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