Line data Source code
1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 : #ifndef INCLUDED_BASEBMP_METAFUNCTIONS_HXX
21 : #define INCLUDED_BASEBMP_METAFUNCTIONS_HXX
22 :
23 : #include <boost/mpl/integral_c.hpp>
24 : #include <vigra/metaprogramming.hxx>
25 : #include <vigra/numerictraits.hxx>
26 :
27 : #include <functional>
28 :
29 : namespace basebmp
30 : {
31 :
32 : // TODO(Q3): move to generic place (o3tl?)
33 :
34 : /** template meta function: add const qualifier to 2nd type, if given
35 : 1st type has it
36 : */
37 : template<typename A, typename B> struct clone_const
38 : {
39 : typedef B type;
40 : };
41 : template<typename A, typename B> struct clone_const<const A,B>
42 : {
43 : typedef const B type;
44 : };
45 :
46 : /** template meta function: add const qualifier to plain type (if not
47 : already there)
48 : */
49 : template <typename T> struct add_const
50 : {
51 : typedef const T type;
52 : };
53 : template <typename T> struct add_const<const T>
54 : {
55 : typedef const T type;
56 : };
57 :
58 : /// template meta function: remove const qualifier from plain type
59 : template <typename T> struct remove_const
60 : {
61 : typedef T type;
62 : };
63 : template <typename T> struct remove_const<const T>
64 : {
65 : typedef T type;
66 : };
67 :
68 :
69 :
70 : /// Base class for an adaptable ternary functor
71 : template< typename A1, typename A2, typename A3, typename R > struct TernaryFunctorBase
72 : {
73 : typedef A1 first_argument_type;
74 : typedef A2 second_argument_type;
75 : typedef A3 third_argument_type;
76 : typedef R result_type;
77 : };
78 :
79 :
80 :
81 : /** template meta function: ensure that given integer type is unsigned
82 :
83 : If given integer type is already unsigned, return as-is -
84 : otherwise, convert to unsigned type of same or greater range.
85 : */
86 : template< typename T > struct make_unsigned;
87 :
88 : #define BASEBMP_MAKE_UNSIGNED(T,U) \
89 : template<> struct make_unsigned<T> { \
90 : typedef U type; \
91 : };
92 :
93 : BASEBMP_MAKE_UNSIGNED(signed char,unsigned char)
94 : BASEBMP_MAKE_UNSIGNED(unsigned char,unsigned char)
95 : BASEBMP_MAKE_UNSIGNED(short,unsigned short)
96 : BASEBMP_MAKE_UNSIGNED(unsigned short,unsigned short)
97 : BASEBMP_MAKE_UNSIGNED(int,unsigned int)
98 : BASEBMP_MAKE_UNSIGNED(unsigned int,unsigned int)
99 : BASEBMP_MAKE_UNSIGNED(long,unsigned long)
100 : BASEBMP_MAKE_UNSIGNED(unsigned long,unsigned long)
101 :
102 : #undef BASEBMP_MAKE_UNSIGNED
103 :
104 : /// cast integer to unsigned type of similar size
105 0 : template< typename T > inline typename make_unsigned<T>::type unsigned_cast( T value )
106 : {
107 0 : return static_cast< typename make_unsigned<T>::type >(value);
108 : }
109 :
110 :
111 :
112 : /// returns true, if given number is strictly less than 0
113 : template< typename T > inline bool is_negative( T x )
114 : {
115 : return x < 0;
116 : }
117 :
118 : /// Overload for ints (branch-free)
119 0 : inline bool is_negative( int x )
120 : {
121 : // force logic shift (result for signed shift right is undefined)
122 0 : return static_cast<unsigned int>(x) >> (sizeof(int)*8-1);
123 : }
124 :
125 :
126 :
127 : /// Results in VigraTrueType, if T is of integer type and scalar
128 : template< typename T, typename trueCase, typename falseCase >
129 : struct ifScalarIntegral
130 : {
131 : typedef
132 : typename vigra::If<
133 : typename vigra::NumericTraits< T >::isIntegral,
134 : typename vigra::If<
135 : typename vigra::NumericTraits< T >::isScalar,
136 : trueCase,
137 : falseCase >::type,
138 : falseCase >::type type;
139 : };
140 :
141 : /// Results in VigraTrueType, if T is of non-integer type and scalar
142 : template< typename T, typename trueCase, typename falseCase >
143 : struct ifScalarNonIntegral
144 : {
145 : typedef
146 : typename vigra::If<
147 : typename vigra::NumericTraits< T >::isIntegral,
148 : falseCase,
149 : typename vigra::If<
150 : typename vigra::NumericTraits< T >::isScalar,
151 : trueCase,
152 : falseCase >::type >::type type;
153 : };
154 :
155 : /// Results in VigraTrueType, if both T1 and T2 are of integer type and scalar
156 : template< typename T1, typename T2, typename trueCase, typename falseCase >
157 : struct ifBothScalarIntegral
158 : {
159 : typedef
160 : typename ifScalarIntegral<
161 : T1,
162 : typename ifScalarIntegral<
163 : T2,
164 : trueCase,
165 : falseCase >::type,
166 : falseCase >::type type;
167 : };
168 :
169 :
170 :
171 : /// Count number of trailing zeros
172 : template< unsigned int val > struct numberOfTrailingZeros
173 : {
174 : enum { next = val >> 1 };
175 : enum { value = vigra::IfBool< (val & 1) == 0,
176 : numberOfTrailingZeros<next>,
177 : boost::mpl::integral_c< int,-1 > > ::type::value + 1 };
178 : };
179 :
180 : template<> struct numberOfTrailingZeros<0>
181 : {
182 : enum { value = 0 };
183 : };
184 :
185 :
186 :
187 : /// Count number of one bits
188 : template< unsigned int val > struct bitcount
189 : {
190 : enum { next = val >> 1 };
191 : enum { value = bitcount<next>::value + (val & 1) };
192 : };
193 :
194 : template<> struct bitcount<0>
195 : {
196 : enum { value = 0 };
197 : };
198 :
199 :
200 :
201 : /// Shift left for positive shift value, and right otherwise
202 0 : template< typename T > inline T shiftLeft( T v, int shift )
203 : {
204 0 : return shift > 0 ? v << shift : v >> (-shift);
205 : }
206 :
207 : /// Shift right for positive shift value, and left otherwise
208 0 : template< typename T > inline T shiftRight( T v, int shift )
209 : {
210 0 : return shift > 0 ? v >> shift : v << (-shift);
211 : }
212 :
213 :
214 :
215 : /// Replace non-std project2nd from SGI extensions
216 : template< typename T1, typename T2 >
217 : struct project2nd : public std::binary_function<T1, T2, T2>
218 : {
219 : T2 operator() (const T1&, const T2& v) const { return v; }
220 : };
221 :
222 : } // namespace basebmp
223 :
224 : #endif /* INCLUDED_BASEBMP_METAFUNCTIONS_HXX */
225 :
226 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
