utilities.hpp

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00001 /*
00002     Copyright 2005-2007 Adobe Systems Incorporated
00003    
00004     Use, modification and distribution are subject to the Boost Software License,
00005     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
00006     http://www.boost.org/LICENSE_1_0.txt).
00007 
00008     See http://opensource.adobe.com/gil for most recent version including documentation.
00009 */
00010 
00011 /*************************************************************************************************/
00012 
00013 #ifndef GIL_UTILITIES_H
00014 #define GIL_UTILITIES_H
00015 
00016 #include "gil_config.hpp"
00017 #include <functional>
00018 #include <cmath>
00019 #include <cstddef>
00020 #include <boost/static_assert.hpp>
00021 #include <boost/type_traits.hpp>
00022 #include <boost/mpl/size.hpp>
00023 #include <boost/mpl/distance.hpp>
00024 #include <boost/mpl/begin.hpp>
00025 #include <boost/mpl/find.hpp>
00026 #include <boost/mpl/range_c.hpp>
00027 #include <boost/iterator/iterator_adaptor.hpp>
00028 #include <boost/iterator/iterator_facade.hpp>
00029 
00039 
00040 namespace boost { namespace gil {
00041 
00054 
00055 //                           CLASS point2
00062 
00063 template <typename T>
00064 class point2 {
00065 public:
00066     typedef T value_type;
00067     template <std::size_t D> struct axis { typedef value_type coord_t; };
00068     static const std::size_t num_dimensions=2;
00069 
00070     point2()                : x(0),     y(0)    {}
00071     point2(T newX, T newY)  : x(newX),  y(newY) {}
00072     point2(const point2& p) : x(p.x), y(p.y) {}
00073     ~point2() {}
00074 
00075     point2& operator=(const point2& p)            { x=p.x; y=p.y; return *this; }
00076 
00077     point2        operator<<(int shift)         const   { return point2(x<<shift,y<<shift); }
00078     point2        operator>>(int shift)         const   { return point2(x>>shift,y>>shift); }
00079     point2& operator+=(const point2& p)           { x+=p.x; y+=p.y; return *this; }
00080     point2& operator-=(const point2& p)           { x-=p.x; y-=p.y; return *this; }
00081     point2& operator/=(double t)                  { x/=t; y/=t; return *this; }
00082 
00083     const T& operator[](std::size_t i)          const   { return this->*mem_array[i]; }
00084           T& operator[](std::size_t i)                  { return this->*mem_array[i]; }
00085 
00086     T x,y;
00087 private:
00088     // this static array of pointers to member variables makes operator[] safe and doesn't seem to exhibit any performance penalty
00089     static T point2<T>::* const mem_array[num_dimensions];
00090 };
00091 
00092 template <typename T>
00093 T point2<T>::* const point2<T>::mem_array[point2<T>::num_dimensions] = { &point2<T>::x, &point2<T>::y };
00094 
00096 template <typename T> GIL_FORCEINLINE
00097 bool operator==(const point2<T>& p1, const point2<T>& p2) { return (p1.x==p2.x && p1.y==p2.y); }
00099 template <typename T> GIL_FORCEINLINE
00100 bool operator!=(const point2<T>& p1, const point2<T>& p2) { return  p1.x!=p2.x || p1.y!=p2.y; }
00102 template <typename T> GIL_FORCEINLINE
00103 point2<T> operator+(const point2<T>& p1, const point2<T>& p2) { return point2<T>(p1.x+p2.x,p1.y+p2.y); }
00105 template <typename T> GIL_FORCEINLINE
00106 point2<T> operator-(const point2<T>& p) { return point2<T>(-p.x,-p.y); }
00108 template <typename T> GIL_FORCEINLINE
00109 point2<T> operator-(const point2<T>& p1, const point2<T>& p2) { return point2<T>(p1.x-p2.x,p1.y-p2.y); }
00111 template <typename T> GIL_FORCEINLINE
00112 point2<double> operator/(const point2<T>& p, double t)      { return t==0 ? point2<double>(0,0):point2<double>(p.x/t,p.y/t); }
00114 template <typename T> GIL_FORCEINLINE
00115 point2<T> operator*(const point2<T>& p, int t)      { return point2<T>(p.x*t,p.y*t); }
00117 template <typename T> GIL_FORCEINLINE
00118 point2<T> operator*(int t, const point2<T>& p)      { return point2<T>(p.x*t,p.y*t); }
00119 
00121 template <std::size_t K, typename T> GIL_FORCEINLINE
00122 const T& axis_value(const point2<T>& p) { return p[K]; }
00123 
00125 template <std::size_t K, typename T> GIL_FORCEINLINE
00126       T& axis_value(      point2<T>& p) { return p[K]; }
00127 
00133 
00134 inline int iround(float x ) { return static_cast<int>(x + (x < 0.0f ? -0.5f : 0.5f)); }
00135 inline int iround(double x) { return static_cast<int>(x + (x < 0.0 ? -0.5 : 0.5)); }
00136 inline int ifloor(float x ) { return static_cast<int>(std::floor(x)); }
00137 inline int ifloor(double x) { return static_cast<int>(std::floor(x)); }
00138 inline int iceil(float x )  { return static_cast<int>(std::ceil(x)); }
00139 inline int iceil(double x)  { return static_cast<int>(std::ceil(x)); }
00140 
00150 
00151 inline point2<int> iround(const point2<float >& p)  { return point2<int>(iround(p.x),iround(p.y)); }
00153 inline point2<int> iround(const point2<double>& p)  { return point2<int>(iround(p.x),iround(p.y)); }
00155 inline point2<int> ifloor(const point2<float >& p)  { return point2<int>(ifloor(p.x),ifloor(p.y)); }
00157 inline point2<int> ifloor(const point2<double>& p)  { return point2<int>(ifloor(p.x),ifloor(p.y)); }
00159 inline point2<int> iceil (const point2<float >& p)  { return point2<int>(iceil(p.x), iceil(p.y)); }
00161 inline point2<int> iceil (const point2<double>& p)  { return point2<int>(iceil(p.x), iceil(p.y)); }
00162 
00168 
00169 template <typename T> 
00170 inline T align(T val, std::size_t alignment) { 
00171     return val+(alignment - val%alignment)%alignment; 
00172 }
00173 
00177 template <typename ConstT, typename Value, typename Reference, typename ConstReference,
00178                   typename ArgType, typename ResultType, bool IsMutable>
00179 struct deref_base : public std::unary_function<ArgType, ResultType> {
00180     typedef ConstT         const_t;
00181         typedef Value          value_type;
00182         typedef Reference      reference;
00183         typedef ConstReference const_reference;
00184         BOOST_STATIC_CONSTANT(bool, is_mutable = IsMutable);
00185 };
00186 
00190 template <typename D1, typename D2>
00191 class deref_compose : public deref_base<
00192       deref_compose<typename D1::const_t, typename D2::const_t>,
00193           typename D1::value_type, typename D1::reference, typename D1::const_reference, 
00194           typename D2::argument_type, typename D1::result_type, D1::is_mutable && D2::is_mutable>
00195 {
00196 public:
00197     D1 _fn1;
00198     D2 _fn2;
00199 
00200     typedef typename D2::argument_type   argument_type;
00201     typedef typename D1::result_type     result_type;
00202 
00203     deref_compose() {}
00204     deref_compose(const D1& x, const D2& y) : _fn1(x), _fn2(y) {}
00205     deref_compose(const deref_compose& dc)  : _fn1(dc._fn1), _fn2(dc._fn2) {}
00206     template <typename _D1, typename _D2> deref_compose(const deref_compose<_D1,_D2>& dc) : _fn1(dc._fn1), _fn2(dc._fn2) {}
00207 
00208     result_type operator()(argument_type x) const { return _fn1(_fn2(x)); }
00209     result_type operator()(argument_type x)       { return _fn1(_fn2(x)); }
00210 };
00211 
00212 // reinterpret_cast is implementation-defined. Static cast is not.
00213 template <typename OutPtr, typename In> GIL_FORCEINLINE
00214       OutPtr gil_reinterpret_cast(      In* p) { return static_cast<OutPtr>(static_cast<void*>(p)); }
00215 
00216 template <typename OutPtr, typename In> GIL_FORCEINLINE
00217 const OutPtr gil_reinterpret_cast_c(const In* p) { return static_cast<const OutPtr>(static_cast<const void*>(p)); }
00218 
00219 namespace detail {
00220 
00226 
00227 template <class InputIter, class Size, class OutputIter>
00228 std::pair<InputIter, OutputIter> _copy_n(InputIter first, Size count,
00229                                          OutputIter result,
00230                                          std::input_iterator_tag) {
00231    for ( ; count > 0; --count) {
00232       *result = *first;
00233       ++first;
00234       ++result;
00235    }
00236    return std::pair<InputIter, OutputIter>(first, result);
00237 }
00238 
00239 template <class RAIter, class Size, class OutputIter>
00240 inline std::pair<RAIter, OutputIter>
00241 _copy_n(RAIter first, Size count, OutputIter result, std::random_access_iterator_tag) {
00242    RAIter last = first + count;
00243    return std::pair<RAIter, OutputIter>(last, std::copy(first, last, result));
00244 }
00245 
00246 template <class InputIter, class Size, class OutputIter>
00247 inline std::pair<InputIter, OutputIter>
00248 _copy_n(InputIter first, Size count, OutputIter result) {
00249    return _copy_n(first, count, result, typename std::iterator_traits<InputIter>::iterator_category());
00250 }
00251 
00252 template <class InputIter, class Size, class OutputIter>
00253 inline std::pair<InputIter, OutputIter>
00254 copy_n(InputIter first, Size count, OutputIter result) {
00255     return detail::_copy_n(first, count, result);
00256 }
00257 
00259 template <typename T> 
00260 struct identity : public std::unary_function<T,T> {
00261     const T& operator()(const T& val) const { return val; }
00262 };
00263 
00264 /*************************************************************************************************/
00265 
00267 template <typename T1, typename T2>
00268 struct plus_asymmetric : public std::binary_function<T1,T2,T1> {
00269     T1 operator()(T1 f1, T2 f2) const {
00270         return f1+f2;
00271     }
00272 };
00273 
00274 /*************************************************************************************************/
00275 
00277 template <typename T>
00278 struct inc : public std::unary_function<T,T> {
00279     T operator()(T x) const { return ++x; }
00280 };
00281 
00282 /*************************************************************************************************/
00283 
00285 template <typename T>
00286 struct dec : public std::unary_function<T,T> {
00287     T operator()(T x) const { return --x; }
00288 };
00289 
00291 //         a given MPL RandomAccessSequence (or size if the type is not present)
00292 template <typename Types, typename T>
00293 struct type_to_index 
00294     : public mpl::distance<typename mpl::begin<Types>::type, 
00295                                   typename mpl::find<Types,T>::type>::type {};
00296 } // namespace detail
00297 
00298 
00299 
00302 template <typename ColorSpace, typename ChannelMapping = mpl::range_c<int,0,mpl::size<ColorSpace>::value> >
00303 struct layout {
00304     typedef ColorSpace      color_space_t;
00305     typedef ChannelMapping  channel_mapping_t;
00306 };
00307 
00309 template <typename Value, typename T1, typename T2> // where value_type<T1>  == value_type<T2> == Value
00310 void swap_proxy(T1& left, T2& right) {
00311     Value tmp = left;
00312     left = right;
00313     right = tmp;
00314 }
00315 
00317 inline bool little_endian() {
00318     short tester = 0x0001;
00319     return  *(char*)&tester!=0;
00320 }
00322 inline bool big_endian() {
00323     return !little_endian();
00324 }
00325 
00326 } }  // namespace boost::gil
00327 
00328 #endif

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