1 | // -*- C++ -*- |
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2 | /*************************************************************************** |
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3 | * blitz/array/iter.h Basic iterator for arrays. |
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4 | * |
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5 | * Copyright (C) 1997-2001 Todd Veldhuizen <tveldhui@oonumerics.org> |
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6 | * |
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7 | * This program is free software; you can redistribute it and/or |
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8 | * modify it under the terms of the GNU General Public License |
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9 | * as published by the Free Software Foundation; either version 2 |
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10 | * of the License, or (at your option) any later version. |
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11 | * |
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12 | * This program is distributed in the hope that it will be useful, |
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | * GNU General Public License for more details. |
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16 | * |
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17 | * Suggestions: blitz-dev@oonumerics.org |
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18 | * Bugs: blitz-bugs@oonumerics.org |
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19 | * |
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20 | * For more information, please see the Blitz++ Home Page: |
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21 | * http://oonumerics.org/blitz/ |
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22 | * |
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23 | ****************************************************************************/ |
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24 | #ifndef BZ_ARRAY_H |
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25 | #error <blitz/array/iter.h> must be included via <blitz/array.h> |
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26 | #endif |
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27 | |
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28 | #ifndef BZ_ARRAY_ITER_H |
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29 | #define BZ_ARRAY_ITER_H |
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30 | |
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31 | #ifdef BZ_HAVE_STL |
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32 | #include <iterator> |
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33 | #endif |
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34 | |
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35 | BZ_NAMESPACE(blitz) |
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36 | |
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37 | // helper class ConstPointerStack |
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38 | template<typename P_numtype, int N_rank> |
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39 | class ConstPointerStack { |
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40 | public: |
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41 | typedef P_numtype T_numtype; |
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42 | |
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43 | void operator=(const ConstPointerStack<P_numtype,N_rank>& rhs) |
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44 | { |
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45 | for (int i=0; i<N_rank; ++i) |
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46 | stack_[i] = rhs.stack_[i]; |
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47 | } |
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48 | |
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49 | const T_numtype*& operator[](int position) |
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50 | { |
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51 | return stack_[position]; |
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52 | } |
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53 | |
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54 | private: |
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55 | const T_numtype * stack_[N_rank]; |
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56 | }; |
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57 | |
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58 | |
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59 | template<typename T, int N> |
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60 | class ConstArrayIterator { |
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61 | public: |
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62 | ConstArrayIterator() : data_(0) { } |
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63 | |
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64 | ConstArrayIterator(const Array<T,N>& array) |
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65 | { |
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66 | // Making internal copies of these avoids keeping |
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67 | // a pointer to the array and doing indirection. |
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68 | strides_ = array.stride(); |
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69 | lbound_ = array.lbound(); |
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70 | extent_ = array.extent(); |
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71 | order_ = array.ordering(); |
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72 | data_ = const_cast<T*>(array.dataFirst()); |
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73 | |
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74 | maxRank_ = order_(0); |
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75 | stride_ = strides_(maxRank_); |
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76 | |
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77 | for (int i=0; i < N; ++i) |
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78 | { |
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79 | stack_[i] = data_; |
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80 | last_[i] = data_ + extent_(order_(i)) * strides_(order_(i)); |
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81 | } |
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82 | |
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83 | pos_ = lbound_; |
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84 | } |
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85 | |
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86 | bool operator==(const ConstArrayIterator<T,N>& x) const |
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87 | { |
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88 | return data_ == x.data_; |
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89 | } |
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90 | |
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91 | bool operator!=(const ConstArrayIterator<T,N>& x) const |
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92 | { |
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93 | return data_ != x.data_; |
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94 | } |
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95 | |
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96 | const T& operator*() const |
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97 | { |
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98 | BZPRECHECK(data_ != 0, "Attempted to dereference invalid iterator " |
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99 | << "(empty array or past end of array)"); |
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100 | return *data_; |
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101 | } |
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102 | |
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103 | const T* restrict operator->() const |
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104 | { |
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105 | BZPRECHECK(data_ != 0, "Attempted to dereference invalid iterator " |
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106 | << "(empty array or past end of array)"); |
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107 | return data_; |
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108 | } |
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109 | |
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110 | ConstArrayIterator<T,N>& operator++(); |
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111 | |
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112 | ConstArrayIterator<T,N> operator++(int) |
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113 | { |
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114 | ConstArrayIterator<T,N> tmp = *this; |
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115 | ++(*this); |
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116 | return tmp; |
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117 | } |
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118 | |
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119 | // get the current position of the Array iterator in index space |
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120 | const TinyVector<int,N>& position() const |
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121 | { |
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122 | BZPRECHECK(data_ != 0, "Array<T,N>::iterator::position() called on" |
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123 | << " invalid iterator"); |
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124 | return pos_; |
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125 | } |
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126 | |
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127 | private: |
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128 | TinyVector<int,N> strides_, lbound_, extent_, order_; |
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129 | ConstPointerStack<T,N> stack_; |
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130 | ConstPointerStack<T,N> last_; |
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131 | int stride_; |
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132 | int maxRank_; |
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133 | |
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134 | protected: |
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135 | TinyVector<int,N> pos_; |
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136 | T * restrict data_; |
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137 | }; |
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138 | |
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139 | |
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140 | template<typename T, int N> |
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141 | class ArrayIterator : public ConstArrayIterator<T,N> { |
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142 | private: |
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143 | typedef ConstArrayIterator<T,N> T_base; |
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144 | using T_base::data_; |
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145 | |
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146 | public: |
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147 | ArrayIterator() { } |
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148 | |
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149 | ArrayIterator(Array<T,N>& x) : T_base(x) { } |
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150 | |
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151 | T& operator*() const |
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152 | { |
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153 | BZPRECHECK(data_ != 0, "Attempted to dereference invalid iterator " |
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154 | << "(empty array or past end of array)"); |
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155 | return *data_; |
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156 | } |
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157 | |
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158 | T* restrict operator->() const |
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159 | { |
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160 | BZPRECHECK(data_ != 0, "Attempted to dereference invalid iterator " |
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161 | << "(empty array or past end of array)"); |
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162 | return data_; |
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163 | } |
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164 | |
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165 | ArrayIterator<T,N>& operator++() |
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166 | { |
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167 | T_base::operator++(); |
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168 | return *this; |
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169 | } |
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170 | |
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171 | ArrayIterator<T,N> operator++(int) |
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172 | { |
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173 | ArrayIterator<T,N> tmp = *this; |
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174 | ++(*this); |
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175 | return tmp; |
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176 | } |
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177 | }; |
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178 | |
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179 | |
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180 | template<typename T, int N> |
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181 | ConstArrayIterator<T,N>& ConstArrayIterator<T,N>::operator++() |
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182 | { |
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183 | BZPRECHECK(data_ != 0, "Attempted to iterate past the end of an array."); |
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184 | |
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185 | data_ += stride_; |
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186 | |
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187 | if (data_ != last_[0]) |
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188 | { |
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189 | // We hit this case almost all the time. |
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190 | ++pos_[maxRank_]; |
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191 | return *this; |
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192 | } |
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193 | |
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194 | // We've hit the end of a row/column/whatever. Need to |
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195 | // increment one of the loops over another dimension. |
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196 | |
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197 | int j = 1; |
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198 | for (; j < N; ++j) |
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199 | { |
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200 | int r = order_(j); |
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201 | data_ = const_cast<T*>(stack_[j]); |
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202 | data_ += strides_[r]; |
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203 | ++pos_(r); |
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204 | |
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205 | if (data_ != last_[j]) |
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206 | break; |
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207 | } |
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208 | |
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209 | // All done? |
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210 | if (j == N) |
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211 | { |
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212 | // Setting data_ to 0 indicates the end of the array has |
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213 | // been reached, and will match the end iterator. |
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214 | data_ = 0; |
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215 | return *this; |
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216 | } |
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217 | |
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218 | stack_[j] = data_; |
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219 | |
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220 | // Now reset all the last pointers |
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221 | for (--j; j >= 0; --j) |
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222 | { |
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223 | int r2 = order_(j); |
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224 | stack_[j] = data_; |
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225 | last_[j] = data_ + extent_(r2) * strides_(r2); |
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226 | pos_(r2) = lbound_(r2); |
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227 | } |
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228 | |
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229 | return *this; |
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230 | } |
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231 | |
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232 | |
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233 | BZ_NAMESPACE_END |
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234 | |
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235 | |
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236 | #ifdef BZ_HAVE_STL |
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237 | // support for std::iterator_traits |
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238 | BZ_NAMESPACE(std) |
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239 | |
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240 | template <typename T, int N> |
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241 | struct iterator_traits< BZ_BLITZ_SCOPE(ConstArrayIterator)<T,N> > |
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242 | { |
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243 | typedef forward_iterator_tag iterator_category; |
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244 | typedef T value_type; |
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245 | typedef ptrdiff_t difference_type; |
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246 | typedef const T* pointer; |
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247 | typedef const T& reference; |
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248 | }; |
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249 | |
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250 | template <typename T, int N> |
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251 | struct iterator_traits< BZ_BLITZ_SCOPE(ArrayIterator)<T,N> > |
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252 | { |
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253 | typedef forward_iterator_tag iterator_category; |
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254 | typedef T value_type; |
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255 | typedef ptrdiff_t difference_type; |
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256 | typedef T* pointer; |
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257 | typedef T& reference; |
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258 | }; |
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259 | |
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260 | BZ_NAMESPACE_END |
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261 | |
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262 | #endif // BZ_HAVE_STL |
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263 | |
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264 | #endif // BZ_ARRAY_ITER_H |
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265 | |
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