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Diffstat (limited to 'include/basebmp/metafunctions.hxx')
| -rw-r--r-- | include/basebmp/metafunctions.hxx | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/include/basebmp/metafunctions.hxx b/include/basebmp/metafunctions.hxx new file mode 100644 index 000000000000..e451dce8e4d9 --- /dev/null +++ b/include/basebmp/metafunctions.hxx @@ -0,0 +1,226 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ + +#ifndef INCLUDED_BASEBMP_METAFUNCTIONS_HXX +#define INCLUDED_BASEBMP_METAFUNCTIONS_HXX + +#include <boost/mpl/integral_c.hpp> +#include <vigra/metaprogramming.hxx> +#include <vigra/numerictraits.hxx> + +#include <functional> + +namespace basebmp +{ + +// TODO(Q3): move to generic place (o3tl?) + +/** template meta function: add const qualifier to 2nd type, if given + 1st type has it +*/ +template<typename A, typename B> struct clone_const +{ + typedef B type; +}; +template<typename A, typename B> struct clone_const<const A,B> +{ + typedef const B type; +}; + +/** template meta function: add const qualifier to plain type (if not + already there) + */ +template <typename T> struct add_const +{ + typedef const T type; +}; +template <typename T> struct add_const<const T> +{ + typedef const T type; +}; + +/// template meta function: remove const qualifier from plain type +template <typename T> struct remove_const +{ + typedef T type; +}; +template <typename T> struct remove_const<const T> +{ + typedef T type; +}; + +//-------------------------------------------------------------- + +/// Base class for an adaptable ternary functor +template< typename A1, typename A2, typename A3, typename R > struct TernaryFunctorBase +{ + typedef A1 first_argument_type; + typedef A2 second_argument_type; + typedef A3 third_argument_type; + typedef R result_type; +}; + +//-------------------------------------------------------------- + +/** template meta function: ensure that given integer type is unsigned + + If given integer type is already unsigned, return as-is - + otherwise, convert to unsigned type of same or greater range. + */ +template< typename T > struct make_unsigned; + +#define BASEBMP_MAKE_UNSIGNED(T,U) \ + template<> struct make_unsigned<T> { \ + typedef U type; \ + }; + +BASEBMP_MAKE_UNSIGNED(signed char,unsigned char) +BASEBMP_MAKE_UNSIGNED(unsigned char,unsigned char) +BASEBMP_MAKE_UNSIGNED(short,unsigned short) +BASEBMP_MAKE_UNSIGNED(unsigned short,unsigned short) +BASEBMP_MAKE_UNSIGNED(int,unsigned int) +BASEBMP_MAKE_UNSIGNED(unsigned int,unsigned int) +BASEBMP_MAKE_UNSIGNED(long,unsigned long) +BASEBMP_MAKE_UNSIGNED(unsigned long,unsigned long) + +#undef BASEBMP_MAKE_UNSIGNED + +/// cast integer to unsigned type of similar size +template< typename T > inline typename make_unsigned<T>::type unsigned_cast( T value ) +{ + return static_cast< typename make_unsigned<T>::type >(value); +} + +//-------------------------------------------------------------- + +/// returns true, if given number is strictly less than 0 +template< typename T > inline bool is_negative( T x ) +{ + return x < 0; +} + +/// Overload for ints (branch-free) +inline bool is_negative( int x ) +{ + // force logic shift (result for signed shift right is undefined) + return static_cast<unsigned int>(x) >> (sizeof(int)*8-1); +} + +//-------------------------------------------------------------- + +/// Results in VigraTrueType, if T is of integer type and scalar +template< typename T, typename trueCase, typename falseCase > +struct ifScalarIntegral +{ + typedef + typename vigra::If< + typename vigra::NumericTraits< T >::isIntegral, + typename vigra::If< + typename vigra::NumericTraits< T >::isScalar, + trueCase, + falseCase >::type, + falseCase >::type type; +}; + +/// Results in VigraTrueType, if T is of non-integer type and scalar +template< typename T, typename trueCase, typename falseCase > +struct ifScalarNonIntegral +{ + typedef + typename vigra::If< + typename vigra::NumericTraits< T >::isIntegral, + falseCase, + typename vigra::If< + typename vigra::NumericTraits< T >::isScalar, + trueCase, + falseCase >::type >::type type; +}; + +/// Results in VigraTrueType, if both T1 and T2 are of integer type and scalar +template< typename T1, typename T2, typename trueCase, typename falseCase > +struct ifBothScalarIntegral +{ + typedef + typename ifScalarIntegral< + T1, + typename ifScalarIntegral< + T2, + trueCase, + falseCase >::type, + falseCase >::type type; +}; + +//-------------------------------------------------------------- + +/// Count number of trailing zeros +template< unsigned int val > struct numberOfTrailingZeros +{ + enum { next = val >> 1 }; + enum { value = vigra::IfBool< (val & 1) == 0, + numberOfTrailingZeros<next>, + boost::mpl::integral_c< int,-1 > > ::type::value + 1 }; +}; + +template<> struct numberOfTrailingZeros<0> +{ + enum { value = 0 }; +}; + +//-------------------------------------------------------------- + +/// Count number of one bits +template< unsigned int val > struct bitcount +{ + enum { next = val >> 1 }; + enum { value = bitcount<next>::value + (val & 1) }; +}; + +template<> struct bitcount<0> +{ + enum { value = 0 }; +}; + +//-------------------------------------------------------------- + +/// Shift left for positive shift value, and right otherwise +template< typename T > inline T shiftLeft( T v, int shift ) +{ + return shift > 0 ? v << shift : v >> (-shift); +} + +/// Shift right for positive shift value, and left otherwise +template< typename T > inline T shiftRight( T v, int shift ) +{ + return shift > 0 ? v >> shift : v << (-shift); +} + +//-------------------------------------------------------------- + +/// Replace non-std project2nd from SGI extensions +template< typename T1, typename T2 > +struct project2nd : public std::binary_function<T1, T2, T2> +{ + T2 operator() (const T1&, const T2& v) const { return v; } +}; + +} // namespace basebmp + +#endif /* INCLUDED_BASEBMP_METAFUNCTIONS_HXX */ + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |