sized_int.hxx

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/*               Copyright 1998-2002 by Ullrich Koethe                  */
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#ifndef VIGRA_SIZED_INT_HXX
#define VIGRA_SIZED_INT_HXX

#include "metaprogramming.hxx"
#include <limits>

#if   SHRT_MAX  == 0x7FL
# define VIGRA_BITSOF_SHORT 8
#elif SHRT_MAX  == 0x7FFFL
# define VIGRA_BITSOF_SHORT 16
#elif SHRT_MAX  == 0x7FFFFFFFL
# define VIGRA_BITSOF_SHORT 32
#elif SHRT_MAX  > 0xFFFFFFFFL
# define VIGRA_BITSOF_SHORT 64
#else
# define VIGRA_BITSOF_SHORT -1
#endif

#if   INT_MAX  == 0x7FL
# define VIGRA_BITSOF_INT 8
#elif INT_MAX  == 0x7FFFL
# define VIGRA_BITSOF_INT 16
#elif INT_MAX  == 0x7FFFFFFFL
# define VIGRA_BITSOF_INT 32
#elif INT_MAX  > 0xFFFFFFFFL
# define VIGRA_BITSOF_INT 64
#else
# define VIGRA_BITSOF_INT -1
#endif

#if   LONG_MAX  == 0x7FL
# define VIGRA_BITSOF_LONG 8
#elif LONG_MAX  == 0x7FFFL
# define VIGRA_BITSOF_LONG 16
#elif LONG_MAX  == 0x7FFFFFFFL
# define VIGRA_BITSOF_LONG 32
#elif LONG_MAX  > 0xFFFFFFFFL
# define VIGRA_BITSOF_LONG 64
#else
# define VIGRA_BITSOF_LONG -1
#endif

#if   LLONG_MAX  == 0x7FL
# define VIGRA_BITSOF_LONG_LONG 8
#elif LLONG_MAX  == 0x7FFFL
# define VIGRA_BITSOF_LONG_LONG 16
#elif LLONG_MAX  == 0x7FFFFFFFL
# define VIGRA_BITSOF_LONG_LONG 32
#elif LLONG_MAX  > 0xFFFFFFFFL
# define VIGRA_BITSOF_LONG_LONG 64
#else
# define VIGRA_BITSOF_LONG_LONG -1
#endif

namespace vigra {

class Int_type_not_supported_on_this_platform {};

#ifndef NO_PARTIAL_TEMPLATE_SPECIALIZATION

namespace detail {

template<class T, class NEXT>
struct IntTypeList
{
    enum { size = sizeof(T)*8 };
    typedef T type;
    typedef NEXT next;
};

template<int SIZE, class LIST>
struct SelectIntegerType
{
    typedef typename 
       IfBool<(SIZE == LIST::size), 
           typename LIST::type,
           typename SelectIntegerType<SIZE, typename LIST::next>::type >::type
       type;
};

template<int SIZE>
struct SelectIntegerType<SIZE, Int_type_not_supported_on_this_platform>
{
    typedef Int_type_not_supported_on_this_platform type;
};

template<class LIST>
struct SelectBiggestIntegerType
{
    enum { cursize = static_cast<int>(LIST::size), 
           nextsize = static_cast<int>(SelectBiggestIntegerType<typename LIST::next>::size),
           size = (cursize < nextsize) ? nextsize : cursize };
    typedef typename 
       IfBool<(cursize < nextsize), 
           typename SelectBiggestIntegerType<typename LIST::next>::type,
           typename LIST::type>::type
       type;
};

template<>
struct SelectBiggestIntegerType<Int_type_not_supported_on_this_platform>
{
    enum { size = 0 };
    typedef Int_type_not_supported_on_this_platform type;
};

typedef IntTypeList<signed char, 
        IntTypeList<signed short,
        IntTypeList<signed int,
        IntTypeList<signed long,
        IntTypeList<signed long long,
        Int_type_not_supported_on_this_platform > > > > > SignedIntTypes;
typedef IntTypeList<unsigned char, 
        IntTypeList<unsigned short,
        IntTypeList<unsigned int,
        IntTypeList<unsigned long,
        IntTypeList<unsigned long long,
        Int_type_not_supported_on_this_platform > > > > > UnsignedIntTypes;

} // namespace detail

/** \addtogroup FixedSizeInt Fixed Size Integer Types

    Since the C++ standard does only specify minimal sizes for the built-in 
    integer types, one cannot rely on them to have a specific size. But
    pixel types with a specific size are often required in image processing,
    especially when reading or writing binary files. The VIGRA typedefs
    are guaranteed to have exactly the correct size. If the system
    does not provide a suitable type, the typedef will evaluate to
    <tt>Int_type_not_supported_on_this_platform</tt>.
*/
//@{

    /// 8-bit signed int
typedef detail::SelectIntegerType<8,  detail::SignedIntTypes>::type Int8;
    /// 16-bit signed int
typedef detail::SelectIntegerType<16, detail::SignedIntTypes>::type Int16;
    /// 32-bit signed int
typedef detail::SelectIntegerType<32, detail::SignedIntTypes>::type Int32;
    /// 64-bit signed int
typedef detail::SelectIntegerType<64, detail::SignedIntTypes>::type Int64;
    /// 8-bit unsigned int
typedef detail::SelectIntegerType<8,  detail::UnsignedIntTypes>::type UInt8;
    /// 16-bit unsigned int
typedef detail::SelectIntegerType<16, detail::UnsignedIntTypes>::type UInt16;
    /// 32-bit unsigned int
typedef detail::SelectIntegerType<32, detail::UnsignedIntTypes>::type UInt32;
    /// 64-bit unsigned int
typedef detail::SelectIntegerType<64, detail::UnsignedIntTypes>::type UInt64;

    /// the biggest signed integer type of the system
typedef detail::SelectBiggestIntegerType<detail::SignedIntTypes>::type   IntBiggest;
    /// the biggest unsigned integer type of the system
typedef detail::SelectBiggestIntegerType<detail::UnsignedIntTypes>::type UIntBiggest;

//@}

#else // NO_PARTIAL_TEMPLATE_SPECIALIZATION

typedef signed char    Int8;
typedef signed short   Int16;
typedef signed int     Int32;
typedef Int_type_not_supported_on_this_platform Int64;
typedef unsigned char  UInt8;
typedef unsigned short UInt16;
typedef unsigned int   UInt32;
typedef Int_type_not_supported_on_this_platform UInt64;

typedef Int32  IntBiggest;
typedef UInt32 UIntBiggest;

#endif // NO_PARTIAL_TEMPLATE_SPECIALIZATION

} // namespace vigra

#endif /* VIGRA_SIZED_INT_HXX */