/home/ntakagi/work/STLport-5.1.5/src/num_get_float.cpp Go to the documentation of this file. /* * Copyright (c) 1999 * Silicon Graphics Computer Systems, Inc. * * Copyright (c) 1999 * Boris Fomitchev * * This material is provided "as is", with absolutely no warranty expressed * or implied. Any use is at your own risk. * * Permission to use or copy this software for any purpose is hereby granted * without fee, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice. * */ #include "stlport_prefix.h" #include <limits> #include <locale> #include <istream> #if defined (__GNUC__) && !defined (__sun) || \ defined (__DMC__) # include <stdint.h> #endif #if defined (__linux__) # include <ieee754.h> union _ll { uint64_t i64; struct { # if defined (_STLP_BIG_ENDIAN) uint32_t hi; uint32_t lo; # elif defined (_STLP_LITTLE_ENDIAN) uint32_t lo; uint32_t hi; # else # error Unknown endianess # endif } i32; }; #endif #if defined (N_PLAT_NLM) # include <nlm/nwintxx.h> # if defined (INT64) typedef unsigned INT64 uint64_t; # else // #error "Can't find INT64" // 64-bit int really not defined in headers // (_INTEGRAL_MAX_BITS < 64 in any case?), but compiler indeed know __int64 // - ptr, 2005-05-06 typedef unsigned __int64 uint64_t; # endif # if defined (INT32) typedef unsigned INT32 uint32_t; # else # error Can not find INT32 # endif union _ll { uint64_t i64; struct { uint32_t lo; uint32_t hi; } i32; }; #endif _STLP_BEGIN_NAMESPACE _STLP_MOVE_TO_PRIV_NAMESPACE //---------------------------------------------------------------------- // num_get // Helper functions for _M_do_get_float. #if !defined (_STLP_NO_WCHAR_T) void _STLP_CALL _Initialize_get_float( const ctype<wchar_t>& ct, wchar_t& Plus, wchar_t& Minus, wchar_t& pow_e, wchar_t& pow_E, wchar_t* digits) { char ndigits[11] = "0123456789"; Plus = ct.widen('+'); Minus = ct.widen('-'); pow_e = ct.widen('e'); pow_E = ct.widen('E'); ct.widen(ndigits + 0, ndigits + 10, digits); } #endif /* WCHAR_T */ /* * __string_to_double is just lifted from atof, the difference being * that we just use '.' for the decimal point, rather than let it * be taken from the current C locale, which of course is not accessible * to us. */ #if defined (_STLP_MSVC) || defined (__BORLANDC__) || defined (__ICL) typedef unsigned long uint32; typedef unsigned __int64 uint64; # define ULL(x) x##Ui64 #elif defined (__MRC__) || defined (__SC__) typedef unsigned long uint32; # include "uint64.h" //*TY 03/25/2000 - added 64bit math type definition #elif defined (__unix) || defined (__MINGW32__) || defined (N_PLAT_NLM) || \ (defined (__DMC__) && (__LONGLONG)) typedef uint32_t uint32; typedef uint64_t uint64; # define ULL(x) x##ULL #else # error There should be some unsigned 64-bit integer on the system! #endif // Multiplication of two 64-bit integers, giving a 128-bit result. // Taken from Algorithm M in Knuth section 4.3.1, with the loop // hand-unrolled. static void _Stl_mult64(const uint64 u, const uint64 v, uint64& high, uint64& low) { const uint64 low_mask = ULL(0xffffffff); const uint64 u0 = u & low_mask; const uint64 u1 = u >> 32; const uint64 v0 = v & low_mask; const uint64 v1 = v >> 32; uint64 t = u0 * v0; low = t & low_mask; t = u1 * v0 + (t >> 32); uint64 w1 = t & low_mask; uint64 w2 = t >> 32; uint64 x = u0 * v1 + w1; low += (x & low_mask) << 32; high = u1 * v1 + w2 + (x >> 32); } #define bit11 ULL(0x7ff) #define exponent_mask (bit11 << 52) #if !defined (__GNUC__) || (__GNUC__ != 3) || (__GNUC_MINOR__ != 4) || \ (!defined (__CYGWIN__) && !defined (__MINGW32__)) //Generate bad code when compiled with -O2 option. inline #endif void _Stl_set_exponent(uint64 &val, uint64 exp) { val = (val & ~exponent_mask) | ((exp & bit11) << 52); } /* Power of ten fractions for tenscale*/ /* The constants are factored so that at most two constants * and two multiplies are needed. Furthermore, one of the constants * is represented exactly - 10**n where 1<= n <= 27. */ #if !defined (__SC__) //*TY 03/25/2000 - no native 64bit integer under SCpp static const uint64 _Stl_tenpow[80] = { ULL(0xa000000000000000), /* _Stl_tenpow[0]=(10**1)/(2**4) */ ULL(0xc800000000000000), /* _Stl_tenpow[1]=(10**2)/(2**7) */ ULL(0xfa00000000000000), /* _Stl_tenpow[2]=(10**3)/(2**10) */ ULL(0x9c40000000000000), /* _Stl_tenpow[3]=(10**4)/(2**14) */ ULL(0xc350000000000000), /* _Stl_tenpow[4]=(10**5)/(2**17) */ ULL(0xf424000000000000), /* _Stl_tenpow[5]=(10**6)/(2**20) */ ULL(0x9896800000000000), /* _Stl_tenpow[6]=(10**7)/(2**24) */ ULL(0xbebc200000000000), /* _Stl_tenpow[7]=(10**8)/(2**27) */ ULL(0xee6b280000000000), /* _Stl_tenpow[8]=(10**9)/(2**30) */ ULL(0x9502f90000000000), /* _Stl_tenpow[9]=(10**10)/(2**34) */ ULL(0xba43b74000000000), /* _Stl_tenpow[10]=(10**11)/(2**37) */ ULL(0xe8d4a51000000000), /* _Stl_tenpow[11]=(10**12)/(2**40) */ ULL(0x9184e72a00000000), /* _Stl_tenpow[12]=(10**13)/(2**44) */ ULL(0xb5e620f480000000), /* _Stl_tenpow[13]=(10**14)/(2**47) */ ULL(0xe35fa931a0000000), /* _Stl_tenpow[14]=(10**15)/(2**50) */ ULL(0x8e1bc9bf04000000), /* _Stl_tenpow[15]=(10**16)/(2**54) */ ULL(0xb1a2bc2ec5000000), /* _Stl_tenpow[16]=(10**17)/(2**57) */ ULL(0xde0b6b3a76400000), /* _Stl_tenpow[17]=(10**18)/(2**60) */ ULL(0x8ac7230489e80000), /* _Stl_tenpow[18]=(10**19)/(2**64) */ ULL(0xad78ebc5ac620000), /* _Stl_tenpow[19]=(10**20)/(2**67) */ ULL(0xd8d726b7177a8000), /* _Stl_tenpow[20]=(10**21)/(2**70) */ ULL(0x878678326eac9000), /* _Stl_tenpow[21]=(10**22)/(2**74) */ ULL(0xa968163f0a57b400), /* _Stl_tenpow[22]=(10**23)/(2**77) */ ULL(0xd3c21bcecceda100), /* _Stl_tenpow[23]=(10**24)/(2**80) */ ULL(0x84595161401484a0), /* _Stl_tenpow[24]=(10**25)/(2**84) */ ULL(0xa56fa5b99019a5c8), /* _Stl_tenpow[25]=(10**26)/(2**87) */ ULL(0xcecb8f27f4200f3a), /* _Stl_tenpow[26]=(10**27)/(2**90) */ ULL(0xd0cf4b50cfe20766), /* _Stl_tenpow[27]=(10**55)/(2**183) */ ULL(0xd2d80db02aabd62c), /* _Stl_tenpow[28]=(10**83)/(2**276) */ ULL(0xd4e5e2cdc1d1ea96), /* _Stl_tenpow[29]=(10**111)/(2**369) */ ULL(0xd6f8d7509292d603), /* _Stl_tenpow[30]=(10**139)/(2**462) */ ULL(0xd910f7ff28069da4), /* _Stl_tenpow[31]=(10**167)/(2**555) */ ULL(0xdb2e51bfe9d0696a), /* _Stl_tenpow[32]=(10**195)/(2**648) */ ULL(0xdd50f1996b947519), /* _Stl_tenpow[33]=(10**223)/(2**741) */ ULL(0xdf78e4b2bd342cf7), /* _Stl_tenpow[34]=(10**251)/(2**834) */ ULL(0xe1a63853bbd26451), /* _Stl_tenpow[35]=(10**279)/(2**927) */ ULL(0xe3d8f9e563a198e5), /* _Stl_tenpow[36]=(10**307)/(2**1020) */ ULL(0xfd87b5f28300ca0e), /* _Stl_tenpow[37]=(10**-28)/(2**-93) */ ULL(0xfb158592be068d2f), /* _Stl_tenpow[38]=(10**-56)/(2**-186) */ ULL(0xf8a95fcf88747d94), /* _Stl_tenpow[39]=(10**-84)/(2**-279) */ ULL(0xf64335bcf065d37d), /* _Stl_tenpow[40]=(10**-112)/(2**-372) */ ULL(0xf3e2f893dec3f126), /* _Stl_tenpow[41]=(10**-140)/(2**-465) */ ULL(0xf18899b1bc3f8ca2), /* _Stl_tenpow[42]=(10**-168)/(2**-558) */ ULL(0xef340a98172aace5), /* _Stl_tenpow[43]=(10**-196)/(2**-651) */ ULL(0xece53cec4a314ebe), /* _Stl_tenpow[44]=(10**-224)/(2**-744) */ ULL(0xea9c227723ee8bcb), /* _Stl_tenpow[45]=(10**-252)/(2**-837) */ ULL(0xe858ad248f5c22ca), /* _Stl_tenpow[46]=(10**-280)/(2**-930) */ ULL(0xe61acf033d1a45df), /* _Stl_tenpow[47]=(10**-308)/(2**-1023) */ ULL(0xe3e27a444d8d98b8), /* _Stl_tenpow[48]=(10**-336)/(2**-1116) */ ULL(0xe1afa13afbd14d6e) /* _Stl_tenpow[49]=(10**-364)/(2**-1209) */ #else //*TY 03/20/2000 - added support for SCpp which lacks native 64bit integer type static const UnsignedWide _Stl_tenpow[80] = { ULL2(0xa0000000,0x00000000), /* _Stl_tenpow[0]=(10**1)/(2**4) */ ULL2(0xc8000000,0x00000000), /* _Stl_tenpow[1]=(10**2)/(2**7) */ ULL2(0xfa000000,0x00000000), /* _Stl_tenpow[2]=(10**3)/(2**10) */ ULL2(0x9c400000,0x00000000), /* _Stl_tenpow[3]=(10**4)/(2**14) */ ULL2(0xc3500000,0x00000000), /* _Stl_tenpow[4]=(10**5)/(2**17) */ ULL2(0xf4240000,0x00000000), /* _Stl_tenpow[5]=(10**6)/(2**20) */ ULL2(0x98968000,0x00000000), /* _Stl_tenpow[6]=(10**7)/(2**24) */ ULL2(0xbebc2000,0x00000000), /* _Stl_tenpow[7]=(10**8)/(2**27) */ ULL2(0xee6b2800,0x00000000), /* _Stl_tenpow[8]=(10**9)/(2**30) */ ULL2(0x9502f900,0x00000000), /* _Stl_tenpow[9]=(10**10)/(2**34) */ ULL2(0xba43b740,0x00000000), /* _Stl_tenpow[10]=(10**11)/(2**37) */ ULL2(0xe8d4a510,0x00000000), /* _Stl_tenpow[11]=(10**12)/(2**40) */ ULL2(0x9184e72a,0x00000000), /* _Stl_tenpow[12]=(10**13)/(2**44) */ ULL2(0xb5e620f4,0x80000000), /* _Stl_tenpow[13]=(10**14)/(2**47) */ ULL2(0xe35fa931,0xa0000000), /* _Stl_tenpow[14]=(10**15)/(2**50) */ ULL2(0x8e1bc9bf,0x04000000), /* _Stl_tenpow[15]=(10**16)/(2**54) */ ULL2(0xb1a2bc2e,0xc5000000), /* _Stl_tenpow[16]=(10**17)/(2**57) */ ULL2(0xde0b6b3a,0x76400000), /* _Stl_tenpow[17]=(10**18)/(2**60) */ ULL2(0x8ac72304,0x89e80000), /* _Stl_tenpow[18]=(10**19)/(2**64) */ ULL2(0xad78ebc5,0xac620000), /* _Stl_tenpow[19]=(10**20)/(2**67) */ ULL2(0xd8d726b7,0x177a8000), /* _Stl_tenpow[20]=(10**21)/(2**70) */ ULL2(0x87867832,0x6eac9000), /* _Stl_tenpow[21]=(10**22)/(2**74) */ ULL2(0xa968163f,0x0a57b400), /* _Stl_tenpow[22]=(10**23)/(2**77) */ ULL2(0xd3c21bce,0xcceda100), /* _Stl_tenpow[23]=(10**24)/(2**80) */ ULL2(0x84595161,0x401484a0), /* _Stl_tenpow[24]=(10**25)/(2**84) */ ULL2(0xa56fa5b9,0x9019a5c8), /* _Stl_tenpow[25]=(10**26)/(2**87) */ ULL2(0xcecb8f27,0xf4200f3a), /* _Stl_tenpow[26]=(10**27)/(2**90) */ ULL2(0xd0cf4b50,0xcfe20766), /* _Stl_tenpow[27]=(10**55)/(2**183) */ ULL2(0xd2d80db0,0x2aabd62c), /* _Stl_tenpow[28]=(10**83)/(2**276) */ ULL2(0xd4e5e2cd,0xc1d1ea96), /* _Stl_tenpow[29]=(10**111)/(2**369) */ ULL2(0xd6f8d750,0x9292d603), /* _Stl_tenpow[30]=(10**139)/(2**462) */ ULL2(0xd910f7ff,0x28069da4), /* _Stl_tenpow[31]=(10**167)/(2**555) */ ULL2(0xdb2e51bf,0xe9d0696a), /* _Stl_tenpow[32]=(10**195)/(2**648) */ ULL2(0xdd50f199,0x6b947519), /* _Stl_tenpow[33]=(10**223)/(2**741) */ ULL2(0xdf78e4b2,0xbd342cf7), /* _Stl_tenpow[34]=(10**251)/(2**834) */ ULL2(0xe1a63853,0xbbd26451), /* _Stl_tenpow[35]=(10**279)/(2**927) */ ULL2(0xe3d8f9e5,0x63a198e5), /* _Stl_tenpow[36]=(10**307)/(2**1020) */ ULL2(0xfd87b5f2,0x8300ca0e), /* _Stl_tenpow[37]=(10**-28)/(2**-93) */ ULL2(0xfb158592,0xbe068d2f), /* _Stl_tenpow[38]=(10**-56)/(2**-186) */ ULL2(0xf8a95fcf,0x88747d94), /* _Stl_tenpow[39]=(10**-84)/(2**-279) */ ULL2(0xf64335bc,0xf065d37d), /* _Stl_tenpow[40]=(10**-112)/(2**-372) */ ULL2(0xf3e2f893,0xdec3f126), /* _Stl_tenpow[41]=(10**-140)/(2**-465) */ ULL2(0xf18899b1,0xbc3f8ca2), /* _Stl_tenpow[42]=(10**-168)/(2**-558) */ ULL2(0xef340a98,0x172aace5), /* _Stl_tenpow[43]=(10**-196)/(2**-651) */ ULL2(0xece53cec,0x4a314ebe), /* _Stl_tenpow[44]=(10**-224)/(2**-744) */ ULL2(0xea9c2277,0x23ee8bcb), /* _Stl_tenpow[45]=(10**-252)/(2**-837) */ ULL2(0xe858ad24,0x8f5c22ca), /* _Stl_tenpow[46]=(10**-280)/(2**-930) */ ULL2(0xe61acf03,0x3d1a45df), /* _Stl_tenpow[47]=(10**-308)/(2**-1023) */ ULL2(0xe3e27a44,0x4d8d98b8), /* _Stl_tenpow[48]=(10**-336)/(2**-1116) */ ULL2(0xe1afa13a,0xfbd14d6e) /* _Stl_tenpow[49]=(10**-364)/(2**-1209) */ #endif }; static const short _Stl_twoexp[80] = { 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, 183,276,369,462,555,648,741,834,927,1020, -93,-186,-279,-372,-465,-558,-651,-744,-837,-930,-1023,-1116,-1209 }; #define TEN_1 0 /* offset to 10 ** 1 */ #define TEN_27 26 /* offset to 10 ** 27 */ #define TEN_M28 37 /* offset to 10 ** -28 */ #define NUM_HI_P 11 #define NUM_HI_N 13 #define _Stl_HIBITULL (ULL(1) << 63) static void _Stl_norm_and_round(uint64& p, int& norm, uint64 prodhi, uint64 prodlo) { norm = 0; if ((prodhi & _Stl_HIBITULL) == 0) { /* leading bit is a zero * may have to normalize */ if ((prodhi == ~_Stl_HIBITULL) && ((prodlo >> 62) == 0x3)) { /* normalization followed by round * would cause carry to create * extra bit, so don't normalize */ p = _Stl_HIBITULL; return; } p = (prodhi << 1) | (prodlo >> 63); /* normalize */ norm = 1; prodlo <<= 1; } else { p = prodhi; } if ((prodlo & _Stl_HIBITULL) != 0) { /* first guard bit a one */ //*TY 03/25/2000 - added explicit comparison to zero to avoid reliance to the implicit conversion from uint64 to bool #if !defined (__SC__) //*TY 03/25/2000 - if (((p & 0x1) != 0) || prodlo != _Stl_HIBITULL ) { /* not borderline for round to even */ #else //*TY 03/25/2000 - added workaround for SCpp compiler bool b1 = ((p & 0x1) != 0); if (b1 || prodlo != _Stl_HIBITULL) { //*TY 03/25/2000 - SCpp confuses on this particular original boolean expression #endif //*TY 03/25/2000 - /* round */ ++p; if (p == 0) ++p; } } return; } // Convert a 64-bitb fraction * 10^exp to a 64-bit fraction * 2^bexp. // p: 64-bit fraction // exp: base-10 exponent // bexp: base-2 exponent (output parameter) static void _Stl_tenscale(uint64& p, int exp, int& bexp) { uint64 prodhi, prodlo; /* 128b product */ int exp_hi, exp_lo; /* exp = exp_hi*32 + exp_lo */ int hi, lo, tlo, thi; /* offsets in power of ten table */ int norm; /* number of bits of normalization */ int num_hi; /* number of high exponent powers */ bexp = 0; if (exp > 0) { /* split exponent */ exp_lo = exp; exp_hi = 0; if (exp_lo > 27) { exp_lo++; while (exp_lo > 27) { exp_hi++; exp_lo -= 28; } } tlo = TEN_1; thi = TEN_27; num_hi = NUM_HI_P; } else if (exp < 0) { exp_lo = exp; exp_hi = 0; while (exp_lo < 0) { exp_hi++; exp_lo += 28; } tlo = TEN_1; thi = TEN_M28; num_hi = NUM_HI_N; } else { /* no scaling needed */ return; } while (exp_hi) { /* scale */ hi = (min) (exp_hi, num_hi); /* only a few large powers of 10 */ exp_hi -= hi; /* could iterate in extreme case */ hi += thi-1; _Stl_mult64(p, _Stl_tenpow[hi], prodhi, prodlo); _Stl_norm_and_round(p, norm, prodhi, prodlo); bexp += _Stl_twoexp[hi] - norm; } if (exp_lo) { lo = tlo + exp_lo -1; _Stl_mult64(p, _Stl_tenpow[lo], prodhi, prodlo); _Stl_norm_and_round(p, norm, prodhi, prodlo); bexp += _Stl_twoexp[lo] - norm; } return; } // First argument is a buffer of values from 0 to 9, NOT ascii. // Second argument is number of digits in buffer, 1 <= digits <= 17. // Third argument is base-10 exponent. #if defined (__SC__) || defined (__MRC__) //*TY 04/06/2000 - powermac's 68K emulator utilizes apple's SANE floating point, which is not compatible with IEEE format. _STLP_MOVE_TO_STD_NAMESPACE _STLP_END_NAMESPACE # include <fp.h> _STLP_BEGIN_NAMESPACE _STLP_MOVE_TO_PRIV_NAMESPACE static inline double _Stl_atod(char *buffer, int ndigit, int dexp) { decimal d; // ref. inside macintosh powerpc numerics p.9-13 d.sgn = 0; d.exp = dexp; d.sig.length = ndigit; for (int i = 0; i < ndigit; ++i) { d.sig.text[i] = buffer[i] + '0'; } return dec2num(&d); } #else /* IEEE representation */ # if !defined (__linux__) static double _Stl_atod(char *buffer, int ndigit, int dexp) { uint64 value; /* Value develops as follows: * 1) decimal digits as an integer * 2) left adjusted fraction * 3) right adjusted fraction * 4) exponent and fraction */ uint32 guard; /* First guard bit */ uint64 rest; /* Remaining guard bits */ int bexp; /* binary exponent */ int nzero; /* number of non-zero bits */ int sexp; /* scaling exponent */ char *bufferend; /* pointer to char after last digit */ /* Check for zero and treat it as a special case */ if (buffer == 0){ return 0.0; } /* Convert the decimal digits to a binary integer. */ bufferend = buffer + ndigit; value = 0; while (buffer < bufferend) { value *= 10; value += *buffer++; } /* Check for zero and treat it as a special case */ if (value == 0) { return 0.0; } /* Normalize value */ bexp = 64; /* convert from 64b int to fraction */ /* Count number of non-zeroes in value */ nzero = 0; if ((value >> 32) != 0) { nzero = 32; } //*TY 03/25/2000 - added explicit comparison to zero to avoid uint64 to bool conversion operator if ((value >> (16 + nzero)) != 0) { nzero += 16; } if ((value >> ( 8 + nzero)) != 0) { nzero += 8; } if ((value >> ( 4 + nzero)) != 0) { nzero += 4; } if ((value >> ( 2 + nzero)) != 0) { nzero += 2; } if ((value >> ( 1 + nzero)) != 0) { nzero += 1; } if ((value >> ( nzero)) != 0) { nzero += 1; } /* Normalize */ value <<= /*(uint64)*/ (64 - nzero); //*TY 03/25/2000 - removed extraneous cast to uint64 bexp -= 64 - nzero; /* At this point we have a 64b fraction and a binary exponent * but have yet to incorporate the decimal exponent. */ /* multiply by 10^dexp */ _Stl_tenscale(value, dexp, sexp); bexp += sexp; if (bexp <= -1022) { /* HI denorm or underflow */ bexp += 1022; if (bexp < -53) { /* guaranteed underflow */ value = 0; } else { /* denorm or possible underflow */ int lead0 = 12 - bexp; /* 12 sign and exponent bits */ /* we must special case right shifts of more than 63 */ if (lead0 > 64) { rest = value; guard = 0; value = 0; } else if (lead0 == 64) { rest = value & ((ULL(1)<< 63)-1); #if !defined(__SC__) guard = (uint32) ((value>> 63) & 1 ); #else guard = to_ulong((value>> 63) & 1 ); //*TY 03/25/2000 - use member function instead of problematic conversion operator utilization #endif value = 0; } else { rest = value & (((ULL(1) << lead0)-1)-1); #if !defined(__SC__) guard = (uint32) (((value>> lead0)-1) & 1); #else //*TY 03/25/2000 - guard = to_ulong(((value>> lead0)-1) & 1); #endif //*TY 03/25/2000 - value >>= /*(uint64)*/ lead0; /* exponent is zero */ } /* Round */ if (guard && ((value & 1) || rest) ) { ++value; if (value == (ULL(1) << 52)) { /* carry created normal number */ value = 0; _Stl_set_exponent(value, 1); } } } } else { /* not zero or denorm */ /* Round to 53 bits */ rest = value & (1<<10)-1; value >>= 10; #if !defined(__SC__) guard = (uint32) value & 1; #else //*TY 03/25/2000 - guard = to_ulong(value & 1); #endif value >>= 1; /* value&1 guard rest Action * * dc 0 dc none * 1 1 dc round * 0 1 0 none * 0 1 !=0 round */ if (guard) { if (((value&1)!=0) || (rest!=0)) { ++value; /* round */ if ((value >> 53) != 0) { /* carry all the way across */ value >>= 1; /* renormalize */ ++bexp; } } } /* * Check for overflow * IEEE Double Precision Format * (From Table 7-8 of Kane and Heinrich) * * Fraction bits 52 * Emax +1023 * Emin -1022 * Exponent bias +1023 * Exponent bits 11 * Integer bit hidden * Total width in bits 64 */ if (bexp > 1024) { /* overflow */ return numeric_limits<double>::infinity(); } else { /* value is normal */ value &= ~(ULL(1) << 52); /* hide hidden bit */ _Stl_set_exponent(value, bexp + 1022); /* add bias */ } } _STLP_STATIC_ASSERT(sizeof(value) == sizeof(double)) return *((double *) &value); } # else // __linux__ static double _Stl_atod(char *buffer, int ndigit, int dexp) { ieee754_double v; char *bufferend; /* pointer to char after last digit */ /* Check for zero and treat it as a special case */ if (buffer == 0) { return 0.0; } /* Convert the decimal digits to a binary integer. */ bufferend = buffer + ndigit; _ll vv; vv.i64 = 0L; while (buffer < bufferend) { vv.i64 *= 10; vv.i64 += *buffer++; } /* Check for zero and treat it as a special case */ if (vv.i64 == 0){ return 0.0; } /* Normalize value */ int bexp = 64; /* convert from 64b int to fraction */ /* Count number of non-zeroes in value */ int nzero = 0; if ((vv.i64 >> 32) !=0 ) { nzero = 32; } //*TY 03/25/2000 - added explicit comparison to zero to avoid uint64 to bool conversion operator if ((vv.i64 >> (16 + nzero)) != 0) { nzero += 16; } if ((vv.i64 >> ( 8 + nzero)) != 0) { nzero += 8; } if ((vv.i64 >> ( 4 + nzero)) != 0) { nzero += 4; } if ((vv.i64 >> ( 2 + nzero)) != 0) { nzero += 2; } if ((vv.i64 >> ( 1 + nzero)) != 0) { nzero += 1; } if ((vv.i64 >> ( nzero)) != 0) { nzero += 1; } /* Normalize */ nzero = 64 - nzero; vv.i64 <<= nzero; //*TY 03/25/2000 - removed extraneous cast to uint64 bexp -= nzero; /* At this point we have a 64b fraction and a binary exponent * but have yet to incorporate the decimal exponent. */ /* multiply by 10^dexp */ int sexp; _Stl_tenscale(vv.i64, dexp, sexp); bexp += sexp; if (bexp <= -1022) { /* HI denorm or underflow */ bexp += 1022; if (bexp < -53) { /* guaranteed underflow */ vv.i64 = 0; } else { /* denorm or possible underflow */ int lead0; uint64_t rest; uint32_t guard; lead0 = 12-bexp; /* 12 sign and exponent bits */ /* we must special case right shifts of more than 63 */ if (lead0 > 64) { rest = vv.i64; guard = 0; vv.i64 = 0; } else if (lead0 == 64) { rest = vv.i64 & ((ULL(1) << 63)-1); #if !defined(__SC__) guard = (uint32) ((vv.i64 >> 63) & 1 ); #else guard = to_ulong((vv.i64 >> 63) & 1 ); //*TY 03/25/2000 - use member function instead of problematic conversion operator utilization #endif vv.i64 = 0; } else { rest = vv.i64 & (((ULL(1) << lead0)-1)-1); #if !defined(__SC__) guard = (uint32) (((vv.i64 >> lead0)-1) & 1); #else //*TY 03/25/2000 - guard = to_ulong(((vv.i64 >> lead0)-1) & 1); #endif //*TY 03/25/2000 - vv.i64 >>= /*(uint64)*/ lead0; /* exponent is zero */ } /* Round */ if (guard && ( (vv.i64 & 1) || rest)) { vv.i64++; if (vv.i64 == (ULL(1) << 52)) { /* carry created normal number */ v.ieee.mantissa0 = 0; v.ieee.mantissa1 = 0; v.ieee.negative = 0; v.ieee.exponent = 1; return v.d; } } } } else { /* not zero or denorm */ /* Round to 53 bits */ uint64_t rest = vv.i64 & (1<<10)-1; vv.i64 >>= 10; #if !defined(__SC__) uint32_t guard = (uint32) vv.i64 & 1; #else //*TY 03/25/2000 - uint32_t guard = to_ulong(vv.i64 & 1); #endif vv.i64 >>= 1; /* value&1 guard rest Action * * dc 0 dc none * 1 1 dc round * 0 1 0 none * 0 1 !=0 round */ if (guard) { if (((vv.i64&1)!=0) || (rest!=0)) { vv.i64++; /* round */ if ((vv.i64>>53)!=0) { /* carry all the way across */ vv.i64 >>= 1; /* renormalize */ ++bexp; } } } /* * Check for overflow * IEEE Double Precision Format * (From Table 7-8 of Kane and Heinrich) * * Fraction bits 52 * Emax +1023 * Emin -1022 * Exponent bias +1023 * Exponent bits 11 * Integer bit hidden * Total width in bits 64 */ if (bexp > 1024) { /* overflow */ return numeric_limits<double>::infinity(); } else { /* value is normal */ vv.i64 &= ~(ULL(1) << 52); /* hide hidden bit */ v.ieee.mantissa0 = vv.i32.hi; v.ieee.mantissa1 = vv.i32.lo; v.ieee.negative = 0; v.ieee.exponent = bexp + 1022; return v.d; } } v.ieee.mantissa0 = vv.i32.hi; v.ieee.mantissa1 = vv.i32.lo; v.ieee.negative = 0; v.ieee.exponent = 0; return v.d; } # endif // __linux__ #endif static double _Stl_string_to_double(const char *s) { const int max_digits = 17; unsigned c; unsigned Negate, decimal_point; char *d; int exp; double x; int dpchar; char digits[max_digits]; // Skip leading whitespace, if any. const ctype<char>& ct = use_facet<ctype<char> >(locale::classic()); while (c = *s++, ct.is(ctype_base::space, char(c))) {} /* process sign */ Negate = 0; if (c == '+') { c = *s++; } else if (c == '-') { Negate = 1; c = *s++; } d = digits; dpchar = '.' - '0'; decimal_point = 0; exp = 0; for (;;) { c -= '0'; if (c < 10) { if (d == digits + max_digits) { /* ignore more than 17 digits, but adjust exponent */ exp += (decimal_point ^ 1); } else { if (c == 0 && d == digits) { /* ignore leading zeros */ } else { *d++ = (char) c; } exp -= decimal_point; } } else if (c == (unsigned int) dpchar && !decimal_point) { /* INTERNATIONAL */ decimal_point = 1; } else { break; } c = *s++; } /* strtod cant return until it finds the end of the exponent */ if (d == digits) { return 0.0; } if (c == 'e'-'0' || c == 'E'-'0') { register unsigned negate_exp = 0; register int e = 0; c = *s++; if (c == '+' || c == ' ') { c = *s++; } else if (c == '-') { negate_exp = 1; c = *s++; } if (c -= '0', c < 10) { do { if (e <= 340) e = e * 10 + (int)c; else break; c = *s++; } while (c -= '0', c < 10); if (negate_exp) { e = -e; } if (e < -340 || e > 340) exp = e; else exp += e; } } if (exp < -340) { x = 0; } else if (exp > 308) { x = numeric_limits<double>::infinity(); } else { /* let _Stl_atod diagnose under- and over-flows */ /* if the input was == 0.0, we have already returned, so retval of +-Inf signals OVERFLOW, 0.0 UNDERFLOW */ x = _Stl_atod(digits, (int)(d - digits), exp); } if (Negate) { x = -x; } return x; } #if !defined (_STLP_NO_LONG_DOUBLE) /* * __string_to_long_double is just lifted from atold, the difference being * that we just use '.' for the decimal point, rather than let it * be taken from the current C locale, which of course is not accessible * to us. */ static long double _Stl_string_to_long_double(const char * s) { const int max_digits = 34; register unsigned c; register unsigned Negate, decimal_point; register char *d; register int exp; long double x; register int dpchar; char digits[max_digits]; const ctype<char>& ct = use_facet<ctype<char> >(locale::classic()); while (c = *s++, ct.is(ctype_base::space, char(c))) ; /* process sign */ Negate = 0; if (c == '+') { c = *s++; } else if (c == '-') { Negate = 1; c = *s++; } d = digits; dpchar = '.' - '0'; decimal_point = 0; exp = 0; for (;;) { c -= '0'; if (c < 10) { if (d == digits+max_digits) { /* ignore more than 34 digits, but adjust exponent */ exp += (decimal_point ^ 1); } else { if (c == 0 && d == digits) { /* ignore leading zeros */ ; } else { *d++ = (char)c; } exp -= decimal_point; } } else if ((char)c == dpchar && !decimal_point) { /* INTERNATIONAL */ decimal_point = 1; } else { break; } c = *s++; } /* for */ if (d == digits) { return 0.0L; } if (c == 'e'-'0' || c == 'E'-'0') { register unsigned negate_exp = 0; register int e = 0; c = *s++; if (c == '+' || c == ' ') { c = *s++; } else if (c == '-') { negate_exp = 1; c = *s++; } if (c -= '0', c < 10) { do { if (e <= 340) e = e * 10 + c; else break; c = *s++; } while (c -= '0', c < 10); if (negate_exp) { e = -e; } if (e < -(323+max_digits) || e > 308) exp = e; else exp += e; } } if (exp < -(324+max_digits)) { x = 0; } else if (exp > 308) { x = numeric_limits<long double>::infinity(); } else { /* let _Stl_atod diagnose under- and over-flows */ /* if the input was == 0.0, we have already returned, so retval of +-Inf signals OVERFLOW, 0.0 UNDERFLOW */ // x = _Stl_atod (digits, (int)(d - digits), exp); // TEMPORARY!!:1 double tmp = _Stl_atod (digits, (int)(d - digits), exp); // TEMPORARY!!:1 x = tmp == numeric_limits<double>::infinity() ? numeric_limits<long double>::infinity() : tmp; } if (Negate) { x = -x; } return x; } #endif void _STLP_CALL __string_to_float(const __iostring& v, float& val) { val = (float)_Stl_string_to_double(v.c_str()); } void _STLP_CALL __string_to_float(const __iostring& v, double& val) { val = _Stl_string_to_double(v.c_str()); } #if !defined (_STLP_NO_LONG_DOUBLE) void _STLP_CALL __string_to_float(const __iostring& v, long double& val) { val = _Stl_string_to_long_double(v.c_str()); } #endif _STLP_MOVE_TO_STD_NAMESPACE _STLP_END_NAMESPACE // Local Variables: // mode:C++ // End:

• ソフトウェア開発
• ホームページ制作
• Doxygen Source Document
• Tcl Source Document