1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2004-2009 Jean Privat <jean@pryen.org>
5 # This file is free software, which comes along with NIT. This software is
6 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
7 # without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
8 # PARTICULAR PURPOSE. You can modify it is you want, provided this header
9 # is kept unaltered, and a notification of the changes is added.
10 # You are allowed to redistribute it and sell it, alone or is a part of
13 # Introduce Hashmap and Hashset.
14 module hash_collection
18 # A HashCollection is an array of HashNode[K] indexed by the K hash value
19 private abstract class HashCollection[K
: Object]
22 var array
: nullable NativeArray[nullable N
] = null # Used to store items
23 var capacity
: Int = 0 # Size of _array
24 var the_length
: Int = 0 # Number of items in the map
26 var first_item
: nullable N
= null # First added item (used to visit items in nice order)
27 var last_item
: nullable N
= null # Last added item (same)
29 # The last key accessed (used for cache)
30 var last_accessed_key
: nullable K
= null
32 # The last node accessed (used for cache)
33 var last_accessed_node
: nullable N
= null
35 # Return the index of the key k
36 fun index_at
(k
: K
): Int
38 var i
= k
.hash
% _capacity
43 # Return the node assosiated with the key
44 fun node_at
(k
: K
): nullable N
46 # cache: `is` is used instead of `==` because it is a faster filter (even if not exact)
47 if k
.is_same_instance
(_last_accessed_key
) then return _last_accessed_node
49 var res
= node_at_idx
(index_at
(k
), k
)
50 _last_accessed_key
= k
51 _last_accessed_node
= res
55 # Return the node assosiated with the key (but with the index already known)
56 fun node_at_idx
(i
: Int, k
: K
): nullable N
61 if ck
.is_same_instance
(k
) or ck
== k
then # FIXME prefilter because the compiler is not smart enought yet
64 c
= c
._next_in_bucklet
69 # Add a new node at a given index
70 fun store
(index
: Int, node
: N
)
72 # Store the item in the list
73 if _first_item
== null then
76 _last_item
._next_item
= node
78 node
._prev_item
= _last_item
79 node
._next_item
= null
82 # Then store it in the array
83 var next
= _array
[index
]
85 node
._next_in_bucklet
= next
86 if next
!= null then next
._prev_in_bucklet
= node
88 _last_accessed_key
= node
._key
89 _last_accessed_node
= node
95 # Magic values determined empirically
96 # We do not want to enlarge too much
97 # We also want a odd capacity so that the modulo is more distributive
99 if l
>= _capacity
then
100 enlarge
(l
* 3 / 2 + 1)
104 # Remove the node assosiated with the key
105 fun remove_node
(k
: K
)
108 var node
= node_at_idx
(i
, k
)
109 if node
== null then return
111 # Remove the item in the list
112 var prev
= node
._prev_item
113 var next
= node
._next_item
115 prev
._next_item
= next
120 next
._prev_item
= prev
125 # Remove the item in the array
127 prev
= node
._prev_in_bucklet
128 next
= node
._next_in_bucklet
130 prev
._next_in_bucklet
= next
135 next
._prev_in_bucklet
= prev
138 _last_accessed_key
= null
141 # Clear the whole structure
144 var i
= _capacity
- 1
152 _last_accessed_key
= null
156 fun enlarge
(cap
: Int)
158 var old_cap
= _capacity
160 if cap
< _the_length
+ 1 then cap
= _the_length
+ 1
161 if cap
<= _capacity
then return
163 _last_accessed_key
= null
166 var new_array
= new NativeArray[nullable N
](cap
)
169 # clean the new array
176 if _capacity
<= old_cap
then return
178 # Reput items in the array
179 var node
= _first_item
180 while node
!= null do
181 var index
= index_at
(node
._key
)
182 # Then store it in the array
183 var next
= new_array
[index
]
184 new_array
[index
] = node
185 node
._prev_in_bucklet
= null
186 node
._next_in_bucklet
= next
187 if next
!= null then next
._prev_in_bucklet
= node
188 node
= node
._next_item
193 private abstract class HashNode[K
: Object]
196 var next_item
: nullable N
= null
197 var prev_item
: nullable N
= null
198 var prev_in_bucklet
: nullable N
= null
199 var next_in_bucklet
: nullable N
= null
202 # A map implemented with a hash table.
203 # Keys of such a map cannot be null and require a working `hash` method
204 class HashMap[K
: Object, V
]
206 super HashCollection[K
]
208 redef type N
: HashMapNode[K
, V
] is fixed
214 return provide_default_value
(key
)
220 redef fun iterator
: HashMapIterator[K
, V
] do return new HashMapIterator[K
,V
](self)
222 redef fun length
do return _the_length
224 redef fun is_empty
do return _the_length
== 0
226 redef fun []=(key
, v
)
228 var i
= index_at
(key
)
229 var c
= node_at_idx
(i
, key
)
234 store
(i
, new HashMapNode[K
, V
](key
, v
))
238 redef fun clear
do raz
247 redef var keys
: RemovableCollection[K
] = new HashMapKeys[K
, V
](self)
248 redef var values
: RemovableCollection[V
] = new HashMapValues[K
, V
](self)
251 # View of the keys of a HashMap
252 private class HashMapKeys[K
: Object, V
]
253 super RemovableCollection[K
]
255 var map
: HashMap[K
, V
]
257 redef fun count
(k
) do if self.has
(k
) then return 1 else return 0
258 redef fun first
do return self.map
._first_item
._key
259 redef fun has
(k
) do return self.map
.node_at
(k
) != null
260 redef fun has_only
(k
) do return (self.has
(k
) and self.length
== 1) or self.is_empty
261 redef fun is_empty
do return self.map
.is_empty
262 redef fun length
do return self.map
.length
264 redef fun iterator
do return new MapKeysIterator[K
, V
](self.map
.iterator
)
266 redef fun clear
do self.map
.clear
268 redef fun remove
(key
) do self.map
.remove_node
(key
)
269 redef fun remove_all
(key
) do self.map
.remove_node
(key
)
272 # View of the values of a Map
273 private class HashMapValues[K
: Object, V
]
274 super RemovableCollection[V
]
276 var map
: HashMap[K
, V
]
278 redef fun count
(item
)
281 var c
= self.map
._first_item
283 if c
._value
== item
then nb
+= 1
288 redef fun first
do return self.map
._first_item
._value
292 var c
= self.map
._first_item
294 if c
._value
== item
then return true
300 redef fun has_only
(item
)
302 var c
= self.map
._first_item
304 if c
._value
!= item
then return false
310 redef fun is_empty
do return self.map
.is_empty
311 redef fun length
do return self.map
.length
313 redef fun iterator
do return new MapValuesIterator[K
, V
](self.map
.iterator
)
315 redef fun clear
do self.map
.clear
317 redef fun remove
(item
)
320 var c
= map
._first_item
322 if c
._value
== item
then
323 map
.remove_node
(c
._key
)
330 redef fun remove_all
(item
)
333 var c
= map
._first_item
335 if c
._value
== item
then
336 map
.remove_node
(c
._key
)
343 private class HashMapNode[K
: Object, V
]
345 redef type N
: HashMapNode[K
, V
]
349 # A `MapIterator` over a `HashMap`.
350 class HashMapIterator[K
: Object, V
]
351 super MapIterator[K
, V
]
352 redef fun is_ok
do return _node
!= null
360 #redef fun item=(value)
363 # _node.second = value
375 _node
= _node
._next_item
378 # The map to iterate on
379 private var map
: HashMap[K
, V
]
382 private var node
: nullable HashMapNode[K
, V
] = null
387 _node
= _map
._first_item
391 # A `Set` implemented with a hash table.
392 # Keys of such a map cannot be null and require a working `hash` method
393 class HashSet[E
: Object]
395 super HashCollection[E
]
397 redef type N
: HashSetNode[E
] is fixed
399 redef fun length
do return _the_length
401 redef fun is_empty
do return _the_length
== 0
405 assert _the_length
> 0
406 return _first_item
._key
411 return node_at
(item
) != null
416 var i
= index_at
(item
)
417 var c
= node_at_idx
(i
, item
)
421 store
(i
,new HashSetNode[E
](item
))
425 redef fun remove
(item
) do remove_node
(item
)
427 redef fun clear
do raz
429 redef fun iterator
do return new HashSetIterator[E
](self)
438 # Build a list filled with the items of `coll`.
439 init from
(coll
: Collection[E
]) do
444 redef fun new_set
do return new HashSet[E
]
447 private class HashSetNode[E
: Object]
449 redef type N
: HashSetNode[E
]
452 private class HashSetIterator[E
: Object]
454 redef fun is_ok
do return _node
!= null
465 _node
= _node
._next_item
468 # The set to iterate on
471 # The position in the internal map storage
472 var node
: nullable HashSetNode[E
] = null
476 _node
= _set
._first_item