1 // Copyright 2001 John Maddock

     2 // Distributed under the Boost Software License, Version 1.0. (See accompany-

     3 // ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

     4 

     5 /*

     6  * Copyright (c) 1997

     7  * Silicon Graphics Computer Systems, Inc.

     8  *

     9  * Permission to use, copy, modify, distribute and sell this software

    10  * and its documentation for any purpose is hereby granted without fee,

    11  * provided that the above copyright notice appear in all copies and

    12  * that both that copyright notice and this permission notice appear

    13  * in supporting documentation.  Silicon Graphics makes no

    14  * representations about the suitability of this software for any

    15  * purpose.  It is provided "as is" without express or implied warranty.

    16  */

    17 

    18 /* NOTE: This is not portable code.  Parts of numeric_limits<> are

    19  * inherently machine-dependent, and this file is written for the MIPS

    20  * architecture and the SGI MIPSpro C++ compiler.  Parts of it (in

    21  * particular, some of the characteristics of floating-point types)

    22  * are almost certainly incorrect for any other platform.

    23  */

    24 

    25 /* The above comment is almost certainly out of date. This file works

    26  * on systems other than SGI MIPSpro C++ now.

    27  */

    28 

    29 /*

    30  * Revision history:

    31  * 21 Sep 2001:

    32  *    Only include <cwchar> if BOOST_NO_CWCHAR is defined. (Darin Adler)

    33  * 10 Aug 2001:

    34  *    Added MIPS (big endian) to the big endian family. (Jens Maurer)

    35  * 13 Apr 2001:

    36  *    Added powerpc to the big endian family. (Jeremy Siek)

    37  * 5 Apr 2001:

    38  *    Added sparc (big endian) processor support (John Maddock).

    39  * Initial sub:

    40  *      Modified by Jens Maurer for gcc 2.95 on x86.

    41  */

    42 

    43 #ifndef BOOST_SGI_CPP_LIMITS

    44 #define BOOST_SGI_CPP_LIMITS

    45 

    46 #include <climits>

    47 #include <cfloat>

    48 #include <boost/config.hpp>

    49 #include <boost/detail/endian.hpp>

    50 

    51 #ifndef BOOST_NO_CWCHAR

    52 #include <cwchar> // for WCHAR_MIN and WCHAR_MAX

    53 #endif

    54 

    55 namespace std {

    56 

    57 enum float_round_style {

    58   round_indeterminate       = -1,

    59   round_toward_zero         =  0,

    60   round_to_nearest          =  1,

    61   round_toward_infinity     =  2,

    62   round_toward_neg_infinity =  3

    63 };

    64 

    65 enum float_denorm_style {

    66   denorm_indeterminate = -1,

    67   denorm_absent        =  0,

    68   denorm_present       =  1

    69 };

    70 

    71 // The C++ standard (section 18.2.1) requires that some of the members of

    72 // numeric_limits be static const data members that are given constant-

    73 // initializers within the class declaration.  On compilers where the

    74 // BOOST_NO_INCLASS_MEMBER_INITIALIZATION macro is defined, it is impossible to write

    75 // a standard-conforming numeric_limits class.

    76 //

    77 // There are two possible workarounds: either initialize the data

    78 // members outside the class, or change them from data members to

    79 // enums.  Neither workaround is satisfactory: the former makes it

    80 // impossible to use the data members in constant-expressions, and the

    81 // latter means they have the wrong type and that it is impossible to

    82 // take their addresses.  We choose the former workaround.

    83 

    84 #ifdef BOOST_NO_INCLASS_MEMBER_INITIALIZATION

    85 # define BOOST_STL_DECLARE_LIMITS_MEMBER(__mem_type, __mem_name, __mem_value) \

    86   enum { __mem_name = __mem_value }

    87 #else /* BOOST_NO_INCLASS_MEMBER_INITIALIZATION */

    88 # define BOOST_STL_DECLARE_LIMITS_MEMBER(__mem_type, __mem_name, __mem_value) \

    89   static const __mem_type __mem_name = __mem_value

    90 #endif /* BOOST_NO_INCLASS_MEMBER_INITIALIZATION */

    91 

    92 // Base class for all specializations of numeric_limits.

    93 template <class __number>

    94 class _Numeric_limits_base {

    95 public:

    96   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_specialized, false);

    97 

    98   static __number min BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return __number(); }

    99   static __number max BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return __number(); }

   100 

   101   BOOST_STL_DECLARE_LIMITS_MEMBER(int, digits,   0);

   102   BOOST_STL_DECLARE_LIMITS_MEMBER(int, digits10, 0);

   103 

   104   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_signed,  false);

   105   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_integer, false);

   106   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_exact,   false);

   107 

   108   BOOST_STL_DECLARE_LIMITS_MEMBER(int, radix, 0);

   109 

   110   static __number epsilon() throw()     { return __number(); }

   111   static __number round_error() throw() { return __number(); }

   112 

   113   BOOST_STL_DECLARE_LIMITS_MEMBER(int, min_exponent,   0);

   114   BOOST_STL_DECLARE_LIMITS_MEMBER(int, min_exponent10, 0);

   115   BOOST_STL_DECLARE_LIMITS_MEMBER(int, max_exponent,   0);

   116   BOOST_STL_DECLARE_LIMITS_MEMBER(int, max_exponent10, 0);

   117 

   118   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_infinity,      false);

   119   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_quiet_NaN,     false);

   120   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_signaling_NaN, false);

   121   BOOST_STL_DECLARE_LIMITS_MEMBER(float_denorm_style,

   122                               has_denorm,

   123                               denorm_absent);

   124   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_denorm_loss,   false);

   125 

   126   static __number infinity() throw()      { return __number(); }

   127   static __number quiet_NaN() throw()     { return __number(); }

   128   static __number signaling_NaN() throw() { return __number(); }

   129   static __number denorm_min() throw()    { return __number(); }

   130 

   131   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_iec559,  false);

   132   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_bounded, false);

   133   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_modulo,  false);

   134 

   135   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, traps,            false);

   136   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, tinyness_before,  false);

   137   BOOST_STL_DECLARE_LIMITS_MEMBER(float_round_style,

   138                               round_style,

   139                               round_toward_zero);

   140 };

   141 

   142 // Base class for integers.

   143 

   144 template <class _Int,

   145           _Int __imin,

   146           _Int __imax,

   147           int __idigits = -1>

   148 class _Integer_limits : public _Numeric_limits_base<_Int> 

   149 {

   150 public:

   151   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_specialized, true);

   152 

   153   static _Int min BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return __imin; }

   154   static _Int max BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return __imax; }

   155 

   156   BOOST_STL_DECLARE_LIMITS_MEMBER(int,

   157                               digits,

   158                               (__idigits < 0) ? (int)(sizeof(_Int) * CHAR_BIT)

   159                                                    - (__imin == 0 ? 0 : 1) 

   160                                               : __idigits);

   161   BOOST_STL_DECLARE_LIMITS_MEMBER(int, digits10, (digits * 301) / 1000); 

   162                                 // log 2 = 0.301029995664...

   163 

   164   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_signed,  __imin != 0);

   165   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_integer, true);

   166   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_exact,   true);

   167   BOOST_STL_DECLARE_LIMITS_MEMBER(int,  radix,      2);

   168 

   169   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_bounded, true);

   170   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_modulo, true);

   171 };

   172 

   173 #if defined(BOOST_BIG_ENDIAN)

   174 

   175  template<class Number, unsigned int Word>

   176  struct float_helper{

   177   static Number get_word() throw() {

   178     // sizeof(long double) == 16

   179     const unsigned int _S_word[4] = { Word, 0, 0, 0 };

   180     return *reinterpret_cast<const Number*>(&_S_word);

   181   } 

   182 };

   183 

   184 #else

   185 

   186  template<class Number, unsigned int Word>

   187  struct float_helper{

   188   static Number get_word() throw() {

   189     // sizeof(long double) == 12, but only 10 bytes significant

   190     const unsigned int _S_word[4] = { 0, 0, 0, Word };

   191     return *reinterpret_cast<const Number*>(

   192         reinterpret_cast<const char *>(&_S_word)+16-

   193                 (sizeof(Number) == 12 ? 10 : sizeof(Number)));

   194   } 

   195 };

   196 

   197 #endif

   198 

   199 // Base class for floating-point numbers.

   200 template <class __number,

   201          int __Digits, int __Digits10,

   202          int __MinExp, int __MaxExp,

   203          int __MinExp10, int __MaxExp10,

   204          unsigned int __InfinityWord,

   205          unsigned int __QNaNWord, unsigned int __SNaNWord,

   206          bool __IsIEC559,

   207          float_round_style __RoundStyle>

   208 class _Floating_limits : public _Numeric_limits_base<__number>

   209 {

   210 public:

   211   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_specialized, true);

   212 

   213   BOOST_STL_DECLARE_LIMITS_MEMBER(int, digits,   __Digits);

   214   BOOST_STL_DECLARE_LIMITS_MEMBER(int, digits10, __Digits10);

   215 

   216   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_signed, true);

   217 

   218   BOOST_STL_DECLARE_LIMITS_MEMBER(int, radix, 2);

   219 

   220   BOOST_STL_DECLARE_LIMITS_MEMBER(int, min_exponent,   __MinExp);

   221   BOOST_STL_DECLARE_LIMITS_MEMBER(int, max_exponent,   __MaxExp);

   222   BOOST_STL_DECLARE_LIMITS_MEMBER(int, min_exponent10, __MinExp10);

   223   BOOST_STL_DECLARE_LIMITS_MEMBER(int, max_exponent10, __MaxExp10);

   224 

   225   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_infinity,      true);

   226   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_quiet_NaN,     true);

   227   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_signaling_NaN, true);

   228   BOOST_STL_DECLARE_LIMITS_MEMBER(float_denorm_style,

   229                               has_denorm,

   230                               denorm_indeterminate);

   231   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, has_denorm_loss,   false);

   232 

   233  

   234   static __number infinity() throw() {

   235     return float_helper<__number, __InfinityWord>::get_word();

   236   }

   237   static __number quiet_NaN() throw() {

   238     return float_helper<__number,__QNaNWord>::get_word();

   239   }

   240   static __number signaling_NaN() throw() {

   241     return float_helper<__number,__SNaNWord>::get_word();

   242   }

   243 

   244   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_iec559,       __IsIEC559);

   245   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, is_bounded,      true);

   246   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, traps,           false /* was: true */ );

   247   BOOST_STL_DECLARE_LIMITS_MEMBER(bool, tinyness_before, false);

   248 

   249   BOOST_STL_DECLARE_LIMITS_MEMBER(float_round_style, round_style, __RoundStyle);

   250 };

   251 

   252 // Class numeric_limits

   253 

   254 // The unspecialized class.

   255 

   256 template<class T> 

   257 class numeric_limits : public _Numeric_limits_base<T> {};

   258 

   259 // Specializations for all built-in integral types.

   260 

   261 template<>

   262 class numeric_limits<bool>

   263   : public _Integer_limits<bool, false, true, 0>

   264 {};

   265 

   266 template<>

   267 class numeric_limits<char>

   268   : public _Integer_limits<char, CHAR_MIN, CHAR_MAX>

   269 {};

   270 

   271 template<>

   272 class numeric_limits<signed char>

   273   : public _Integer_limits<signed char, SCHAR_MIN, SCHAR_MAX>

   274 {};

   275 

   276 template<>

   277 class numeric_limits<unsigned char>

   278   : public _Integer_limits<unsigned char, 0, UCHAR_MAX>

   279 {};

   280 

   281 #ifndef BOOST_NO_INTRINSIC_WCHAR_T

   282 template<>

   283 class numeric_limits<wchar_t>

   284 #if !defined(WCHAR_MAX) || !defined(WCHAR_MIN)

   285 #if defined(_WIN32) || defined(__CYGWIN__)

   286   : public _Integer_limits<wchar_t, 0, USHRT_MAX>

   287 #elif defined(__hppa)

   288 // wchar_t has "unsigned int" as the underlying type

   289   : public _Integer_limits<wchar_t, 0, UINT_MAX>

   290 #else

   291 // assume that wchar_t has "int" as the underlying type

   292   : public _Integer_limits<wchar_t, INT_MIN, INT_MAX>

   293 #endif

   294 #else

   295 // we have WCHAR_MIN and WCHAR_MAX defined, so use it

   296   : public _Integer_limits<wchar_t, WCHAR_MIN, WCHAR_MAX>

   297 #endif

   298 {};

   299 #endif

   300 

   301 template<>

   302 class numeric_limits<short>

   303   : public _Integer_limits<short, SHRT_MIN, SHRT_MAX>

   304 {};

   305 

   306 template<>

   307 class numeric_limits<unsigned short>

   308   : public _Integer_limits<unsigned short, 0, USHRT_MAX>

   309 {};

   310 

   311 template<>

   312 class numeric_limits<int>

   313   : public _Integer_limits<int, INT_MIN, INT_MAX>

   314 {};

   315 

   316 template<>

   317 class numeric_limits<unsigned int>

   318   : public _Integer_limits<unsigned int, 0, UINT_MAX>

   319 {};

   320 

   321 template<>

   322 class numeric_limits<long>

   323   : public _Integer_limits<long, LONG_MIN, LONG_MAX>

   324 {};

   325 

   326 template<>

   327 class numeric_limits<unsigned long>

   328   : public _Integer_limits<unsigned long, 0, ULONG_MAX>

   329 {};

   330 

   331 #ifdef __GNUC__

   332 

   333 // Some compilers have long long, but don't define the

   334 // LONGLONG_MIN and LONGLONG_MAX macros in limits.h.  This

   335 // assumes that long long is 64 bits.

   336 #if !defined(LONGLONG_MAX) && !defined(ULONGLONG_MAX)

   337 

   338 # define ULONGLONG_MAX 0xffffffffffffffffLLU

   339 # define LONGLONG_MAX 0x7fffffffffffffffLL

   340 

   341 #endif

   342 

   343 #if !defined(LONGLONG_MIN)

   344 # define LONGLONG_MIN (-LONGLONG_MAX - 1)

   345 #endif 

   346 

   347 

   348 #if !defined(ULONGLONG_MIN)

   349 # define ULONGLONG_MIN 0

   350 #endif 

   351 

   352 #endif /* __GNUC__ */

   353 

   354 // Specializations for all built-in floating-point type.

   355 

   356 template<> class numeric_limits<float>

   357   : public _Floating_limits<float, 

   358                             FLT_MANT_DIG,   // Binary digits of precision

   359                             FLT_DIG,        // Decimal digits of precision

   360                             FLT_MIN_EXP,    // Minimum exponent

   361                             FLT_MAX_EXP,    // Maximum exponent

   362                             FLT_MIN_10_EXP, // Minimum base 10 exponent

   363                             FLT_MAX_10_EXP, // Maximum base 10 exponent

   364 #if defined(BOOST_BIG_ENDIAN)

   365                             0x7f80 << (sizeof(int)*CHAR_BIT-16),    // Last word of +infinity

   366                             0x7f81 << (sizeof(int)*CHAR_BIT-16),    // Last word of quiet NaN

   367                             0x7fc1 << (sizeof(int)*CHAR_BIT-16),    // Last word of signaling NaN

   368 #else

   369                             0x7f800000u,    // Last word of +infinity

   370                             0x7f810000u,    // Last word of quiet NaN

   371                             0x7fc10000u,    // Last word of signaling NaN

   372 #endif

   373                             true,           // conforms to iec559

   374                             round_to_nearest>

   375 {

   376 public:

   377   static float min BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return FLT_MIN; }

   378   static float denorm_min() throw() { return FLT_MIN; }

   379   static float max BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return FLT_MAX; }

   380   static float epsilon() throw() { return FLT_EPSILON; }

   381   static float round_error() throw() { return 0.5f; } // Units: ulps.

   382 };

   383 

   384 template<> class numeric_limits<double>

   385   : public _Floating_limits<double, 

   386                             DBL_MANT_DIG,   // Binary digits of precision

   387                             DBL_DIG,        // Decimal digits of precision

   388                             DBL_MIN_EXP,    // Minimum exponent

   389                             DBL_MAX_EXP,    // Maximum exponent

   390                             DBL_MIN_10_EXP, // Minimum base 10 exponent

   391                             DBL_MAX_10_EXP, // Maximum base 10 exponent

   392 #if defined(BOOST_BIG_ENDIAN)

   393                             0x7ff0 << (sizeof(int)*CHAR_BIT-16),    // Last word of +infinity

   394                             0x7ff1 << (sizeof(int)*CHAR_BIT-16),    // Last word of quiet NaN

   395                             0x7ff9 << (sizeof(int)*CHAR_BIT-16),    // Last word of signaling NaN

   396 #else

   397                             0x7ff00000u,    // Last word of +infinity

   398                             0x7ff10000u,    // Last word of quiet NaN

   399                             0x7ff90000u,    // Last word of signaling NaN

   400 #endif

   401                             true,           // conforms to iec559

   402                             round_to_nearest>

   403 {

   404 public:

   405   static double min BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return DBL_MIN; }

   406   static double denorm_min() throw() { return DBL_MIN; }

   407   static double max BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return DBL_MAX; }

   408   static double epsilon() throw() { return DBL_EPSILON; }

   409   static double round_error() throw() { return 0.5; } // Units: ulps.

   410 };

   411 

   412 template<> class numeric_limits<long double>

   413   : public _Floating_limits<long double, 

   414                             LDBL_MANT_DIG,  // Binary digits of precision

   415                             LDBL_DIG,       // Decimal digits of precision

   416                             LDBL_MIN_EXP,   // Minimum exponent

   417                             LDBL_MAX_EXP,   // Maximum exponent

   418                             LDBL_MIN_10_EXP,// Minimum base 10 exponent

   419                             LDBL_MAX_10_EXP,// Maximum base 10 exponent

   420 #if defined(BOOST_BIG_ENDIAN)

   421                             0x7ff0 << (sizeof(int)*CHAR_BIT-16),    // Last word of +infinity

   422                             0x7ff1 << (sizeof(int)*CHAR_BIT-16),    // Last word of quiet NaN

   423                             0x7ff9 << (sizeof(int)*CHAR_BIT-16),    // Last word of signaling NaN

   424 #else

   425                             0x7fff8000u,    // Last word of +infinity

   426                             0x7fffc000u,    // Last word of quiet NaN

   427                             0x7fff9000u,    // Last word of signaling NaN

   428 #endif

   429                             false,          // Doesn't conform to iec559

   430                             round_to_nearest>

   431 {

   432 public:

   433   static long double min BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return LDBL_MIN; }

   434   static long double denorm_min() throw() { return LDBL_MIN; }

   435   static long double max BOOST_PREVENT_MACRO_SUBSTITUTION () throw() { return LDBL_MAX; }

   436   static long double epsilon() throw() { return LDBL_EPSILON; }

   437   static long double round_error() throw() { return 4; } // Units: ulps.

   438 };

   439 

   440 } // namespace std

   441 

   442 #endif /* BOOST_SGI_CPP_LIMITS */

   443 

   444 // Local Variables:

   445 // mode:C++

   446 // End:

   447 

   448 

   449