The Tor Browser / file comparison

comparison: build/stlport/src/num_get_float.cpp

build/stlport/src/num_get_float.cpp

branch
TOR_BUG_3246
changeset 7
129ffea94266
equal deleted inserted replaced
-1:000000000000 0:f877c53077c9
1 /*
2 * Copyright (c) 1999
3 * Silicon Graphics Computer Systems, Inc.
4 *
5 * Copyright (c) 1999
6 * Boris Fomitchev
7 *
8 * This material is provided "as is", with absolutely no warranty expressed
9 * or implied. Any use is at your own risk.
10 *
11 * Permission to use or copy this software for any purpose is hereby granted
12 * without fee, provided the above notices are retained on all copies.
13 * Permission to modify the code and to distribute modified code is granted,
14 * provided the above notices are retained, and a notice that the code was
15 * modified is included with the above copyright notice.
16 *
17 */
18
19 #include "stlport_prefix.h"
20
21 #include <limits>
22 #include <locale>
23 #include <istream>
24
25 #if (defined (__GNUC__) && !defined (__sun) && !defined (__hpux)) || \
26 defined (__DMC__)
27 # include <stdint.h>
28 #endif
29
30 #if defined (__linux__) || defined (__MINGW32__) || defined (__CYGWIN__) || \
31 defined (__BORLANDC__) || defined (__DMC__) || defined (__HP_aCC)
32
33 # if defined (__BORLANDC__)
34 typedef unsigned int uint32_t;
35 typedef unsigned __int64 uint64_t;
36 # endif
37
38 union _ll {
39 uint64_t i64;
40 struct {
41 # if defined (_STLP_BIG_ENDIAN)
42 uint32_t hi;
43 uint32_t lo;
44 # elif defined (_STLP_LITTLE_ENDIAN)
45 uint32_t lo;
46 uint32_t hi;
47 # else
48 # error Unknown endianess
49 # endif
50 } i32;
51 };
52
53 # if defined (__linux__) && !defined (__ANDROID__)
54 # include <ieee754.h>
55 # else
56 union ieee854_long_double {
57 long double d;
58
59 /* This is the IEEE 854 double-extended-precision format. */
60 struct {
61 unsigned int mantissa1:32;
62 unsigned int mantissa0:32;
63 unsigned int exponent:15;
64 unsigned int negative:1;
65 unsigned int empty:16;
66 } ieee;
67 };
68
69 # define IEEE854_LONG_DOUBLE_BIAS 0x3fff
70 # endif
71 #endif
72
73 _STLP_BEGIN_NAMESPACE
74 _STLP_MOVE_TO_PRIV_NAMESPACE
75
76 //----------------------------------------------------------------------
77 // num_get
78
79 // Helper functions for _M_do_get_float.
80
81 #if !defined (_STLP_NO_WCHAR_T)
82 void _STLP_CALL
83 _Initialize_get_float( const ctype<wchar_t>& ct,
84 wchar_t& Plus, wchar_t& Minus,
85 wchar_t& pow_e, wchar_t& pow_E,
86 wchar_t* digits) {
87 char ndigits[11] = "0123456789";
88 Plus = ct.widen('+');
89 Minus = ct.widen('-');
90 pow_e = ct.widen('e');
91 pow_E = ct.widen('E');
92 ct.widen(ndigits + 0, ndigits + 10, digits);
93 }
94 #endif /* WCHAR_T */
95
96 /*
97 * __string_to_double is just lifted from atof, the difference being
98 * that we just use '.' for the decimal point, rather than let it
99 * be taken from the current C locale, which of course is not accessible
100 * to us.
101 */
102 #if defined (_STLP_MSVC) || defined (__BORLANDC__) || defined (__ICL)
103 typedef unsigned long uint32;
104 typedef unsigned __int64 uint64;
105 # define ULL(x) x##Ui64
106 #elif defined (__unix) || defined (__MINGW32__) || \
107 (defined (__DMC__) && (__LONGLONG)) || defined (__WATCOMC__) || \
108 defined (__ANDROID__)
109 typedef uint32_t uint32;
110 typedef uint64_t uint64;
111 # define ULL(x) x##ULL
112 #else
113 # error There should be some unsigned 64-bit integer on the system!
114 #endif
115
116 // Multiplication of two 64-bit integers, giving a 128-bit result.
117 // Taken from Algorithm M in Knuth section 4.3.1, with the loop
118 // hand-unrolled.
119 static void _Stl_mult64(const uint64 u, const uint64 v,
120 uint64& high, uint64& low) {
121 const uint64 low_mask = ULL(0xffffffff);
122 const uint64 u0 = u & low_mask;
123 const uint64 u1 = u >> 32;
124 const uint64 v0 = v & low_mask;
125 const uint64 v1 = v >> 32;
126
127 uint64 t = u0 * v0;
128 low = t & low_mask;
129
130 t = u1 * v0 + (t >> 32);
131 uint64 w1 = t & low_mask;
132 uint64 w2 = t >> 32;
133
134 uint64 x = u0 * v1 + w1;
135 low += (x & low_mask) << 32;
136 high = u1 * v1 + w2 + (x >> 32);
137 }
138
139 #if !defined (__linux__) || defined (__ANDROID__)
140
141 # define bit11 ULL(0x7ff)
142 # define exponent_mask (bit11 << 52)
143
144 # if !defined (__GNUC__) || (__GNUC__ != 3) || (__GNUC_MINOR__ != 4) || \
145 (!defined (__CYGWIN__) && !defined (__MINGW32__))
146 //Generate bad code when compiled with -O2 option.
147 inline
148 # endif
149 void _Stl_set_exponent(uint64 &val, uint64 exp)
150 { val = (val & ~exponent_mask) | ((exp & bit11) << 52); }
151
152 #endif // __linux__
153
154 /* Power of ten fractions for tenscale*/
155 /* The constants are factored so that at most two constants
156 * and two multiplies are needed. Furthermore, one of the constants
157 * is represented exactly - 10**n where 1<= n <= 27.
158 */
159
160 static const uint64 _Stl_tenpow[80] = {
161 ULL(0xa000000000000000), /* _Stl_tenpow[0]=(10**1)/(2**4) */
162 ULL(0xc800000000000000), /* _Stl_tenpow[1]=(10**2)/(2**7) */
163 ULL(0xfa00000000000000), /* _Stl_tenpow[2]=(10**3)/(2**10) */
164 ULL(0x9c40000000000000), /* _Stl_tenpow[3]=(10**4)/(2**14) */
165 ULL(0xc350000000000000), /* _Stl_tenpow[4]=(10**5)/(2**17) */
166 ULL(0xf424000000000000), /* _Stl_tenpow[5]=(10**6)/(2**20) */
167 ULL(0x9896800000000000), /* _Stl_tenpow[6]=(10**7)/(2**24) */
168 ULL(0xbebc200000000000), /* _Stl_tenpow[7]=(10**8)/(2**27) */
169 ULL(0xee6b280000000000), /* _Stl_tenpow[8]=(10**9)/(2**30) */
170 ULL(0x9502f90000000000), /* _Stl_tenpow[9]=(10**10)/(2**34) */
171 ULL(0xba43b74000000000), /* _Stl_tenpow[10]=(10**11)/(2**37) */
172 ULL(0xe8d4a51000000000), /* _Stl_tenpow[11]=(10**12)/(2**40) */
173 ULL(0x9184e72a00000000), /* _Stl_tenpow[12]=(10**13)/(2**44) */
174 ULL(0xb5e620f480000000), /* _Stl_tenpow[13]=(10**14)/(2**47) */
175 ULL(0xe35fa931a0000000), /* _Stl_tenpow[14]=(10**15)/(2**50) */
176 ULL(0x8e1bc9bf04000000), /* _Stl_tenpow[15]=(10**16)/(2**54) */
177 ULL(0xb1a2bc2ec5000000), /* _Stl_tenpow[16]=(10**17)/(2**57) */
178 ULL(0xde0b6b3a76400000), /* _Stl_tenpow[17]=(10**18)/(2**60) */
179 ULL(0x8ac7230489e80000), /* _Stl_tenpow[18]=(10**19)/(2**64) */
180 ULL(0xad78ebc5ac620000), /* _Stl_tenpow[19]=(10**20)/(2**67) */
181 ULL(0xd8d726b7177a8000), /* _Stl_tenpow[20]=(10**21)/(2**70) */
182 ULL(0x878678326eac9000), /* _Stl_tenpow[21]=(10**22)/(2**74) */
183 ULL(0xa968163f0a57b400), /* _Stl_tenpow[22]=(10**23)/(2**77) */
184 ULL(0xd3c21bcecceda100), /* _Stl_tenpow[23]=(10**24)/(2**80) */
185 ULL(0x84595161401484a0), /* _Stl_tenpow[24]=(10**25)/(2**84) */
186 ULL(0xa56fa5b99019a5c8), /* _Stl_tenpow[25]=(10**26)/(2**87) */
187 ULL(0xcecb8f27f4200f3a), /* _Stl_tenpow[26]=(10**27)/(2**90) */
188
189 ULL(0xd0cf4b50cfe20766), /* _Stl_tenpow[27]=(10**55)/(2**183) */
190 ULL(0xd2d80db02aabd62c), /* _Stl_tenpow[28]=(10**83)/(2**276) */
191 ULL(0xd4e5e2cdc1d1ea96), /* _Stl_tenpow[29]=(10**111)/(2**369) */
192 ULL(0xd6f8d7509292d603), /* _Stl_tenpow[30]=(10**139)/(2**462) */
193 ULL(0xd910f7ff28069da4), /* _Stl_tenpow[31]=(10**167)/(2**555) */
194 ULL(0xdb2e51bfe9d0696a), /* _Stl_tenpow[32]=(10**195)/(2**648) */
195 ULL(0xdd50f1996b947519), /* _Stl_tenpow[33]=(10**223)/(2**741) */
196 ULL(0xdf78e4b2bd342cf7), /* _Stl_tenpow[34]=(10**251)/(2**834) */
197 ULL(0xe1a63853bbd26451), /* _Stl_tenpow[35]=(10**279)/(2**927) */
198 ULL(0xe3d8f9e563a198e5), /* _Stl_tenpow[36]=(10**307)/(2**1020) */
199
200 // /* _Stl_tenpow[36]=(10**335)/(2**) */
201 // /* _Stl_tenpow[36]=(10**335)/(2**) */
202
203 ULL(0xfd87b5f28300ca0e), /* _Stl_tenpow[37]=(10**-28)/(2**-93) */
204 ULL(0xfb158592be068d2f), /* _Stl_tenpow[38]=(10**-56)/(2**-186) */
205 ULL(0xf8a95fcf88747d94), /* _Stl_tenpow[39]=(10**-84)/(2**-279) */
206 ULL(0xf64335bcf065d37d), /* _Stl_tenpow[40]=(10**-112)/(2**-372) */
207 ULL(0xf3e2f893dec3f126), /* _Stl_tenpow[41]=(10**-140)/(2**-465) */
208 ULL(0xf18899b1bc3f8ca2), /* _Stl_tenpow[42]=(10**-168)/(2**-558) */
209 ULL(0xef340a98172aace5), /* _Stl_tenpow[43]=(10**-196)/(2**-651) */
210 ULL(0xece53cec4a314ebe), /* _Stl_tenpow[44]=(10**-224)/(2**-744) */
211 ULL(0xea9c227723ee8bcb), /* _Stl_tenpow[45]=(10**-252)/(2**-837) */
212 ULL(0xe858ad248f5c22ca), /* _Stl_tenpow[46]=(10**-280)/(2**-930) */
213 ULL(0xe61acf033d1a45df), /* _Stl_tenpow[47]=(10**-308)/(2**-1023) */
214 ULL(0xe3e27a444d8d98b8), /* _Stl_tenpow[48]=(10**-336)/(2**-1116) */
215 ULL(0xe1afa13afbd14d6e) /* _Stl_tenpow[49]=(10**-364)/(2**-1209) */
216 };
217
218 static const short _Stl_twoexp[80] = {
219 4,7,10,14,17,20,24,27,30,34,37,40,44,47,50,54,57,60,64,67,70,74,77,80,84,87,90,
220 183,276,369,462,555,648,741,834,927,1020,
221 -93,-186,-279,-372,-465,-558,-651,-744,-837,-930,-1023,-1116,-1209
222 };
223
224 #define TEN_1 0 /* offset to 10 ** 1 */
225 #define TEN_27 26 /* offset to 10 ** 27 */
226 #define TEN_M28 37 /* offset to 10 ** -28 */
227 #define NUM_HI_P 11
228 #define NUM_HI_N 13
229
230 #define _Stl_HIBITULL (ULL(1) << 63)
231
232 static void _Stl_norm_and_round(uint64& p, int& norm, uint64 prodhi, uint64 prodlo) {
233 norm = 0;
234 if ((prodhi & _Stl_HIBITULL) == 0) {
235 /* leading bit is a zero
236 * may have to normalize
237 */
238 if ((prodhi == ~_Stl_HIBITULL) &&
239 ((prodlo >> 62) == 0x3)) { /* normalization followed by round
240 * would cause carry to create
241 * extra bit, so don't normalize
242 */
243 p = _Stl_HIBITULL;
244 return;
245 }
246 p = (prodhi << 1) | (prodlo >> 63); /* normalize */
247 norm = 1;
248 prodlo <<= 1;
249 }
250 else {
251 p = prodhi;
252 }
253
254 if ((prodlo & _Stl_HIBITULL) != 0) { /* first guard bit a one */
255 if (((p & 0x1) != 0) ||
256 prodlo != _Stl_HIBITULL ) { /* not borderline for round to even */
257 /* round */
258 ++p;
259 if (p == 0)
260 ++p;
261 }
262 }
263 }
264
265 // Convert a 64-bitb fraction * 10^exp to a 64-bit fraction * 2^bexp.
266 // p: 64-bit fraction
267 // exp: base-10 exponent
268 // bexp: base-2 exponent (output parameter)
269 static void _Stl_tenscale(uint64& p, int exp, int& bexp) {
270 bexp = 0;
271
272 if ( exp == 0 ) { /* no scaling needed */
273 return;
274 }
275
276 int exp_hi = 0, exp_lo = exp; /* exp = exp_hi*32 + exp_lo */
277 int tlo = TEN_1, thi; /* offsets in power of ten table */
278 int num_hi; /* number of high exponent powers */
279
280 if (exp > 0) { /* split exponent */
281 if (exp_lo > 27) {
282 exp_lo++;
283 while (exp_lo > 27) {
284 exp_hi++;
285 exp_lo -= 28;
286 }
287 }
288 thi = TEN_27;
289 num_hi = NUM_HI_P;
290 } else { // exp < 0
291 while (exp_lo < 0) {
292 exp_hi++;
293 exp_lo += 28;
294 }
295 thi = TEN_M28;
296 num_hi = NUM_HI_N;
297 }
298
299 uint64 prodhi, prodlo; /* 128b product */
300 int norm; /* number of bits of normalization */
301
302 int hi, lo; /* offsets in power of ten table */
303 while (exp_hi) { /* scale */
304 hi = (min) (exp_hi, num_hi); /* only a few large powers of 10 */
305 exp_hi -= hi; /* could iterate in extreme case */
306 hi += thi-1;
307 _Stl_mult64(p, _Stl_tenpow[hi], prodhi, prodlo);
308 _Stl_norm_and_round(p, norm, prodhi, prodlo);
309 bexp += _Stl_twoexp[hi] - norm;
310 }
311
312 if (exp_lo) {
313 lo = tlo + exp_lo -1;
314 _Stl_mult64(p, _Stl_tenpow[lo], prodhi, prodlo);
315 _Stl_norm_and_round(p, norm, prodhi, prodlo);
316 bexp += _Stl_twoexp[lo] - norm;
317 }
318
319 return;
320 }
321
322 // First argument is a buffer of values from 0 to 9, NOT ascii.
323 // Second argument is number of digits in buffer, 1 <= digits <= 17.
324 // Third argument is base-10 exponent.
325
326 /* IEEE representation */
327 #if !defined (__linux__) || defined (__ANDROID__)
328
329 union _Double_rep {
330 uint64 ival;
331 double val;
332 };
333
334 static double _Stl_atod(char *buffer, ptrdiff_t ndigit, int dexp) {
335 typedef numeric_limits<double> limits;
336 _Double_rep drep;
337 uint64 &value = drep.ival; /* Value develops as follows:
338 * 1) decimal digits as an integer
339 * 2) left adjusted fraction
340 * 3) right adjusted fraction
341 * 4) exponent and fraction
342 */
343
344 uint32 guard; /* First guard bit */
345 uint64 rest; /* Remaining guard bits */
346
347 int bexp; /* binary exponent */
348 int nzero; /* number of non-zero bits */
349 int sexp; /* scaling exponent */
350
351 char *bufferend; /* pointer to char after last digit */
352
353 /* Convert the decimal digits to a binary integer. */
354 bufferend = buffer + ndigit;
355 value = 0;
356
357 while (buffer < bufferend) {
358 value *= 10;
359 value += *buffer++;
360 }
361
362 /* Check for zero and treat it as a special case */
363 if (value == 0) {
364 return 0.0;
365 }
366
367 /* Normalize value */
368 bexp = 64; /* convert from 64b int to fraction */
369
370 /* Count number of non-zeroes in value */
371 nzero = 0;
372 if ((value >> 32) != 0) { nzero = 32; } //*TY 03/25/2000 - added explicit comparison to zero to avoid uint64 to bool conversion operator
373 if ((value >> (16 + nzero)) != 0) { nzero += 16; }
374 if ((value >> ( 8 + nzero)) != 0) { nzero += 8; }
375 if ((value >> ( 4 + nzero)) != 0) { nzero += 4; }
376 if ((value >> ( 2 + nzero)) != 0) { nzero += 2; }
377 if ((value >> ( 1 + nzero)) != 0) { nzero += 1; }
378 if ((value >> ( nzero)) != 0) { nzero += 1; }
379
380 /* Normalize */
381 value <<= /*(uint64)*/ (64 - nzero); //*TY 03/25/2000 - removed extraneous cast to uint64
382 bexp -= 64 - nzero;
383
384 /* At this point we have a 64b fraction and a binary exponent
385 * but have yet to incorporate the decimal exponent.
386 */
387
388 /* multiply by 10^dexp */
389 _Stl_tenscale(value, dexp, sexp);
390 bexp += sexp;
391
392 if (bexp <= -1022) { /* HI denorm or underflow */
393 bexp += 1022;
394 if (bexp < -53) { /* guaranteed underflow */
395 value = 0;
396 }
397 else { /* denorm or possible underflow */
398 int lead0 = 12 - bexp; /* 12 sign and exponent bits */
399
400 /* we must special case right shifts of more than 63 */
401 if (lead0 > 64) {
402 rest = value;
403 guard = 0;
404 value = 0;
405 }
406 else if (lead0 == 64) {
407 rest = value & ((ULL(1)<< 63)-1);
408 guard = (uint32) ((value>> 63) & 1 );
409 value = 0;
410 }
411 else {
412 rest = value & (((ULL(1) << lead0)-1)-1);
413 guard = (uint32) (((value>> lead0)-1) & 1);
414 value >>= /*(uint64)*/ lead0; /* exponent is zero */
415 }
416
417 /* Round */
418 if (guard && ((value & 1) || rest) ) {
419 ++value;
420 if (value == (ULL(1) << (limits::digits - 1))) { /* carry created normal number */
421 value = 0;
422 _Stl_set_exponent(value, 1);
423 }
424 }
425 }
426 }
427 else { /* not zero or denorm */
428 /* Round to 53 bits */
429 rest = value & ((1 << 10) - 1);
430 value >>= 10;
431 guard = (uint32) value & 1;
432 value >>= 1;
433
434 /* value&1 guard rest Action
435 *
436 * dc 0 dc none
437 * 1 1 dc round
438 * 0 1 0 none
439 * 0 1 !=0 round
440 */
441 if (guard) {
442 if (((value&1)!=0) || (rest!=0)) {
443 ++value; /* round */
444 if ((value >> 53) != 0) { /* carry all the way across */
445 value >>= 1; /* renormalize */
446 ++bexp;
447 }
448 }
449 }
450 /*
451 * Check for overflow
452 * IEEE Double Precision Format
453 * (From Table 7-8 of Kane and Heinrich)
454 *
455 * Fraction bits 52
456 * Emax +1023
457 * Emin -1022
458 * Exponent bias +1023
459 * Exponent bits 11
460 * Integer bit hidden
461 * Total width in bits 64
462 */
463
464 if (bexp > limits::max_exponent) { /* overflow */
465 return limits::infinity();
466 }
467 else { /* value is normal */
468 value &= ~(ULL(1) << (limits::digits - 1)); /* hide hidden bit */
469 _Stl_set_exponent(value, bexp + 1022); /* add bias */
470 }
471 }
472
473 _STLP_STATIC_ASSERT(sizeof(uint64) >= sizeof(double))
474 return drep.val;
475 }
476
477 #endif
478
479 #if defined (__linux__) || defined (__MINGW32__) || defined (__CYGWIN__) || \
480 defined (__BORLANDC__) || defined (__DMC__) || defined (__HP_aCC)
481
482 template <class D, class IEEE, int M, int BIAS>
483 D _Stl_atodT(char *buffer, ptrdiff_t ndigit, int dexp)
484 {
485 typedef numeric_limits<D> limits;
486
487 /* Convert the decimal digits to a binary integer. */
488 char *bufferend = buffer + ndigit; /* pointer to char after last digit */
489 _ll vv;
490 vv.i64 = 0L;
491
492 while ( buffer < bufferend ) {
493 vv.i64 *= 10;
494 vv.i64 += *buffer++;
495 }
496
497 if ( vv.i64 == ULL(0) ) { /* Check for zero and treat it as a special case */
498 return D(0.0);
499 }
500
501 /* Normalize value */
502
503 int bexp = 64; /* convert from 64b int to fraction */
504
505 /* Count number of non-zeroes in value */
506 int nzero = 0;
507 if ((vv.i64 >> 32) != 0) { nzero = 32; }
508 if ((vv.i64 >> (16 + nzero)) != 0) { nzero += 16; }
509 if ((vv.i64 >> ( 8 + nzero)) != 0) { nzero += 8; }
510 if ((vv.i64 >> ( 4 + nzero)) != 0) { nzero += 4; }
511 if ((vv.i64 >> ( 2 + nzero)) != 0) { nzero += 2; }
512 if ((vv.i64 >> ( 1 + nzero)) != 0) { nzero += 1; }
513 if ((vv.i64 >> ( nzero)) != 0) { nzero += 1; }
514
515 /* Normalize */
516 nzero = 64 - nzero;
517 vv.i64 <<= nzero; // * TY 03/25/2000 - removed extraneous cast to uint64
518 bexp -= nzero;
519
520 /* At this point we have a 64b fraction and a binary exponent
521 * but have yet to incorporate the decimal exponent.
522 */
523
524 /* multiply by 10^dexp */
525 int sexp;
526 _Stl_tenscale(vv.i64, dexp, sexp);
527 bexp += sexp;
528
529 if ( bexp >= limits::min_exponent ) { /* not zero or denorm */
530 if ( limits::digits < 64 ) {
531 /* Round to (64 - M + 1) bits */
532 uint64_t rest = vv.i64 & ((~ULL(0) / ULL(2)) >> (limits::digits - 1));
533 vv.i64 >>= M - 2;
534 uint32_t guard = (uint32) vv.i64 & 1;
535 vv.i64 >>= 1;
536
537 /* value&1 guard rest Action
538 *
539 * dc 0 dc none
540 * 1 1 dc round
541 * 0 1 0 none
542 * 0 1 !=0 round
543 */
544
545 if (guard) {
546 if ( ((vv.i64 & 1) != 0) || (rest != 0) ) {
547 vv.i64++; /* round */
548 if ( (vv.i64 >> (limits::digits < 64 ? limits::digits : 0)) != 0 ) { /* carry all the way across */
549 vv.i64 >>= 1; /* renormalize */
550 ++bexp;
551 }
552 }
553 }
554
555 vv.i64 &= ~(ULL(1) << (limits::digits - 1)); /* hide hidden bit */
556 }
557 /*
558 * Check for overflow
559 * IEEE Double Precision Format
560 * (From Table 7-8 of Kane and Heinrich)
561 *
562 * Fraction bits 52
563 * Emax +1023
564 * Emin -1022
565 * Exponent bias +1023
566 * Exponent bits 11
567 * Integer bit hidden
568 * Total width in bits 64
569 */
570
571 if (bexp > limits::max_exponent) { /* overflow */
572 return limits::infinity();
573 }
574
575 /* value is normal */
576
577 IEEE v;
578
579 v.ieee.mantissa0 = vv.i32.hi;
580 v.ieee.mantissa1 = vv.i32.lo;
581 v.ieee.negative = 0;
582 v.ieee.exponent = bexp + BIAS - 1;
583
584 return v.d;
585 }
586
587 /* HI denorm or underflow */
588 bexp += BIAS - 1;
589 if (bexp < -limits::digits) { /* guaranteed underflow */
590 vv.i64 = 0;
591 } else { /* denorm or possible underflow */
592
593 /*
594 * Problem point for long double: looks like this code reflect shareing of mantissa
595 * and exponent in 64b int; not so for long double
596 */
597
598 int lead0 = M - bexp; /* M = 12 sign and exponent bits */
599 uint64_t rest;
600 uint32_t guard;
601
602 /* we must special case right shifts of more than 63 */
603
604 if (lead0 > 64) {
605 rest = vv.i64;
606 guard = 0;
607 vv.i64 = 0;
608 } else if (lead0 == 64) {
609 rest = vv.i64 & ((ULL(1) << 63)-1);
610 guard = (uint32) ((vv.i64 >> 63) & 1 );
611 vv.i64 = 0;
612 } else {
613 rest = vv.i64 & (((ULL(1) << lead0)-1)-1);
614 guard = (uint32) (((vv.i64 >> lead0)-1) & 1);
615 vv.i64 >>= /*(uint64)*/ lead0; /* exponent is zero */
616 }
617
618 /* Round */
619 if (guard && ( (vv.i64 & 1) || rest)) {
620 vv.i64++;
621 if (vv.i64 == (ULL(1) << (limits::digits - 1))) { /* carry created normal number */
622 IEEE v;
623
624 v.ieee.mantissa0 = 0;
625 v.ieee.mantissa1 = 0;
626 v.ieee.negative = 0;
627 v.ieee.exponent = 1;
628 return v.d;
629 }
630 }
631 }
632
633 IEEE v;
634
635 v.ieee.mantissa0 = vv.i32.hi;
636 v.ieee.mantissa1 = vv.i32.lo;
637 v.ieee.negative = 0;
638 v.ieee.exponent = 0;
639
640 return v.d;
641 }
642 #endif // __linux__
643
644 #if !defined (__linux__) || defined (__ANDROID__)
645 static double _Stl_string_to_double(const char *s) {
646 typedef numeric_limits<double> limits;
647 const int max_digits = limits::digits10 + 2;
648 unsigned c;
649 unsigned Negate, decimal_point;
650 char *d;
651 int exp;
652 int dpchar;
653 char digits[max_digits];
654
655 c = *s++;
656
657 /* process sign */
658 Negate = 0;
659 if (c == '+') {
660 c = *s++;
661 } else if (c == '-') {
662 Negate = 1;
663 c = *s++;
664 }
665
666 d = digits;
667 dpchar = '.' - '0';
668 decimal_point = 0;
669 exp = 0;
670
671 for (;;) {
672 c -= '0';
673 if (c < 10) {
674 if (d == digits + max_digits) {
675 /* ignore more than max_digits digits, but adjust exponent */
676 exp += (decimal_point ^ 1);
677 } else {
678 if (c == 0 && d == digits) {
679 /* ignore leading zeros */
680 } else {
681 *d++ = (char) c;
682 }
683 exp -= decimal_point;
684 }
685 } else if (c == (unsigned int) dpchar && !decimal_point) { /* INTERNATIONAL */
686 decimal_point = 1;
687 } else {
688 break;
689 }
690 c = *s++;
691 }
692
693 /* strtod cant return until it finds the end of the exponent */
694 if (d == digits) {
695 return 0.0;
696 }
697
698 if (c == 'e' - '0' || c == 'E' - '0') {
699 register unsigned negate_exp = 0;
700 register int e = 0;
701 c = *s++;
702 if (c == '+' || c == ' ') {
703 c = *s++;
704 } else if (c == '-') {
705 negate_exp = 1;
706 c = *s++;
707 }
708 if (c -= '0', c < 10) {
709 do {
710 e = e * 10 + (int)c;
711 c = *s++;
712 } while (c -= '0', c < 10);
713
714 if (negate_exp) {
715 e = -e;
716 }
717 exp += e;
718 }
719 }
720
721 double x;
722 ptrdiff_t n = d - digits;
723 if ((exp + n - 1) < limits::min_exponent10) {
724 x = 0;
725 }
726 else if ((exp + n - 1) > limits::max_exponent10) {
727 x = limits::infinity();
728 }
729 else {
730 /* Let _Stl_atod diagnose under- and over-flows.
731 * If the input was == 0.0, we have already returned,
732 * so retval of +-Inf signals OVERFLOW, 0.0 UNDERFLOW */
733 x = _Stl_atod(digits, n, exp);
734 }
735
736 if (Negate) {
737 x = -x;
738 }
739
740 return x;
741 }
742
743 #endif
744
745 #if defined (__linux__) || defined (__MINGW32__) || defined (__CYGWIN__) || \
746 defined (__BORLANDC__) || defined (__DMC__) || defined (__HP_aCC)
747
748 template <class D, class IEEE, int M, int BIAS>
749 D _Stl_string_to_doubleT(const char *s)
750 {
751 typedef numeric_limits<D> limits;
752 const int max_digits = limits::digits10; /* + 2 17 */;
753 unsigned c;
754 unsigned decimal_point;
755 char *d;
756 int exp;
757 D x;
758 int dpchar;
759 char digits[max_digits];
760
761 c = *s++;
762
763 /* process sign */
764 bool Negate = false;
765 if (c == '+') {
766 c = *s++;
767 } else if (c == '-') {
768 Negate = true;
769 c = *s++;
770 }
771
772 d = digits;
773 dpchar = '.' - '0';
774 decimal_point = 0;
775 exp = 0;
776
777 for (;;) {
778 c -= '0';
779 if (c < 10) {
780 if (d == digits + max_digits) {
781 /* ignore more than max_digits digits, but adjust exponent */
782 exp += (decimal_point ^ 1);
783 } else {
784 if (c == 0 && d == digits) {
785 /* ignore leading zeros */
786 } else {
787 *d++ = (char) c;
788 }
789 exp -= decimal_point;
790 }
791 } else if (c == (unsigned int) dpchar && !decimal_point) { /* INTERNATIONAL */
792 decimal_point = 1;
793 } else {
794 break;
795 }
796 c = *s++;
797 }
798 /* strtod cant return until it finds the end of the exponent */
799 if (d == digits) {
800 return D(0.0);
801 }
802
803 if (c == 'e'-'0' || c == 'E'-'0') {
804 bool negate_exp = false;
805 register int e = 0;
806 c = *s++;
807 if (c == '+' || c == ' ') {
808 c = *s++;
809 } else if (c == '-') {
810 negate_exp = true;
811 c = *s++;
812 }
813 if (c -= '0', c < 10) {
814 do {
815 e = e * 10 + (int)c;
816 c = *s++;
817 } while (c -= '0', c < 10);
818
819 if (negate_exp) {
820 e = -e;
821 }
822 exp += e;
823 }
824 }
825
826 ptrdiff_t n = d - digits;
827 if ((exp + n - 1) < limits::min_exponent10) {
828 return D(0.0); // +0.0 is the same as -0.0
829 } else if ((exp + n - 1) > limits::max_exponent10 ) {
830 // not good, because of x = -x below; this may lead to portability problems
831 x = limits::infinity();
832 } else {
833 /* let _Stl_atod diagnose under- and over-flows */
834 /* if the input was == 0.0, we have already returned,
835 so retval of +-Inf signals OVERFLOW, 0.0 UNDERFLOW
836 */
837 x = _Stl_atodT<D,IEEE,M,BIAS>(digits, n, exp);
838 }
839
840 return Negate ? -x : x;
841 }
842
843 #endif // __linux__
844
845 void _STLP_CALL
846 __string_to_float(const __iostring& v, float& val)
847 {
848 #if !defined (__linux__) || defined (__ANDROID__)
849 val = (float)_Stl_string_to_double(v.c_str());
850 #else
851 val = (float)_Stl_string_to_doubleT<double,ieee754_double,12,IEEE754_DOUBLE_BIAS>(v.c_str());
852 #endif
853 }
854
855 void _STLP_CALL
856 __string_to_float(const __iostring& v, double& val)
857 {
858 #if !defined (__linux__) || defined (__ANDROID__)
859 val = _Stl_string_to_double(v.c_str());
860 #else
861 val = _Stl_string_to_doubleT<double,ieee754_double,12,IEEE754_DOUBLE_BIAS>(v.c_str());
862 #endif
863 }
864
865 #if !defined (_STLP_NO_LONG_DOUBLE)
866 void _STLP_CALL
867 __string_to_float(const __iostring& v, long double& val) {
868 #if !defined (__linux__) && !defined (__MINGW32__) && !defined (__CYGWIN__) && \
869 !defined (__BORLANDC__) && !defined (__DMC__) && !defined (__HP_aCC)
870 //The following function is valid only if long double is an alias for double.
871 _STLP_STATIC_ASSERT( sizeof(long double) <= sizeof(double) )
872 val = _Stl_string_to_double(v.c_str());
873 #else
874 val = _Stl_string_to_doubleT<long double,ieee854_long_double,16,IEEE854_LONG_DOUBLE_BIAS>(v.c_str());
875 #endif
876 }
877 #endif
878
879 _STLP_MOVE_TO_STD_NAMESPACE
880 _STLP_END_NAMESPACE
881
882 // Local Variables:
883 // mode:C++
884 // End:

Mercurial Repository: The Tor Browser

Europalab SCM Repository Server

mercurial