forked from nothings/stb
-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathstb_sprintf.h
1087 lines (932 loc) · 39.5 KB
/
stb_sprintf.h
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
// stb_sprintf - v1.02 - public domain snprintf() implementation
// originally by Jeff Roberts / RAD Game Tools, 2015/10/20
// http://github.com/nothings/stb
//
// allowed types: sc uidBboXx p AaGgEef n
// lengths : h ll j z t I64 I32 I
//
// Contributors (bugfixes):
// github:d26435
// github:trex78
#ifndef STB_SPRINTF_H_INCLUDE
#define STB_SPRINTF_H_INCLUDE
/*
Single file sprintf replacement.
Originally written by Jeff Roberts at RAD Game Tools - 2015/10/20.
Hereby placed in public domain.
This is a full sprintf replacement that supports everything that
the C runtime sprintfs support, including float/double, 64-bit integers,
hex floats, field parameters (%*.*d stuff), length reads backs, etc.
Why would you need this if sprintf already exists? Well, first off,
it's *much* faster (see below). It's also much smaller than the CRT
versions code-space-wise. We've also added some simple improvements
that are super handy (commas in thousands, callbacks at buffer full,
for example). Finally, the format strings for MSVC and GCC differ
for 64-bit integers (among other small things), so this lets you use
the same format strings in cross platform code.
It uses the standard single file trick of being both the header file
and the source itself. If you just include it normally, you just get
the header file function definitions. To get the code, you include
it from a C or C++ file and define STB_SPRINTF_IMPLEMENTATION first.
It only uses va_args macros from the C runtime to do it's work. It
does cast doubles to S64s and shifts and divides U64s, which does
drag in CRT code on most platforms.
It compiles to roughly 8K with float support, and 4K without.
As a comparison, when using MSVC static libs, calling sprintf drags
in 16K.
API:
====
int stbsp_sprintf( char * buf, char const * fmt, ... )
int stbsp_snprintf( char * buf, int count, char const * fmt, ... )
Convert an arg list into a buffer. stbsp_snprintf always returns
a zero-terminated string (unlike regular snprintf).
int stbsp_vsprintf( char * buf, char const * fmt, va_list va )
int stbsp_vsnprintf( char * buf, int count, char const * fmt, va_list va )
Convert a va_list arg list into a buffer. stbsp_vsnprintf always returns
a zero-terminated string (unlike regular snprintf).
int stbsp_vsprintfcb( STBSP_SPRINTFCB * callback, void * user, char * buf, char const * fmt, va_list va )
typedef char * STBSP_SPRINTFCB( char const * buf, void * user, int len );
Convert into a buffer, calling back every STB_SPRINTF_MIN chars.
Your callback can then copy the chars out, print them or whatever.
This function is actually the workhorse for everything else.
The buffer you pass in must hold at least STB_SPRINTF_MIN characters.
// you return the next buffer to use or 0 to stop converting
void stbsp_set_separators( char comma, char period )
Set the comma and period characters to use.
FLOATS/DOUBLES:
===============
This code uses a internal float->ascii conversion method that uses
doubles with error correction (double-doubles, for ~105 bits of
precision). This conversion is round-trip perfect - that is, an atof
of the values output here will give you the bit-exact double back.
One difference is that our insignificant digits will be different than
with MSVC or GCC (but they don't match each other either). We also
don't attempt to find the minimum length matching float (pre-MSVC15
doesn't either).
If you don't need float or doubles at all, define STB_SPRINTF_NOFLOAT
and you'll save 4K of code space.
64-BIT INTS:
============
This library also supports 64-bit integers and you can use MSVC style or
GCC style indicators (%I64d or %lld). It supports the C99 specifiers
for size_t and ptr_diff_t (%jd %zd) as well.
EXTRAS:
=======
Like some GCCs, for integers and floats, you can use a ' (single quote)
specifier and commas will be inserted on the thousands: "%'d" on 12345
would print 12,345.
For integers and floats, you can use a "$" specifier and the number
will be converted to float and then divided to get kilo, mega, giga or
tera and then printed, so "%$d" 1024 is "1.0 k", "%$.2d" 2536000 is
"2.42 m", etc.
In addition to octal and hexadecimal conversions, you can print
integers in binary: "%b" for 256 would print 100.
PERFORMANCE vs MSVC 2008 32-/64-bit (GCC is even slower than MSVC):
===================================================================
"%d" across all 32-bit ints (4.8x/4.0x faster than 32-/64-bit MSVC)
"%24d" across all 32-bit ints (4.5x/4.2x faster)
"%x" across all 32-bit ints (4.5x/3.8x faster)
"%08x" across all 32-bit ints (4.3x/3.8x faster)
"%f" across e-10 to e+10 floats (7.3x/6.0x faster)
"%e" across e-10 to e+10 floats (8.1x/6.0x faster)
"%g" across e-10 to e+10 floats (10.0x/7.1x faster)
"%f" for values near e-300 (7.9x/6.5x faster)
"%f" for values near e+300 (10.0x/9.1x faster)
"%e" for values near e-300 (10.1x/7.0x faster)
"%e" for values near e+300 (9.2x/6.0x faster)
"%.320f" for values near e-300 (12.6x/11.2x faster)
"%a" for random values (8.6x/4.3x faster)
"%I64d" for 64-bits with 32-bit values (4.8x/3.4x faster)
"%I64d" for 64-bits > 32-bit values (4.9x/5.5x faster)
"%s%s%s" for 64 char strings (7.1x/7.3x faster)
"...512 char string..." ( 35.0x/32.5x faster!)
*/
#if defined(__has_feature)
#if __has_feature(address_sanitizer)
#define STBI__ASAN __attribute__((no_sanitize("address")))
#endif
#endif
#ifndef STBI__ASAN
#define STBI__ASAN
#endif
#ifdef STB_SPRINTF_STATIC
#define STBSP__PUBLICDEC static
#define STBSP__PUBLICDEF static STBI__ASAN
#else
#ifdef __cplusplus
#define STBSP__PUBLICDEC extern "C"
#define STBSP__PUBLICDEF extern "C" STBI__ASAN
#else
#define STBSP__PUBLICDEC extern
#define STBSP__PUBLICDEF STBI__ASAN
#endif
#endif
#include <stdarg.h> // for va_list()
#ifndef STB_SPRINTF_MIN
#define STB_SPRINTF_MIN 512 // how many characters per callback
#endif
typedef char * STBSP_SPRINTFCB( char * buf, void * user, int len );
#ifndef STB_SPRINTF_DECORATE
#define STB_SPRINTF_DECORATE(name) stbsp_##name // define this before including if you want to change the names
#endif
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsprintf )( char * buf, char const * fmt, va_list va );
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsnprintf )( char * buf, int count, char const * fmt, va_list va );
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( sprintf ) ( char * buf, char const * fmt, ... );
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( snprintf )( char * buf, int count, char const * fmt, ... );
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsprintfcb )( STBSP_SPRINTFCB * callback, void * user, char * buf, char const * fmt, va_list va );
STBSP__PUBLICDEF void STB_SPRINTF_DECORATE( set_separators )( char comma, char period );
#endif // STB_SPRINTF_H_INCLUDE
#ifdef STB_SPRINTF_IMPLEMENTATION
#include <stdlib.h> // for va_arg()
#define stbsp__uint32 unsigned int
#define stbsp__int32 signed int
#ifdef _MSC_VER
#define stbsp__uint64 unsigned __int64
#define stbsp__int64 signed __int64
#else
#define stbsp__uint64 unsigned long long
#define stbsp__int64 signed long long
#endif
#define stbsp__uint16 unsigned short
#ifndef stbsp__uintptr
#if defined(__ppc64__) || defined(__aarch64__) || defined(_M_X64) || defined(__x86_64__) || defined(__x86_64)
#define stbsp__uintptr stbsp__uint64
#else
#define stbsp__uintptr stbsp__uint32
#endif
#endif
#ifndef STB_SPRINTF_MSVC_MODE // used for MSVC2013 and earlier (MSVC2015 matches GCC)
#if defined(_MSC_VER) && (_MSC_VER<1900)
#define STB_SPRINTF_MSVC_MODE
#endif
#endif
#ifdef STB_SPRINTF_NOUNALIGNED // define this before inclusion to force stbsp_sprintf to always use aligned accesses
#define STBSP__UNALIGNED(code)
#else
#define STBSP__UNALIGNED(code) code
#endif
#ifndef STB_SPRINTF_NOFLOAT
// internal float utility functions
static stbsp__int32 stbsp__real_to_str( char const * * start, stbsp__uint32 * len, char *out, stbsp__int32 * decimal_pos, double value, stbsp__uint32 frac_digits );
static stbsp__int32 stbsp__real_to_parts( stbsp__int64 * bits, stbsp__int32 * expo, double value );
#define STBSP__SPECIAL 0x7000
#endif
static char stbsp__period='.';
static char stbsp__comma=',';
static char stbsp__digitpair[201]="00010203040506070809101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899";
STBSP__PUBLICDEF void STB_SPRINTF_DECORATE( set_separators )( char pcomma, char pperiod )
{
stbsp__period=pperiod;
stbsp__comma=pcomma;
}
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsprintfcb )( STBSP_SPRINTFCB * callback, void * user, char * buf, char const * fmt, va_list va )
{
static char hex[]="0123456789abcdefxp";
static char hexu[]="0123456789ABCDEFXP";
char * bf;
char const * f;
int tlen = 0;
bf = buf;
f = fmt;
for(;;)
{
stbsp__int32 fw,pr,tz; stbsp__uint32 fl;
#define STBSP__LEFTJUST 1
#define STBSP__LEADINGPLUS 2
#define STBSP__LEADINGSPACE 4
#define STBSP__LEADING_0X 8
#define STBSP__LEADINGZERO 16
#define STBSP__INTMAX 32
#define STBSP__TRIPLET_COMMA 64
#define STBSP__NEGATIVE 128
#define STBSP__METRIC_SUFFIX 256
#define STBSP__HALFWIDTH 512
// macros for the callback buffer stuff
#define stbsp__chk_cb_bufL(bytes) { int len = (int)(bf-buf); if ((len+(bytes))>=STB_SPRINTF_MIN) { tlen+=len; if (0==(bf=buf=callback(buf,user,len))) goto done; } }
#define stbsp__chk_cb_buf(bytes) { if ( callback ) { stbsp__chk_cb_bufL(bytes); } }
#define stbsp__flush_cb() { stbsp__chk_cb_bufL(STB_SPRINTF_MIN-1); } //flush if there is even one byte in the buffer
#define stbsp__cb_buf_clamp(cl,v) cl = v; if ( callback ) { int lg = STB_SPRINTF_MIN-(int)(bf-buf); if (cl>lg) cl=lg; }
// fast copy everything up to the next % (or end of string)
for(;;)
{
while (((stbsp__uintptr)f)&3)
{
schk1: if (f[0]=='%') goto scandd;
schk2: if (f[0]==0) goto endfmt;
stbsp__chk_cb_buf(1); *bf++=f[0]; ++f;
}
for(;;)
{
// Check if the next 4 bytes contain %(0x25) or end of string.
// Using the 'hasless' trick:
// https://graphics.stanford.edu/~seander/bithacks.html#HasLessInWord
stbsp__uint32 v,c;
v=*(stbsp__uint32*)f; c=(~v)&0x80808080;
if (((v^0x25252525)-0x01010101)&c) goto schk1;
if ((v-0x01010101)&c) goto schk2;
if (callback) if ((STB_SPRINTF_MIN-(int)(bf-buf))<4) goto schk1;
*(stbsp__uint32*)bf=v; bf+=4; f+=4;
}
} scandd:
++f;
// ok, we have a percent, read the modifiers first
fw = 0; pr = -1; fl = 0; tz = 0;
// flags
for(;;)
{
switch(f[0])
{
// if we have left justify
case '-': fl|=STBSP__LEFTJUST; ++f; continue;
// if we have leading plus
case '+': fl|=STBSP__LEADINGPLUS; ++f; continue;
// if we have leading space
case ' ': fl|=STBSP__LEADINGSPACE; ++f; continue;
// if we have leading 0x
case '#': fl|=STBSP__LEADING_0X; ++f; continue;
// if we have thousand commas
case '\'': fl|=STBSP__TRIPLET_COMMA; ++f; continue;
// if we have kilo marker
case '$': fl|=STBSP__METRIC_SUFFIX; ++f; continue;
// if we have leading zero
case '0': fl|=STBSP__LEADINGZERO; ++f; goto flags_done;
default: goto flags_done;
}
}
flags_done:
// get the field width
if ( f[0] == '*' ) {fw = va_arg(va,stbsp__uint32); ++f;} else { while (( f[0] >= '0' ) && ( f[0] <= '9' )) { fw = fw * 10 + f[0] - '0'; f++; } }
// get the precision
if ( f[0]=='.' ) { ++f; if ( f[0] == '*' ) {pr = va_arg(va,stbsp__uint32); ++f;} else { pr = 0; while (( f[0] >= '0' ) && ( f[0] <= '9' )) { pr = pr * 10 + f[0] - '0'; f++; } } }
// handle integer size overrides
switch(f[0])
{
// are we halfwidth?
case 'h': fl|=STBSP__HALFWIDTH; ++f; break;
// are we 64-bit (unix style)
case 'l': ++f; if ( f[0]=='l') { fl|=STBSP__INTMAX; ++f; } break;
// are we 64-bit on intmax? (c99)
case 'j': fl|=STBSP__INTMAX; ++f; break;
// are we 64-bit on size_t or ptrdiff_t? (c99)
case 'z': case 't': fl|=((sizeof(char*)==8)?STBSP__INTMAX:0); ++f; break;
// are we 64-bit (msft style)
case 'I': if ( ( f[1]=='6') && ( f[2]=='4') ) { fl|=STBSP__INTMAX; f+=3; }
else if ( ( f[1]=='3') && ( f[2]=='2') ) { f+=3; }
else { fl|=((sizeof(void*)==8)?STBSP__INTMAX:0); ++f; } break;
default: break;
}
// handle each replacement
switch( f[0] )
{
#define STBSP__NUMSZ 512 // big enough for e308 (with commas) or e-307
char num[STBSP__NUMSZ];
char lead[8];
char tail[8];
char *s;
char const *h;
stbsp__uint32 l,n,cs;
stbsp__uint64 n64;
#ifndef STB_SPRINTF_NOFLOAT
double fv;
#endif
stbsp__int32 dp; char const * sn;
case 's':
// get the string
s = va_arg(va,char*); if (s==0) s = (char*)"null";
// get the length
sn = s;
for(;;)
{
if ((((stbsp__uintptr)sn)&3)==0) break;
lchk:
if (sn[0]==0) goto ld;
++sn;
}
n = 0xffffffff;
if (pr>=0) { n=(stbsp__uint32)(sn-s); if (n>=(stbsp__uint32)pr) goto ld; n=((stbsp__uint32)(pr-n))>>2; }
while(n)
{
stbsp__uint32 v=*(stbsp__uint32*)sn;
if ((v-0x01010101)&(~v)&0x80808080UL) goto lchk;
sn+=4;
--n;
}
goto lchk;
ld:
l = (stbsp__uint32) ( sn - s );
// clamp to precision
if ( l > (stbsp__uint32)pr ) l = pr;
lead[0]=0; tail[0]=0; pr = 0; dp = 0; cs = 0;
// copy the string in
goto scopy;
case 'c': // char
// get the character
s = num + STBSP__NUMSZ -1; *s = (char)va_arg(va,int);
l = 1;
lead[0]=0; tail[0]=0; pr = 0; dp = 0; cs = 0;
goto scopy;
case 'n': // weird write-bytes specifier
{ int * d = va_arg(va,int*);
*d = tlen + (int)( bf - buf ); }
break;
#ifdef STB_SPRINTF_NOFLOAT
case 'A': // float
case 'a': // hex float
case 'G': // float
case 'g': // float
case 'E': // float
case 'e': // float
case 'f': // float
va_arg(va,double); // eat it
s = (char*)"No float";
l = 8;
lead[0]=0; tail[0]=0; pr = 0; dp = 0; cs = 0;
goto scopy;
#else
case 'A': // float
h=hexu;
goto hexfloat;
case 'a': // hex float
h=hex;
hexfloat:
fv = va_arg(va,double);
if (pr==-1) pr=6; // default is 6
// read the double into a string
if ( stbsp__real_to_parts( (stbsp__int64*)&n64, &dp, fv ) )
fl |= STBSP__NEGATIVE;
s = num+64;
// sign
lead[0]=0; if (fl&STBSP__NEGATIVE) { lead[0]=1; lead[1]='-'; } else if (fl&STBSP__LEADINGSPACE) { lead[0]=1; lead[1]=' '; } else if (fl&STBSP__LEADINGPLUS) { lead[0]=1; lead[1]='+'; };
if (dp==-1023) dp=(n64)?-1022:0; else n64|=(((stbsp__uint64)1)<<52);
n64<<=(64-56);
if (pr<15) n64+=((((stbsp__uint64)8)<<56)>>(pr*4));
// add leading chars
#ifdef STB_SPRINTF_MSVC_MODE
*s++='0';*s++='x';
#else
lead[1+lead[0]]='0'; lead[2+lead[0]]='x'; lead[0]+=2;
#endif
*s++=h[(n64>>60)&15]; n64<<=4;
if ( pr ) *s++=stbsp__period;
sn = s;
// print the bits
n = pr; if (n>13) n = 13; if (pr>(stbsp__int32)n) tz=pr-n; pr = 0;
while(n--) { *s++=h[(n64>>60)&15]; n64<<=4; }
// print the expo
tail[1]=h[17];
if (dp<0) { tail[2]='-'; dp=-dp;} else tail[2]='+';
n = (dp>=1000)?6:((dp>=100)?5:((dp>=10)?4:3));
tail[0]=(char)n;
for(;;) { tail[n]='0'+dp%10; if (n<=3) break; --n; dp/=10; }
dp = (int)(s-sn);
l = (int)(s-(num+64));
s = num+64;
cs = 1 + (3<<24);
goto scopy;
case 'G': // float
h=hexu;
goto dosmallfloat;
case 'g': // float
h=hex;
dosmallfloat:
fv = va_arg(va,double);
if (pr==-1) pr=6; else if (pr==0) pr = 1; // default is 6
// read the double into a string
if ( stbsp__real_to_str( &sn, &l, num, &dp, fv, (pr-1)|0x80000000 ) )
fl |= STBSP__NEGATIVE;
// clamp the precision and delete extra zeros after clamp
n = pr;
if ( l > (stbsp__uint32)pr ) l = pr; while ((l>1)&&(pr)&&(sn[l-1]=='0')) { --pr; --l; }
// should we use %e
if ((dp<=-4)||(dp>(stbsp__int32)n))
{
if ( pr > (stbsp__int32)l ) pr = l-1; else if ( pr ) --pr; // when using %e, there is one digit before the decimal
goto doexpfromg;
}
// this is the insane action to get the pr to match %g sematics for %f
if(dp>0) { pr=(dp<(stbsp__int32)l)?l-dp:0; } else { pr = -dp+((pr>(stbsp__int32)l)?l:pr); }
goto dofloatfromg;
case 'E': // float
h=hexu;
goto doexp;
case 'e': // float
h=hex;
doexp:
fv = va_arg(va,double);
if (pr==-1) pr=6; // default is 6
// read the double into a string
if ( stbsp__real_to_str( &sn, &l, num, &dp, fv, pr|0x80000000 ) )
fl |= STBSP__NEGATIVE;
doexpfromg:
tail[0]=0;
lead[0]=0; if (fl&STBSP__NEGATIVE) { lead[0]=1; lead[1]='-'; } else if (fl&STBSP__LEADINGSPACE) { lead[0]=1; lead[1]=' '; } else if (fl&STBSP__LEADINGPLUS) { lead[0]=1; lead[1]='+'; };
if ( dp == STBSP__SPECIAL ) { s=(char*)sn; cs=0; pr=0; goto scopy; }
s=num+64;
// handle leading chars
*s++=sn[0];
if (pr) *s++=stbsp__period;
// handle after decimal
if ((l-1)>(stbsp__uint32)pr) l=pr+1;
for(n=1;n<l;n++) *s++=sn[n];
// trailing zeros
tz = pr-(l-1); pr=0;
// dump expo
tail[1]=h[0xe];
dp -= 1;
if (dp<0) { tail[2]='-'; dp=-dp;} else tail[2]='+';
#ifdef STB_SPRINTF_MSVC_MODE
n = 5;
#else
n = (dp>=100)?5:4;
#endif
tail[0]=(char)n;
for(;;) { tail[n]='0'+dp%10; if (n<=3) break; --n; dp/=10; }
cs = 1 + (3<<24); // how many tens
goto flt_lead;
case 'f': // float
fv = va_arg(va,double);
doafloat:
// do kilos
if (fl&STBSP__METRIC_SUFFIX) {while(fl<0x4000000) { if ((fv<1024.0) && (fv>-1024.0)) break; fv/=1024.0; fl+=0x1000000; }}
if (pr==-1) pr=6; // default is 6
// read the double into a string
if ( stbsp__real_to_str( &sn, &l, num, &dp, fv, pr ) )
fl |= STBSP__NEGATIVE;
dofloatfromg:
tail[0]=0;
// sign
lead[0]=0; if (fl&STBSP__NEGATIVE) { lead[0]=1; lead[1]='-'; } else if (fl&STBSP__LEADINGSPACE) { lead[0]=1; lead[1]=' '; } else if (fl&STBSP__LEADINGPLUS) { lead[0]=1; lead[1]='+'; };
if ( dp == STBSP__SPECIAL ) { s=(char*)sn; cs=0; pr=0; goto scopy; }
s=num+64;
// handle the three decimal varieties
if (dp<=0)
{
stbsp__int32 i;
// handle 0.000*000xxxx
*s++='0'; if (pr) *s++=stbsp__period;
n=-dp; if((stbsp__int32)n>pr) n=pr; i=n; while(i) { if ((((stbsp__uintptr)s)&3)==0) break; *s++='0'; --i; } while(i>=4) { *(stbsp__uint32*)s=0x30303030; s+=4; i-=4; } while(i) { *s++='0'; --i; }
if ((stbsp__int32)(l+n)>pr) l=pr-n; i=l; while(i) { *s++=*sn++; --i; }
tz = pr-(n+l);
cs = 1 + (3<<24); // how many tens did we write (for commas below)
}
else
{
cs = (fl&STBSP__TRIPLET_COMMA)?((600-(stbsp__uint32)dp)%3):0;
if ((stbsp__uint32)dp>=l)
{
// handle xxxx000*000.0
n=0; for(;;) { if ((fl&STBSP__TRIPLET_COMMA) && (++cs==4)) { cs = 0; *s++=stbsp__comma; } else { *s++=sn[n]; ++n; if (n>=l) break; } }
if (n<(stbsp__uint32)dp)
{
n = dp - n;
if ((fl&STBSP__TRIPLET_COMMA)==0) { while(n) { if ((((stbsp__uintptr)s)&3)==0) break; *s++='0'; --n; } while(n>=4) { *(stbsp__uint32*)s=0x30303030; s+=4; n-=4; } }
while(n) { if ((fl&STBSP__TRIPLET_COMMA) && (++cs==4)) { cs = 0; *s++=stbsp__comma; } else { *s++='0'; --n; } }
}
cs = (int)(s-(num+64)) + (3<<24); // cs is how many tens
if (pr) { *s++=stbsp__period; tz=pr;}
}
else
{
// handle xxxxx.xxxx000*000
n=0; for(;;) { if ((fl&STBSP__TRIPLET_COMMA) && (++cs==4)) { cs = 0; *s++=stbsp__comma; } else { *s++=sn[n]; ++n; if (n>=(stbsp__uint32)dp) break; } }
cs = (int)(s-(num+64)) + (3<<24); // cs is how many tens
if (pr) *s++=stbsp__period;
if ((l-dp)>(stbsp__uint32)pr) l=pr+dp;
while(n<l) { *s++=sn[n]; ++n; }
tz = pr-(l-dp);
}
}
pr = 0;
// handle k,m,g,t
if (fl&STBSP__METRIC_SUFFIX) { tail[0]=1; tail[1]=' '; { if (fl>>24) { tail[2]="_kmgt"[fl>>24]; tail[0]=2; } } };
flt_lead:
// get the length that we copied
l = (stbsp__uint32) ( s-(num+64) );
s=num+64;
goto scopy;
#endif
case 'B': // upper binary
h = hexu;
goto binary;
case 'b': // lower binary
h = hex;
binary:
lead[0]=0;
if (fl&STBSP__LEADING_0X) { lead[0]=2;lead[1]='0';lead[2]=h[0xb]; }
l=(8<<4)|(1<<8);
goto radixnum;
case 'o': // octal
h = hexu;
lead[0]=0;
if (fl&STBSP__LEADING_0X) { lead[0]=1;lead[1]='0'; }
l=(3<<4)|(3<<8);
goto radixnum;
case 'p': // pointer
fl |= (sizeof(void*)==8)?STBSP__INTMAX:0;
pr = sizeof(void*)*2;
fl &= ~STBSP__LEADINGZERO; // 'p' only prints the pointer with zeros
// drop through to X
case 'X': // upper binary
h = hexu;
goto dohexb;
case 'x': // lower binary
h = hex; dohexb:
l=(4<<4)|(4<<8);
lead[0]=0;
if (fl&STBSP__LEADING_0X) { lead[0]=2;lead[1]='0';lead[2]=h[16]; }
radixnum:
// get the number
if ( fl&STBSP__INTMAX )
n64 = va_arg(va,stbsp__uint64);
else
n64 = va_arg(va,stbsp__uint32);
s = num + STBSP__NUMSZ; dp = 0;
// clear tail, and clear leading if value is zero
tail[0]=0; if (n64==0) { lead[0]=0; if (pr==0) { l=0; cs = ( ((l>>4)&15)) << 24; goto scopy; } }
// convert to string
for(;;) { *--s = h[n64&((1<<(l>>8))-1)]; n64>>=(l>>8); if ( ! ( (n64) || ((stbsp__int32) ( (num+STBSP__NUMSZ) - s ) < pr ) ) ) break; if ( fl&STBSP__TRIPLET_COMMA) { ++l; if ((l&15)==((l>>4)&15)) { l&=~15; *--s=stbsp__comma; } } };
// get the tens and the comma pos
cs = (stbsp__uint32) ( (num+STBSP__NUMSZ) - s ) + ( ( ((l>>4)&15)) << 24 );
// get the length that we copied
l = (stbsp__uint32) ( (num+STBSP__NUMSZ) - s );
// copy it
goto scopy;
case 'u': // unsigned
case 'i':
case 'd': // integer
// get the integer and abs it
if ( fl&STBSP__INTMAX )
{
stbsp__int64 i64 = va_arg(va,stbsp__int64); n64 = (stbsp__uint64)i64; if ((f[0]!='u') && (i64<0)) { n64=(stbsp__uint64)-i64; fl|=STBSP__NEGATIVE; }
}
else
{
stbsp__int32 i = va_arg(va,stbsp__int32); n64 = (stbsp__uint32)i; if ((f[0]!='u') && (i<0)) { n64=(stbsp__uint32)-i; fl|=STBSP__NEGATIVE; }
}
#ifndef STB_SPRINTF_NOFLOAT
if (fl&STBSP__METRIC_SUFFIX) { if (n64<1024) pr=0; else if (pr==-1) pr=1; fv=(double)(stbsp__int64)n64; goto doafloat; }
#endif
// convert to string
s = num+STBSP__NUMSZ; l=0;
for(;;)
{
// do in 32-bit chunks (avoid lots of 64-bit divides even with constant denominators)
char * o=s-8;
if (n64>=100000000) { n = (stbsp__uint32)( n64 % 100000000); n64 /= 100000000; } else {n = (stbsp__uint32)n64; n64 = 0; }
if((fl&STBSP__TRIPLET_COMMA)==0) { while(n) { s-=2; *(stbsp__uint16*)s=*(stbsp__uint16*)&stbsp__digitpair[(n%100)*2]; n/=100; } }
while (n) { if ( ( fl&STBSP__TRIPLET_COMMA) && (l++==3) ) { l=0; *--s=stbsp__comma; --o; } else { *--s=(char)(n%10)+'0'; n/=10; } }
if (n64==0) { if ((s[0]=='0') && (s!=(num+STBSP__NUMSZ))) ++s; break; }
while (s!=o) if ( ( fl&STBSP__TRIPLET_COMMA) && (l++==3) ) { l=0; *--s=stbsp__comma; --o; } else { *--s='0'; }
}
tail[0]=0;
// sign
lead[0]=0; if (fl&STBSP__NEGATIVE) { lead[0]=1; lead[1]='-'; } else if (fl&STBSP__LEADINGSPACE) { lead[0]=1; lead[1]=' '; } else if (fl&STBSP__LEADINGPLUS) { lead[0]=1; lead[1]='+'; };
// get the length that we copied
l = (stbsp__uint32) ( (num+STBSP__NUMSZ) - s ); if ( l == 0 ) { *--s='0'; l = 1; }
cs = l + (3<<24);
if (pr<0) pr = 0;
scopy:
// get fw=leading/trailing space, pr=leading zeros
if (pr<(stbsp__int32)l) pr = l;
n = pr + lead[0] + tail[0] + tz;
if (fw<(stbsp__int32)n) fw = n;
fw -= n;
pr -= l;
// handle right justify and leading zeros
if ( (fl&STBSP__LEFTJUST)==0 )
{
if (fl&STBSP__LEADINGZERO) // if leading zeros, everything is in pr
{
pr = (fw>pr)?fw:pr;
fw = 0;
}
else
{
fl &= ~STBSP__TRIPLET_COMMA; // if no leading zeros, then no commas
}
}
// copy the spaces and/or zeros
if (fw+pr)
{
stbsp__int32 i; stbsp__uint32 c;
// copy leading spaces (or when doing %8.4d stuff)
if ( (fl&STBSP__LEFTJUST)==0 ) while(fw>0) { stbsp__cb_buf_clamp(i,fw); fw -= i; while(i) { if ((((stbsp__uintptr)bf)&3)==0) break; *bf++=' '; --i; } while(i>=4) { *(stbsp__uint32*)bf=0x20202020; bf+=4; i-=4; } while (i) {*bf++=' '; --i;} stbsp__chk_cb_buf(1); }
// copy leader
sn=lead+1; while(lead[0]) { stbsp__cb_buf_clamp(i,lead[0]); lead[0] -= (char)i; while (i) {*bf++=*sn++; --i;} stbsp__chk_cb_buf(1); }
// copy leading zeros
c = cs >> 24; cs &= 0xffffff;
cs = (fl&STBSP__TRIPLET_COMMA)?((stbsp__uint32)(c-((pr+cs)%(c+1)))):0;
while(pr>0) { stbsp__cb_buf_clamp(i,pr); pr -= i; if((fl&STBSP__TRIPLET_COMMA)==0) { while(i) { if ((((stbsp__uintptr)bf)&3)==0) break; *bf++='0'; --i; } while(i>=4) { *(stbsp__uint32*)bf=0x30303030; bf+=4; i-=4; } } while (i) { if((fl&STBSP__TRIPLET_COMMA) && (cs++==c)) { cs = 0; *bf++=stbsp__comma; } else *bf++='0'; --i; } stbsp__chk_cb_buf(1); }
}
// copy leader if there is still one
sn=lead+1; while(lead[0]) { stbsp__int32 i; stbsp__cb_buf_clamp(i,lead[0]); lead[0] -= (char)i; while (i) {*bf++=*sn++; --i;} stbsp__chk_cb_buf(1); }
// copy the string
n = l; while (n) { stbsp__int32 i; stbsp__cb_buf_clamp(i,n); n-=i; STBSP__UNALIGNED( while(i>=4) { *(stbsp__uint32*)bf=*(stbsp__uint32*)s; bf+=4; s+=4; i-=4; } ) while (i) {*bf++=*s++; --i;} stbsp__chk_cb_buf(1); }
// copy trailing zeros
while(tz) { stbsp__int32 i; stbsp__cb_buf_clamp(i,tz); tz -= i; while(i) { if ((((stbsp__uintptr)bf)&3)==0) break; *bf++='0'; --i; } while(i>=4) { *(stbsp__uint32*)bf=0x30303030; bf+=4; i-=4; } while (i) {*bf++='0'; --i;} stbsp__chk_cb_buf(1); }
// copy tail if there is one
sn=tail+1; while(tail[0]) { stbsp__int32 i; stbsp__cb_buf_clamp(i,tail[0]); tail[0] -= (char)i; while (i) {*bf++=*sn++; --i;} stbsp__chk_cb_buf(1); }
// handle the left justify
if (fl&STBSP__LEFTJUST) if (fw>0) { while (fw) { stbsp__int32 i; stbsp__cb_buf_clamp(i,fw); fw-=i; while(i) { if ((((stbsp__uintptr)bf)&3)==0) break; *bf++=' '; --i; } while(i>=4) { *(stbsp__uint32*)bf=0x20202020; bf+=4; i-=4; } while (i--) *bf++=' '; stbsp__chk_cb_buf(1); } }
break;
default: // unknown, just copy code
s = num + STBSP__NUMSZ -1; *s = f[0];
l = 1;
fw=pr=fl=0;
lead[0]=0; tail[0]=0; pr = 0; dp = 0; cs = 0;
goto scopy;
}
++f;
}
endfmt:
if (!callback)
*bf = 0;
else
stbsp__flush_cb();
done:
return tlen + (int)(bf-buf);
}
// cleanup
#undef STBSP__LEFTJUST
#undef STBSP__LEADINGPLUS
#undef STBSP__LEADINGSPACE
#undef STBSP__LEADING_0X
#undef STBSP__LEADINGZERO
#undef STBSP__INTMAX
#undef STBSP__TRIPLET_COMMA
#undef STBSP__NEGATIVE
#undef STBSP__METRIC_SUFFIX
#undef STBSP__NUMSZ
#undef stbsp__chk_cb_bufL
#undef stbsp__chk_cb_buf
#undef stbsp__flush_cb
#undef stbsp__cb_buf_clamp
// ============================================================================
// wrapper functions
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( sprintf )( char * buf, char const * fmt, ... )
{
int result;
va_list va;
va_start( va, fmt );
result = STB_SPRINTF_DECORATE( vsprintfcb )( 0, 0, buf, fmt, va );
va_end(va);
return result;
}
typedef struct stbsp__context
{
char * buf;
int count;
char tmp[ STB_SPRINTF_MIN ];
} stbsp__context;
static char * stbsp__clamp_callback( char * buf, void * user, int len )
{
stbsp__context * c = (stbsp__context*)user;
if ( len > c->count ) len = c->count;
if (len)
{
if ( buf != c->buf )
{
char * s, * d, * se;
d = c->buf; s = buf; se = buf+len;
do{ *d++ = *s++; } while (s<se);
}
c->buf += len;
c->count -= len;
}
if ( c->count <= 0 ) return 0;
return ( c->count >= STB_SPRINTF_MIN ) ? c->buf : c->tmp; // go direct into buffer if you can
}
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsnprintf )( char * buf, int count, char const * fmt, va_list va )
{
stbsp__context c;
int l;
if ( count == 0 )
return 0;
c.buf = buf;
c.count = count;
STB_SPRINTF_DECORATE( vsprintfcb )( stbsp__clamp_callback, &c, stbsp__clamp_callback(0,&c,0), fmt, va );
// zero-terminate
l = (int)( c.buf - buf );
if ( l >= count ) // should never be greater, only equal (or less) than count
l = count - 1;
buf[l] = 0;
return l;
}
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( snprintf )( char * buf, int count, char const * fmt, ... )
{
int result;
va_list va;
va_start( va, fmt );
result = STB_SPRINTF_DECORATE( vsnprintf )( buf, count, fmt, va );
va_end(va);
return result;
}
STBSP__PUBLICDEF int STB_SPRINTF_DECORATE( vsprintf )( char * buf, char const * fmt, va_list va )
{
return STB_SPRINTF_DECORATE( vsprintfcb )( 0, 0, buf, fmt, va );
}
// =======================================================================
// low level float utility functions
#ifndef STB_SPRINTF_NOFLOAT
// copies d to bits w/ strict aliasing (this compiles to nothing on /Ox)
#define STBSP__COPYFP(dest,src) { int cn; for(cn=0;cn<8;cn++) ((char*)&dest)[cn]=((char*)&src)[cn]; }
// get float info
static stbsp__int32 stbsp__real_to_parts( stbsp__int64 * bits, stbsp__int32 * expo, double value )
{
double d;
stbsp__int64 b = 0;
// load value and round at the frac_digits
d = value;
STBSP__COPYFP( b, d );
*bits = b & ((((stbsp__uint64)1)<<52)-1);
*expo = (stbsp__int32) (((b >> 52) & 2047)-1023);
return (stbsp__int32)(b >> 63);
}
static double const stbsp__bot[23]={1e+000,1e+001,1e+002,1e+003,1e+004,1e+005,1e+006,1e+007,1e+008,1e+009,1e+010,1e+011,1e+012,1e+013,1e+014,1e+015,1e+016,1e+017,1e+018,1e+019,1e+020,1e+021,1e+022};
static double const stbsp__negbot[22]={1e-001,1e-002,1e-003,1e-004,1e-005,1e-006,1e-007,1e-008,1e-009,1e-010,1e-011,1e-012,1e-013,1e-014,1e-015,1e-016,1e-017,1e-018,1e-019,1e-020,1e-021,1e-022};
static double const stbsp__negboterr[22]={-5.551115123125783e-018,-2.0816681711721684e-019,-2.0816681711721686e-020,-4.7921736023859299e-021,-8.1803053914031305e-022,4.5251888174113741e-023,4.5251888174113739e-024,-2.0922560830128471e-025,-6.2281591457779853e-026,-3.6432197315497743e-027,6.0503030718060191e-028,2.0113352370744385e-029,-3.0373745563400371e-030,1.1806906454401013e-032,-7.7705399876661076e-032,2.0902213275965398e-033,-7.1542424054621921e-034,-7.1542424054621926e-035,2.4754073164739869e-036,5.4846728545790429e-037,9.2462547772103625e-038,-4.8596774326570872e-039};
static double const stbsp__top[13]={1e+023,1e+046,1e+069,1e+092,1e+115,1e+138,1e+161,1e+184,1e+207,1e+230,1e+253,1e+276,1e+299};
static double const stbsp__negtop[13]={1e-023,1e-046,1e-069,1e-092,1e-115,1e-138,1e-161,1e-184,1e-207,1e-230,1e-253,1e-276,1e-299};
static double const stbsp__toperr[13]={8388608,6.8601809640529717e+028,-7.253143638152921e+052,-4.3377296974619174e+075,-1.5559416129466825e+098,-3.2841562489204913e+121,-3.7745893248228135e+144,-1.7356668416969134e+167,-3.8893577551088374e+190,-9.9566444326005119e+213,6.3641293062232429e+236,-5.2069140800249813e+259,-5.2504760255204387e+282};
static double const stbsp__negtoperr[13]={3.9565301985100693e-040,-2.299904345391321e-063,3.6506201437945798e-086,1.1875228833981544e-109,-5.0644902316928607e-132,-6.7156837247865426e-155,-2.812077463003139e-178,-5.7778912386589953e-201,7.4997100559334532e-224,-4.6439668915134491e-247,-6.3691100762962136e-270,-9.436808465446358e-293,8.0970921678014997e-317};
#if defined(_MSC_VER) && (_MSC_VER<=1200)
static stbsp__uint64 const stbsp__powten[20]={1,10,100,1000, 10000,100000,1000000,10000000, 100000000,1000000000,10000000000,100000000000, 1000000000000,10000000000000,100000000000000,1000000000000000, 10000000000000000,100000000000000000,1000000000000000000,10000000000000000000U };
#define stbsp__tento19th ((stbsp__uint64)1000000000000000000)
#else
static stbsp__uint64 const stbsp__powten[20]={1,10,100,1000, 10000,100000,1000000,10000000, 100000000,1000000000,10000000000ULL,100000000000ULL, 1000000000000ULL,10000000000000ULL,100000000000000ULL,1000000000000000ULL, 10000000000000000ULL,100000000000000000ULL,1000000000000000000ULL,10000000000000000000ULL };
#define stbsp__tento19th (1000000000000000000ULL)
#endif
#define stbsp__ddmulthi(oh,ol,xh,yh) \
{ \
double ahi=0,alo,bhi=0,blo; \
stbsp__int64 bt; \
oh = xh * yh; \
STBSP__COPYFP(bt,xh); bt&=((~(stbsp__uint64)0)<<27); STBSP__COPYFP(ahi,bt); alo = xh-ahi; \
STBSP__COPYFP(bt,yh); bt&=((~(stbsp__uint64)0)<<27); STBSP__COPYFP(bhi,bt); blo = yh-bhi; \
ol = ((ahi*bhi-oh)+ahi*blo+alo*bhi)+alo*blo; \
}
#define stbsp__ddtoS64(ob,xh,xl) \
{ \
double ahi=0,alo,vh,t;\
ob = (stbsp__int64)ph;\
vh=(double)ob;\
ahi = ( xh - vh );\
t = ( ahi - xh );\
alo = (xh-(ahi-t))-(vh+t);\
ob += (stbsp__int64)(ahi+alo+xl);\
}
#define stbsp__ddrenorm(oh,ol) { double s; s=oh+ol; ol=ol-(s-oh); oh=s; }
#define stbsp__ddmultlo(oh,ol,xh,xl,yh,yl) \
ol = ol + ( xh*yl + xl*yh ); \
#define stbsp__ddmultlos(oh,ol,xh,yl) \
ol = ol + ( xh*yl ); \
static void stbsp__raise_to_power10( double *ohi, double *olo, double d, stbsp__int32 power ) // power can be -323 to +350
{
double ph, pl;
if ((power>=0) && (power<=22))
{
stbsp__ddmulthi(ph,pl,d,stbsp__bot[power]);
}
else
{
stbsp__int32 e,et,eb;
double p2h,p2l;
e=power; if (power<0) e=-e;
et = (e*0x2c9)>>14;/* %23 */ if (et>13) et=13; eb = e-(et*23);
ph = d; pl = 0.0;
if (power<0)
{
if (eb) { --eb; stbsp__ddmulthi(ph,pl,d,stbsp__negbot[eb]); stbsp__ddmultlos(ph,pl,d,stbsp__negboterr[eb]); }
if (et)
{
stbsp__ddrenorm(ph,pl);
--et; stbsp__ddmulthi(p2h,p2l,ph,stbsp__negtop[et]); stbsp__ddmultlo(p2h,p2l,ph,pl,stbsp__negtop[et],stbsp__negtoperr[et]); ph=p2h;pl=p2l;
}
}
else
{
if (eb)
{
e = eb; if (eb>22) eb=22; e -= eb;
stbsp__ddmulthi(ph,pl,d,stbsp__bot[eb]);
if ( e ) { stbsp__ddrenorm(ph,pl); stbsp__ddmulthi(p2h,p2l,ph,stbsp__bot[e]); stbsp__ddmultlos(p2h,p2l,stbsp__bot[e],pl); ph=p2h;pl=p2l; }
}
if (et)
{
stbsp__ddrenorm(ph,pl);
--et; stbsp__ddmulthi(p2h,p2l,ph,stbsp__top[et]); stbsp__ddmultlo(p2h,p2l,ph,pl,stbsp__top[et],stbsp__toperr[et]); ph=p2h;pl=p2l;
}
}
}
stbsp__ddrenorm(ph,pl);
*ohi = ph; *olo = pl;
}
// given a float value, returns the significant bits in bits, and the position of the
// decimal point in decimal_pos. +/-INF and NAN are specified by special values
// returned in the decimal_pos parameter.
// frac_digits is absolute normally, but if you want from first significant digits (got %g and %e), or in 0x80000000
static stbsp__int32 stbsp__real_to_str( char const * * start, stbsp__uint32 * len, char *out, stbsp__int32 * decimal_pos, double value, stbsp__uint32 frac_digits )
{
double d;
stbsp__int64 bits = 0;
stbsp__int32 expo, e, ng, tens;
d = value;
STBSP__COPYFP(bits,d);
expo = (stbsp__int32) ((bits >> 52) & 2047);
ng = (stbsp__int32)(bits >> 63);
if (ng) d=-d;
if ( expo == 2047 ) // is nan or inf?
{
*start = (bits&((((stbsp__uint64)1)<<52)-1)) ? "NaN" : "Inf";
*decimal_pos = STBSP__SPECIAL;
*len = 3;
return ng;
}
if ( expo == 0 ) // is zero or denormal
{
if ((bits<<1)==0) // do zero
{
*decimal_pos = 1;
*start = out;
out[0] = '0'; *len = 1;
return ng;
}
// find the right expo for denormals
{
stbsp__int64 v = ((stbsp__uint64)1)<<51;
while ((bits&v)==0) { --expo; v >>= 1; }
}