ncbi_limits.hpp

ncbi源码

/*
 * ===========================================================================
 * PRODUCTION $Log: ncbi_limits.hpp,v $
 * PRODUCTION Revision 1000.1  2004/06/01 19:07:36  gouriano
 * PRODUCTION PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.7
 * PRODUCTION
 * ===========================================================================
 */

#ifndef NCBI_LIMITS__HPP
#define NCBI_LIMITS__HPP

/*  $Id: ncbi_limits.hpp,v 1000.1 2004/06/01 19:07:36 gouriano Exp $
 * ===========================================================================
 *
 *                            PUBLIC DOMAIN NOTICE
 *               National Center for Biotechnology Information
 *
 *  This software/database is a "United States Government Work" under the
 *  terms of the United States Copyright Act.  It was written as part of
 *  the author's official duties as a United States Government employee and
 *  thus cannot be copyrighted.  This software/database is freely available
 *  to the public for use. The National Library of Medicine and the U.S.
 *  Government have not placed any restriction on its use or reproduction.
 *
 *  Although all reasonable efforts have been taken to ensure the accuracy
 *  and reliability of the software and data, the NLM and the U.S.
 *  Government do not and cannot warrant the performance or results that
 *  may be obtained by using this software or data. The NLM and the U.S.
 *  Government disclaim all warranties, express or implied, including
 *  warranties of performance, merchantability or fitness for any particular
 *  purpose.
 *
 *  Please cite the author in any work or product based on this material.
 *
 * ===========================================================================
 *
 * Author:  Denis Vakatov
 *
 * File Description:
 *
 *   Temporary replacement for "numeric_limits<>".
 *   Extremely incomplete implementation,
 *
 *    only min() and max() methods for:
 *
 *      numeric_limits<char>
 *      numeric_limits<signed   char>
 *      numeric_limits<unsigned char>
 *
 *      numeric_limits<signed   short>
 *      numeric_limits<unsigned short>
 *      numeric_limits<signed   int>
 *      numeric_limits<unsigned int>
 *      numeric_limits<signed   long>
 *      numeric_limits<unsigned long>
 *
 *      numeric_limits<float>
 *      numeric_limits<double>
 *
 *      (platform-specific)
 *      numeric_limits<signed   long long>
 *      numeric_limits<unsigned long long>
 *      numeric_limits<signed   __int64>
 *      numeric_limits<unsigned __int64>
 *
 */

#include <corelib/ncbistd.hpp>
#include <corelib/ncbi_limits.h>


/** @addtogroup Portability
 *
 * @{
 */


#if defined(HAVE_LIMITS) && !defined(NCBI_COMPILER_WORKSHOP)
// Ideally, we would use std::numeric_limits<> whenever available.
// However, certain compilers leave out support for extensions such as
// long long, so we still have to use our implementation with them.
#  include <limits>
#else

BEGIN_NCBI_SCOPE

///
///  Pre-declaration of the "numeric_limits<>" template
///  Forcibly overrides (using preprocessor) the original "numeric_limits<>"!
///

#  define numeric_limits ncbi_numeric_limits
template <class T> class numeric_limits;


///
///  Auxiliary macro to implement (a limited edition of) the
///  "numeric_limits<>" template
///

#  define NCBI_NUMERIC_LIMITS(type, alias) \
  template <> \
  class numeric_limits<type> \
  { \
  public: \
      static inline type min() THROWS_NONE { return kMin_##alias; } \
      static inline type max() THROWS_NONE { return kMax_##alias; } \
  }

#  define NCBI_NUMERIC_LIMITS_UNSIGNED(type, alias) \
  template <> \
  class numeric_limits<type> \
  { \
  public: \
      static inline type min() THROWS_NONE { return 0; } \
      static inline type max() THROWS_NONE { return kMax_##alias; } \
  }


//
//  Implement (a limited edition of) the "numeric_limits<>" template
//  for various built-in types
//

NCBI_NUMERIC_LIMITS          (         char,  Char);
NCBI_NUMERIC_LIMITS          (signed   char, SChar);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned char, UChar);

NCBI_NUMERIC_LIMITS          (signed   short,  Short);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned short, UShort);

NCBI_NUMERIC_LIMITS          (signed   int,  Int);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned int, UInt);

NCBI_NUMERIC_LIMITS          (signed   long,  Long);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned long, ULong);

NCBI_NUMERIC_LIMITS          (float,  Float);
NCBI_NUMERIC_LIMITS          (double, Double);

#  if (SIZEOF_LONG_LONG > 0)
NCBI_NUMERIC_LIMITS          (signed   long long,  LongLong);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned long long, ULongLong);
#  endif

#  if defined(NCBI_USE_INT64)
NCBI_NUMERIC_LIMITS          (signed   __int64,  Int64);
NCBI_NUMERIC_LIMITS_UNSIGNED (unsigned __int64, UInt64);
#  endif


END_NCBI_SCOPE

#endif // !HAVE_LIMITS  ||  NCBI_COMPILER_WORKSHOP


BEGIN_NCBI_SCOPE

/// Generic template to get STD limits by a variable.
/// Typical use:
/// <pre>
///  int a = 10; 
///  
/// @note 
///   Causes a compile-time failure if used
///    instead of the specialized implementations.
template<typename T> 
inline numeric_limits<T> get_limits(const T&)
{
	typename T::TypeIsNotSupported tmp; 
	return numeric_limits<T>();
}

/// Macro to declare specilized get_limits
#  define NCBI_GET_NUMERIC_LIMITS(type) \
    EMPTY_TEMPLATE \
    inline numeric_limits<type> get_limits(const type&) \
	{ return numeric_limits<type>(); }

NCBI_GET_NUMERIC_LIMITS(         char)
NCBI_GET_NUMERIC_LIMITS(signed   char)
NCBI_GET_NUMERIC_LIMITS(unsigned char)

NCBI_GET_NUMERIC_LIMITS(signed   short)
NCBI_GET_NUMERIC_LIMITS(unsigned short)

NCBI_GET_NUMERIC_LIMITS(signed   int)
NCBI_GET_NUMERIC_LIMITS(unsigned int)

NCBI_GET_NUMERIC_LIMITS(signed   long)
NCBI_GET_NUMERIC_LIMITS(unsigned long)

NCBI_GET_NUMERIC_LIMITS(float)
NCBI_GET_NUMERIC_LIMITS(double)

#  if (SIZEOF_LONG_LONG > 0)
NCBI_GET_NUMERIC_LIMITS(signed   long long)
NCBI_GET_NUMERIC_LIMITS(unsigned long long)
#  endif

#  if defined(NCBI_USE_INT64)
NCBI_GET_NUMERIC_LIMITS(signed   __int64)
NCBI_GET_NUMERIC_LIMITS(unsigned __int64)
#  endif


END_NCBI_SCOPE

/* @} */


/*
 * ==========================================================================
 * $Log: ncbi_limits.hpp,v $
 * Revision 1000.1  2004/06/01 19:07:36  gouriano
 * PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.7
 *
 * Revision 1.7  2004/06/01 12:09:45  kuznets
 * + get_limits
 *
 * Revision 1.6  2003/04/01 14:18:50  siyan
 * Added doxygen support
 *
 * Revision 1.5  2002/11/04 21:47:56  ucko
 * Use system numeric_limits<> whenever <limits> exists, except on
 * WorkShop (which has "long long" but not numeric_limits<long long>).
 *
 * Revision 1.4  2002/04/11 20:39:15  ivanov
 * CVS log moved to end of the file
 *
 * Revision 1.3  2002/02/14 17:15:44  kans
 * use standard numeric limits on MacOS (AU)
 *
 * Revision 1.2  2001/05/30 16:17:23  vakatov
 * Introduced #NCBI_USE_INT64 -- in oreder to use "__int64" type
 * only when absolutely necessary (otherwise it conflicted with
 * "long long" for the Intel C++ compiler).
 *
 * Revision 1.1  2001/01/03 17:35:23  vakatov
 * Initial revision
 *
 * ==========================================================================
 */

#endif /* NCBI_LIMITS__HPP */