summaryrefslogtreecommitdiffstats
path: root/src/H5Omessage.c
blob: 70e2b2a1ca088d9ccd439c840862157d619ccb82 (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
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
 * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:		H5Omessage.c
 *			Dec  3 2006
 *			Quincey Koziol <koziol@hdfgroup.org>
 *
 * Purpose:		Object header message routines.
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/

#define H5O_PACKAGE		/*suppress error about including H5Opkg	  */

/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5Aprivate.h"		/* Attributes	  			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fprivate.h"		/* File access				*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Opkg.h"             /* Object headers			*/
#include "H5SMprivate.h"        /* Shared object header messages        */


/****************/
/* Local Macros */
/****************/

/* Load native information for a message, if it's not already present */
/* (Only works for messages with decode callback) */
#define H5O_LOAD_NATIVE(F, DXPL, MSG, ERR)                                        \
    if(NULL == (MSG)->native) {                                               \
        const H5O_msg_class_t	*decode_type;                                 \
                                                                              \
        /* Check for shared message */                                        \
        if((MSG)->flags & H5O_MSG_FLAG_SHARED)                                \
            decode_type = H5O_MSG_SHARED;                                     \
        else                                                                  \
            decode_type = (MSG)->type;                                        \
                                                                              \
        /* Decode the message */                                              \
        HDassert(decode_type->decode);                                        \
        if(NULL == ((MSG)->native = (decode_type->decode)((F), (DXPL), (MSG)->raw))) \
            HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, ERR, "unable to decode message") \
    } /* end if */


/******************/
/* Local Typedefs */
/******************/

/* User data for iteration while removing a message */
typedef struct {
    H5F_t      *f;              /* Pointer to file for insertion */
    hid_t dxpl_id;              /* DXPL during iteration */
    int sequence;               /* Sequence # to search for */
    unsigned nfailed;           /* # of failed message removals */
    H5O_operator_t op;          /* Callback routine for removal operations */
    void *op_data;              /* Callback data for removal operations */
    hbool_t adj_link;           /* Whether to adjust links when removing messages */
} H5O_iter_rm_t;


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/

static herr_t H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
    unsigned overwrite, unsigned mesg_flags, unsigned update_flags,
    const void *mesg, hid_t dxpl_id, unsigned *oh_flags_ptr);
static herr_t H5O_msg_reset_real(const H5O_msg_class_t *type, void *native);
static void *H5O_msg_copy_real(const H5O_msg_class_t *type, const void *mesg,
        void *dst);
static herr_t H5O_msg_remove_real(const H5O_loc_t *loc, const H5O_msg_class_t *type,
    int sequence, H5O_operator_t op, void *op_data, hbool_t adj_link, hid_t dxpl_id);
static herr_t H5O_msg_remove_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, 
    unsigned sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/);
static unsigned H5O_new_mesg(H5F_t *f, H5O_t *oh, unsigned *flags,
    const H5O_msg_class_t *orig_type, const void *orig_mesg, H5O_shared_t *sh_mesg,
    const H5O_msg_class_t **new_type, const void **new_mesg, hid_t dxpl_id,
    unsigned *oh_flags_ptr);
static herr_t H5O_write_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx,
    const H5O_msg_class_t *type, const void *mesg, unsigned flags,
    unsigned update_flags, unsigned *oh_flags_ptr);


/*********************/
/* Package Variables */
/*********************/


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/



/*-------------------------------------------------------------------------
 * Function:	H5O_msg_create
 *
 * Purpose:	Create a new object header message
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@hdfgroup.org
 *		Dec  1 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_create(H5O_loc_t *loc, unsigned type_id, unsigned mesg_flags,
    unsigned update_flags, void *mesg, hid_t dxpl_id)
{
    H5O_t *oh = NULL;                   /* Object header */
    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Metadata cache flags for object header */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_create, FAIL)

    /* check args */
    HDassert(loc);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    HDassert(0 == (mesg_flags & ~H5O_MSG_FLAG_BITS));
    HDassert(mesg);

    /* Check for write access on the file */
    if(0 == (H5F_INTENT(loc->file) & H5F_ACC_RDWR))
	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "no write intent on file")

    /* Protect the object header */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Go append message to object header */
    if(H5O_msg_append(loc->file, dxpl_id, oh, type_id, mesg_flags, update_flags, mesg, &oh_flags) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to append to object header")

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_create() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_append
 *
 * Purpose:	Simplified version of H5O_msg_create, used when creating a new
 *              object header message (usually during object creation) and
 *              several messages will be added to the object header at once.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Dec 31 2002
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_append(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned type_id,
    unsigned mesg_flags, unsigned update_flags, void *mesg,
    unsigned *oh_flags_ptr)
{
    const H5O_msg_class_t *type;        /* Original H5O class type for the ID */
    htri_t shared_mesg;                 /* Should this message be stored in the Shared Message table? */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_append, FAIL)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(H5O_ATTR_ID != type_id);   /* Attributes are modified in another routine */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(0 == (mesg_flags & ~H5O_MSG_FLAG_BITS));
    HDassert(mesg);
    HDassert(oh_flags_ptr);

    /* Should this message be written as a SOHM? */
    if((shared_mesg = H5SM_try_share(f, dxpl_id, type_id, mesg)) > 0)
        /* Mark the message as shared */
        mesg_flags |= H5O_MSG_FLAG_SHARED;
    else if(shared_mesg < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "error determining if message should be shared")

    /* Append new message to object header */
    if(H5O_msg_append_real(f, dxpl_id, oh, type, mesg_flags, update_flags, mesg, oh_flags_ptr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to create new message in header")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_append() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_append_real
 *
 * Purpose:	Append a new message to an object header.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@hdfgroup.org
 *		Dec  8 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_append_real(H5F_t *f, hid_t dxpl_id, H5O_t *oh, const H5O_msg_class_t *type,
    unsigned mesg_flags, unsigned update_flags, void *mesg,
    unsigned *oh_flags_ptr)
{
    const H5O_msg_class_t *new_type;    /* Actual H5O class type for the ID */
    const void *new_mesg;               /* Actual message to write */
    H5O_shared_t sh_mesg;               /* Shared object header info */
    unsigned idx;                       /* Index of message to modify */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_append_real, FAIL)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(type);
    HDassert(0 == (mesg_flags & ~H5O_MSG_FLAG_BITS));
    HDassert(mesg);
    HDassert(oh_flags_ptr);

    /* Create a new message */
    if((idx = H5O_new_mesg(f, oh, &mesg_flags, type, mesg, &sh_mesg, &new_type, &new_mesg, dxpl_id, oh_flags_ptr)) == UFAIL)
        HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, FAIL, "unable to create new message")

    /* Write the information to the message */
    if(H5O_write_mesg(f, dxpl_id, oh, idx, new_type, new_mesg, mesg_flags, update_flags, oh_flags_ptr) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to write message")
#ifdef H5O_DEBUG
H5O_assert(oh);
#endif /* H5O_DEBUG */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_append_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_write
 *
 * Purpose:	Modifies an existing message or creates a new message.
 *
 *		The OVERWRITE argument is a sequence number of a
 *		message to overwrite (usually zero).
 *		If the message to overwrite doesn't exist then this routine
 *              fails.
 *
 *              The UPDATE_FLAGS argument are flags that allow the caller
 *              to skip updating the modification time or reseting the message
 *              data.  This is useful when several calls to H5O_msg_write will be
 *              made in a sequence.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug  6 1997
 *
 *-------------------------------------------------------------------------
 */
/* JAMES: this will probably get put through its paces when extending shared
 * dataspaces */
herr_t
H5O_msg_write(H5O_loc_t *loc, unsigned type_id, unsigned overwrite,
   unsigned mesg_flags, unsigned update_flags, void *mesg, hid_t dxpl_id)
{
    H5O_t *oh = NULL;                   /* Object header to use */
    unsigned oh_flags = H5AC__NO_FLAGS_SET;     /* Flags to unprotect object header */
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    htri_t shared_mesg;                 /* Whether the message should be shared */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_write, FAIL)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(H5O_ATTR_ID != type_id);   /* Attributes are modified in another routine */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(mesg);
    HDassert(0 == (mesg_flags & ~H5O_MSG_FLAG_BITS));

    /* Check for write access on the file */
    if(0 == (H5F_INTENT(loc->file) & H5F_ACC_RDWR))
	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "no write intent on file")

    /* Should this message be written as a SOHM? */
    if((shared_mesg = H5SM_try_share(loc->file, dxpl_id, type_id, mesg)) > 0)
        /* Mark the message as shared */
        mesg_flags |= H5O_MSG_FLAG_SHARED;
    else if(shared_mesg < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "error while trying to share message")

    /* Protect the object header */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Call the "real" modify routine */
    if(H5O_msg_write_real(loc->file, oh, type, overwrite, mesg_flags, update_flags, mesg, dxpl_id, &oh_flags) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to write object header message")

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_write() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_write_real
 *
 * Purpose:	Modifies an existing message or creates a new message.
 *
 *		The OVERWRITE argument is a sequence number of a
 *		message to overwrite (usually zero).
 *		If the message to overwrite doesn't exist then this routine
 *              fails.
 *
 *              The UPDATE_FLAGS argument are flags that allow the caller
 *              to skip updating the modification time or reseting the message
 *              data.  This is useful when several calls to H5O_msg_write will be
 *              made in a sequence.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug  6 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
    unsigned overwrite, unsigned mesg_flags, unsigned update_flags,
    const void *mesg, hid_t dxpl_id, unsigned *oh_flags_ptr)
{
    int	        	sequence;       /* Sequence # of message type to modify */
    unsigned		idx;            /* Index of message to modify */
    H5O_mesg_t         *idx_msg;        /* Pointer to message to modify */
    H5O_shared_t	sh_mesg;        /* Shared message to store */
    const H5O_msg_class_t *write_type = type;   /* Type of message to be written */
    const void          *write_mesg = mesg;     /* Actual message being written */
    herr_t	        ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_write_real)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(type);
    HDassert(mesg);
    HDassert(0 == (mesg_flags & ~H5O_MSG_FLAG_BITS));
    HDassert(oh_flags_ptr);

    /* Count similar messages */
    for(idx = 0, sequence = -1, idx_msg = &oh->mesg[0]; idx < oh->nmesgs; idx++, idx_msg++) {
	if(type->id != idx_msg->type->id)
            continue;
	if(++sequence == (int)overwrite)
            break;
    } /* end for */

    /* Was the right message found? */
    if(sequence != (int)overwrite)
        HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "message not found")

    /* Check for modifying a constant message */
    if(oh->mesg[idx].flags & H5O_MSG_FLAG_CONSTANT) {
	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to modify constant message")
    } else if(oh->mesg[idx].flags & H5O_MSG_FLAG_SHARED) {
        /* This message is shared, but it's being modified.  This is valid if
         * it's shared in the heap .
         * First, make sure it's not a committed message; these can't ever
         * be modified.
         */
        HDassert(!(((H5O_shared_t *)oh->mesg[idx].native)->flags & H5O_COMMITTED_FLAG));

        /* Remove the old message from the SOHM index */
        if(H5SM_try_delete(f, dxpl_id, oh->mesg[idx].type->id, oh->mesg[idx].native) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")

        /* Now this message is no longer shared and we can safely overwrite it.
         * We need to make sure that the message we're writing is shared,
         * though, and that the library doesn't try to reset the current
         * message like it would in a normal overwrite (this message is
         * realy a shared pointer, not a real message).
         * JAMES: will this break if a shared message is overwritten with a larger
         * non-shared message?
         */
        HDassert(H5O_msg_is_shared(type->id, mesg) > 0); /* JAMES: this should work with
                                                      * replacement messages that aren't shared, too. */

        /* Extract shared message info from current message */
        if(NULL == H5O_msg_get_share(type->id, mesg, &sh_mesg))
            HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "can't get shared message")

        /* Instead of writing the original message, write a shared message */
        write_type = H5O_MSG_SHARED;
        write_mesg = &sh_mesg;
    } /* end if */

    /* Write the information to the message */
    if(H5O_write_mesg(f, dxpl_id, oh, idx, write_type, write_mesg, mesg_flags, update_flags, oh_flags_ptr) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to write message")
#ifdef H5O_DEBUG
H5O_assert(oh);
#endif /* H5O_DEBUG */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_write_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_read
 *
 * Purpose:	Reads a message from an object header and returns a pointer
 *		to it.	The caller will usually supply the memory through
 *		MESG and the return value will be MESG.	 But if MESG is
 *		the null pointer, then this function will malloc() memory
 *		to hold the result and return its pointer instead.
 *
 * Return:	Success:	Ptr to message in native format.  The message
 *				should be freed by calling H5O_msg_reset().  If
 *				MESG is a null pointer then the caller should
 *				also call H5MM_xfree() on the return value
 *				after calling H5O_msg_reset().
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug  6 1997
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_read(const H5O_loc_t *loc, unsigned type_id, int sequence, void *mesg,
    hid_t dxpl_id)
{
    H5O_t *oh = NULL;                   /* Object header to use */
    void *ret_value;                    /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_read, NULL)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    HDassert(sequence >= 0);

    /* Get the object header */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "unable to load object header")

    /* Call the "real" read routine */
    if((ret_value = H5O_msg_read_real(loc->file, oh, type_id, sequence, mesg, dxpl_id)) == NULL)
	HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL, "unable to load object header")

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, H5AC__NO_FLAGS_SET) < 0)
	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, NULL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_read() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_read_real
 *
 * Purpose:	Reads a message from an object header and returns a pointer
 *		to it.	The caller will usually supply the memory through
 *		MESG and the return value will be MESG.	 But if MESG is
 *		the null pointer, then this function will malloc() memory
 *		to hold the result and return its pointer instead.
 *
 * Return:	Success:	Ptr to message in native format.  The message
 *				should be freed by calling H5O_msg_reset().  If
 *				MESG is a null pointer then the caller should
 *				also call H5MM_xfree() on the return value
 *				after calling H5O_msg_reset().
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug  6 1997
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_read_real(H5F_t *f, H5O_t *oh, unsigned type_id, int sequence,
    void *mesg, hid_t dxpl_id)
{
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    unsigned       idx;                 /* Message's index in object header */
    void           *ret_value = NULL;

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_read_real)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(sequence >= 0);

    /* Scan through the messages looking for the right one */
    for(idx = 0; idx < oh->nmesgs; idx++) {
	if(type_id != oh->mesg[idx].type->id)
            continue;
	if(--sequence < 0)
            break;
    } /* end for */
    if(sequence >= 0)
	HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, NULL, "unable to find object header message")

    /*
     * Decode the message if necessary.  If the message is shared then decode
     * a shared message, ignoring the message type.
     */
    H5O_LOAD_NATIVE(f, dxpl_id, &(oh->mesg[idx]), NULL)

    /* Read the message in */
    if(oh->mesg[idx].flags & H5O_MSG_FLAG_SHARED) {
	/*
	 * If the message is shared then then the native pointer points to an
	 * H5O_MSG_SHARED message.  We use that information to look up the real
	 * message in the global heap or some other object header.
	 */
        if(NULL == (ret_value = H5O_shared_read(f, dxpl_id, oh->mesg[idx].native, type, mesg)))
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy message to user space")
    } else {
	/*
	 * The message is not shared, but rather exists in the object
	 * header.  The object header caches the native message (along with
	 * the raw message) so we must copy the native message before
	 * returning.
	 */
	if(NULL == (ret_value = (type->copy)(oh->mesg[idx].native, mesg)))
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy message to user space")
    } /* end else */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_read_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_reset
 *
 * Purpose:	Some message data structures have internal fields that
 *		need to be freed.  This function does that if appropriate
 *		but doesn't free NATIVE.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug 12 1997
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_reset(unsigned type_id, void *native)
{
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_reset, FAIL)

    /* check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Call the "real" reset routine */
    if(H5O_msg_reset_real(type, native) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTRESET, FAIL, "unable to reset object header")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_reset() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_reset_real
 *
 * Purpose:	Some message data structures have internal fields that
 *		need to be freed.  This function does that if appropriate
 *		but doesn't free NATIVE.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug 12 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_msg_reset_real(const H5O_msg_class_t *type, void *native)
{
    herr_t      ret_value = SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_reset_real)

    /* check args */
    HDassert(type);

    if(native) {
	if(type->reset) {
	    if((type->reset)(native) < 0)
		HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "reset method failed")
	} else
	    HDmemset(native, 0, type->native_size);
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_reset_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_free
 *
 * Purpose:	Similar to H5O_msg_reset() except it also frees the message
 *		pointer.
 *
 * Return:	Success:	NULL
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, May 21, 1998
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_free(unsigned type_id, void *mesg)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    void * ret_value;                   /* Return value */

    FUNC_ENTER_NOAPI_NOFUNC(H5O_msg_free)

    /* check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Call the "real" free routine */
    ret_value = H5O_msg_free_real(type, mesg);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_free() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_free_mesg
 *
 * Purpose:	Call H5O_msg_free_real() on a message.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *              Tuesday, Sep  6, 2005
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_free_mesg(H5O_mesg_t *mesg)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_msg_free_mesg)

    /* check args */
    HDassert(mesg);

    /* Free any native information */
    if(mesg->flags & H5O_MSG_FLAG_SHARED)
        mesg->native = H5O_msg_free_real(H5O_MSG_SHARED, mesg->native);
    else
        mesg->native = H5O_msg_free_real(mesg->type, mesg->native);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5O_msg_free_mesg() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_free_real
 *
 * Purpose:	Similar to H5O_msg_reset() except it also frees the message
 *		pointer.
 *
 * Return:	Success:	NULL
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, May 21, 1998
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_free_real(const H5O_msg_class_t *type, void *msg_native)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_msg_free_real)

    /* check args */
    HDassert(type);

    if(msg_native) {
        H5O_msg_reset_real(type, msg_native);
        if(NULL != (type->free))
            (type->free)(msg_native);
        else
            H5MM_xfree(msg_native);
    } /* end if */

    FUNC_LEAVE_NOAPI(NULL)
} /* end H5O_msg_free_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_copy
 *
 * Purpose:	Copies a message.  If MESG is is the null pointer then a null
 *		pointer is returned with no error.
 *
 * Return:	Success:	Ptr to the new message
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, May 21, 1998
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_copy(unsigned type_id, const void *mesg, void *dst)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    void	*ret_value;             /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_copy, NULL)

    /* check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Call the "real" copy routine */
    if((ret_value = H5O_msg_copy_real(type, mesg, dst)) == NULL)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, NULL, "unable to copy object header message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_copy() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_copy_real
 *
 * Purpose:	Copies a message.  If MESG is is the null pointer then a null
 *		pointer is returned with no error.
 *
 * Return:	Success:	Ptr to the new message
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, May 21, 1998
 *
 *-------------------------------------------------------------------------
 */
static void *
H5O_msg_copy_real(const H5O_msg_class_t *type, const void *mesg, void *dst)
{
    void	*ret_value = NULL;

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_copy_real)

    /* check args */
    HDassert(type);
    HDassert(type->copy);

    if(mesg)
	if(NULL == (ret_value = (type->copy)(mesg, dst)))
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy object header message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_copy_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_count
 *
 * Purpose:	Counts the number of messages in an object header which are a
 *		certain type.
 *
 * Return:	Success:	Number of messages of specified type.
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Tuesday, April 21, 1998
 *
 *-------------------------------------------------------------------------
 */
int
H5O_msg_count(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
{
    H5O_t *oh = NULL;           /* Object header to operate on */
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    int	acc;                    /* Count of the message type found */
    unsigned u;                 /* Local index variable */
    int	ret_value;              /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_count, FAIL)

    /* Check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Load the object header */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Loop over all messages, counting the ones of the type looked for */
    for(u = acc = 0; u < oh->nmesgs; u++)
	if(oh->mesg[u].type == type)
            acc++;

    /* Set return value */
    ret_value = acc;

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, H5AC__NO_FLAGS_SET) < 0)
	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_count() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_exists
 *
 * Purpose:	Determines if a particular message exists in an object
 *		header without trying to decode the message.
 *
 * Return:	Success:	FALSE if the message does not exist; TRUE if
 *				th message exists.
 *
 *		Failure:	FAIL if the existence of the message could
 *				not be determined due to some error such as
 *				not being able to read the object header.
 *
 * Programmer:	Robb Matzke
 *              Monday, November  2, 1998
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5O_msg_exists(H5O_loc_t *loc, unsigned type_id, int sequence, hid_t dxpl_id)
{
    H5O_t	*oh = NULL;             /* Object header for location */
    htri_t      ret_value;              /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_exists, FAIL)

    HDassert(loc);
    HDassert(loc->file);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    HDassert(sequence >= 0);

    /* Load the object header */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_READ)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Call the "real" exists routine */
    if((ret_value = H5O_msg_exists_oh(oh, type_id, sequence)) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_READERROR, FAIL, "unable to verify object header message")

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, H5AC__NO_FLAGS_SET) != SUCCEED)
	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_exists() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_exists_oh
 *
 * Purpose:	Determines if a particular message exists in an object
 *		header without trying to decode the message.
 *
 * Return:	Success:	FALSE if the message does not exist; TRUE if
 *				th message exists.
 *
 *		Failure:	FAIL if the existence of the message could
 *				not be determined due to some error such as
 *				not being able to read the object header.
 *
 * Programmer:	Robb Matzke
 *              Monday, November  2, 1998
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5O_msg_exists_oh(H5O_t *oh, unsigned type_id, int sequence)
{
    const H5O_msg_class_t *type;    /* Actual H5O class type for the ID */
    unsigned	u;              /* Local index variable */
    htri_t      ret_value;      /* Return value */

    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_msg_exists_oh)

    HDassert(oh);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(sequence >= 0);

    /* Scan through the messages looking for the right one */
    for(u = 0; u < oh->nmesgs; u++) {
	if(type->id != oh->mesg[u].type->id)
            continue;
	if(--sequence < 0)
            break;
    } /* end for */

    /* Set return value */
    ret_value = (sequence < 0);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_exists_oh() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_remove
 *
 * Purpose:	Removes the specified message from the object header.
 *		If sequence is H5O_ALL (-1) then all messages of the
 *		specified type are removed.  Removing a message causes
 *		the sequence numbers to change for subsequent messages of
 *		the same type.
 *
 *		No attempt is made to join adjacent free areas of the
 *		object header into a single larger free area.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug 28 1997
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_remove(H5O_loc_t *loc, unsigned type_id, int sequence, hbool_t adj_link,
    hid_t dxpl_id)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    herr_t      ret_value;              /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_remove, FAIL)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(H5O_ATTR_ID != type_id);   /* Attributes are modified in another routine */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Call the "real" remove routine */
    if((ret_value = H5O_msg_remove_real(loc, type, sequence, NULL, NULL, adj_link, dxpl_id)) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "unable to remove object header message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_remove() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_remove_op
 *
 * Purpose:	Removes messages from the object header that a callback
 *              routine indicates should be removed.
 *
 *		No attempt is made to join adjacent free areas of the
 *		object header into a single larger free area.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep  6 2005
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_remove_op(const H5O_loc_t *loc, unsigned type_id, int sequence,
    H5O_operator_t op, void *op_data, hbool_t adj_link, hid_t dxpl_id)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    herr_t      ret_value;              /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_remove_op, FAIL)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(H5O_ATTR_ID != type_id);   /* Attributes are modified in another routine */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Call the "real" remove routine */
    if((ret_value = H5O_msg_remove_real(loc, type, sequence, op, op_data, adj_link, dxpl_id)) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "unable to remove object header message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_remove_op() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_remove_cb
 *
 * Purpose:	Object header iterator callback routine to remove messages
 *              of a particular type that match a particular sequence number,
 *              or all messages if the sequence number is H5O_ALL (-1).
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep  6 2005
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_msg_remove_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, unsigned sequence,
    unsigned *oh_flags_ptr, void *_udata/*in,out*/)
{
    H5O_iter_rm_t *udata = (H5O_iter_rm_t *)_udata;   /* Operator user data */
    htri_t try_remove = FALSE;         /* Whether to try removing a message */
    herr_t ret_value = H5_ITER_CONT;   /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_remove_cb)

    /* check args */
    HDassert(mesg);

    /* Check for callback routine */
    if(udata->op) {
        /* Call the iterator callback */
        if((try_remove = (udata->op)(mesg->native, sequence, udata->op_data)) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, H5_ITER_ERROR, "object header message deletion callback failed")
    } /* end if */
    else {
        /* If there's no callback routine, does the sequence # match? */
        if((int)sequence == udata->sequence || H5O_ALL == udata->sequence)
            try_remove = TRUE;
    } /* end else */

    /* Try removing the message, if indicated */
    if(try_remove) {
        /*
         * Keep track of how many times we failed trying to remove constant
         * messages.
         */
        if(mesg->flags & H5O_MSG_FLAG_CONSTANT)
            udata->nfailed++;
        else {
            /* Convert message into a null message */
            if(H5O_release_mesg(udata->f, udata->dxpl_id, oh, mesg, TRUE, udata->adj_link) < 0)
                HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, H5_ITER_ERROR, "unable to convert into null message")

            /* Indicate that the object header was modified */
            *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
        } /* end else */

        /* Break out now, if we've found the correct message */
        if(udata->sequence == H5O_FIRST || udata->sequence != H5O_ALL)
            HGOTO_DONE(H5_ITER_STOP)
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_remove_cb() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_remove_real
 *
 * Purpose:	Removes the specified message from the object header.
 *		If sequence is H5O_ALL (-1) then all messages of the
 *		specified type are removed.  Removing a message causes
 *		the sequence numbers to change for subsequent messages of
 *		the same type.
 *
 *		No attempt is made to join adjacent free areas of the
 *		object header into a single larger free area.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug 28 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_msg_remove_real(const H5O_loc_t *loc, const H5O_msg_class_t *type, int sequence,
    H5O_operator_t app_op, void *op_data, hbool_t adj_link, hid_t dxpl_id)
{
    H5O_t *oh = NULL;                   /* Pointer to actual object header */
    unsigned oh_flags = H5AC__NO_FLAGS_SET;  /* Start iteration with no flags set on object header */
    H5O_iter_rm_t udata;                /* User data for iterator */
    H5O_mesg_operator_t op;             /* Wrapper for operator */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_remove_real)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(type);

    /* Make certain we are allowed to modify the file */
    if(0 == (H5F_INTENT(loc->file) & H5F_ACC_RDWR))
	HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file")

    /* Set up iterator operator data */
    udata.f = loc->file;
    udata.dxpl_id = dxpl_id;
    udata.sequence = sequence;
    udata.nfailed = 0;
    udata.op = app_op;
    udata.op_data = op_data;
    udata.adj_link = adj_link;

    /* Protect the object header to iterate over */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Iterate over the messages, deleting appropriate one(s) */
    op.lib_op = H5O_msg_remove_cb;
    if(H5O_msg_iterate_real(loc->file, oh, type, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "error iterating over messages")

    /* Fail if we tried to remove any constant messages */
    if(udata.nfailed)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to remove constant message(s)")

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
        HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_remove_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_iterate
 *
 * Purpose:	Iterate through object headers of a certain type.
 *
 * Return:	Returns a negative value if something is wrong, the return
 *      value of the last operator if it was non-zero, or zero if all
 *      object headers were processed.
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Nov 19 2004
 *
 * Description:
 *      This function interates over the object headers of an object
 *  specified with 'loc' of type 'type_id'.  For each object header of the
 *  object, the 'op_data' and some additional information (specified below) are
 *  passed to the 'op' function.
 *      The operation receives a pointer to the object header message for the
 *  object being iterated over ('mesg'), and the pointer to the operator data
 *  passed in to H5O_msg_iterate ('op_data').  The return values from an operator
 *  are:
 *      A. Zero causes the iterator to continue, returning zero when all
 *          object headers of that type have been processed.
 *      B. Positive causes the iterator to immediately return that positive
 *          value, indicating short-circuit success.
 *      C. Negative causes the iterator to immediately return that value,
 *          indicating failure.
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_iterate(const H5O_loc_t *loc, unsigned type_id, H5O_operator_t app_op,
    void *op_data, hid_t dxpl_id)
{
    H5O_t *oh = NULL;               /* Pointer to actual object header */
    unsigned oh_flags = H5AC__NO_FLAGS_SET;  /* Start iteration with no flags set on object header */
    const H5O_msg_class_t *type;    /* Actual H5O class type for the ID */
    H5O_mesg_operator_t op;         /* Wrapper for operator */
    herr_t ret_value;               /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_iterate, FAIL)

    /* check args */
    HDassert(loc);
    HDassert(loc->file);
    HDassert(H5F_addr_defined(loc->addr));
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Protect the object header to iterate over */
    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")

    /* Call the "real" iterate routine */
    op.app_op = app_op;
    if((ret_value = H5O_msg_iterate_real(loc->file, oh, type, FALSE, op, op_data, dxpl_id, &oh_flags)) < 0)
        HERROR(H5E_OHDR, H5E_BADITER, "unable to iterate over object header messages");

done:
    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
        HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_iterate() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_iterate_real
 *
 * Purpose:	Iterate through object headers of a certain type.
 *
 * Return:	Returns a negative value if something is wrong, the return
 *      value of the last operator if it was non-zero, or zero if all
 *      object headers were processed.
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep  6 2005
 *
 * Description:
 *      This function interates over the object headers of an object
 *  specified with 'ent' of type 'type_id'.  For each object header of the
 *  object, the 'op_data' and some additional information (specified below) are
 *  passed to the 'op' function.
 *      The operation receives a pointer to the object header message for the
 *  object being iterated over ('mesg'), and the pointer to the operator data
 *  passed in to H5O_msg_iterate ('op_data').  The return values from an operator
 *  are:
 *      A. Zero causes the iterator to continue, returning zero when all
 *          object headers of that type have been processed.
 *      B. Positive causes the iterator to immediately return that positive
 *          value, indicating short-circuit success.
 *      C. Negative causes the iterator to immediately return that value,
 *          indicating failure.
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_iterate_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
    hbool_t internal, H5O_mesg_operator_t op, void *op_data, hid_t dxpl_id,
    unsigned *oh_flags_ptr)
{
    unsigned		idx;            /* Absolute index of current message in all messages */
    unsigned		sequence;       /* Relative index of current message for messages of type */
    H5O_mesg_t         *idx_msg;        /* Pointer to current message */
    void               *native_mesg;    /* Native, readable message */
    hbool_t             native_mesg_alloc = FALSE;  /* True if native_mesg needs to be freed */
    herr_t              ret_value = H5_ITER_CONT;      /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_iterate_real)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(type);
    HDassert(op.app_op);
    HDassert(oh_flags_ptr);

    /* Iterate over messages */
    for(sequence = 0, idx = 0, idx_msg = &oh->mesg[0]; idx < oh->nmesgs && !ret_value; idx++, idx_msg++) {
	if(type->id == idx_msg->type->id) {
            /* Decode the message if necessary.  */
            H5O_LOAD_NATIVE(f, dxpl_id, idx_msg, FAIL)

            /* Check for making an "internal" (i.e. within the H5O package) callback */
            if(internal) {
                /* Call the "internal" iterator callback */
                if((ret_value = (op.lib_op)(oh, idx_msg, sequence, oh_flags_ptr, op_data)) != 0)
                    break;
            } /* end if */
            else {
                /* If the message is shared, get the real message it points to */
                /* JAMES: test */
                if(idx_msg->flags & H5O_MSG_FLAG_SHARED) {
                    if(NULL == (native_mesg = H5O_shared_read(f, dxpl_id,
                                idx_msg->native, idx_msg->type, NULL)))
                        HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "unable to read shared message")
                    native_mesg_alloc = TRUE;
                } /* end if */
                else
                    native_mesg = idx_msg->native;

                /* Call the iterator callback */
                if((ret_value = (op.app_op)(native_mesg, sequence, op_data)) != 0)
                    break;

                /* Free the "real" message if it was allocated */
                if(native_mesg_alloc) {
                    H5O_msg_free(idx_msg->type->id, native_mesg);
                    native_mesg_alloc = FALSE;
                } /* end if */
            } /* end else */

            /* Increment sequence value for message type */
            sequence++;
        } /* end if */
    } /* end for */

    /* Check for error from iterator */
    if(ret_value < 0)
        HERROR(H5E_OHDR, H5E_CANTLIST, "iterator function failed");

done:
    /* Free the native message if it was allocated */
    if(native_mesg_alloc)
        H5O_msg_free(idx_msg->type->id, native_mesg);

    /* Check if object message was modified */
    if(*oh_flags_ptr & H5AC__DIRTIED_FLAG) {
        /* Try to condense object header info */
        /* (Since this routine is used to remove messages from an
         *  object header, the header will be condensed after each
         *  message removal)
         */
        if(H5O_condense_header(f, oh, dxpl_id) < 0)
            HDONE_ERROR(H5E_OHDR, H5E_CANTPACK, FAIL, "can't pack object header")

        if(H5O_touch_oh(f, dxpl_id, oh, FALSE, oh_flags_ptr) < 0)
            HDONE_ERROR(H5E_OHDR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_iterate_real() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_raw_size
 *
 * Purpose:	Call the 'raw_size' method for a
 *              particular class of object header.
 *
 * Return:	Size of message on success, 0 on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Feb 13 2003
 *
 *-------------------------------------------------------------------------
 */
size_t
H5O_msg_raw_size(const H5F_t *f, unsigned type_id, const void *mesg)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    size_t      ret_value;       /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_raw_size, 0)

    /* Check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(type->raw_size);
    HDassert(f);
    HDassert(mesg);

    /* Compute the raw data size for the mesg */
    if((ret_value = (type->raw_size)(f, mesg)) == 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOUNT, 0, "unable to determine size of message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_raw_size() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_mesg_size
 *
 * Purpose:	Calculate the final size of an encoded message in an object
 *              header.
 *
 * Note:	This routine assumes that the message size will be used in the
 *              creation of a new object header.
 *
 * Return:	Size of message on success, 0 on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep  6 2005
 *
 *-------------------------------------------------------------------------
 */
size_t
H5O_msg_mesg_size(const H5F_t *f, unsigned type_id, const void *mesg, size_t extra_raw)
{
    const H5O_msg_class_t *type;            /* Actual H5O class type for the ID */
    size_t      ret_value;       /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_mesg_size, 0)

    /* Check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(type->raw_size);
    HDassert(f);
    HDassert(mesg);

    /* Compute the raw data size for the mesg */
    if((ret_value = (type->raw_size)(f, mesg)) == 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOUNT, 0, "unable to determine size of message")

    /* Add in "extra" raw space */
    ret_value += extra_raw;

    /* Adjust size for alignment, if necessary */
    ret_value = H5O_ALIGN_F(f, ret_value);

    /* Add space for message header */
    ret_value += H5O_SIZEOF_MSGHDR_F(f);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_mesg_size() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_get_share
 *
 * Purpose:	Call the 'get_share' method for a
 *              particular class of object header.  Fills SHARE
 *              with the shared object, or allocated an H5O_shared_t
 *              message and returns it.
 *
 *              If SHARE is NULL, the return value must be freed
 *              with H5O_msg_free.
 *
 * Return:	Success:	H5O_shared_t describing the shared information
 *                              for the message.
 *
 *		Failure:	NULL
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Oct  2 2003
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_get_share(unsigned type_id, const void *mesg, H5O_shared_t *share)
{
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    void  *ret_value;                   /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_get_share, NULL)

    /* Check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(type->get_share);
    HDassert(mesg);

    /* Get shared data for the mesg */
    if((ret_value = (type->get_share)(mesg, share)) == NULL)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, NULL, "unable to retrieve shared message information")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_get_share() */


/*-------------------------------------------------------------------------
 * Function:    H5O_msg_is_shared
 *
 * Purpose:     Call the 'is_shared' method for a
 *              particular class of object header.
 *
 * Return:      Object is shared:        TRUE
 *              Object is not shared:    FALSE
 *
 * Programmer:  James Laird
 *              jlaird@ncsa.uiuc.edu
 *              April 5 2006
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5O_msg_is_shared(unsigned type_id, const void *mesg)
{
    const H5O_msg_class_t *type;    /* Actual H5O class type for the ID */
    htri_t ret_value;

    FUNC_ENTER_NOAPI_NOFUNC(H5O_msg_is_shared)

    /* Check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(mesg);

    HDassert(type_id != H5O_SHARED_ID); /* JAMES: check for this mistake elsewhere, too */

    /* If there is no is_shared function, then obviously it's not a shared message! */
    if(!(type->is_shared))
        ret_value = FALSE;
    else
        ret_value = (type->is_shared)(mesg);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_is_shared() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_set_share
 *
 * Purpose:	Set the shared information for an object header message.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	James Laird
 *		jlaird@hdfgroup.org
 *		November 1 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_set_share(unsigned type_id, H5O_shared_t *share, void *mesg)
{
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    herr_t ret_value;                   /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_set_share, FAIL)

    /* Check args */
    HDassert(share);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(type->set_share);
    HDassert(mesg);
    HDassert(share->flags != H5O_NOT_SHARED);

    /* Set this message as the shared message for the message, wiping out
     * any information that was there before
     */
    if((ret_value = (type->set_share)(mesg, share)) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "unable to set shared message information")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_set_share() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_reset_share
 *
 * Purpose:	Reset the shared information for an object header message.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	James Laird
 *		jlaird@hdfgroup.org
 *		Oct 17 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_reset_share(unsigned type_id, void *mesg)
{
    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
    H5O_shared_t sh_mesg;               /* Shared message */
    herr_t ret_value;                   /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_reset_share, FAIL)

    /* Check args */
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);
    HDassert(type->set_share);
    HDassert(mesg);

    /* Initialize the shared message to zero. */
    HDmemset(&sh_mesg, 0, sizeof(H5O_shared_t));

    /* Set this message as the shared message for the message, wiping out
     * any information that was there before
     */
    if((ret_value = (type->set_share)(mesg, &sh_mesg)) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "unable to reset shared message information")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_reset_share() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_encode
 *
 * Purpose:	Encode an object(data type and simple data space only)
 *              description into a buffer.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Raymond Lu
 *		slu@ncsa.uiuc.edu
 *		July 13, 2004
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_encode(H5F_t *f, unsigned type_id, unsigned char *buf, const void *mesg)
{
    const H5O_msg_class_t   *type;      /* Actual H5O class type for the ID */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_encode,FAIL)

    /* check args */
    HDassert(f);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* Encode */
    if((type->encode)(f, buf, mesg) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTENCODE, FAIL, "unable to encode message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_encode() */


/*-------------------------------------------------------------------------
 * Function:	H5O_msg_decode
 *
 * Purpose:	Decode a binary object description and return a new
 *              object handle.
 *
 * Note:	This routine is not guaranteed to work with all possible
 *              header messages, use with care.
 *
 * Return:	Success:        Pointer to object(data type or space)
 *
 *		Failure:	NULL
 *
 * Programmer:	Raymond Lu
 *		slu@ncsa.uiuc.edu
 *		July 14, 2004
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_decode(H5F_t *f, hid_t dxpl_id, unsigned type_id, const unsigned char *buf)
{
    const H5O_msg_class_t   *type;      /* Actual H5O class type for the ID */
    void *ret_value;                    /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_decode, NULL)

    /* check args */
    HDassert(f);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* decode */
    if((ret_value = (type->decode)(f, dxpl_id, buf)) == NULL)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, NULL, "unable to decode message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_decode() */


/*-------------------------------------------------------------------------
 * Function:    H5O_msg_copy_file
 *
 * Purpose:     Copies a message to file.  If MESG is is the null pointer then a null
 *              pointer is returned with no error.
 *
 *              Attempts to share the message in the destination and sets
 *              SHARED to TRUE or FALSE depending on whether this succeeds.
 *
 * Return:      Success:        Ptr to the new message
 *
 *              Failure:        NULL
 *
 * Programmer:  Peter Cao
 *              June 4, 2005
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_msg_copy_file(const H5O_msg_class_t *copy_type, const H5O_msg_class_t *mesg_type, H5F_t *file_src, void *native_src,
    H5F_t *file_dst, hid_t dxpl_id, hbool_t *shared, H5O_copy_t *cpy_info, void *udata)
{
    void        *native_mesg=NULL;
    void        *shared_mesg=NULL;
    hbool_t      committed;         /* TRUE if message is a committed message */
    htri_t       try_share_ret;     /* Value returned from H5SM_try_share */
    void        *ret_value;

    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_copy_file)

    /* check args */
    HDassert(copy_type);
    HDassert(mesg_type);
    HDassert(copy_type->copy_file);
    HDassert(file_src);
    HDassert(native_src);
    HDassert(file_dst);
    HDassert(cpy_info);

    /* Check if this message is committed.  We'll need to know this later. */
    committed = FALSE;
    if(copy_type->id == H5O_SHARED_ID) {
        H5O_shared_t *tmp_shared_mesg = (H5O_shared_t *) native_src;

        if( tmp_shared_mesg->flags & H5O_COMMITTED_FLAG) {
            HDassert(!(tmp_shared_mesg->flags & H5O_SHARED_IN_HEAP_FLAG));
            committed = TRUE;
        } /* end if */
    } /* end if */

    /* The copy_file callback will return an H5O_shared_t only if the message
     * to be copied is a committed datatype.
     */
    if(NULL == (native_mesg = (copy_type->copy_file)(file_src, mesg_type, native_src, file_dst, dxpl_id, cpy_info, udata)))
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy object header message to file")

    /* Committed messages are always committed in the destination.  Messages in
     * the heap are not shared by default--they need to be "re-shared" in the
     * destination.
     */
    if(committed == TRUE)
        *shared = TRUE;
    else
        *shared = FALSE;

    /* If message isn't committed but can be shared, handle with implicit sharing. */
    if(committed == FALSE && (mesg_type->set_share)) {
        /* Try to share it in the destination file. */
        if((try_share_ret = H5SM_try_share(file_dst, dxpl_id, mesg_type->id, native_mesg)) < 0)
            HGOTO_ERROR(H5E_SOHM, H5E_WRITEERROR, NULL, "unable to determine if message should be shared")

        /* If it isn't shared, reset its sharing information.  If it is
         * shared, its sharing information will have been overwritten by
         * H5SM_try_share.
         */
        if(try_share_ret == FALSE) {
            if(H5O_msg_reset_share(mesg_type->id, native_mesg) < 0)
                HGOTO_ERROR(H5E_SOHM, H5E_WRITEERROR, NULL, "unable to reset sharing information in message")
        }
        else {
            /* Get shared message from native message */
            if(NULL == (shared_mesg = H5O_msg_get_share(mesg_type->id, native_mesg, NULL)))
                HGOTO_ERROR(H5E_SOHM, H5E_READERROR, NULL, "unable to get shared location from message")

            /* Free native message; the shared message is all we need to return */
            H5O_msg_free(mesg_type->id, native_mesg);

            native_mesg = shared_mesg;
            *shared = TRUE;
        }
    }

    ret_value = native_mesg;

done:
    if(NULL == ret_value)
        H5O_msg_free(mesg_type->id, native_mesg);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_copy_file() */


/*-------------------------------------------------------------------------
 * Function:	H5O_new_mesg
 *
 * Purpose:	Create a new message in an object header
 *
 * Return:	Success:	Index of message
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              Friday, September  3, 2003
 *
 *-------------------------------------------------------------------------
 */
static unsigned
H5O_new_mesg(H5F_t *f, H5O_t *oh, unsigned *mesg_flags, const H5O_msg_class_t *orig_type,
    const void *orig_mesg, H5O_shared_t *sh_mesg, const H5O_msg_class_t **new_type,
    const void **new_mesg, hid_t dxpl_id, unsigned *oh_flags_ptr)
{
    size_t	size;                   /* Size of space allocated for object header */
    htri_t      is_shared;              /* Is this a shared message? */
    unsigned    ret_value = UFAIL;      /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_new_mesg)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(mesg_flags);
    HDassert(orig_type);
    HDassert(orig_mesg);
    HDassert(sh_mesg);
    HDassert(new_type);
    HDassert(new_mesg);
    HDassert(oh_flags_ptr);

    /* Check for shared message */
    if(*mesg_flags & H5O_MSG_FLAG_SHARED) {
        if((NULL == orig_type->is_shared) || (NULL == orig_type->get_share))
            HGOTO_ERROR(H5E_OHDR, H5E_UNSUPPORTED, UFAIL, "message class is not sharable")
        if((is_shared = (orig_type->is_shared)(orig_mesg)) == FALSE) {
            /*
             * If the message isn't shared then turn off the shared bit
             * and treat it as an unshared message.
             */
            *mesg_flags &= ~H5O_MSG_FLAG_SHARED;
            *new_type = orig_type;
            *new_mesg = orig_mesg;
        } else if(is_shared > 0) {
            /* Message is shared. Get shared message, change message type,
             * and use shared information */
            HDmemset(sh_mesg, 0, sizeof(H5O_shared_t));
            if(NULL == (orig_type->get_share)(orig_mesg, sh_mesg/*out*/))
                HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, UFAIL, "can't get shared message")

            *new_type = H5O_MSG_SHARED;
            *new_mesg = sh_mesg;
        } else {
            HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, UFAIL, "can't determine if message is shared")
        } /* end else */
    } /* end if */
    else {
        *new_type = orig_type;
        *new_mesg = orig_mesg;
    } /* end else */

    /* Compute the size needed to store the message on disk */
    if((size = ((*new_type)->raw_size)(f, *new_mesg)) >= H5O_MESG_MAX_SIZE)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, UFAIL, "object header message is too large")

    /* Allocate space in the object header for the message */
    if((ret_value = H5O_alloc(f, dxpl_id, oh, orig_type, size, oh_flags_ptr)) == UFAIL)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, UFAIL, "unable to allocate space for message")

    /* Increment any links in message */
    if((*new_type)->link && ((*new_type)->link)(f, dxpl_id, (*new_mesg)) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_LINKCOUNT, UFAIL, "unable to adjust shared object link count")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_new_mesg() */


/*-------------------------------------------------------------------------
 * Function:	H5O_write_mesg
 *
 * Purpose:	Write message to object header
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *              Friday, September  3, 2003
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_write_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx,
    const H5O_msg_class_t *type, const void *mesg, unsigned mesg_flags,
    unsigned update_flags, unsigned *oh_flags_ptr)
{
    H5O_mesg_t         *idx_msg;        /* Pointer to message to modify */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_write_mesg)

    /* check args */
    HDassert(f);
    HDassert(oh);
    HDassert(type);
    HDassert(mesg);
    HDassert(oh_flags_ptr);

    /* Set pointer to the correct message */
    idx_msg = &oh->mesg[idx];

    /* Reset existing native information */
    H5O_msg_reset_real(type, idx_msg->native);

    /* Copy the native value for the message */
    if(NULL == (idx_msg->native = (type->copy)(mesg, idx_msg->native)))
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to copy message to object header")

    /* Update the message flags and mark the message as modified */
    idx_msg->flags = mesg_flags;
    idx_msg->dirty = TRUE;

    /* Update the modification time, if requested */
    if(update_flags & H5O_UPDATE_TIME)
        if(H5O_touch_oh(f, dxpl_id, oh, FALSE, oh_flags_ptr) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTUPDATE, FAIL, "unable to update time on object")

    /* Mark the object header as modified */
    *oh_flags_ptr |= H5AC__DIRTIED_FLAG;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_write_mesg() */


/*-------------------------------------------------------------------------
 * Function:    H5O_msg_delete
 *
 * Purpose:     Calls a message's delete callback.
 *
 *              JAMES: this is mostly redundant with H5O_delete_mesg below,
 *              but H5O_delete_mesg only works on messages in object headers
 *              (i.e., not shared messages).
 *
 * Return:      Success:        Non-negative
 *              Failure:        Negative
 *
 * Programmer:  James Laird
 *              December 21, 2006
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_msg_delete(H5F_t *f, hid_t dxpl_id, unsigned type_id, const void *mesg)
{
    const H5O_msg_class_t   *type;      /* Actual H5O class type for the ID */
    herr_t ret_value = SUCCEED;                    /* Return value */

    FUNC_ENTER_NOAPI(H5O_msg_delete, NULL)

    /* check args */
    HDassert(f);
    HDassert(type_id < NELMTS(H5O_msg_class_g));
    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
    HDassert(type);

    /* delete */
    if((type->del) && (type->del)(f, dxpl_id, mesg, 1) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "unable to delete file space for object header message")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_msg_delete() */


/*-------------------------------------------------------------------------
 * Function:	H5O_delete_mesg
 *
 * Purpose:	Internal function to:
 *              Delete an object header message from a file.  This frees the file
 *              space used for anything referred to in the object header message.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		September 26 2003
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5O_delete_mesg(H5F_t *f, hid_t dxpl_id, H5O_mesg_t *mesg, hbool_t adj_link)
{
    const H5O_msg_class_t *type;  /* Type of object to free */
    herr_t ret_value = SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(H5O_delete_mesg, FAIL)

    /* Check args */
    HDassert(f);
    HDassert(mesg);

    /* Get the message to free's type */
    if(mesg->flags & H5O_MSG_FLAG_SHARED)
        type = H5O_MSG_SHARED;
    else
        type = mesg->type;

    /* Check if there is a file space deletion callback for this type of message */
    if(type->del) {
        /* Decode the message if necessary. */
        if(NULL == mesg->native) {
            HDassert(type->decode);
            if(NULL == (mesg->native = (type->decode)(f, dxpl_id, mesg->raw)))
                HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, FAIL, "unable to decode message")
        } /* end if */

        /* Check if this message needs to be removed from the SOHM table */
        /* JAMES: there should be a callback, maybe in H5O_shared_delete, to fiddle w/ the ref. count.
        * We shouldn't need to do a search in the SOHM table on delete. */
        if(type == H5O_MSG_SHARED) {
            /* The native message here is actually a shared message.    */
            if(H5SM_try_delete(f, dxpl_id, mesg->type->id, mesg->native) < 0)
                HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")
        } /* end if */

        if((type->del)(f, dxpl_id, mesg->native, adj_link) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "unable to delete file space for object header message")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_delete_msg() */