HDfprintf(H5DEBUG(S), "\n" );
      }
#endif
            if(0 == d[u].block)
                goto empty;
            if(0 == d[u].count)
                goto empty;
            if(0 == d[u].xtent)
                goto empty;
        } /* end for */
    } /* end if */
    else {
        /* Non-flattened selection */
        rank = space->extent.rank;
        HDassert(rank <= H5S_MAX_RANK);	/* within array bounds */
        if(0 == rank)
            goto empty;
#ifdef H5S_DEBUG
  if(H5DEBUG(S))
            HDfprintf(H5DEBUG(S),"%s: Non-flattened selection\n",FUNC);
#endif
        for(u = 0; u < rank; ++u) {
            H5_CHECK_OVERFLOW(diminfo[u].start, hsize_t, hssize_t)
            d[u].start = (hssize_t)diminfo[u].start + space->select.offset[u];
            d[u].strid = diminfo[u].stride;
            d[u].block = diminfo[u].block;
            d[u].count = diminfo[u].count;
            d[u].xtent = space->extent.size[u];
#ifdef H5S_DEBUG
  if(H5DEBUG(S)){
    HDfprintf(H5DEBUG(S), "%s: start=%Hd  stride=%Hu  count=%Hu  block=%Hu  xtent=%Hu",
              FUNC, d[u].start, d[u].strid, d[u].count, d[u].block, d[u].xtent );
    if (u==0)
        HDfprintf(H5DEBUG(S), "  rank=%u\n", rank );
    else
        HDfprintf(H5DEBUG(S), "\n" );
  }
#endif
            if(0 == d[u].block)
                goto empty;
            if(0 == d[u].count)
                goto empty;
            if(0 == d[u].xtent)
                goto empty;
        } /* end for */
    } /* end else */

/**********************************************************************
    Compute array "offset[rank]" which gives the offsets for a multi-
    dimensional array with dimensions "d[i].xtent" (i=0,1,...,rank-1).
**********************************************************************/
    offset[rank - 1] = 1;
    max_xtent[rank - 1] = d[rank - 1].xtent;
#ifdef H5S_DEBUG
  if(H5DEBUG(S)) {
     i = ((int)rank) - 1;
     HDfprintf(H5DEBUG(S), " offset[%2d]=%Hu; max_xtent[%2d]=%Hu\n",
                          i, offset[i], i, max_xtent[i]);
  }
#endif
    for(i = ((int)rank) - 2; i >= 0; --i) {
        offset[i] = offset[i + 1] * d[i + 1].xtent;
        max_xtent[i] = max_xtent[i + 1] * d[i].xtent;
#ifdef H5S_DEBUG
  if(H5DEBUG(S))
    HDfprintf(H5DEBUG(S), " offset[%2d]=%Hu; max_xtent[%2d]=%Hu\n",
                          i, offset[i], i, max_xtent[i]);
#endif
    } /* end for */

    /*  Create a type covering the selected hyperslab.
     *  Multidimensional dataspaces are stored in row-major order.
     *  The type is built from the inside out, going from the
     *  fastest-changing (i.e., inner) dimension * to the slowest (outer). */

/*******************************************************
*  Construct contig type for inner contig dims:
*******************************************************/
#ifdef H5S_DEBUG
  if(H5DEBUG(S)) {
    HDfprintf(H5DEBUG(S), "%s: Making contig type %Zu MPI_BYTEs\n", FUNC, elmt_size);
    for(i = ((int)rank) - 1; i >= 0; --i)
        HDfprintf(H5DEBUG(S), "d[%d].xtent=%Hu \n", i, d[i].xtent);
  }
#endif
    if(MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)elmt_size, MPI_BYTE, &inner_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)

/*******************************************************
*  Construct the type by walking the hyperslab dims
*  from the inside out:
*******************************************************/
    for(i = ((int)rank) - 1; i >= 0; --i) {
#ifdef H5S_DEBUG
  if(H5DEBUG(S))
    HDfprintf(H5DEBUG(S), "%s: Dimension i=%d \n"
            "start=%Hd count=%Hu block=%Hu stride=%Hu, xtent=%Hu max_xtent=%d\n",
            FUNC, i, d[i].start, d[i].count, d[i].block, d[i].strid, d[i].xtent, max_xtent[i]);
#endif

#ifdef H5S_DEBUG
  if(H5DEBUG(S))
    HDfprintf(H5DEBUG(S), "%s: i=%d  Making vector-type \n", FUNC,i);
#endif
       /****************************************
       *  Build vector type of the selection.
       ****************************************/
	mpi_code = MPI_Type_vector((int)(d[i].count),       /* count */
				   (int)(d[i].block),       /* blocklength */
				   (int)(d[i].strid),       /* stride */
				   inner_type,	            /* old type */
				   &outer_type);            /* new type */

        MPI_Type_free(&inner_type);
        if(mpi_code != MPI_SUCCESS)
            HMPI_GOTO_ERROR(FAIL, "couldn't create MPI vector type", mpi_code)

        /****************************************
        *  Then build the dimension type as (start, vector type, xtent).
        ****************************************/
        /* calculate start and extent values of this dimension */
	displacement[1] = d[i].start * offset[i] * elmt_size;
        displacement[2] = (MPI_Aint)elmt_size * max_xtent[i];
        if(MPI_SUCCESS != (mpi_code = MPI_Type_get_extent(outer_type, &lb, &extent_len)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_get_extent failed", mpi_code)

        /*************************************************
        *  Restructure this datatype ("outer_type")
        *  so that it still starts at 0, but its extent
        *  is the full extent in this dimension.
        *************************************************/
        if(displacement[1] > 0 || (int)extent_len < displacement[2]) {

            block_length[0] = 1;
            block_length[1] = 1;
            block_length[2] = 1;

            displacement[0] = 0;

            old_types[0] = MPI_LB;
            old_types[1] = outer_type;
            old_types[2] = MPI_UB;
#ifdef H5S_DEBUG
  if(H5DEBUG(S))
    HDfprintf(H5DEBUG(S), "%s: i=%d Extending struct type\n"
        "***displacements: %ld, %ld, %ld\n",
        FUNC, i, (long)displacement[0], (long)displacement[1], (long)displacement[2]);
#endif

            mpi_code = MPI_Type_create_struct(3,               /* count */
                                              block_length,    /* blocklengths */
                                              displacement,    /* displacements */
                                              old_types,       /* old types */
                                              &inner_type);    /* new type */

            MPI_Type_free(&outer_type);
    	    if(mpi_code != MPI_SUCCESS)
                HMPI_GOTO_ERROR(FAIL, "couldn't resize MPI vector type", mpi_code)
        } /* end if */
        else
            inner_type = outer_type;
    } /* end for */
/***************************
*  End of loop, walking
*  thru dimensions.
***************************/

    /* At this point inner_type is actually the outermost type, even for 0-trip loop */
    *new_type = inner_type;
    if(MPI_SUCCESS != (mpi_code = MPI_Type_commit(new_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)

    /* fill in the remaining return values */
    *count = 1;			/* only have to move one of these suckers! */
    *is_derived_type = TRUE;
    HGOTO_DONE(SUCCEED);

empty:
    /* special case: empty hyperslab */
    *new_type = MPI_BYTE;
    *count = 0;
    *is_derived_type = FALSE;

done:
    /* Release selection iterator */
    if(sel_iter_init)
        if(H5S_SELECT_ITER_RELEASE(&sel_iter) < 0)
            HDONE_ERROR(H5E_DATASPACE, H5E_CANTRELEASE, FAIL, "unable to release selection iterator")

#ifdef H5S_DEBUG
  if(H5DEBUG(S))
    HDfprintf(H5DEBUG(S), "Leave %s, count=%ld  is_derived_type=%t\n",
		FUNC, *count, *is_derived_type );
#endif
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5S_mpio_hyper_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_span_hyper_type
 *
 * Purpose:	Translate an HDF5 irregular hyperslab selection into an
                MPI type.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:  kyang
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_mpio_span_hyper_type(const H5S_t *space, size_t elmt_size,
    MPI_Datatype *new_type, int *count, hbool_t *is_derived_type)
{
    MPI_Datatype  elmt_type;            /* MPI datatype for an element */
    hbool_t elmt_type_is_derived = FALSE;       /* Whether the element type has been created */
    MPI_Datatype  span_type;            /* MPI datatype for overall span tree */
    hsize_t       down[H5S_MAX_RANK];   /* 'down' sizes for each dimension */
    int           mpi_code;             /* MPI return code */
    herr_t        ret_value = SUCCEED;  /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);
    HDassert(space->extent.size);
    HDassert(space->select.sel_info.hslab->span_lst);
    HDassert(space->select.sel_info.hslab->span_lst->head);

    /* Create the base type for an element */
    if(MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)elmt_size, MPI_BYTE, &elmt_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
    elmt_type_is_derived = TRUE;

    /* Compute 'down' sizes for each dimension */
    if(H5VM_array_down(space->extent.rank, space->extent.size, down) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGETSIZE, FAIL, "couldn't compute 'down' dimension sizes")

    /* Obtain derived data type */
    if(H5S_obtain_datatype(down, space->select.sel_info.hslab->span_lst->head, &elmt_type, &span_type, elmt_size) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't obtain  MPI derived data type")
    if(MPI_SUCCESS != (mpi_code = MPI_Type_commit(&span_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)
    *new_type = span_type;

    /* fill in the remaining return values */
    *count = 1;
    *is_derived_type = TRUE;

done:
    /* Release resources */
    if(elmt_type_is_derived)
        if(MPI_SUCCESS != (mpi_code = MPI_Type_free(&elmt_type)))
            HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code)

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5S_mpio_span_hyper_type() */


/*-------------------------------------------------------------------------
 * Function:	H5S_obtain_datatype
 *
 * Purpose:	Obtain an MPI derived datatype based on span-tree
 *              implementation
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*span_type	 the MPI type corresponding to the selection
 *
 * Programmer:  kyang
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5S_obtain_datatype(const hsize_t *down, H5S_hyper_span_t *span,
    const MPI_Datatype *elmt_type, MPI_Datatype *span_type, size_t elmt_size)
{
    size_t                alloc_count;          /* Number of span tree nodes allocated at this level */
    size_t                outercount;           /* Number of span tree nodes at this level */
    MPI_Datatype          *inner_type = NULL;
    hbool_t inner_types_freed = FALSE;          /* Whether the inner_type MPI datatypes have been freed */
    hbool_t span_type_valid = FALSE;            /* Whether the span_type MPI datatypes is valid */
    int                   *blocklen = NULL;
    MPI_Aint              *disp = NULL;
    H5S_hyper_span_t      *tspan;               /* Temporary pointer to span tree node */
    int                   mpi_code;             /* MPI return status code */
    herr_t                ret_value = SUCCEED;  /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(span);

    /* Allocate the initial displacement & block length buffers */
    alloc_count = H5S_MPIO_INITIAL_ALLOC_COUNT;
    if(NULL == (disp = (MPI_Aint *)H5MM_malloc(alloc_count * sizeof(MPI_Aint))))
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of displacements")
    if(NULL == (blocklen = (int *)H5MM_malloc(alloc_count * sizeof(int))))
        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of block lengths")

    /* if this is the fastest changing dimension, it is the base case for derived datatype. */
    if(NULL == span->down) {
        tspan = span;
        outercount = 0;
        while(tspan) {
            /* Check if we need to increase the size of the buffers */
            if(outercount >= alloc_count) {
                MPI_Aint     *tmp_disp;         /* Temporary pointer to new displacement buffer */
                int          *tmp_blocklen;     /* Temporary pointer to new block length buffer */

                /* Double the allocation count */
                alloc_count *= 2;

                /* Re-allocate the buffers */
                if(NULL == (tmp_disp = (MPI_Aint *)H5MM_realloc(disp, alloc_count * sizeof(MPI_Aint))))
                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of displacements")
                disp = tmp_disp;
                if(NULL == (tmp_blocklen = (int *)H5MM_realloc(blocklen, alloc_count * sizeof(int))))
                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of block lengths")
                blocklen = tmp_blocklen;
            } /* end if */

            /* Store displacement & block length */
            disp[outercount]      = (MPI_Aint)elmt_size * tspan->low;
            H5_CHECK_OVERFLOW(tspan->nelem, hsize_t, int)
            blocklen[outercount]  = (int)tspan->nelem;

            tspan                 = tspan->next;
            outercount++;
        } /* end while */

        if(MPI_SUCCESS != (mpi_code = MPI_Type_create_hindexed((int)outercount, blocklen, disp, *elmt_type, span_type)))
              HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hindexed failed", mpi_code)
        span_type_valid = TRUE;
    } /* end if */
    else {
        size_t u;               /* Local index variable */

        if(NULL == (inner_type = (MPI_Datatype *)H5MM_malloc(alloc_count * sizeof(MPI_Datatype))))
            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of inner MPI datatypes")

        tspan = span;
        outercount = 0;
        while(tspan) {
            MPI_Datatype down_type;     /* Temporary MPI datatype for a span tree node's children */
            MPI_Aint stride;            /* Distance between inner MPI datatypes */

            /* Check if we need to increase the size of the buffers */
            if(outercount >= alloc_count) {
                MPI_Aint     *tmp_disp;         /* Temporary pointer to new displacement buffer */
                int          *tmp_blocklen;     /* Temporary pointer to new block length buffer */
                MPI_Datatype *tmp_inner_type;   /* Temporary pointer to inner MPI datatype buffer */

                /* Double the allocation count */
                alloc_count *= 2;

                /* Re-allocate the buffers */
                if(NULL == (tmp_disp = (MPI_Aint *)H5MM_realloc(disp, alloc_count * sizeof(MPI_Aint))))
                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of displacements")
                disp = tmp_disp;
                if(NULL == (tmp_blocklen = (int *)H5MM_realloc(blocklen, alloc_count * sizeof(int))))
                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of block lengths")
                blocklen = tmp_blocklen;
                if(NULL == (tmp_inner_type = (MPI_Datatype *)H5MM_realloc(inner_type, alloc_count * sizeof(MPI_Datatype))))
                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTALLOC, FAIL, "can't allocate array of inner MPI datatypes")
                inner_type = tmp_inner_type;
            } /* end if */

            /* Displacement should be in byte and should have dimension information */
            /* First using MPI Type vector to build derived data type for this span only */
            /* Need to calculate the disp in byte for this dimension. */
            /* Calculate the total bytes of the lower dimension */
            disp[outercount]      = tspan->low * (*down) * elmt_size;
            blocklen[outercount]  = 1;

            /* Generate MPI datatype for next dimension down */
            if(H5S_obtain_datatype(down + 1, tspan->down->head, elmt_type, &down_type, elmt_size) < 0)
                HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't obtain  MPI derived data type")

            /* Build the MPI datatype for this node */
            stride = (*down) * elmt_size;
            H5_CHECK_OVERFLOW(tspan->nelem, hsize_t, int)
            if(MPI_SUCCESS != (mpi_code = MPI_Type_create_hvector((int)tspan->nelem, 1, stride, down_type, &inner_type[outercount]))) {
                MPI_Type_free(&down_type);
                HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)
            } /* end if */

            /* Release MPI datatype for next dimension down */
            if(MPI_SUCCESS != (mpi_code = MPI_Type_free(&down_type)))
                HMPI_GOTO_ERROR(FAIL, "MPI_Type_free failed", mpi_code)

            tspan = tspan->next;
            outercount++;
         } /* end while */

        /* building the whole vector datatype */
        H5_CHECK_OVERFLOW(outercount, size_t, int)
        if(MPI_SUCCESS != (mpi_code = MPI_Type_create_struct((int)outercount, blocklen, disp, inner_type, span_type)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_struct failed", mpi_code)
        span_type_valid = TRUE;

        /* Release inner node types */
        for(u = 0; u < outercount; u++)
            if(MPI_SUCCESS != (mpi_code = MPI_Type_free(&inner_type[u])))
                HMPI_GOTO_ERROR(FAIL, "MPI_Type_free failed", mpi_code)
        inner_types_freed = TRUE;
    } /* end else */

done:
    /* General cleanup */
    if(inner_type != NULL) {
        if(!inner_types_freed) {
            size_t u;          /* Local index variable */

            for(u = 0; u < outercount; u++)
                if(MPI_SUCCESS != (mpi_code = MPI_Type_free(&inner_type[u])))
                    HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code)
        } /* end if */

        H5MM_free(inner_type);
    } /* end if */
    if(blocklen != NULL)
        H5MM_free(blocklen);
    if(disp != NULL)
        H5MM_free(disp);

    /* Error cleanup */
    if(ret_value < 0) {
        if(span_type_valid)
            if(MPI_SUCCESS != (mpi_code = MPI_Type_free(span_type)))
                HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code)
    } /* end if */

  FUNC_LEAVE_NOAPI(ret_value)
} /* end H5S_obtain_datatype() */


/*-------------------------------------------------------------------------
 * Function:	H5S_mpio_space_type
 *
 * Purpose:	Translate an HDF5 dataspace selection into an MPI type.
 *		Currently handle only hyperslab and "all" selections.
 *
 * Return:	non-negative on success, negative on failure.
 *
 * Outputs:	*new_type	  the MPI type corresponding to the selection
 *		*count		  how many objects of the new_type in selection
 *				  (useful if this is the buffer type for xfer)
 *		*is_derived_type  0 if MPI primitive type, 1 if derived
 *
 * Programmer:	rky 980813
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5S_mpio_space_type(const H5S_t *space, size_t elmt_size, MPI_Datatype *new_type, 
    int *count, hbool_t *is_derived_type, hbool_t do_permute, hsize_t **permute_map,
    hbool_t *is_permuted)
{
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    HDassert(space);
    HDassert(elmt_size);

    /* Create MPI type based on the kind of selection */
    switch(H5S_GET_EXTENT_TYPE(space)) {
        case H5S_NULL:
        case H5S_SCALAR:
        case H5S_SIMPLE:
            /* If the file space has been permuted previously due to
             * out-of-order point selection, then permute this selection which
             * should be a memory selection to match the file space permutation.
             */
            if(TRUE == *is_permuted) { 
                switch(H5S_GET_SELECT_TYPE(space)) {
                    case H5S_SEL_NONE:
                        if(H5S_mpio_none_type(new_type, count, is_derived_type) < 0)
                            HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't convert 'none' selection to MPI type")
                        break;

                    case H5S_SEL_ALL:
                    case H5S_SEL_POINTS:
                    case H5S_SEL_HYPERSLABS:
                        /* Sanity check */
                        HDassert(!do_permute);

                        if(H5S_mpio_permute_type(space, elmt_size, permute_map, new_type, count, is_derived_type) < 0)
                            HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't convert 'all' selection to MPI type")
                        break;

                    case H5S_SEL_ERROR:
                    case H5S_SEL_N:
                    default:
                        HDassert("unknown selection type" && 0);
                        break;
                } /* end switch */
            } /* end if */
            /* the file space is not permuted, so do a regular selection */
            else {
                switch(H5S_GET_SELECT_TYPE(space)) {
                    case H5S_SEL_NONE:
                        if(H5S_mpio_none_type(new_type, count, is_derived_type) < 0)
                            HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't convert 'none' selection to MPI type")
                        break;

                    case H5S_SEL_ALL:
                        if(H5S_mpio_all_type(space, elmt_size, new_type, count, is_derived_type) < 0)
                            HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't convert 'all' selection to MPI type")
                        break;

                    case H5S_SEL_POINTS:
                        if(H5S_mpio_point_type(space, elmt_size, new_type, count, is_derived_type, do_permute, permute_map, is_permuted) < 0)
                           HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL, "couldn't convert 'point' selection to MPI type")
                        break;

                    case H5S_SEL_HYPERSLABS:
                        if((H5S_SELECT_IS_REGULAR(space) == TRUE)) {
                            if(H5S_mpio_hyper_type(space, elmt_size, new_type, count, is_derived_type) < 0)
                                HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't convert regular 'hyperslab' selection to MPI type")
                        } /* end if */
                        else {
                            if(H5S_mpio_span_hyper_type(space, elmt_size, new_type, count, is_derived_type) < 0)
                                HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't convert irregular 'hyperslab' selection to MPI type")
                        } /* end else */
                        break;

                    case H5S_SEL_ERROR:
                    case H5S_SEL_N:
                    default:
                        HDassert("unknown selection type" && 0);
                        break;
                } /* end switch */
            } /* end else */
            break;

        case H5S_NO_CLASS:
        default:
            HDassert("unknown dataspace type" && 0);
            break;
    } /* end switch */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5S_mpio_space_type() */
#endif  /* H5_HAVE_PARALLEL */