summaryrefslogtreecommitdiffstats
path: root/util.c
blob: c2c1929bc36a912166f2fca4855a418c480136de (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
/**********************************************************************

  util.c -

  $Author$
  $Date$
  created at: Fri Mar 10 17:22:34 JST 1995

  Copyright (C) 1993-2003 Yukihiro Matsumoto

**********************************************************************/

#include "ruby.h"

#include <ctype.h>
#include <stdio.h>
#include <errno.h>

#ifdef _WIN32
#include "missing/file.h"
#endif

#include "util.h"
#ifndef HAVE_STRING_H
char *strchr _((char*,char));
#endif

unsigned long
scan_oct(start, len, retlen)
    const char *start;
    int len;
    int *retlen;
{
    register const char *s = start;
    register unsigned long retval = 0;

    while (len-- && *s >= '0' && *s <= '7') {
	retval <<= 3;
	retval |= *s++ - '0';
    }
    *retlen = s - start;
    return retval;
}

unsigned long
scan_hex(start, len, retlen)
    const char *start;
    int len;
    int *retlen;
{
    static char hexdigit[] = "0123456789abcdef0123456789ABCDEF";
    register const char *s = start;
    register unsigned long retval = 0;
    char *tmp;

    while (len-- && *s && (tmp = strchr(hexdigit, *s))) {
	retval <<= 4;
	retval |= (tmp - hexdigit) & 15;
	s++;
    }
    *retlen = s - start;
    return retval;
}

#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if defined(HAVE_FCNTL_H)
#include <fcntl.h>
#endif

#ifndef S_ISDIR
#   define S_ISDIR(m) ((m & S_IFMT) == S_IFDIR)
#endif

#if defined(MSDOS) || defined(__CYGWIN32__) || defined(_WIN32)
/*
 *  Copyright (c) 1993, Intergraph Corporation
 *
 *  You may distribute under the terms of either the GNU General Public
 *  License or the Artistic License, as specified in the perl README file.
 *
 *  Various Unix compatibility functions and NT specific functions.
 *
 *  Some of this code was derived from the MSDOS port(s) and the OS/2 port.
 *
 */


/*
 * Suffix appending for in-place editing under MS-DOS and OS/2 (and now NT!).
 *
 * Here are the rules:
 *
 * Style 0:  Append the suffix exactly as standard perl would do it.
 *           If the filesystem groks it, use it.  (HPFS will always
 *           grok it.  So will NTFS. FAT will rarely accept it.)
 *
 * Style 1:  The suffix begins with a '.'.  The extension is replaced.
 *           If the name matches the original name, use the fallback method.
 *
 * Style 2:  The suffix is a single character, not a '.'.  Try to add the 
 *           suffix to the following places, using the first one that works.
 *               [1] Append to extension.  
 *               [2] Append to filename, 
 *               [3] Replace end of extension, 
 *               [4] Replace end of filename.
 *           If the name matches the original name, use the fallback method.
 *
 * Style 3:  Any other case:  Ignore the suffix completely and use the
 *           fallback method.
 *
 * Fallback method:  Change the extension to ".$$$".  If that matches the
 *           original name, then change the extension to ".~~~".
 *
 * If filename is more than 1000 characters long, we die a horrible
 * death.  Sorry.
 *
 * The filename restriction is a cheat so that we can use buf[] to store
 * assorted temporary goo.
 *
 * Examples, assuming style 0 failed.
 *
 * suffix = ".bak" (style 1)
 *                foo.bar => foo.bak
 *                foo.bak => foo.$$$	(fallback)
 *                foo.$$$ => foo.~~~	(fallback)
 *                makefile => makefile.bak
 *
 * suffix = "~" (style 2)
 *                foo.c => foo.c~
 *                foo.c~ => foo.c~~
 *                foo.c~~ => foo~.c~~
 *                foo~.c~~ => foo~~.c~~
 *                foo~~~~~.c~~ => foo~~~~~.$$$ (fallback)
 *
 *                foo.pas => foo~.pas
 *                makefile => makefile.~
 *                longname.fil => longname.fi~
 *                longname.fi~ => longnam~.fi~
 *                longnam~.fi~ => longnam~.$$$
 *                
 */


static int valid_filename(char *s);

static char suffix1[] = ".$$$";
static char suffix2[] = ".~~~";

#define ext (&buf[1000])

#define strEQ(s1,s2) (strcmp(s1,s2) == 0)

void
ruby_add_suffix(str, suffix)
    VALUE str;
    char *suffix;
{
    int baselen;
    int extlen = strlen(suffix);
    char *s, *t, *p;
    long slen;
    char buf[1024];

    if (RSTRING(str)->len > 1000)
        rb_fatal("Cannot do inplace edit on long filename (%ld characters)",
		 RSTRING(str)->len);

#if defined(DJGPP) || defined(__CYGWIN32__) || defined(_WIN32)
    /* Style 0 */
    slen = RSTRING(str)->len;
    rb_str_cat(str, suffix, extlen);
#if defined(DJGPP)
    if (_USE_LFN) return;
#else
    if (valid_filename(RSTRING(str)->ptr)) return;
#endif

    /* Fooey, style 0 failed.  Fix str before continuing. */
    RSTRING(str)->ptr[RSTRING(str)->len = slen] = '\0';
#endif

    slen = extlen;
    t = buf; baselen = 0; s = RSTRING(str)->ptr;
    while ((*t = *s) && *s != '.') {
	baselen++;
	if (*s == '\\' || *s == '/') baselen = 0;
 	s++; t++;
    }
    p = t;

    t = ext; extlen = 0;
    while (*t++ = *s++) extlen++;
    if (extlen == 0) { ext[0] = '.'; ext[1] = 0; extlen++; }

    if (*suffix == '.') {        /* Style 1 */
        if (strEQ(ext, suffix)) goto fallback;
	strcpy(p, suffix);
    }
    else if (suffix[1] == '\0') {  /* Style 2 */
        if (extlen < 4) { 
	    ext[extlen] = *suffix;
	    ext[++extlen] = '\0';
        }
	else if (baselen < 8) {
   	    *p++ = *suffix;
	}
	else if (ext[3] != *suffix) {
	    ext[3] = *suffix;
	}
	else if (buf[7] != *suffix) {
	    buf[7] = *suffix;
	}
	else goto fallback;
	strcpy(p, ext);
    }
    else { /* Style 3:  Panic */
fallback:
	(void)memcpy(p, strEQ(ext, suffix1) ? suffix2 : suffix1, 5);
    }
    rb_str_resize(str, strlen(buf));
    memcpy(RSTRING(str)->ptr, buf, RSTRING(str)->len);
}

#if defined(__CYGWIN32__) || defined(_WIN32)
static int 
valid_filename(char *s)
{
    int fd;

    /*
    // if the file exists, then it's a valid filename!
    */

    if (_access(s, 0) == 0) {
	return 1;
    }

    /*
    // It doesn't exist, so see if we can open it.
    */

    if ((fd = _open(s, O_CREAT, 0666)) >= 0) {
	_close(fd);
	_unlink(s);	/* don't leave it laying around */
	return 1;
    }
    return 0;
}
#endif
#endif

#if defined __DJGPP__

#include <dpmi.h>

static char dbcs_table[256];

int
make_dbcs_table()
{
    __dpmi_regs r;
    struct {
	unsigned char start;
	unsigned char end;
    } vec;
    int offset;

    memset(&r, 0, sizeof(r));
    r.x.ax = 0x6300;
    __dpmi_int(0x21, &r);
    offset = r.x.ds * 16 + r.x.si;

    for (;;) {
	int i;
	dosmemget(offset, sizeof vec, &vec);
	if (!vec.start && !vec.end)
	    break;
	for (i = vec.start; i <= vec.end; i++)
	    dbcs_table[i] = 1;
	offset += 2;
    }
}

int
mblen(const char *s, size_t n)
{
    static int need_init = 1;
    if (need_init) {
	make_dbcs_table();
	need_init = 0;
    }
    if (s) {
	if (n == 0 || *s == 0)
	    return 0;
	else if (!s[1])
	    return 1;
	return dbcs_table[(unsigned char)*s] + 1;
    }
    else
	return 1;
}

struct PathList {
    struct PathList *next;
    char *path;
};

struct PathInfo {
    struct PathList *head;
    int count;
};

static void
push_element(const char *path, VALUE vinfo)
{
    struct PathList *p;
    struct PathInfo *info = (struct PathInfo *)vinfo;

    p = ALLOC(struct PathList);
    MEMZERO(p, struct PathList, 1);
    p->path = ruby_strdup(path);
    p->next = info->head;
    info->head = p;
    info->count++;
}

#include <dirent.h>
int __opendir_flags = __OPENDIR_PRESERVE_CASE;

char **
__crt0_glob_function(char *path)
{
    int len = strlen(path);
    int i;
    char **rv;
    char path_buffer[PATH_MAX];
    char *buf = path_buffer;
    char *p;
    struct PathInfo info;
    struct PathList *plist;

    if (PATH_MAX <= len)
	buf = ruby_xmalloc(len + 1);

    strncpy(buf, path, len);
    buf[len] = '\0';

    for (p = buf; *p; p += mblen(p, MB_CUR_MAX))
	if (*p == '\\')
	    *p = '/';

    info.count = 0;
    info.head = 0;

    rb_globi(buf, push_element, (VALUE)&info);

    if (buf != path_buffer)
	ruby_xfree(buf);

    if (info.count == 0)
	return 0;

    rv = ruby_xmalloc((info.count + 1) * sizeof (char *));

    plist = info.head;
    i = 0;
    while (plist) {
	struct PathList *cur;
	rv[i] = plist->path;
	cur = plist;
	plist = plist->next;
	ruby_xfree(cur);
	i++;
    }
    rv[i] = 0;
    return rv;
}

#endif

/* mm.c */

#define A ((int*)a)
#define B ((int*)b)
#define C ((int*)c)
#define D ((int*)d)

#define mmprepare(base, size) do {\
 if (((long)base & (0x3)) == 0)\
   if (size >= 16) mmkind = 1;\
   else            mmkind = 0;\
 else              mmkind = -1;\
 high = (size & (~0xf));\
 low  = (size &  0x0c);\
} while (0)\

#define mmarg mmkind, size, high, low

static void mmswap_(a, b, mmarg)
    register char *a, *b;
    int mmarg;
{
 register int s;
 if (a == b) return;
 if (mmkind >= 0) {
   if (mmkind > 0) {
     register char *t = a + high;
     do {
       s = A[0]; A[0] = B[0]; B[0] = s;
       s = A[1]; A[1] = B[1]; B[1] = s;
       s = A[2]; A[2] = B[2]; B[2] = s;
       s = A[3]; A[3] = B[3]; B[3] = s;  a += 16; b += 16;
     } while (a < t);
   }
   if (low != 0) { s = A[0]; A[0] = B[0]; B[0] = s;
     if (low >= 8) { s = A[1]; A[1] = B[1]; B[1] = s;
       if (low == 12) {s = A[2]; A[2] = B[2]; B[2] = s;}}}
 }
 else {
   register char *t = a + size;
   do {s = *a; *a++ = *b; *b++ = s;} while (a < t);
 }
}
#define mmswap(a,b) mmswap_((a),(b),mmarg)

static void mmrot3_(a, b, c, mmarg)
    register char *a, *b, *c;
    int mmarg;
{
 register int s;
 if (mmkind >= 0) {
   if (mmkind > 0) {
     register char *t = a + high;
     do {
       s = A[0]; A[0] = B[0]; B[0] = C[0]; C[0] = s;
       s = A[1]; A[1] = B[1]; B[1] = C[1]; C[1] = s;
       s = A[2]; A[2] = B[2]; B[2] = C[2]; C[2] = s;
       s = A[3]; A[3] = B[3]; B[3] = C[3]; C[3] = s; a += 16; b += 16; c += 16;
     } while (a < t);
   }
   if (low != 0) { s = A[0]; A[0] = B[0]; B[0] = C[0]; C[0] = s;
     if (low >= 8) { s = A[1]; A[1] = B[1]; B[1] = C[1]; C[1] = s;
       if (low == 12) {s = A[2]; A[2] = B[2]; B[2] = C[2]; C[2] = s;}}}
 }
 else {
   register char *t = a + size;
   do {s = *a; *a++ = *b; *b++ = *c; *c++ = s;} while (a < t);
 }
}
#define mmrot3(a,b,c) mmrot3_((a),(b),(c),mmarg)

/* qs6.c */
/*****************************************************/
/*                                                   */
/*          qs6   (Quick sort function)              */
/*                                                   */
/* by  Tomoyuki Kawamura              1995.4.21      */
/* kawamura@tokuyama.ac.jp                           */
/*****************************************************/

typedef struct { char *LL, *RR; } stack_node; /* Stack structure for L,l,R,r */
#define PUSH(ll,rr) do { top->LL = (ll); top->RR = (rr); ++top; } while (0)  /* Push L,l,R,r */
#define POP(ll,rr)  do { --top; ll = top->LL; rr = top->RR; } while (0)      /* Pop L,l,R,r */

#define med3(a,b,c) ((*cmp)(a,b,d)<0 ?                                   \
                       ((*cmp)(b,c,d)<0 ? b : ((*cmp)(a,c,d)<0 ? c : a)) : \
                       ((*cmp)(b,c,d)>0 ? b : ((*cmp)(a,c,d)<0 ? a : c)))

void ruby_qsort (base, nel, size, cmp, d)
     void* base;
     const int nel;
     const int size;
     int (*cmp)();
     void *d;
{
  register char *l, *r, *m;          	/* l,r:left,right group   m:median point */
  register int  t, eq_l, eq_r;       	/* eq_l: all items in left group are equal to S */
  char *L = base;                    	/* left end of curren region */
  char *R = (char*)base + size*(nel-1); /* right end of current region */
  int  chklim = 63;                     /* threshold of ordering element check */
  stack_node stack[32], *top = stack;   /* 32 is enough for 32bit CPU */
  int mmkind, high, low;

  if (nel <= 1) return;        /* need not to sort */
  mmprepare(base, size);
  goto start;

  nxt:
  if (stack == top) return;    /* return if stack is empty */
  POP(L,R);

  for (;;) {
    start:
    if (L + size == R) {       /* 2 elements */
      if ((*cmp)(L,R,d) > 0) mmswap(L,R); goto nxt;
    }

    l = L; r = R;
    t = (r - l + size) / size;  /* number of elements */
    m = l + size * (t >> 1);    /* calculate median value */

    if (t >= 60) {
      register char *m1;
      register char *m3;
      if (t >= 200) {
	t = size*(t>>3); /* number of bytes in splitting 8 */
	{
	  register char *p1 = l  + t;
	  register char *p2 = p1 + t;
	  register char *p3 = p2 + t;
	  m1 = med3(p1, p2, p3);
	  p1 = m  + t;
	  p2 = p1 + t;
	  p3 = p2 + t;
	  m3 = med3(p1, p2, p3);
	}
      }
      else {
	t = size*(t>>2); /* number of bytes in splitting 4 */
	m1 = l + t;
	m3 = m + t;
      }
      m = med3(m1, m, m3);
    }

    if ((t = (*cmp)(l,m,d)) < 0) {                           /*3-5-?*/
      if ((t = (*cmp)(m,r,d)) < 0) {                         /*3-5-7*/
	if (chklim && nel >= chklim) {   /* check if already ascending order */
	  char *p;
	  chklim = 0;
	  for (p=l; p<r; p+=size) if ((*cmp)(p,p+size,d) > 0) goto fail;
	  goto nxt;
	}
	fail: goto loopA;                                    /*3-5-7*/
      }
      if (t > 0) {
	if ((*cmp)(l,r,d) <= 0) {mmswap(m,r); goto loopA;}     /*3-5-4*/
	mmrot3(r,m,l); goto loopA;                           /*3-5-2*/
      }
      goto loopB;                                            /*3-5-5*/
    }

    if (t > 0) {                                             /*7-5-?*/
      if ((t = (*cmp)(m,r,d)) > 0) {                         /*7-5-3*/
	if (chklim && nel >= chklim) {   /* check if already ascending order */
	  char *p;
	  chklim = 0;
	  for (p=l; p<r; p+=size) if ((*cmp)(p,p+size,d) < 0) goto fail2;
	  while (l<r) {mmswap(l,r); l+=size; r-=size;}  /* reverse region */
	  goto nxt;
	}
	fail2: mmswap(l,r); goto loopA;                      /*7-5-3*/
      }
      if (t < 0) {
	if ((*cmp)(l,r,d) <= 0) {mmswap(l,m); goto loopB;}   /*7-5-8*/
	mmrot3(l,m,r); goto loopA;                           /*7-5-6*/
      }
      mmswap(l,r); goto loopA;                               /*7-5-5*/
    }

    if ((t = (*cmp)(m,r,d)) < 0)  {goto loopA;}              /*5-5-7*/
    if (t > 0) {mmswap(l,r); goto loopB;}                    /*5-5-3*/

    /* determining splitting type in case 5-5-5 */           /*5-5-5*/
    for (;;) {
      if ((l += size) == r)      goto nxt;                   /*5-5-5*/
      if (l == m) continue;
      if ((t = (*cmp)(l,m,d)) > 0) {mmswap(l,r); l = L; goto loopA;}/*575-5*/
      if (t < 0)                 {mmswap(L,l); l = L; goto loopB;}  /*535-5*/
    }

    loopA: eq_l = 1; eq_r = 1;  /* splitting type A */ /* left <= median < right */
    for (;;) {
      for (;;) {
	if ((l += size) == r)
	  {l -= size; if (l != m) mmswap(m,l); l -= size; goto fin;}
	if (l == m) continue;
	if ((t = (*cmp)(l,m,d)) > 0) {eq_r = 0; break;}
	if (t < 0) eq_l = 0;
      }
      for (;;) {
	if (l == (r -= size))
	  {l -= size; if (l != m) mmswap(m,l); l -= size; goto fin;}
	if (r == m) {m = l; break;}
	if ((t = (*cmp)(r,m,d)) < 0) {eq_l = 0; break;}
	if (t == 0) break;
      }
      mmswap(l,r);    /* swap left and right */
    }

    loopB: eq_l = 1; eq_r = 1;  /* splitting type B */ /* left < median <= right */
    for (;;) {
      for (;;) {
	if (l == (r -= size))
	  {r += size; if (r != m) mmswap(r,m); r += size; goto fin;}
	if (r == m) continue;
	if ((t = (*cmp)(r,m,d)) < 0) {eq_l = 0; break;}
	if (t > 0) eq_r = 0;
      }
      for (;;) {
	if ((l += size) == r)
	  {r += size; if (r != m) mmswap(r,m); r += size; goto fin;}
	if (l == m) {m = r; break;}
	if ((t = (*cmp)(l,m,d)) > 0) {eq_r = 0; break;}
	if (t == 0) break;
      }
      mmswap(l,r);    /* swap left and right */
    }

    fin:
    if (eq_l == 0)                         /* need to sort left side */
      if (eq_r == 0)                       /* need to sort right side */
	if (l-L < R-r) {PUSH(r,R); R = l;} /* sort left side first */
	else           {PUSH(L,l); L = r;} /* sort right side first */
      else R = l;                          /* need to sort left side only */
    else if (eq_r == 0) L = r;             /* need to sort right side only */
    else goto nxt;                         /* need not to sort both sides */
  }
}

char *
ruby_strdup(str)
    const char *str;
{
    char *tmp;
    int len = strlen(str) + 1;

    tmp = xmalloc(len);
    memcpy(tmp, str, len);

    return tmp;
}

char *
ruby_getcwd()
{
#ifdef HAVE_GETCWD
    int size = 200;
    char *buf = xmalloc(size);

    while (!getcwd(buf, size)) {
	if (errno != ERANGE) {
	    free(buf);
	    rb_sys_fail("getcwd");
	}
	size *= 2;
	buf = xrealloc(buf, size);
    }
#else
# ifndef PATH_MAX
#  define PATH_MAX 8192
# endif
    char *buf = xmalloc(PATH_MAX+1);

    if (!getwd(buf)) {
	free(buf);
	rb_sys_fail("getwd");
    }
#endif
    return buf;
}

/* copyright notice for strtod implementation --
 *
 * Copyright (c) 1988-1993 The Regents of the University of California.
 * Copyright (c) 1994 Sun Microsystems, Inc.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 *
 */

#define TRUE 1
#define FALSE 0

static  int     MDMINEXPT       = -323;
static  int     MDMAXEXPT       =  309;
static double powersOf10[] = {	/* Table giving binary powers of 10.  Entry */
    10.0,			/* is 10^2^i.  Used to convert decimal */
    100.0,			/* exponents into floating-point numbers. */
    1.0e4,
    1.0e8,
    1.0e16,
    1.0e32,
    1.0e64,
    1.0e128,
    1.0e256
};

/*
 *----------------------------------------------------------------------
 *
 * strtod --
 *
 *	This procedure converts a floating-point number from an ASCII
 *	decimal representation to internal double-precision format.
 *
 * Results:
 *	The return value is the double-precision floating-point
 *	representation of the characters in string.  If endPtr isn't
 *	NULL, then *endPtr is filled in with the address of the
 *	next character after the last one that was part of the
 *	floating-point number.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

double
ruby_strtod(string, endPtr)
    const char *string;		/* A decimal ASCII floating-point number,
				 * optionally preceded by white space.
				 * Must have form "-I.FE-X", where I is the
				 * integer part of the mantissa, F is the
				 * fractional part of the mantissa, and X
				 * is the exponent.  Either of the signs
				 * may be "+", "-", or omitted.  Either I
				 * or F may be omitted, but both cannot be
				 * ommitted at once. The decimal
				 * point isn't necessary unless F is present.
				 * The "E" may actually be an "e".  E and X
				 * may both be omitted (but not just one).
				 */
    char **endPtr;		/* If non-NULL, store terminating character's
				 * address here. */
{
    int sign, expSign = FALSE;
    double fraction, dblExp, *d;
    register const char *p;
    register int c;
    int exp = 0;		/* Exponent read from "EX" field. */
    int fracExp = 0;		/* Exponent that derives from the fractional
				 * part.  Under normal circumstatnces, it is
				 * the negative of the number of digits in F.
				 * However, if I is very long, the last digits
				 * of I get dropped (otherwise a long I with a
				 * large negative exponent could cause an
				 * unnecessary overflow on I alone).  In this
				 * case, fracExp is incremented one for each
				 * dropped digit. */
    int mantSize = 0;		/* Number of digits in mantissa. */
    int hasPoint = FALSE;	/* Decimal point exists. */
    int hasDigit = FALSE;	/* I or F exists. */
    const char *pMant;		/* Temporarily holds location of mantissa
				 * in string. */
    const char *pExp;		/* Temporarily holds location of exponent
				 * in string. */

    /*
     * Strip off leading blanks and check for a sign.
     */

    errno = 0;
    p = string;
    while (ISSPACE(*p)) {
	p += 1;
    }
    if (*p == '-') {
	sign = TRUE;
	p += 1;
    }
    else {
	if (*p == '+') {
	    p += 1;
	}
	sign = FALSE;
    }

    /*
     * Count the number of digits in the mantissa
     * and also locate the decimal point.
     */

    for ( ; c = *p; p += 1) {
	if (!ISDIGIT(c)) {
	    if (c != '.' || hasPoint) {
		break;
	    }
	    hasPoint = TRUE;
	}
	else {
	    if (hasPoint) { /* already in fractional part */
		fracExp -= 1;
	    }
	    if (mantSize) { /* already in mantissa */
		mantSize += 1;
	    }
	    else if (c != '0') { /* have entered mantissa */
		mantSize += 1;
		pMant = p;
	    }
	    hasDigit = TRUE;
	}
    }

    /*
     * Now suck up the digits in the mantissa.  Use two integers to
     * collect 9 digits each (this is faster than using floating-point).
     * If the mantissa has more than 18 digits, ignore the extras, since
     * they can't affect the value anyway.
     */
    
    pExp  = p;
    if (mantSize) {
	p = pMant;
    }
    if (mantSize > 18) {
	fracExp += (mantSize - 18);
	mantSize = 18;
    }
    if (!hasDigit) {
	fraction = 0.0;
	p = string;
    }
    else {
	int frac1, frac2;
	frac1 = 0;
	for ( ; mantSize > 9; mantSize -= 1) {
	    c = *p;
	    p += 1;
	    if (c == '.') {
		c = *p;
		p += 1;
	    }
	    frac1 = 10*frac1 + (c - '0');
	}
	frac2 = 0;
	for (; mantSize > 0; mantSize -= 1) {
	    c = *p;
	    p += 1;
	    if (c == '.') {
		c = *p;
		p += 1;
	    }
	    frac2 = 10*frac2 + (c - '0');
	}

	/*
	 * Skim off the exponent.
	 */

	p = pExp;
	if ((*p == 'E') || (*p == 'e')) {
	    p += 1;
	    if (*p == '-') {
		expSign = TRUE;
		p += 1;
	    }
	    else {
		if (*p == '+') {
		    p += 1;
		}
		expSign = FALSE;
	    }
	    while (ISDIGIT(*p)) {
		exp = exp * 10 + (*p - '0');
		p += 1;
	    }
	}
	if (expSign) {
	    exp = fracExp - exp;
	}
	else {
	    exp = fracExp + exp;
	}

	/*
	 * Generate a floating-point number that represents the exponent.
	 * Do this by processing the exponent one bit at a time to combine
	 * many powers of 2 of 10. Then combine the exponent with the
	 * fraction.
	 */
    
	if (exp >= MDMAXEXPT - 18) {
	    exp = MDMAXEXPT;
	    errno = ERANGE;
	}
	else if (exp < MDMINEXPT + 18) {
	    exp = MDMINEXPT;
	    errno = ERANGE;
	}
	fracExp = exp;
	exp += 9;
	if (exp < 0) {
	    expSign = TRUE;
	    exp = -exp;
	}
	else {
	    expSign = FALSE;
	}
	dblExp = 1.0;
	for (d = powersOf10; exp != 0; exp >>= 1, d += 1) {
	    if (exp & 01) {
		dblExp *= *d;
	    }
	}
	if (expSign) {
	    fraction = frac1 / dblExp;
	}
	else {
	    fraction = frac1 * dblExp;
	}
	exp = fracExp;
	if (exp < 0) {
	    expSign = TRUE;
	    exp = -exp;
	}
	else {
	    expSign = FALSE;
	}
	dblExp = 1.0;
	for (d = powersOf10; exp != 0; exp >>= 1, d += 1) {
	    if (exp & 01) {
		dblExp *= *d;
	    }
	}
	if (expSign) {
	    fraction += frac2 / dblExp;
	}
	else {
	    fraction += frac2 * dblExp;
	}
    }

    if (endPtr != NULL) {
	*endPtr = (char *) p;
    }

    if (sign) {
	return -fraction;
    }
    return fraction;
}