ossrv_pub/boost_apis/boost/integer.hpp
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     1 //  boost integer.hpp header file  -------------------------------------------//
       
     2 
       
     3 //  Copyright Beman Dawes and Daryle Walker 1999.  Distributed under the Boost
       
     4 //  Software License, Version 1.0. (See accompanying file
       
     5 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
       
     6 
       
     7 //  See http://www.boost.org/libs/integer for documentation.
       
     8 
       
     9 //  Revision History
       
    10 //   22 Sep 01  Added value-based integer templates. (Daryle Walker)
       
    11 //   01 Apr 01  Modified to use new <boost/limits.hpp> header. (John Maddock)
       
    12 //   30 Jul 00  Add typename syntax fix (Jens Maurer)
       
    13 //   28 Aug 99  Initial version
       
    14 
       
    15 #ifndef BOOST_INTEGER_HPP
       
    16 #define BOOST_INTEGER_HPP
       
    17 
       
    18 #include <boost/integer_fwd.hpp>  // self include
       
    19 
       
    20 #include <boost/integer_traits.hpp>  // for boost::integer_traits
       
    21 #include <boost/limits.hpp>          // for std::numeric_limits
       
    22 
       
    23 namespace boost
       
    24 {
       
    25 
       
    26   //  Helper templates  ------------------------------------------------------//
       
    27 
       
    28   //  fast integers from least integers
       
    29   //  int_fast_t<> works correctly for unsigned too, in spite of the name.
       
    30   template< typename LeastInt >
       
    31   struct int_fast_t { typedef LeastInt fast; }; // imps may specialize
       
    32 
       
    33   //  convert category to type 
       
    34   template< int Category > struct int_least_helper {}; // default is empty
       
    35 
       
    36   //  specializatons: 1=long, 2=int, 3=short, 4=signed char,
       
    37   //     6=unsigned long, 7=unsigned int, 8=unsigned short, 9=unsigned long
       
    38   //  no specializations for 0 and 5: requests for a type > long are in error
       
    39   template<> struct int_least_helper<1> { typedef long least; };
       
    40   template<> struct int_least_helper<2> { typedef int least; };
       
    41   template<> struct int_least_helper<3> { typedef short least; };
       
    42   template<> struct int_least_helper<4> { typedef signed char least; };
       
    43   template<> struct int_least_helper<6> { typedef unsigned long least; };
       
    44   template<> struct int_least_helper<7> { typedef unsigned int least; };
       
    45   template<> struct int_least_helper<8> { typedef unsigned short least; };
       
    46   template<> struct int_least_helper<9> { typedef unsigned char least; };
       
    47 
       
    48   //  integer templates specifying number of bits  ---------------------------//
       
    49 
       
    50   //  signed
       
    51   template< int Bits >   // bits (including sign) required
       
    52   struct int_t 
       
    53   {
       
    54       typedef typename int_least_helper
       
    55         <
       
    56           (Bits-1 <= std::numeric_limits<long>::digits) +
       
    57           (Bits-1 <= std::numeric_limits<int>::digits) +
       
    58           (Bits-1 <= std::numeric_limits<short>::digits) +
       
    59           (Bits-1 <= std::numeric_limits<signed char>::digits)
       
    60         >::least  least;
       
    61       typedef typename int_fast_t<least>::fast  fast;
       
    62   };
       
    63 
       
    64   //  unsigned
       
    65   template< int Bits >   // bits required
       
    66   struct uint_t 
       
    67   {
       
    68       typedef typename int_least_helper
       
    69         < 
       
    70           5 +
       
    71           (Bits <= std::numeric_limits<unsigned long>::digits) +
       
    72           (Bits <= std::numeric_limits<unsigned int>::digits) +
       
    73           (Bits <= std::numeric_limits<unsigned short>::digits) +
       
    74           (Bits <= std::numeric_limits<unsigned char>::digits)
       
    75         >::least  least;
       
    76       typedef typename int_fast_t<least>::fast  fast;
       
    77       // int_fast_t<> works correctly for unsigned too, in spite of the name.
       
    78   };
       
    79 
       
    80   //  integer templates specifying extreme value  ----------------------------//
       
    81 
       
    82   //  signed
       
    83   template< long MaxValue >   // maximum value to require support
       
    84   struct int_max_value_t 
       
    85   {
       
    86       typedef typename int_least_helper
       
    87         <
       
    88           (MaxValue <= integer_traits<long>::const_max) +
       
    89           (MaxValue <= integer_traits<int>::const_max) +
       
    90           (MaxValue <= integer_traits<short>::const_max) +
       
    91           (MaxValue <= integer_traits<signed char>::const_max)
       
    92         >::least  least;
       
    93       typedef typename int_fast_t<least>::fast  fast;
       
    94   };
       
    95 
       
    96   template< long MinValue >   // minimum value to require support
       
    97   struct int_min_value_t 
       
    98   {
       
    99       typedef typename int_least_helper
       
   100         <
       
   101           (MinValue >= integer_traits<long>::const_min) +
       
   102           (MinValue >= integer_traits<int>::const_min) +
       
   103           (MinValue >= integer_traits<short>::const_min) +
       
   104           (MinValue >= integer_traits<signed char>::const_min)
       
   105         >::least  least;
       
   106       typedef typename int_fast_t<least>::fast  fast;
       
   107   };
       
   108 
       
   109   //  unsigned
       
   110   template< unsigned long Value >   // maximum value to require support
       
   111   struct uint_value_t 
       
   112   {
       
   113       typedef typename int_least_helper
       
   114         < 
       
   115           5 +
       
   116           (Value <= integer_traits<unsigned long>::const_max) +
       
   117           (Value <= integer_traits<unsigned int>::const_max) +
       
   118           (Value <= integer_traits<unsigned short>::const_max) +
       
   119           (Value <= integer_traits<unsigned char>::const_max)
       
   120         >::least  least;
       
   121       typedef typename int_fast_t<least>::fast  fast;
       
   122   };
       
   123 
       
   124 
       
   125 } // namespace boost
       
   126 
       
   127 #endif  // BOOST_INTEGER_HPP