1 | #pragma once |
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2 | |
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3 | #include "collection.hfa" |
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4 | |
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5 | struct Seqable { |
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6 | inline Colable; |
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7 | Seqable * back; // pointer to previous node in the list |
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8 | }; |
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9 | |
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10 | inline { |
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11 | void ?{}( Seqable & sq ) with( sq ) { |
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12 | ((Colable & ) sq){}; |
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13 | back = 0p; |
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14 | } // post: ! listed() |
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15 | |
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16 | Seqable * getBack( Seqable & sq ) with( sq ) { |
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17 | return back; |
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18 | } |
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19 | |
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20 | Seqable *& Back( Seqable * sq ) { |
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21 | return sq->back; |
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22 | } |
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23 | } // distribution |
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24 | |
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25 | forall( dtype T ) { |
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26 | struct Sequence { |
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27 | inline Collection; // Plan 9 inheritance |
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28 | }; |
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29 | |
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30 | inline { |
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31 | // wrappers to make Collection have T |
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32 | T * head( Sequence(T) & s ) with( s ) { |
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33 | return (T *)head( (Collection &)s ); |
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34 | } // post: empty() & head() == 0 | !empty() & head() in *s |
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35 | |
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36 | bool empty( Sequence(T) & s ) with( s ) { // 0 <=> *s contains no elements |
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37 | return empty( (Collection &)s ); |
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38 | } |
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39 | |
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40 | bool listed( T * n ) { |
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41 | return Next( (Colable *)n ) != 0; |
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42 | } |
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43 | |
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44 | T *& Next( T * n ) { |
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45 | return (T *)Next( (Colable *)n ); |
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46 | } |
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47 | |
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48 | T *& Back( T * n ) { |
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49 | return (T *)Back( (Seqable *)n ); |
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50 | } |
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51 | |
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52 | T * Root( Sequence(T) & s ) with( s ) { |
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53 | return (T *)root; |
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54 | } |
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55 | |
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56 | void ?{}( Sequence(T) &, const Sequence(T) & ) = void; // no copy |
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57 | Sequence(T) & ?=?( const Sequence(T) & ) = void; // no assignment |
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58 | |
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59 | void ?{}( Sequence(T) & s ) with( s ) { |
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60 | ((Collection &) s){}; |
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61 | } // post: isEmpty(). |
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62 | |
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63 | // Return a pointer to the last sequence element, without removing it. |
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64 | T & tail( Sequence(T) & s ) with( s ) { |
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65 | return root ? (T &)Back( Root( s ) ) : *0p; // needs cast? |
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66 | } // post: empty() & tail() == 0 | !empty() & tail() in *s |
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67 | |
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68 | // Return a pointer to the element after *n, or 0p if there isn't one. |
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69 | T * succ( Sequence(T) & s, T * n ) with( s ) { // pre: *n in *s |
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70 | #ifdef __CFA_DEBUG__ |
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71 | if ( ! listed( n ) ) abort( "(Sequence &)%p.succ( %p ) : Node is not on a list.", &s, n ); |
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72 | #endif // __CFA_DEBUG__ |
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73 | return Next( n ) == Root( s ) ? 0p : Next( n ); |
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74 | } // post: n == tail() & succ(n) == 0 | n != tail() & *succ(n) in *s |
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75 | |
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76 | // Return a pointer to the element before *n, or 0p if there isn't one. |
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77 | T * pred( Sequence(T) & s, T * n ) with( s ) { // pre: *n in *s |
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78 | #ifdef __CFA_DEBUG__ |
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79 | if ( ! listed( n ) ) abort( "(Sequence &)%p.pred( %p ) : Node is not on a list.", &s, n ); |
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80 | #endif // __CFA_DEBUG__ |
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81 | return n == Root( s ) ? 0p : Back( n ); |
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82 | } // post: n == head() & head(n) == 0 | n != head() & *pred(n) in *s |
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83 | |
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84 | |
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85 | // Insert *n into the sequence before *bef, or at the end if bef == 0. |
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86 | void insertBef( Sequence(T) & s, T & n, T & bef ) with( s ) { // pre: !n->listed() & *bef in *s |
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87 | #ifdef __CFA_DEBUG__ |
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88 | if ( listed( &n ) ) abort( "(Sequence &)%p.insertBef( %p, %p ) : Node is already on another list.", &s, n, &bef ); |
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89 | #endif // __CFA_DEBUG__ |
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90 | if ( &bef == Root( s ) ) { // must change root |
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91 | if ( root ) { |
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92 | Next( &n ) = Root( s ); |
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93 | Back( &n ) = Back( Root( s ) ); |
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94 | // inserted node must be consistent before it is seen |
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95 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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96 | Back( Root( s ) ) = &n; |
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97 | Next( Back( &n ) ) = &n; |
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98 | } else { |
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99 | Next( &n ) = &n; |
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100 | Back( &n ) = &n; |
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101 | } // if |
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102 | // inserted node must be consistent before it is seen |
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103 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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104 | root = &n; |
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105 | } else { |
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106 | if ( ! &bef ) &bef = Root( s ); |
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107 | Next( &n ) = &bef; |
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108 | Back( &n ) = Back( &bef ); |
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109 | // inserted node must be consistent before it is seen |
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110 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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111 | Back( &bef ) = &n; |
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112 | Next( Back( &n ) ) = &n; |
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113 | } // if |
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114 | } // post: n->listed() & *n in *s & succ(n) == bef |
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115 | |
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116 | |
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117 | // Insert *n into the sequence after *aft, or at the beginning if aft == 0. |
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118 | void insertAft( Sequence(T) & s, T & aft, T & n ) with( s ) { // pre: !n->listed() & *aft in *s |
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119 | #ifdef __CFA_DEBUG__ |
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120 | if ( listed( &n ) ) abort( "(Sequence &)%p.insertAft( %p, %p ) : Node is already on another list.", &s, &aft, &n ); |
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121 | #endif // __CFA_DEBUG__ |
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122 | if ( ! &aft ) { // must change root |
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123 | if ( root ) { |
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124 | Next( &n ) = Root( s ); |
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125 | Back( &n ) = Back( Root( s ) ); |
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126 | // inserted node must be consistent before it is seen |
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127 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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128 | Back( Root( s ) ) = &n; |
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129 | Next( Back( &n ) ) = &n; |
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130 | } else { |
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131 | Next( &n ) = &n; |
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132 | Back( &n ) = &n; |
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133 | } // if |
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134 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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135 | root = &n; |
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136 | } else { |
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137 | Next( &n ) = Next( &aft ); |
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138 | Back( &n ) = &aft; |
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139 | // inserted node must be consistent before it is seen |
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140 | asm( "" : : : "memory" ); // prevent code movement across barrier |
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141 | Back( Next( &n ) ) = &n; |
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142 | Next( &aft ) = &n; |
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143 | } // if |
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144 | } // post: n->listed() & *n in *s & succ(n) == bef |
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145 | |
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146 | // pre: n->listed() & *n in *s |
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147 | void remove( Sequence(T) & s, T & n ) with( s ) { // O(1) |
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148 | #ifdef __CFA_DEBUG__ |
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149 | if ( ! listed( &n ) ) abort( "(Sequence &)%p.remove( %p ) : Node is not on a list.", &s, &n ); |
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150 | #endif // __CFA_DEBUG__ |
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151 | if ( &n == Root( s ) ) { |
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152 | if ( Next( Root( s ) ) == Root( s ) ) root = 0p; |
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153 | else root = Next( Root(s ) ); |
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154 | } // if |
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155 | Back( Next( &n ) ) = Back( &n ); |
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156 | Next( Back( &n ) ) = Next( &n ); |
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157 | Next( &n ) = Back( &n ) = 0p; |
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158 | } // post: !n->listed(). |
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159 | |
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160 | // Add an element to the head of the sequence. |
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161 | void addHead( Sequence(T) & s, T & n ) { // pre: !n->listed(); post: n->listed() & head() == n |
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162 | insertAft( s, *0p, n ); |
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163 | } |
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164 | // Add an element to the tail of the sequence. |
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165 | void addTail( Sequence(T) & s, T & n ) { // pre: !n->listed(); post: n->listed() & head() == n |
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166 | insertBef( s, n, *0p ); |
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167 | } |
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168 | // Add an element to the tail of the sequence. |
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169 | void add( Sequence(T) & s, T & n ) { // pre: !n->listed(); post: n->listed() & head() == n |
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170 | addTail( s, n ); |
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171 | } |
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172 | // Remove and return the head element in the sequence. |
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173 | T & dropHead( Sequence(T) & s ) { |
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174 | T * n = head( s ); |
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175 | return n ? remove( s, *n ), *n : *0p; |
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176 | } |
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177 | // Remove and return the head element in the sequence. |
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178 | T & drop( Sequence(T) & s ) { |
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179 | return dropHead( s ); |
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180 | } |
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181 | // Remove and return the tail element in the sequence. |
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182 | T & dropTail( Sequence(T) & s ) { |
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183 | T & n = tail( s ); |
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184 | return &n ? remove( s, n ), n : *0p; |
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185 | } |
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186 | |
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187 | // Transfer the "from" list to the end of s sequence; the "from" list is empty after the transfer. |
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188 | void transfer( Sequence(T) & s, Sequence(T) & from ) with( s ) { |
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189 | if ( empty( from ) ) return; // "from" list empty ? |
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190 | if ( empty( s ) ) { // "to" list empty ? |
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191 | root = from.root; |
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192 | } else { // "to" list not empty |
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193 | T * toEnd = Back( Root( s ) ); |
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194 | T * fromEnd = Back( Root( from ) ); |
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195 | Back( root ) = fromEnd; |
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196 | Next( fromEnd ) = Root( s ); |
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197 | Back( from.root ) = toEnd; |
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198 | Next( toEnd ) = Root( from ); |
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199 | } // if |
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200 | from.root = 0p; // mark "from" list empty |
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201 | } |
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202 | |
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203 | // Transfer the "from" list up to node "n" to the end of s list; the "from" list becomes the sequence after node "n". |
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204 | // Node "n" must be in the "from" list. |
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205 | void split( Sequence(T) & s, Sequence(T) & from, T * n ) with( s ) { |
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206 | #ifdef __CFA_DEBUG__ |
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207 | if ( ! listed( n ) ) abort( "(Sequence &)%p.split( %p ) : Node is not on a list.", &s, n ); |
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208 | #endif // __CFA_DEBUG__ |
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209 | Sequence(T) to; |
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210 | to.root = from.root; // start of "to" list |
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211 | from.root = Next( n ); // start of "from" list |
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212 | if ( to.root == from.root ) { // last node in list ? |
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213 | from.root = 0p; // mark "from" list empty |
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214 | } else { |
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215 | Back( Root( from ) ) = Back( Root( to ) ); // fix "from" list |
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216 | Next( Back( Root( to ) ) ) = Root( from ); |
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217 | Next( n ) = Root( to ); // fix "to" list |
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218 | Back( Root( to ) ) = n; |
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219 | } // if |
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220 | transfer( s, to ); |
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221 | } |
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222 | } // distribution |
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223 | } // distribution |
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224 | |
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225 | forall( dtype T ) { |
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226 | // SeqIter(T) is used to iterate over a Sequence(T) in head-to-tail order. |
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227 | struct SeqIter { |
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228 | inline ColIter; |
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229 | Sequence(T) * seq; |
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230 | }; |
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231 | |
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232 | inline { |
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233 | // wrappers to make ColIter have T |
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234 | T * Curr( SeqIter(T) & si ) with( si ) { |
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235 | return (T *)curr; |
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236 | } |
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237 | |
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238 | void ?{}( SeqIter(T) & si ) with( si ) { |
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239 | ((ColIter &) si){}; |
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240 | seq = 0p; |
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241 | } // post: elts = null. |
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242 | |
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243 | void ?{}( SeqIter(T) & si, Sequence(T) & s ) with( si ) { |
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244 | ((ColIter &) si){}; |
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245 | seq = &s; |
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246 | curr = head( s ); |
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247 | } // post: elts = null. |
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248 | |
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249 | void over( SeqIter(T) & si, Sequence(T) & s ) with( si ) { |
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250 | seq = &s; |
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251 | curr = head( s ); |
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252 | } // post: elts = {e in s}. |
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253 | |
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254 | bool ?>>?( SeqIter(T) & si, T && tp ) with( si ) { |
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255 | if ( curr ) { |
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256 | &tp = Curr( si ); |
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257 | T * n = succ( *seq, Curr( si ) ); |
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258 | curr = n == head( *seq ) ? 0p : n; |
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259 | } else &tp = 0p; |
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260 | return &tp != 0p; |
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261 | } |
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262 | } // distribution |
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263 | |
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264 | |
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265 | // A SeqIterRev(T) is used to iterate over a Sequence(T) in tail-to-head order. |
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266 | struct SeqIterRev { |
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267 | inline ColIter; |
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268 | Sequence(T) * seq; |
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269 | }; |
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270 | |
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271 | inline { |
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272 | // wrappers to make ColIter have T |
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273 | T * Curr( SeqIterRev(T) & si ) with( si ) { |
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274 | return (T *)curr; |
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275 | } |
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276 | |
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277 | void ?{}( SeqIterRev(T) & si ) with( si ) { |
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278 | ((ColIter &) si){}; |
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279 | seq = 0p; |
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280 | } // post: elts = null. |
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281 | |
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282 | void ?{}( SeqIterRev(T) & si, Sequence(T) & s ) with( si ) { |
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283 | ((ColIter &) si){}; |
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284 | seq = &s; |
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285 | curr = &tail( s ); |
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286 | } // post: elts = null. |
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287 | |
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288 | void over( SeqIterRev(T) & si, Sequence(T) & s ) with( si ) { |
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289 | seq = &s; |
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290 | curr = &tail( s ); |
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291 | } // post: elts = {e in s}. |
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292 | |
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293 | bool ?>>?( SeqIterRev(T) & si, T && tp ) with( si ) { |
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294 | if ( curr ) { |
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295 | &tp = Curr( si ); |
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296 | T * n = pred( *seq, Curr( si ) ); |
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297 | curr = n == &tail( *seq ) ? 0p : n; |
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298 | } else &tp = 0p; |
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299 | return &tp != 0p; |
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300 | } |
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301 | } // distribution |
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302 | } // distribution |
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303 | |
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304 | // Local Variables: // |
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305 | // compile-command: "make install" // |
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306 | // End: // |
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