summaryrefslogtreecommitdiffstats
path: root/src/H5VMprivate.h
blob: 1f94f0e70ad4e769d46b0162ff3d54652e5b1d84 (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
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer: Robb Matzke
 *             Friday, October 10, 1997
 */
#ifndef H5VMprivate_H
#define H5VMprivate_H

/* Private headers needed by this file */
#include "H5private.h"   /* Generic Functions            */
#include "H5Eprivate.h"  /* Error handling              */
#include "H5MMprivate.h" /* Memory management            */

/* Vector-Vector sequence operation callback */
typedef herr_t (*H5VM_opvv_func_t)(hsize_t dst_off, hsize_t src_off, size_t len, void *udata);

/* Vector comparison functions like Fortran66 comparison operators */
#define H5VM_vector_eq_s(N, V1, V2) (H5VM_vector_cmp_s(N, V1, V2) == 0)
#define H5VM_vector_lt_s(N, V1, V2) (H5VM_vector_cmp_s(N, V1, V2) < 0)
#define H5VM_vector_gt_s(N, V1, V2) (H5VM_vector_cmp_s(N, V1, V2) > 0)
#define H5VM_vector_le_s(N, V1, V2) (H5VM_vector_cmp_s(N, V1, V2) <= 0)
#define H5VM_vector_ge_s(N, V1, V2) (H5VM_vector_cmp_s(N, V1, V2) >= 0)
#define H5VM_vector_eq_u(N, V1, V2) (H5VM_vector_cmp_u(N, V1, V2) == 0)
#define H5VM_vector_lt_u(N, V1, V2) (H5VM_vector_cmp_u(N, V1, V2) < 0)
#define H5VM_vector_gt_u(N, V1, V2) (H5VM_vector_cmp_u(N, V1, V2) > 0)
#define H5VM_vector_le_u(N, V1, V2) (H5VM_vector_cmp_u(N, V1, V2) <= 0)
#define H5VM_vector_ge_u(N, V1, V2) (H5VM_vector_cmp_u(N, V1, V2) >= 0)

/* Other functions */
#define H5VM_vector_cpy(N, DST, SRC)                                                                         \
    {                                                                                                        \
        HDassert(sizeof(*(DST)) == sizeof(*(SRC)));                                                          \
        if (SRC)                                                                                             \
            H5MM_memcpy(DST, SRC, (N) * sizeof(*(DST)));                                                     \
        else                                                                                                 \
            HDmemset(DST, 0, (N) * sizeof(*(DST)));                                                          \
    }

#define H5VM_vector_zero(N, DST) HDmemset(DST, 0, (N) * sizeof(*(DST)))

/* Given a coordinate offset array (COORDS) of type TYPE, move the unlimited
 * dimension (UNLIM_DIM) value to offset 0, sliding any intermediate values down
 * one position. */
#define H5VM_swizzle_coords(TYPE, COORDS, UNLIM_DIM)                                                         \
    {                                                                                                        \
        /* COORDS must be an array of type TYPE */                                                           \
        HDassert(sizeof(COORDS[0]) == sizeof(TYPE));                                                         \
                                                                                                             \
        /* Nothing to do when unlimited dimension is at position 0 */                                        \
        if (0 != (UNLIM_DIM)) {                                                                              \
            TYPE _tmp = (COORDS)[UNLIM_DIM];                                                                 \
                                                                                                             \
            HDmemmove(&(COORDS)[1], &(COORDS)[0], sizeof(TYPE) * (UNLIM_DIM));                               \
            (COORDS)[0] = _tmp;                                                                              \
        } /* end if */                                                                                       \
    }

/* Given a coordinate offset array (COORDS) of type TYPE, move the value at
 * offset 0 to offset of the unlimied dimension (UNLIM_DIM), sliding any
 * intermediate values up one position.  Undoes the "swizzle_coords" operation.
 */
#define H5VM_unswizzle_coords(TYPE, COORDS, UNLIM_DIM)                                                       \
    {                                                                                                        \
        /* COORDS must be an array of type TYPE */                                                           \
        HDassert(sizeof(COORDS[0]) == sizeof(TYPE));                                                         \
                                                                                                             \
        /* Nothing to do when unlimited dimension is at position 0 */                                        \
        if (0 != (UNLIM_DIM)) {                                                                              \
            TYPE _tmp = (COORDS)[0];                                                                         \
                                                                                                             \
            HDmemmove(&(COORDS)[0], &(COORDS)[1], sizeof(TYPE) * (UNLIM_DIM));                               \
            (COORDS)[UNLIM_DIM] = _tmp;                                                                      \
        } /* end if */                                                                                       \
    }

/* A null pointer is equivalent to a zero vector */
#define H5VM_ZERO NULL

H5_DLL hsize_t H5VM_hyper_stride(unsigned n, const hsize_t *size, const hsize_t *total_size,
                                 const hsize_t *offset, hsize_t *stride);
H5_DLL htri_t  H5VM_hyper_eq(unsigned n, const hsize_t *offset1, const hsize_t *size1, const hsize_t *offset2,
                             const hsize_t *size2);
H5_DLL herr_t  H5VM_hyper_fill(unsigned n, const hsize_t *_size, const hsize_t *total_size,
                               const hsize_t *offset, void *_dst, unsigned fill_value);
H5_DLL herr_t  H5VM_hyper_copy(unsigned n, const hsize_t *size, const hsize_t *dst_total_size,
                               const hsize_t *dst_offset, void *_dst, const hsize_t *src_total_size,
                               const hsize_t *src_offset, const void *_src);
H5_DLL herr_t  H5VM_stride_fill(unsigned n, hsize_t elmt_size, const hsize_t *size, const hsize_t *stride,
                                void *_dst, unsigned fill_value);
H5_DLL herr_t H5VM_stride_copy(unsigned n, hsize_t elmt_size, const hsize_t *_size, const hsize_t *dst_stride,
                               void *_dst, const hsize_t *src_stride, const void *_src);
H5_DLL herr_t H5VM_stride_copy_s(unsigned n, hsize_t elmt_size, const hsize_t *_size,
                                 const hssize_t *dst_stride, void *_dst, const hssize_t *src_stride,
                                 const void *_src);
H5_DLL herr_t H5VM_array_fill(void *_dst, const void *src, size_t size, size_t count);
H5_DLL void   H5VM_array_down(unsigned n, const hsize_t *total_size, hsize_t *down);
H5_DLL hsize_t H5VM_array_offset_pre(unsigned n, const hsize_t *acc, const hsize_t *offset);
H5_DLL hsize_t H5VM_array_offset(unsigned n, const hsize_t *total_size, const hsize_t *offset);
H5_DLL herr_t  H5VM_array_calc_pre(hsize_t offset, unsigned n, const hsize_t *down, hsize_t *coords);
H5_DLL herr_t  H5VM_array_calc(hsize_t offset, unsigned n, const hsize_t *total_size, hsize_t *coords);
H5_DLL hsize_t H5VM_chunk_index(unsigned ndims, const hsize_t *coord, const uint32_t *chunk,
                                const hsize_t *down_nchunks);
H5_DLL void H5VM_chunk_scaled(unsigned ndims, const hsize_t *coord, const uint32_t *chunk, hsize_t *scaled);
H5_DLL hsize_t H5VM_chunk_index_scaled(unsigned ndims, const hsize_t *coord, const uint32_t *chunk,
                                       const hsize_t *down_nchunks, hsize_t *scaled);
H5_DLL ssize_t H5VM_opvv(size_t dst_max_nseq, size_t *dst_curr_seq, size_t dst_len_arr[],
                         hsize_t dst_off_arr[], size_t src_max_nseq, size_t *src_curr_seq,
                         size_t src_len_arr[], hsize_t src_off_arr[], H5VM_opvv_func_t op, void *op_data);
H5_DLL ssize_t H5VM_memcpyvv(void *_dst, size_t dst_max_nseq, size_t *dst_curr_seq, size_t dst_len_arr[],
                             hsize_t dst_off_arr[], const void *_src, size_t src_max_nseq,
                             size_t *src_curr_seq, size_t src_len_arr[], hsize_t src_off_arr[]);

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_reduce_product
 *
 * Purpose:     Product reduction of a vector.  Vector elements and return
 *              value are size_t because we usually want the number of
 *              elements in an array and array dimensions are always of type
 *              size_t.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Success:        Product of elements
 *
 *              Failure:        1 if N is zero
 *
 * Programmer:  Robb Matzke
 *              Friday, October 10, 1997
 *
 *-------------------------------------------------------------------------
 */
static inline hsize_t H5_ATTR_UNUSED
H5VM_vector_reduce_product(unsigned n, const hsize_t *v)
{
    hsize_t ret_value = 1;

    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (n && !v)
        HGOTO_DONE(0)
    while (n--)
        ret_value *= *v++;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_zerop_u
 *
 * Purpose:     Determines if all elements of a vector are zero.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Success:        TRUE if all elements are zero,
 *                              FALSE otherwise
 *
 *              Failure:        TRUE if N is zero
 *
 * Programmer:  Robb Matzke
 *              Friday, October 10, 1997
 *
 *-------------------------------------------------------------------------
 */
static inline htri_t H5_ATTR_UNUSED
H5VM_vector_zerop_u(int n, const hsize_t *v)
{
    htri_t ret_value = TRUE; /* Return value */

    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (!v)
        HGOTO_DONE(TRUE)
    while (n--)
        if (*v++)
            HGOTO_DONE(FALSE)

done:
    FUNC_LEAVE_NOAPI(ret_value)
}

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_zerop_s
 *
 * Purpose:     Determines if all elements of a vector are zero.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Success:        TRUE if all elements are zero,
 *                              FALSE otherwise
 *
 *              Failure:        TRUE if N is zero
 *
 * Programmer:  Robb Matzke
 *              Friday, October 10, 1997
 *
 *-------------------------------------------------------------------------
 */
static inline htri_t H5_ATTR_UNUSED
H5VM_vector_zerop_s(int n, const hssize_t *v)
{
    htri_t ret_value = TRUE; /* Return value */

    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (!v)
        HGOTO_DONE(TRUE)
    while (n--)
        if (*v++)
            HGOTO_DONE(FALSE)

done:
    FUNC_LEAVE_NOAPI(ret_value)
}

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_cmp_u
 *
 * Purpose:     Compares two vectors of the same size and determines if V1 is
 *              lexicographically less than, equal, or greater than V2.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Success:        -1 if V1 is less than V2
 *                              0 if they are equal
 *                              1 if V1 is greater than V2
 *
 *              Failure:        0 if N is zero
 *
 * Programmer:  Robb Matzke
 *              Friday, October 10, 1997
 *
 *-------------------------------------------------------------------------
 */
static inline int H5_ATTR_UNUSED
H5VM_vector_cmp_u(unsigned n, const hsize_t *v1, const hsize_t *v2)
{
    int ret_value = 0; /* Return value */

    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (v1 == v2)
        HGOTO_DONE(0)
    if (v1 == NULL)
        HGOTO_DONE(-1)
    if (v2 == NULL)
        HGOTO_DONE(1)
    while (n--) {
        if (*v1 < *v2)
            HGOTO_DONE(-1)
        if (*v1 > *v2)
            HGOTO_DONE(1)
        v1++;
        v2++;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_cmp_s
 *
 * Purpose:     Compares two vectors of the same size and determines if V1 is
 *              lexicographically less than, equal, or greater than V2.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Success:        -1 if V1 is less than V2
 *                              0 if they are equal
 *                              1 if V1 is greater than V2
 *
 *              Failure:        0 if N is zero
 *
 * Programmer:  Robb Matzke
 *              Wednesday, April  8, 1998
 *
 *-------------------------------------------------------------------------
 */
static inline int H5_ATTR_UNUSED
H5VM_vector_cmp_s(unsigned n, const hssize_t *v1, const hssize_t *v2)
{
    int ret_value = 0; /* Return value */

    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (v1 == v2)
        HGOTO_DONE(0)
    if (v1 == NULL)
        HGOTO_DONE(-1)
    if (v2 == NULL)
        HGOTO_DONE(1)
    while (n--) {
        if (*v1 < *v2)
            HGOTO_DONE(-1)
        if (*v1 > *v2)
            HGOTO_DONE(1)
        v1++;
        v2++;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}

/*-------------------------------------------------------------------------
 * Function:    H5VM_vector_inc
 *
 * Purpose:     Increments V1 by V2
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              Monday, October 13, 1997
 *
 *-------------------------------------------------------------------------
 */
static inline void H5_ATTR_UNUSED
H5VM_vector_inc(int n, hsize_t *v1, const hsize_t *v2)
{
    while (n--)
        *v1++ += *v2++;
}

/* Lookup table for general log2(n) routine */
static const unsigned char LogTable256[] = {
    /* clang-clang-format off */
    0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5,
    5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6,
    6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
    6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
    /* clang-clang-format on */
};

/*-------------------------------------------------------------------------
 * Function:    H5VM_log2_gen
 *
 * Purpose:     Determines the log base two of a number (i.e. log2(n)).
 *              (i.e. the highest bit set in a number)
 *
 * Note:        This is from the "Bit Twiddling Hacks" at:
 *                  http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
 *
 *              The version on the web-site is for 32-bit quantities and this
 *              version has been extended for 64-bit quantities.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      log2(n) (always - no failure condition)
 *
 * Programmer:  Quincey Koziol
 *              Monday, March  6, 2006
 *
 *-------------------------------------------------------------------------
 */
static inline unsigned H5_ATTR_UNUSED
H5VM_log2_gen(uint64_t n)
{
    unsigned     r;          /* r will be log2(n) */
    unsigned int t, tt, ttt; /* temporaries */

    if ((ttt = (unsigned)(n >> 32)))
        if ((tt = (unsigned)(n >> 48)))
            r = (t = (unsigned)(n >> 56)) ? 56 + (unsigned)LogTable256[t]
                                          : 48 + (unsigned)LogTable256[tt & 0xFF];
        else
            r = (t = (unsigned)(n >> 40)) ? 40 + (unsigned)LogTable256[t]
                                          : 32 + (unsigned)LogTable256[ttt & 0xFF];
    else if ((tt = (unsigned)(n >> 16)))
        r = (t = (unsigned)(n >> 24)) ? 24 + (unsigned)LogTable256[t] : 16 + (unsigned)LogTable256[tt & 0xFF];
    else
        /* Added 'uint8_t' cast to pacify PGCC compiler */
        r = (t = (unsigned)(n >> 8)) ? 8 + (unsigned)LogTable256[t] : (unsigned)LogTable256[(uint8_t)n];

    return (r);
} /* H5VM_log2_gen() */

/* Lookup table for specialized log2(n) of power of two routine */
static const unsigned MultiplyDeBruijnBitPosition[32] = {0,  1,  28, 2,  29, 14, 24, 3,  30, 22, 20,
                                                         15, 25, 17, 4,  8,  31, 27, 13, 23, 21, 19,
                                                         16, 7,  26, 12, 18, 6,  11, 5,  10, 9};

/*-------------------------------------------------------------------------
 * Function:    H5VM_log2_of2
 *
 * Purpose:     Determines the log base two of a number (i.e. log2(n)).
 *              (i.e. the highest bit set in a number)
 *
 * Note:        **N must be a power of two** and is limited to 32-bit quantities.
 *
 *              This is from the "Bit Twiddling Hacks" at:
 *                  http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      log2(n) (always - no failure condition)
 *
 * Programmer:  Quincey Koziol
 *              Monday, February 27, 2006
 *
 *-------------------------------------------------------------------------
 */
static inline H5_ATTR_PURE unsigned
H5VM_log2_of2(uint32_t n)
{
#ifndef NDEBUG
    HDassert(POWER_OF_TWO(n));
#endif /* NDEBUG */
    return (MultiplyDeBruijnBitPosition[(n * (uint32_t)0x077CB531UL) >> 27]);
} /* H5VM_log2_of2() */

/*-------------------------------------------------------------------------
 * Function:    H5VM_power2up
 *
 * Purpose:    Round up a number to the next power of 2
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:    Return the number which is a power of 2
 *
 * Programmer:    Vailin Choi; Nov 2014
 *
 *-------------------------------------------------------------------------
 */
static inline H5_ATTR_CONST hsize_t
H5VM_power2up(hsize_t n)
{
    hsize_t ret_value = 1; /* Return value */

    /* Returns 0 when n exceeds 2^63 */
    if (n >= (hsize_t)1 << ((sizeof(hsize_t) * CHAR_BIT) - 1))
        ret_value = 0;

    while (ret_value && ret_value < n)
        ret_value <<= 1;

    return (ret_value);
} /* H5VM_power2up */

/*-------------------------------------------------------------------------
 * Function:    H5VM_limit_enc_size
 *
 * Purpose:     Determine the # of bytes needed to encode values within a
 *              range from 0 to a given limit
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      Number of bytes needed
 *
 * Programmer:  Quincey Koziol
 *              Thursday, March 13, 2008
 *
 *-------------------------------------------------------------------------
 */
static inline unsigned H5_ATTR_UNUSED
H5VM_limit_enc_size(uint64_t limit)
{
    return (H5VM_log2_gen(limit) / 8) + 1;
} /* end H5VM_limit_enc_size() */

static const unsigned char H5VM_bit_set_g[8]   = {0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
static const unsigned char H5VM_bit_clear_g[8] = {0x7F, 0xBF, 0xDF, 0xEF, 0xF7, 0xFB, 0xFD, 0xFE};

/*-------------------------------------------------------------------------
 * Function:    H5VM_bit_get
 *
 * Purpose:     Determine the value of the n'th bit in a buffer.
 *
 * Note:        No range checking on <offset> is performed!
 *
 * Note #2:     Bits are sequentially stored in the buffer, starting with bit
 *              offset 0 in the first byte's high-bit position, proceeding down
 *              to bit offset 7 in the first byte's low-bit position, then to
 *              bit offset 8 in the second byte's high-bit position, etc.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      TRUE/FALSE
 *
 * Programmer:  Quincey Koziol
 *              Tuesday, November 25, 2008
 *
 *-------------------------------------------------------------------------
 */
static inline hbool_t H5_ATTR_UNUSED
H5VM_bit_get(const unsigned char *buf, size_t offset)
{
    /* Test the appropriate bit in the buffer */
    return (hbool_t)((buf[offset / 8] & (H5VM_bit_set_g[offset % 8])) ? TRUE : FALSE);
} /* end H5VM_bit_get() */

/*-------------------------------------------------------------------------
 * Function:    H5VM_bit_set
 *
 * Purpose:     Set/reset the n'th bit in a buffer.
 *
 * Note:        No range checking on <offset> is performed!
 *
 * Note #2:     Bits are sequentially stored in the buffer, starting with bit
 *              offset 0 in the first byte's high-bit position, proceeding down
 *              to bit offset 7 in the first byte's low-bit position, then to
 *              bit offset 8 in the second byte's high-bit position, etc.
 *
 * Note:        Although this routine is 'static' in this file, that's intended
 *              only as an optimization and the naming (with a single underscore)
 *              reflects its inclusion in a "private" header file.
 *
 * Return:      None
 *
 * Programmer:  Quincey Koziol
 *              Tuesday, November 25, 2008
 *
 *-------------------------------------------------------------------------
 */
static inline void H5_ATTR_UNUSED
H5VM_bit_set(unsigned char *buf, size_t offset, hbool_t val)
{
    /* Set/reset the appropriate bit in the buffer */
    if (val)
        buf[offset / 8] |= H5VM_bit_set_g[offset % 8];
    else
        buf[offset / 8] &= H5VM_bit_clear_g[offset % 8];
} /* end H5VM_bit_set() */

#endif /* H5VMprivate_H */