1 | #pragma once |
---|
2 | |
---|
3 | #include "bits/collection.hfa" |
---|
4 | |
---|
5 | forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) { |
---|
6 | struct Queue { |
---|
7 | inline Collection; // Plan 9 inheritance |
---|
8 | T * last; // last element, or 0 if queue is empty. |
---|
9 | }; |
---|
10 | |
---|
11 | inline { |
---|
12 | // wrappers to make Collection have T |
---|
13 | T & head( Queue(T) & q ) with( q ) { |
---|
14 | return *(T *)head( (Collection &)q ); |
---|
15 | } // post: empty() & head() == 0 | !empty() & head() in *q |
---|
16 | |
---|
17 | void ?{}( Queue(T) &, const Queue(T) & ) = void; // no copy |
---|
18 | Queue(T) & ?=?( const Queue(T) & ) = void; // no assignment |
---|
19 | |
---|
20 | void ?{}( Queue(T) & q ) with( q ) { |
---|
21 | ((Collection &)q){}; |
---|
22 | last = 0p; |
---|
23 | } // post: empty() |
---|
24 | |
---|
25 | T & tail( Queue(T) & q ) with( q ) { |
---|
26 | return *last; |
---|
27 | } |
---|
28 | |
---|
29 | T * succ( Queue(T) & q, T * n ) with( q ) { // pre: *n in *q |
---|
30 | #ifdef __CFA_DEBUG__ |
---|
31 | if ( ! listed( n ) ) abort( "(Queue &)%p.succ( %p ) : Node is not on a list.", &q, n ); |
---|
32 | #endif // __CFA_DEBUG__ |
---|
33 | return (Next( n ) == n) ? 0p : Next( n ); |
---|
34 | } // post: n == tail() & succ(n) == 0 | n != tail() & *succ(n) in *q |
---|
35 | |
---|
36 | void addHead( Queue(T) & q, T & n ) with( q ) { |
---|
37 | #ifdef __CFA_DEBUG__ |
---|
38 | if ( listed( &n ) ) abort( "(Queue &)%p.addHead( %p ) : Node is already on another list.", &q, &n ); |
---|
39 | #endif // __CFA_DEBUG__ |
---|
40 | if ( last ) { |
---|
41 | Next( &n ) = &head( q ); |
---|
42 | q.root = &n; |
---|
43 | } else { |
---|
44 | root = last = &n; |
---|
45 | Next( &n ) = &n; // last node points to itself |
---|
46 | } |
---|
47 | } |
---|
48 | |
---|
49 | void addTail( Queue(T) & q, T & n ) with( q ) { |
---|
50 | #ifdef __CFA_DEBUG__ |
---|
51 | if ( listed( &n ) ) abort( "(Queue &)%p.addTail( %p ) : Node is already on another list.", &q, &n ); |
---|
52 | #endif // __CFA_DEBUG__ |
---|
53 | if ( last ) Next( last ) = &n; |
---|
54 | else root = &n; |
---|
55 | last = &n; |
---|
56 | Next( &n ) = &n; // last node points to itself |
---|
57 | } |
---|
58 | |
---|
59 | void add( Queue(T) & q, T & n ) with( q ) { |
---|
60 | addTail( q, n ); |
---|
61 | } |
---|
62 | |
---|
63 | T & dropHead( Queue(T) & q ) with( q ) { |
---|
64 | T & t = head( q ); |
---|
65 | if ( root ) { |
---|
66 | root = Next( (T *)root ); |
---|
67 | if ( &head( q ) == &t ) { |
---|
68 | root = last = 0p; // only one element |
---|
69 | } |
---|
70 | Next( &t ) = 0p; |
---|
71 | } |
---|
72 | return t; |
---|
73 | } |
---|
74 | |
---|
75 | T & drop( Queue(T) & q ) with( q ) { |
---|
76 | return dropHead( q ); |
---|
77 | } |
---|
78 | |
---|
79 | void remove( Queue(T) & q, T & n ) with( q ) { // O(n) |
---|
80 | #ifdef __CFA_DEBUG__ |
---|
81 | if ( ! listed( (Colable &)n ) ) abort( "(Queue &)%p.remove( %p ) : Node is not on a list.", &q, &n ); |
---|
82 | #endif // __CFA_DEBUG__ |
---|
83 | T * prev = 0p; |
---|
84 | T * curr = (T *)root; |
---|
85 | for ( ;; ) { |
---|
86 | if ( &n == curr ) { // found => remove |
---|
87 | if ( (T *)root == &n ) { |
---|
88 | dropHead( q ); |
---|
89 | } else if ( last == &n ) { |
---|
90 | last = prev; |
---|
91 | Next( last ) = last; |
---|
92 | } else { |
---|
93 | Next( prev ) = Next( curr ); |
---|
94 | } |
---|
95 | Next( &n ) = 0p; |
---|
96 | break; |
---|
97 | } |
---|
98 | // not found => error |
---|
99 | #ifdef __CFA_DEBUG__ |
---|
100 | if ( curr == last ) abort( "(Queue &)%p.remove( %p ) : Node is not in list.", &q, &n ); |
---|
101 | #endif // __CFA_DEBUG__ |
---|
102 | prev = curr; |
---|
103 | curr = Next( curr ); |
---|
104 | } |
---|
105 | } // post: ! listed( n ) |
---|
106 | |
---|
107 | T & dropTail( Queue(T) & q ) with( q ) { // O(n) |
---|
108 | T & n = tail( q ); |
---|
109 | return &n ? remove( q, n ), n : *0p; |
---|
110 | } |
---|
111 | |
---|
112 | // Transfer the "from" list to the end of queue sequence; the "from" list is empty after the transfer. |
---|
113 | void transfer( Queue(T) & q, Queue(T) & from ) with( q ) { |
---|
114 | if ( empty( from ) ) return; // "from" list empty ? |
---|
115 | if ( empty( q ) ) { // "to" list empty ? |
---|
116 | root = from.root; |
---|
117 | } else { // "to" list not empty |
---|
118 | Next( last ) = &head( from ); |
---|
119 | } |
---|
120 | last = from.last; |
---|
121 | from.root = from.last = 0p; // mark "from" list empty |
---|
122 | } |
---|
123 | |
---|
124 | // Transfer the "from" list up to node "n" to the end of queue list; the "from" list becomes the list after node "n". |
---|
125 | // Node "n" must be in the "from" list. |
---|
126 | void split( Queue(T) & q, Queue(T) & from, T & n ) with( q ) { |
---|
127 | #ifdef __CFA_DEBUG__ |
---|
128 | if ( ! listed( (Colable &)n ) ) abort( "(Queue &)%p.split( %p ) : Node is not on a list.", &q, &n ); |
---|
129 | #endif // __CFA_DEBUG__ |
---|
130 | Queue(T) to; |
---|
131 | to.root = from.root; // start of "to" list |
---|
132 | to.last = &n; // end of "to" list |
---|
133 | from.root = Next( &n ); // start of "from" list |
---|
134 | if ( &n == &head( from ) ) { // last node in list ? |
---|
135 | from.root = from.last = 0p; // mark "from" list empty |
---|
136 | } else { |
---|
137 | Next( &n ) = &n; // fix end of "to" list |
---|
138 | } |
---|
139 | transfer( q, to ); |
---|
140 | } |
---|
141 | } // distribution |
---|
142 | } // distribution |
---|
143 | |
---|
144 | forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) { |
---|
145 | struct QueueIter { |
---|
146 | inline ColIter; // Plan 9 inheritance |
---|
147 | }; |
---|
148 | |
---|
149 | inline { |
---|
150 | void ?{}( QueueIter(T) & qi ) with( qi ) { |
---|
151 | ((ColIter &)qi){}; |
---|
152 | } // post: curr == 0p |
---|
153 | |
---|
154 | // create an iterator active in Queue q |
---|
155 | void ?{}( QueueIter(T) & qi, Queue(T) & q ) with( qi ) { |
---|
156 | curr = &head( q ); |
---|
157 | } // post: curr = {e in q} |
---|
158 | |
---|
159 | void ?{}( QueueIter(T) & qi, T & start ) with( qi ) { |
---|
160 | curr = &start; |
---|
161 | } // post: curr = {e in q} |
---|
162 | |
---|
163 | // make existing iterator active in Queue q |
---|
164 | void over( QueueIter(T) & qi, Queue(T) & q ) with( qi ) { |
---|
165 | curr = &head( q ); |
---|
166 | } // post: curr = {e in q} |
---|
167 | |
---|
168 | bool ?>>?( QueueIter(T) & qi, T && tp ) with( qi ) { |
---|
169 | if ( curr ) { |
---|
170 | &tp = Curr( qi ); |
---|
171 | T * n = Next( Curr( qi ) ); |
---|
172 | curr = (n == Curr( qi ) ) ? 0p : n; |
---|
173 | } else &tp = 0p; |
---|
174 | return &tp != 0p; |
---|
175 | } |
---|
176 | // post: elts == null & !operator>>(tp) | elts != null & *tp' in elts & elts' == elts - *tp & operator>>(tp) |
---|
177 | } // distribution |
---|
178 | } // distribution |
---|