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00001 /************************************************************************/ 00002 /* */ 00003 /* Copyright 2004 by Ullrich Koethe */ 00004 /* Cognitive Systems Group, University of Hamburg, Germany */ 00005 /* */ 00006 /* This file is part of the VIGRA computer vision library. */ 00007 /* The VIGRA Website is */ 00008 /* http://kogs-www.informatik.uni-hamburg.de/~koethe/vigra/ */ 00009 /* Please direct questions, bug reports, and contributions to */ 00010 /* ullrich.koethe@iwr.uni-heidelberg.de or */ 00011 /* vigra@informatik.uni-hamburg.de */ 00012 /* */ 00013 /* Permission is hereby granted, free of charge, to any person */ 00014 /* obtaining a copy of this software and associated documentation */ 00015 /* files (the "Software"), to deal in the Software without */ 00016 /* restriction, including without limitation the rights to use, */ 00017 /* copy, modify, merge, publish, distribute, sublicense, and/or */ 00018 /* sell copies of the Software, and to permit persons to whom the */ 00019 /* Software is furnished to do so, subject to the following */ 00020 /* conditions: */ 00021 /* */ 00022 /* The above copyright notice and this permission notice shall be */ 00023 /* included in all copies or substantial portions of the */ 00024 /* Software. */ 00025 /* */ 00026 /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND */ 00027 /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES */ 00028 /* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND */ 00029 /* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT */ 00030 /* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, */ 00031 /* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING */ 00032 /* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR */ 00033 /* OTHER DEALINGS IN THE SOFTWARE. */ 00034 /* */ 00035 /************************************************************************/ 00036 00037 #ifndef VIGRA_NAVIGATOR_HXX 00038 #define VIGRA_NAVIGATOR_HXX 00039 00040 namespace vigra { 00041 00042 /********************************************************/ 00043 /* */ 00044 /* MultiArrayNavigator */ 00045 /* */ 00046 /********************************************************/ 00047 00048 /** \brief A navigator that provides acces to the 1D subranges of an 00049 n-dimensional range given by a \ref vigra::MultiIterator and an nD shape. 00050 00051 Normally, the innermost loop of an iteration extends over the innermost 00052 dimension of a given array. Sometimes, however, it is necessary to have 00053 some other dimension in the inner loop. For example, instead of iterating over 00054 the rows, the inner loop should extend over the columns. The class MultiArrayNavigator 00055 encapsulates the necessary functionality. Given an arbitrary dimensional 00056 array (represented by a vigra::MultiIterator/shape pair), and the desired 00057 inner loop dimension <TT>d</TT>, it moves the encapsulated iterator to all possible 00058 starting points of 1D subsets along the given dimension (e.g. all columns). By calling 00059 <TT>begin()</TT> and <TT>end()</TT>, one can then obtain an STL-compatible 1-dimensional 00060 iterator for the current subset. 00061 00062 The template parameters specify the embedded iterator type and its dimension. 00063 00064 <b>Usage:</b> 00065 00066 <b>\#include</b> <<a href="navigator_8hxx-source.html">vigra/navigator.hxx</a>> 00067 00068 Namespace: vigra 00069 00070 \code 00071 typedef vigra::MultiArray<3, int> Array; 00072 00073 Array a(Array::size_type(X, Y, Z)); 00074 00075 typedef vigra::MultiArrayNavigator<Array::traverser, 3> Navigator; 00076 00077 for(int d=0; d<3; ++d) 00078 { 00079 // create Navigator for dimension d 00080 Navigator nav(a.traverser_begin(), a.shape(), d); 00081 00082 // outer loop: move navigator to all starting points 00083 // of 1D subsets that run parallel to coordinate axis d 00084 for(; nav.hasMore(); ++nav) 00085 { 00086 // inner loop: linear iteration over current subset 00087 // d == {0, 1, 2}: interate along {x, y, z}-axis respectively 00088 Navigator::iterator i = nav.begin(), end = nav.end(); 00089 for(; i != end; ++i) 00090 // do something 00091 } 00092 } 00093 \endcode 00094 */ 00095 template <class MULTI_ITERATOR, unsigned int N> 00096 class MultiArrayNavigator 00097 #ifndef DOXYGEN // doxygen doesn't understand this inheritance 00098 : public MultiArrayNavigator<MULTI_ITERATOR, N-1> 00099 #endif 00100 { 00101 typedef MultiArrayNavigator<MULTI_ITERATOR, N-1> base_type; 00102 00103 public: 00104 enum { level = N-1 }; 00105 00106 /** The required shape type for the given iterator type. 00107 */ 00108 typedef typename MULTI_ITERATOR::multi_difference_type shape_type; 00109 00110 /** The iterator type for the inner loop (result of begin() and end()). 00111 */ 00112 typedef typename MULTI_ITERATOR::iterator iterator; 00113 00114 /** Construct navigator for multi-dimensional iterator <TT>i</TT>, array shape <TT>shape</TT> 00115 and inner loop dimension <TT>inner_dimension</TT>. 00116 */ 00117 MultiArrayNavigator(MULTI_ITERATOR const & i, shape_type const & shape, unsigned int inner_dimension) 00118 : base_type(i, shape, inner_dimension), 00119 i_(i), 00120 end_(i) 00121 { 00122 if(inner_dimension != level) 00123 end_.template dim<level>() += shape[level]; 00124 } 00125 00126 /** Advance to next starting location. 00127 */ 00128 void operator++() 00129 { 00130 base_type::operator++(); 00131 if(base_type::atEnd() && i_ < end_) // this tests implicitly inner_dimension_ != level 00132 { 00133 ++i_.template dim<level>(); 00134 if(i_ < end_) 00135 base_type::reset(i_); 00136 } 00137 } 00138 00139 /** Advance to next starting location. 00140 */ 00141 void operator++(int) 00142 { 00143 ++*this; 00144 } 00145 00146 /** true if there are more elements. 00147 */ 00148 bool hasMore() const 00149 { 00150 return this->inner_dimension_ == level ? 00151 base_type::hasMore() : 00152 i_ < end_; 00153 } 00154 00155 /** true if iterator is exhausted. 00156 */ 00157 bool atEnd() const 00158 { 00159 return this->inner_dimension_ == level ? 00160 base_type::atEnd() : 00161 !( i_ < end_); 00162 } 00163 00164 protected: 00165 void reset(MULTI_ITERATOR const & i) 00166 { 00167 end_ = i_ = i; 00168 if(this->inner_dimension_ != level) 00169 end_.template dim<level>() += this->shape_[level]; 00170 base_type::reset(i); 00171 } 00172 00173 MULTI_ITERATOR i_, end_; 00174 }; 00175 00176 template <class MULTI_ITERATOR> 00177 class MultiArrayNavigator<MULTI_ITERATOR, 1> 00178 { 00179 public: 00180 enum { level = 0 }; 00181 typedef typename MULTI_ITERATOR::multi_difference_type shape_type; 00182 typedef typename MULTI_ITERATOR::iterator iterator; 00183 00184 MultiArrayNavigator(MULTI_ITERATOR const & i, shape_type const & shape, unsigned int inner_dimension) 00185 : shape_(shape), 00186 inner_dimension_(inner_dimension), 00187 i_(i), 00188 end_(i) 00189 { 00190 if(inner_dimension != level) 00191 end_.template dim<level>() += shape[level]; 00192 } 00193 00194 void operator++() 00195 { 00196 ++i_.template dim<level>(); 00197 } 00198 00199 void operator++(int) 00200 { 00201 ++*this; 00202 } 00203 00204 iterator begin() const 00205 { 00206 return i_.iteratorForDimension(inner_dimension_); 00207 } 00208 00209 iterator end() const 00210 { 00211 return begin() + shape_[inner_dimension_]; 00212 } 00213 00214 bool hasMore() const 00215 { 00216 return i_ < end_; 00217 } 00218 00219 bool atEnd() const 00220 { 00221 return !( i_ < end_); 00222 } 00223 00224 protected: 00225 void reset(MULTI_ITERATOR const & i) 00226 { 00227 end_ = i_ = i; 00228 if(inner_dimension_ != level) 00229 end_.template dim<level>() += shape_[level]; 00230 } 00231 00232 shape_type shape_; 00233 unsigned int inner_dimension_; 00234 MULTI_ITERATOR i_, end_; 00235 }; 00236 00237 } // namespace vigra 00238 00239 #endif /* VIGRA_NAVIGATOR_HXX */
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