summaryrefslogtreecommitdiffstats
path: root/src/H5detect.c
blob: b8e6fb959894de8bf839a60a20942c8eb9ed94dd (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
/**/
static const char *FileHeader = "\n\
/*-------------------------------------------------------------------------\n\
 * Copyright (C) 1997   National Center for Supercomputing Applications.   \n\
 *                      All rights reserved.                               \n\
 *                                                                         \n\
 *-------------------------------------------------------------------------";
/*
 *
 * Created:     H5detect.c
 *              10 Aug 1997
 *              Robb Matzke
 *
 * Purpose:     This code was borrowed heavily from the `detect.c'
 *              program in the AIO distribution from Lawrence
 *              Livermore National Laboratory.
 *
 *              Detects machine byte order and floating point
 *              format and generates a C source file (native.c)
 *              to describe those paramters.
 *
 * Assumptions: We have an ANSI compiler.  We're on a Unix like
 *              system or configure has detected those Unix
 *              features which aren't available.  We're not
 *              running on a Vax or other machine with mixed
 *              endianess.
 *              
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */

#include <assert.h>
#include <math.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>

#define MAXDETECT 16

#ifndef MIN
#  define MIN(X,Y) ((X)<(Y)?(X):(Y))
#endif

/*
 * This structure holds information about a type that
 * was detected.
 */
typedef struct detected_t {
    const char          *varname;
    int                 size;
    int                 padding;
    int                 perm[32];
    int                 sign;
    int                 mpos, msize, imp;
    int                 epos, esize;
    unsigned long	bias;
} detected_t;

static void print_results(int nd, detected_t *d);
static void iprint(detected_t *);
static void print_known_formats(detected_t *);
static int byte_cmp(int, void *, void *);
static int bit_cmp(int, int *, void *, void *);
static void fix_order(int, int, int, int *, const char **);
static void fix_padding(detected_t *);
static int imp_bit(int, int *, void *, void *);
static unsigned long find_bias(int, int, int, int *, void *);
static void print_header(void);

/*-------------------------------------------------------------------------
 * For convenience, we place here in a table descriptions of all
 * architectures we've seen so far.  That way we can print a description
 * of the system on which the program is run.  We place the system name
 * in the VARNAME field.
 *-------------------------------------------------------------------------
 */
#define LE {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,                            \
     16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31}
#define LE_1 LE
#define LE_2 LE
#define LE_4 LE
#define LE_8 LE

#define BE_1 {0}
#define BE_2 {1,0}
#define BE_4 {3,2,1,0}
#define BE_8 {7,6,5,4,3,2,1,0}

#define INTEGER 0,0,0,0,0,0,0

static detected_t       Known[] =
{
   /* Single-byte quantities */
    {"Byte addressable",
     1, 0, LE_1, INTEGER},

   /* Little-endian integer */
    {"Little-endian",
     2, 0, LE_2, INTEGER},
    {"Little-endian",
     4, 0, LE_4, INTEGER},

   /* Big-endian integer */
    {"Big-endian",
     2, 0, BE_2, INTEGER},
    {"Big-endian",
     4, 0, BE_4, INTEGER},

   /* Little-endian IEEE floating-point */
    {"Little-endian IEEE",
     4, 0, LE_4, 31, 0, 23, 1, 23, 8, 127},
    {"Little-endian IEEE",
     8, 0, LE_8, 63, 0, 52, 1, 52, 11, 1023},

   /* Big-endian IEEE floating-point */
    {"Big-endian IEEE",
     4, 0, BE_4, 31, 0, 23, 1, 23, 8, 127},
    {"Big-endian IEEE",
     8, 0, BE_8, 63, 0, 52, 1, 52, 11, 1023},
};

/*-------------------------------------------------------------------------
 * Function:    DETECT_I
 *
 * Purpose:     This macro takes a type like `int' and a base name like
 *              `nati' and detects the byte order.  The VAR is used to
 *              construct the names of the C variables defined.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 12 1996
 *
 * Modifications:
 *
 *      Robb Matzke, 4 Nov 1996
 *      The INFO.perm now contains `-1' for bytes that aren't used and
 *      are always zero.  This happens on the Cray for `short' where
 *      sizeof(short) is 8, but only the low-order 4 bytes are ever used.
 *
 *      Robb Matzke, 4 Nov 1996
 *      Added a `padding' field to indicate how many zero bytes appear to
 *      the left (N) or right (-N) of the value.
 *
 *      Robb Matzke, 5 Nov 1996
 *      Removed HFILE and CFILE arguments.
 *
 *-------------------------------------------------------------------------
 */
#define DETECT_I(TYPE,VAR,INFO) {                                             \
   TYPE _v;                                                                   \
   int _i, _j;                                                                \
   unsigned char *_x;                                                         \
   memset (&INFO, 0, sizeof(INFO));                                           \
   INFO.varname = #VAR;                                                       \
   INFO.size = sizeof(TYPE);                                                  \
   for (_i=sizeof(TYPE),_v=0; _i>0; --_i) _v = (_v<<8) + _i;                  \
   for (_i=0,_x=(unsigned char *)&_v; _i<sizeof(TYPE); _i++) {                \
      _j = (*_x++)-1;                                                         \
      assert (_j<(signed)sizeof(TYPE));                                       \
      INFO.perm[_i] = _j;                                                     \
   }                                                                          \
   fix_padding (&(INFO));                                                     \
   INFO.sign = ('U'!=*(#VAR));                                                \
}

/*-------------------------------------------------------------------------
 * Function:    DETECT_F
 *
 * Purpose:     This macro takes a floating point type like `double' and
 *              a base name like `natd' and detects byte order, mantissa
 *              location, exponent location, sign bit location, presence or
 *              absence of implicit mantissa bit, and exponent bias and
 *              initializes a detected_t structure with those properties.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 12 1996
 *
 * Modifications:
 *
 *      Robb Matzke, 14 Aug 1996
 *      The byte order detection has been changed because on the Cray
 *      the last pass causes a rounding to occur that causes the least
 *      significant mantissa byte to change unexpectedly.
 *
 *      Robb Matzke, 5 Nov 1996
 *      Removed HFILE and CFILE arguments.
 *-------------------------------------------------------------------------
 */
#define DETECT_F(TYPE,VAR,INFO) {                                             \
   TYPE _v1, _v2, _v3;                                                        \
   int _i, _j, _first=(-1), _last=(-1);                                       \
   char *_mesg;                                                               \
                                                                              \
   memset (&INFO, 0, sizeof(INFO));                                           \
   INFO.varname = #VAR;                                                       \
   INFO.size = sizeof(TYPE);                                                  \
   INFO.padding = 0;                                                          \
                                                                              \
   /* Byte Order */                                                           \
   for (_i=0,_v1=0.0,_v2=1.0; _i<sizeof(TYPE); _i++) {                        \
      _v3 = _v1; _v1 += _v2; _v2 /= 256.0;                                    \
      if ((_j=byte_cmp(sizeof(TYPE), &_v3, &_v1))>=0) {                       \
         if (0==_i || INFO.perm[_i-1]!=_j) {                                  \
            INFO.perm[_i] = _j;                                               \
            _last = _i;                                                       \
            if (_first<0) _first = _i;                                        \
         }                                                                    \
      }                                                                       \
   }                                                                          \
   fix_order (sizeof(TYPE), _first, _last, INFO.perm, (const char**)&_mesg);  \
                                                                              \
   /* Implicit mantissa bit */                                                \
   _v1 = 0.5;                                                                 \
   _v2 = 1.0;                                                                 \
   INFO.imp = imp_bit (sizeof(TYPE), INFO.perm, &_v1, &_v2);                  \
                                                                              \
   /* Sign bit */                                                             \
   _v1 = 1.0;                                                                 \
   _v2 = -1.0;                                                                \
   INFO.sign = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2);                 \
                                                                              \
   /* Mantissa */                                                             \
   INFO.mpos = 0;                                                             \
                                                                              \
   _v1 = 1.0;                                                                 \
   _v2 = 1.5;                                                                 \
   INFO.msize = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2);                \
   INFO.msize += 1 + (INFO.imp?0:1) - INFO.mpos;                              \
                                                                              \
   /* Exponent */                                                             \
   INFO.epos = INFO.mpos + INFO.msize;                                        \
                                                                              \
   INFO.esize = INFO.sign - INFO.epos;                                        \
                                                                              \
   _v1 = 1.0;                                                                 \
   INFO.bias = find_bias (INFO.epos, INFO.esize, INFO.imp, INFO.perm, &_v1);  \
}

/*-------------------------------------------------------------------------
 * Function:    print_results
 *
 * Purpose:     Prints information about the detected data types.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 14, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
print_results(int nd, detected_t *d)
{

    int                     i;

    /* Include files */
    printf("\
#define H5T_PACKAGE /*suppress error about including H5Tpkg.h*/\n\
\n\
#include <H5private.h>\n\
#include <H5Aprivate.h>\n\
#include <H5Eprivate.h>\n\
#include <H5MMprivate.h>\n\
#include <H5Tpkg.h>\n\
\n\
static hbool_t interface_initialize_g = FALSE;\n\
#define INTERFACE_INIT NULL\n\
\n");

    /* Function declaration */
    printf("\n\
herr_t\n\
H5T_init (void)\n\
{\n\
   H5T_t        *dt = NULL;\n\
   static intn  ncalls = 0;\n\
\n\
   FUNC_ENTER (H5T_init, FAIL);\n\
\n\
   if (ncalls++) return SUCCEED; /*already initialized*/\n\
\n");

    for (i = 0; i < nd; i++) {

        /* Print a comment to describe this section of definitions. */
        printf("\n   /*\n");
        iprint(d + i);
        print_known_formats(d + i);
        printf("    */\n");

        /* The part common to fixed and floating types */
        printf("\
   dt = H5MM_xcalloc (1, sizeof(H5T_t));\n\
   dt->locked = TRUE;\n\
   dt->type = H5T_%s;\n\
   dt->size = %d;\n\
   dt->u.atomic.order = H5T_ORDER_%s;\n\
   dt->u.atomic.prec = %d;\n\
   dt->u.atomic.lsb_pad = H5T_PAD_ZERO;\n\
   dt->u.atomic.lsb_pad = H5T_PAD_ZERO;\n",
               d[i].msize ? "FLOAT" : "INTEGER",        /*class         */
               d[i].size + abs(d[i].padding),   /*size          */
               d[i].perm[0] ? "BE" : "LE",      /*byte order    */
               8 * d[i].size);  /*precision     */

        if (0 == d[i].msize) {
            /* The part unique to fixed point types */
            printf("\
   dt->u.atomic.u.i.sign = H5T_SGN_%s;\n",
                   d[i].sign ? "2" : "NONE");
        } else {
            /* The part unique to floating point types */
            printf("\
   dt->u.atomic.u.f.sign = %d;\n\
   dt->u.atomic.u.f.epos = %d;\n\
   dt->u.atomic.u.f.esize = %d;\n\
   dt->u.atomic.u.f.ebias = 0x%08lx;\n\
   dt->u.atomic.u.f.mpos = %d;\n\
   dt->u.atomic.u.f.msize = %d;\n\
   dt->u.atomic.u.f.norm = H5T_NORM_%s;\n\
   dt->u.atomic.u.f.pad = H5T_PAD_ZERO;\n",
                   d[i].sign,   /*sign location */
                   d[i].epos,   /*exponent loc  */
                   d[i].esize,  /*exponent size */
                   (unsigned long)(d[i].bias),   /*exponent bias */
                   d[i].mpos,   /*mantissa loc  */
                   d[i].msize,  /*mantissa size */
                   d[i].imp ? "IMPLIED" : "NONE");      /*normalization */
        }

        /* Atomize the type */
        printf("\
   if ((H5T_NATIVE_%s_g = H5A_register (H5_DATATYPE, dt))<0) {\n\
      HRETURN_ERROR (H5E_DATATYPE, H5E_CANTINIT, FAIL,\n\
                     \"can't initialize type system (atom registration \"\n\
                     \"failure\");\n\
   }\n",
               d[i].varname);

    }

    printf("   FUNC_LEAVE (SUCCEED);\n}\n");
}

/*-------------------------------------------------------------------------
 * Function:    iprint
 *
 * Purpose:     Prints information about the fields of a floating point
 *              format.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
iprint(detected_t *d)
{

    int                     i, j, k;

    /*
     * Print the byte ordering above the bit fields.
     */
    printf("    * ");
    for (i = d->size - 1; i >= 0; --i) {
        printf("%4d", d->perm[i]);
        if (i > 0)
            fputs("     ", stdout);
        if (0 == i % 4)
            putchar(' ');
    }
    putchar('\n');

    /*
     * Print the bit fields
     */
    printf("    * ");
    for (i = d->size - 1, k = d->size * 8 - 1; i >= 0; --i) {
        for (j = 7; j >= 0; --j) {
            if (k == d->sign && d->msize) {
                putchar('S');
            } else if (k >= d->epos && k < d->epos + d->esize) {
                putchar('E');
            } else if (k >= d->mpos && k < d->mpos + d->msize) {
                putchar('M');
            } else if (d->msize) {
                putchar('?');   /*unknown floating point bit */
            } else if (d->sign) {
                putchar('I');
            } else {
                putchar('U');
            }
            --k;
        }
        if (i > 0) {
            putchar(' ');
            if (0 == i % 4)
                putchar(' ');
        }
    }
    putchar('\n');

    /*
     * Is there an implicit bit in the mantissa.
     */
    if (d->msize) {
        printf("    * Implicit bit? %s\n", d->imp ? "yes" : "no");
    }
}

/*-------------------------------------------------------------------------
 * Function:    print_known_formats
 *
 * Purpose:     Prints archetecture names for the specified format
 *              description, if any.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
print_known_formats(detected_t *d)
{

    int                     i, j, diff;
    int                     n = sizeof(Known) / sizeof(Known[0]);

    for (i = 0; i < n; i++) {
        if (d->size != Known[i].size)
            continue;
        for (j = diff = 0; !diff && j < d->size; j++) {
            if (d->perm[j] != Known[i].perm[j])
                diff = 1;
        }
        if (diff)
            continue;

        /* if (d->sign  != Known[i].sign)  continue; */
        if (d->mpos != Known[i].mpos)
            continue;
        if (d->msize != Known[i].msize)
            continue;
        if (d->imp != Known[i].imp)
            continue;
        if (d->epos != Known[i].epos)
            continue;
        if (d->esize != Known[i].esize)
            continue;
        if (d->bias != Known[i].bias)
            continue;

        printf("    * %s\n", Known[i].varname);
    }
}

/*-------------------------------------------------------------------------
 * Function:    byte_cmp
 *
 * Purpose:     Compares two chunks of memory A and B and returns the
 *              byte index into those arrays of the first byte that
 *              differs between A and B.
 *
 * Return:      Success:        Index of differing byte.
 *
 *              Failure:        -1 if all bytes are the same.
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 12, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static int
byte_cmp(int n, void *_a, void *_b)
{

    register int            i;
    unsigned char          *a = (unsigned char *) _a;
    unsigned char          *b = (unsigned char *) _b;

    for (i = 0; i < n; i++)
        if (a[i] != b[i])
            return i;
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:    bit_cmp
 *
 * Purpose:     Compares two bit vectors and returns the index for the
 *              first bit that differs between the two vectors.  The
 *              size of the vector is NBYTES.  PERM is a mapping from
 *              actual order to little endian.
 *
 * Return:      Success:        Index of first differing bit.
 *
 *              Failure:        -1
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static int
bit_cmp(int nbytes, int *perm, void *_a, void *_b)
{

    int                     i, j;
    unsigned char          *a = (unsigned char *) _a;
    unsigned char          *b = (unsigned char *) _b;
    unsigned char           aa, bb;

    for (i = 0; i < nbytes; i++) {
        assert(perm[i] < nbytes);
        if ((aa = a[perm[i]]) != (bb = b[perm[i]])) {
            for (j = 0; j < 8; j++, aa >>= 1, bb >>= 1) {
                if ((aa & 1) != (bb & 1))
                    return i * 8 + j;
            }
            assert("INTERNAL ERROR" && 0);
        }
    }
    return -1;
}

/*-------------------------------------------------------------------------
 * Function:    fix_order
 *
 * Purpose:     Given an array PERM with elements FIRST through LAST
 *              initialized with zero origin byte numbers, this function
 *              creates a permutation vector that maps the actual order
 *              of a floating point number to little-endian.
 *
 *              This function assumes that the mantissa byte ordering
 *              implies the total ordering.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
fix_order(int n, int first, int last, int *perm, const char **mesg)
{

    int                     i;

    if (first + 1 < last) {
        /*
         * We have at least three points to consider.
         */
        if (perm[last] < perm[last - 1] && perm[last - 1] < perm[last - 2]) {
            /*
             * Little endian.
             */
            if (mesg)
                *mesg = "Little-endian";
            for (i = 0; i < n; i++)
                perm[i] = i;

        } else if (perm[last] > perm[last - 1] && perm[last - 1] > perm[last - 2]) {
            /*
             * Big endian.
             */
            if (mesg)
                *mesg = "Big-endian";
            for (i = 0; i < n; i++)
                perm[i] = (n - 1) - i;

        } else {
            /*
             * Bi-endian machines like VAX.
             */
            assert(0 == n / 2);
            if (mesg)
                *mesg = "VAX";
            for (i = 0; i < n; i += 2) {
                perm[i] = (n - 2) - i;
                perm[i + 1] = (n - 1) - i;
            }
        }
    } else {
        fprintf(stderr,
             "Failed to detect byte order of %d-byte floating point.\n", n);
        exit(1);
    }
}

/*-------------------------------------------------------------------------
 * Function:    fix_padding
 *
 * Purpose:     The permutation can have negative values at the beginning
 *              or end which represent zero padding.  The amount of padding
 *              is subtracted from the size, the negative values are removed
 *              from the permutation, and the `padding' field is set to an
 *              appropriate value.
 *
 *              If N bytes of padding appear to the left (lower address) of
 *              the value, then `padding=N'.  If N bytes of padding appear
 *              to the right of the value then `padding=(-N)'.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Nov  4 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
fix_padding(detected_t *d)
{

    int                     i, n;

    if (d->perm[0] < 0) {
        /*
         * Left padding.
         */
        for (n = 0; n < d->size && d->perm[n] < 0; n++)         /*void */
            ;
        for (i = n; i < d->size; i++)
            d->perm[i - n] = d->perm[i];
        for (i = d->size - n; i < d->size; i++)
            d->perm[i] = 0;
        d->padding = n;
        d->size -= n;

    } else if (d->perm[d->size - 1] < 0) {
        /*
         * Right padding.
         */
        for (n = 0; n < d->size && d->perm[d->size - (n + 1)]; n++)     /*void */
            ;
        for (i = d->size - n; i < d->size; i++)
            d->perm[i] = 0;
        d->padding = -n;
        d->size -= n;

    } else {
        /*
         * No padding.
         */
        d->padding = 0;
    }
}

/*-------------------------------------------------------------------------
 * Function:    imp_bit
 *
 * Purpose:     Looks for an implicit bit in the mantissa.  The value
 *              of _A should be 1.0 and the value of _B should be 0.5.
 *              Some floating-point formats discard the most significant
 *              bit of the mantissa after normalizing since it will always
 *              be a one (except for 0.0).  If this is true for the native
 *              floating point values stored in _A and _B then the function
 *              returns non-zero.
 *
 *              This function assumes that the exponent occupies higher
 *              order bits than the mantissa and that the most significant
 *              bit of the mantissa is next to the least signficant bit
 *              of the exponent.
 *              
 *
 * Return:      Success:        Non-zero if the most significant bit
 *                              of the mantissa is discarded (ie, the
 *                              mantissa has an implicit `one' as the
 *                              most significant bit).  Otherwise,
 *                              returns zero.
 *
 *              Failure:        exit(1)
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *      Robb Matzke, 6 Nov 1996
 *      Fixed a bug that occurs with non-implicit architectures.
 *
 *-------------------------------------------------------------------------
 */
static int
imp_bit(int n, int *perm, void *_a, void *_b)
{

    unsigned char          *a = (unsigned char *) _a;
    unsigned char          *b = (unsigned char *) _b;
    int                     changed, major, minor;
    int                     msmb;       /*most significant mantissa bit */

    /*
     * Look for the least significant bit that has changed between
     * A and B.  This is the least significant bit of the exponent.
     */
    changed = bit_cmp(n, perm, a, b);
    assert(changed >= 0);

    /*
     * The bit to the right (less significant) of the changed bit should
     * be the most significant bit of the mantissa.  If it is non-zero
     * then the format does not remove the leading `1' of the mantissa.
     */
    msmb = changed - 1;
    major = msmb / 8;
    minor = msmb % 8;

    return (a[perm[major]] >> minor) & 0x01 ? 0 : 1;
}

/*-------------------------------------------------------------------------
 * Function:    find_bias
 *
 * Purpose:     Determines the bias of the exponent.  This function should
 *              be called with _A having a value of `1'.
 *
 * Return:      Success:        The exponent bias.
 *
 *              Failure:        
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 13, 1996
 *
 * Modifications:
 *
 *      Robb Matzke, 6 Nov 1996
 *      Fixed a bug with non-implicit architectures returning the
 *      wrong exponent bias.
 *
 *-------------------------------------------------------------------------
 */
static unsigned long
find_bias(int epos, int esize, int imp, int *perm, void *_a)
{

    unsigned char          *a = (unsigned char *) _a;
    unsigned char           mask;
    unsigned long           b, shift = 0, nbits, bias = 0;

    while (esize > 0) {
        nbits = MIN(esize, (8 - epos % 8));
        mask = (1 << nbits) - 1;
        b = (a[perm[epos / 8]] >> (epos % 8)) & mask;
        bias |= b << shift;

        shift += nbits;
        esize -= nbits;
        epos += nbits;
    }

    return bias - (imp ? 0 : 1);
}

/*-------------------------------------------------------------------------
 * Function:    print_header
 *
 * Purpose:     Prints the C file header for the generated file.
 *
 * Return:      void
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Mar 12 1997
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void
print_header(void)
{

    time_t              now = time(NULL);
    struct tm           *tm = localtime(&now);
    struct passwd       *pwd = getpwuid(getuid());
    char                real_name[30], *comma;
    char                host_name[256];
    int                 i;
    size_t		n;
    const char          *s;
    static const char   *month_name[] =
    {
        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
    static const char   *purpose = "\
This machine-generated source code contains\n\
information about the various integer and\n\
floating point numeric formats found on this\n\
architecture.  The parameters below should be\n\
checked carefully and errors reported to the\n\
HDF5 maintainer.\n\
\n\
Each of the numeric formats listed below are\n\
printed from most significant bit to least\n\
significant bit even though the actual bytes\n\
might be stored in a different order in\n\
memory.  The integers above each binary byte\n\
indicate the relative order of the bytes in\n\
memory; little-endian machines have\n\
decreasing numbers while big-endian machines\n\
have increasing numbers.\n\
\n\
The fields of the numbers are printed as\n\
letters with `S' for the mantissa sign bit,\n\
`M' for the mantissa magnitude, and `E' for\n\
the exponent.  The exponent has an associated\n\
bias which can be subtracted to find the\n\
true exponent.  The radix point is assumed\n\
to be before the first `M' bit.  Any bit\n\
of a floating-point value not falling into one\n\
of these categories is printed as a question\n\
mark.  Bits of integer types are printed as\n\
`I' for 2's complement and `U' for magnitude.\n\
\n\
If the most significant bit of the normalized\n\
mantissa (always a `1' except for `0.0') is\n\
not stored then an `implicit=yes' appears\n\
under the field description.  In thie case,\n\
the radix point is still assumed to be\n\
before the first `M' but after the implicit\n\
bit.\n";

    /*
     * The real name is the first item from the passwd gecos field.
     */
    if (pwd) {
        if ((comma = strchr(pwd->pw_gecos, ','))) {
            n = MIN(sizeof(real_name) - 1, comma - pwd->pw_gecos);
            strncpy(real_name, pwd->pw_gecos, n);
            real_name[n] = '\0';
        } else {
            strncpy(real_name, pwd->pw_gecos, sizeof(real_name));
            real_name[sizeof(real_name) - 1] = '\0';
        }
    } else {
        real_name[0] = '\0';
    }

    /*
     * The FQDM of this host or the empty string.
     */
    if (gethostname(host_name, sizeof(host_name)) < 0)
        host_name[0] = '\0';

    /*
     * The file header: warning, copyright notice, build information.
     */
    printf("/*\n * DO NOT EDIT OR DISTRIBUTE THIS FILE -- "
           "IT IS MACHINE GENERATED!\n */\n\n");
    puts(FileHeader);           /*the copyright notice--see top of this file */

    printf(" *\n * Created:\t\t%s %2d, %4d\n",
           month_name[tm->tm_mon], tm->tm_mday, 1900 + tm->tm_year);
    if (pwd || real_name[0] || host_name[0]) {
        printf(" *\t\t\t");
        if (real_name[0])
            printf("%s <", real_name);
        if (pwd)
            fputs(pwd->pw_name, stdout);
        if (host_name[0])
            printf("@%s", host_name);
        if (real_name[0])
            printf(">");
        putchar('\n');
    }
    printf(" *\n * Purpose:\t\t");
    for (s = purpose; *s; s++) {
        putchar(*s);
        if ('\n' == *s && s[1])
            printf(" *\t\t\t");
    }

    printf(" *\n * Modifications:\n *\n");
    printf(" *\tDO NOT MAKE MODIFICATIONS TO THIS FILE!\n");
    printf(" *\tIt was generated by code in `H5detect.c'.\n");

    printf(" *\n *");
    for (i = 0; i < 73; i++)
        putchar('-');
    printf("\n */\n\n");

}

/*-------------------------------------------------------------------------
 * Function:    main
 *
 * Purpose:     Main entry point.
 *
 * Return:      Success:        exit(0)
 *
 *              Failure:        exit(1)
 *
 * Programmer:  Robb Matzke
 *              matzke@llnl.gov
 *              Jun 12, 1996
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
int
main(int argc, char *argv[])
{

    detected_t              d[MAXDETECT];
    int                     nd = 0;

    print_header();

    DETECT_I(signed char, CHAR, d[nd]);
    nd++;
    DETECT_I(unsigned char, UCHAR, d[nd]);
    nd++;
    DETECT_I(short, SHORT, d[nd]);
    nd++;
    DETECT_I(unsigned short, USHORT, d[nd]);
    nd++;
    DETECT_I(int, INT, d[nd]);
    nd++;
    DETECT_I(unsigned int, UINT, d[nd]);
    nd++;
    DETECT_I(long, LONG, d[nd]);
    nd++;
    DETECT_I(unsigned long, ULONG, d[nd]);
    nd++;
    DETECT_I(long long, LLONG, d[nd]);
    nd++;
    DETECT_I(unsigned long long, ULLONG, d[nd]);
    nd++;
    DETECT_F(float, FLOAT, d[nd]);
    nd++;
    DETECT_F(double, DOUBLE, d[nd]);
    nd++;

    print_results(nd, d);
    return 0;
}