# You are allowed to redistribute it and sell it, alone or is a part of
# another product.
-# Introduce Hashmap and Hashset.
-package hash_collection
+# Introduce `HashMap` and `HashSet`.
+module hash_collection
import array
-import hash
+
+redef class Map[K, V]
+ # Get a `HashMap[K, V]` as default implementation
+ new do return new HashMap[K, V]
+end
# A HashCollection is an array of HashNode[K] indexed by the K hash value
-private class HashCollection[K: Object, N: HashNode[K], E]
-special Collection[E]
-special ArrayCapable[nullable N]
- var _array: nullable NativeArray[nullable N] = null # Used to store items
- var _capacity: Int = 0 # Size of _array
- redef readable var _length: Int = 0 # Number of items in the map
+private abstract class HashCollection[K]
+ type N: HashNode[K]
+
+ var array: nullable NativeArray[nullable N] = null # Used to store items
+ var capacity: Int = 0 # Size of _array
+ var the_length: Int = 0 # Number of items in the map
- readable var _first_item: nullable N = null # First added item (used to visit items in nice order)
- var _last_item: nullable N = null # Last added item (same)
+ var first_item: nullable N = null # First added item (used to visit items in nice order)
+ var last_item: nullable N = null # Last added item (same)
- # The last index accessed
- var _last_accessed_index: Int = -1
+ # The last key accessed (used for cache)
+ var last_accessed_key: nullable K = null
- # The last key accessed
- var _last_accessed_key: nullable K = null
+ # The last node accessed (used for cache)
+ var last_accessed_node: nullable N = null
- # Return the index of the k element
+ # Return the index of the key k
fun index_at(k: K): Int
do
- var arr = _array
-
- # Fisrt step: look in the last indexed elt
- if k == _last_accessed_key then return _last_accessed_index
-
- # Compute the base position of the key
- var base = k.hash % _capacity
- if base < 0 then base = - base
-
- # Look for the key in the array
- var cur = base
- loop
- var c = arr[cur]
- if c == null or c._key == k then # REAL equals
- _last_accessed_index = cur
- _last_accessed_key = k
- return cur
+ if k == null then return 0
+
+ var i = k.hash % _capacity
+ if i < 0 then i = - i
+ return i
+ end
+
+ # Return the node associated with the key
+ fun node_at(k: K): nullable N
+ do
+ # cache: `is` is used instead of `==` because it is a faster filter (even if not exact)
+ if k.is_same_instance(_last_accessed_key) then return _last_accessed_node
+
+ var res = node_at_idx(index_at(k), k)
+ _last_accessed_key = k
+ _last_accessed_node = res
+ return res
+ end
+
+ # Return the node associated with the key (but with the index already known)
+ fun node_at_idx(i: Int, k: K): nullable N
+ do
+ var c = _array[i]
+ while c != null do
+ var ck = c._key
+ if ck.is_same_instance(k) or ck == k then # FIXME prefilter because the compiler is not smart enought yet
+ break
end
- cur -= 1
- if cur < 0 then cur = _capacity - 1
- assert no_loop: cur != base
- if false then break # FIXME remove once unreach loop exits are in c_src
+ c = c._next_in_bucklet
end
- abort #FIXME remove once unreach loop exits are in c_src
+ return c
end
- # Add a new node (should be free)
+ # Add a new node at a given index
fun store(index: Int, node: N)
do
# Store the item in the list
node._prev_item = _last_item
node._next_item = null
_last_item = node
+
# Then store it in the array
- assert _array[index] == null
+ var next = _array[index]
_array[index] = node
- var l = _length
- _length = l + 1
- l = (l + 5) * 150 / 100
+ node._next_in_bucklet = next
+ if next != null then next._prev_in_bucklet = node
+
+ _last_accessed_key = node._key
+ _last_accessed_node = node
+
+ # Enlarge if needed
+ var l = _the_length
+ _the_length = l + 1
+
+ # Magic values determined empirically
+ # We do not want to enlarge too much
+ # We also want a odd capacity so that the modulo is more distributive
+ l = (l + 5) * 2 + 1
if l >= _capacity then
- enlarge(l * 2)
+ enlarge(l * 3 / 2 + 1)
end
end
- fun remove_index(i: Int)
+ # Remove the node assosiated with the key
+ fun remove_node(k: K)
do
- assert correct_index: i >= 0 and i < _capacity
- var node = _array[i]
- assert has_couple: node != null
+ var i = index_at(k)
+ var node = node_at_idx(i, k)
+ if node == null then return
+
# Remove the item in the list
var prev = node._prev_item
var next = node._next_item
else
_last_item = prev
end
+
# Remove the item in the array
- _array[i] = null
- _length -= 1
- # Now replaces things before if needed
- loop
- i -= 1
- if i < 0 then
- i = _capacity - 1
- end
- var n = _array[i]
- if n == null then
- return
- end
- var i2 = index_at(n._key)
- if i != i2 then
- _array[i] = null
- assert _array[i2] == null
- _array[i2] = n
- end
+ _the_length -= 1
+ prev = node._prev_in_bucklet
+ next = node._next_in_bucklet
+ if prev != null then
+ prev._next_in_bucklet = next
+ else
+ _array[i] = next
end
+ if next != null then
+ next._prev_in_bucklet = prev
+ end
+
+ _last_accessed_key = null
end
+ # Clear the whole structure
fun raz
do
var i = _capacity - 1
_array[i] = null
i -= 1
end
- _length = 0
+ _the_length = 0
_first_item = null
_last_item = null
_last_accessed_key = null
end
+ # Force a capacity
fun enlarge(cap: Int)
do
var old_cap = _capacity
# get a new capacity
- # cap = cap * 130 / 100 + 5 + 1000 # /
- if cap < _length + 1 then cap = _length + 1
+ if cap < _the_length + 1 then cap = _the_length + 1
if cap <= _capacity then return
_capacity = cap
_last_accessed_key = null
# get a new array
- var new_array = calloc_array(cap)
+ var new_array = new NativeArray[nullable N](cap)
_array = new_array
# clean the new array
# Reput items in the array
var node = _first_item
while node != null do
- var ind = index_at(node._key)
- assert new_array[ind] == null
- new_array[ind] = node
+ var index = index_at(node._key)
+ # Then store it in the array
+ var next = new_array[index]
+ new_array[index] = node
+ node._prev_in_bucklet = null
+ node._next_in_bucklet = next
+ if next != null then next._prev_in_bucklet = node
node = node._next_item
end
- _last_accessed_key = null
end
end
-private class HashNode[K]
- var _key: K
+private abstract class HashNode[K]
+ var key: K
type N: HashNode[K]
- readable writable var _next_item: nullable N = null
- readable writable var _prev_item: nullable N = null
- init(k: K)
- do
- _key = k
- end
+ var next_item: nullable N = null
+ var prev_item: nullable N = null
+ var prev_in_bucklet: nullable N = null
+ var next_in_bucklet: nullable N = null
end
+# A `Map` implemented with a hash table.
+#
+# ~~~
+# var map = new HashMap[nullable String, Int]
+# map[null] = 0
+# map["one"] = 1
+# map["two"] = 2
+#
+# assert map[null] == 0
+# assert map["one"] == 1
+# assert map.keys.has("two")
+# assert map.values.length == 3
+# ~~~
class HashMap[K, V]
-special Map[K, V]
-special HashCollection[K, HashMapNode[K, V], V]
+ super Map[K, V]
+ super HashCollection[K]
+
+ redef type N: HashMapNode[K, V] is fixed
redef fun [](key)
do
- var c = couple_at(key)
+ var c = node_at(key)
if c == null then
- abort
+ return provide_default_value(key)
else
return c._value
end
end
- redef fun has_key(key) do return couple_at(key) != null
-
redef fun iterator: HashMapIterator[K, V] do return new HashMapIterator[K,V](self)
- redef fun iterate
- !each(e: V)
+ redef fun length do return _the_length
+
+ redef fun is_empty do return _the_length == 0
+
+ redef fun []=(key, v)
do
- var c = _first_item
- while c != null do
- each(c._value)
- c = c._next_item
+ var i = index_at(key)
+ var c = node_at_idx(i, key)
+ if c != null then
+ c._key = key
+ c._value = v
+ else
+ store(i, new HashMapNode[K, V](key, v))
end
end
- redef fun first
+ redef fun clear do raz
+
+ init
do
- assert _length > 0
- return _first_item._value
+ _capacity = 0
+ _the_length = 0
+ enlarge(0)
end
- redef fun is_empty do return _length == 0
+ redef var keys: RemovableCollection[K] = new HashMapKeys[K, V](self)
+ redef var values: RemovableCollection[V] = new HashMapValues[K, V](self)
+end
+
+# View of the keys of a HashMap
+private class HashMapKeys[K, V]
+ super RemovableCollection[K]
+ # The original map
+ var map: HashMap[K, V]
+
+ redef fun count(k) do if self.has(k) then return 1 else return 0
+ redef fun first do return self.map._first_item._key
+ redef fun has(k) do return self.map.node_at(k) != null
+ redef fun has_only(k) do return (self.has(k) and self.length == 1) or self.is_empty
+ redef fun is_empty do return self.map.is_empty
+ redef fun length do return self.map.length
+
+ redef fun iterator do return new MapKeysIterator[K, V](self.map.iterator)
+
+ redef fun clear do self.map.clear
+
+ redef fun remove(key) do self.map.remove_node(key)
+ redef fun remove_all(key) do self.map.remove_node(key)
+end
+
+# View of the values of a Map
+private class HashMapValues[K, V]
+ super RemovableCollection[V]
+ # The original map
+ var map: HashMap[K, V]
redef fun count(item)
do
var nb = 0
- var i = 0
- while i < _capacity do
- var c = _array[i]
- if c != null and c._value == item then nb += 1
- i += 1
+ var c = self.map._first_item
+ while c != null do
+ if c._value == item then nb += 1
+ c = c._next_item
end
return nb
end
+ redef fun first do return self.map._first_item._value
redef fun has(item)
do
- var i = 0
- while i < _capacity do
- var c = _array[i]
- if c != null and c._value == item then return true
- i += 1
+ var c = self.map._first_item
+ while c != null do
+ if c._value == item then return true
+ c = c._next_item
end
return false
end
redef fun has_only(item)
do
- var i = 0
- while i < _capacity do
- var c = _array[i]
- if c != null and c._value != item then return false
- i += 1
+ var c = self.map._first_item
+ while c != null do
+ if c._value != item then return false
+ c = c._next_item
end
return true
end
- redef fun []=(key, v)
- do
- assert key != null
- var i = index_at(key)
- var c = _array[i]
- if c != null then
- c._key = key
- c._value = v
- else
- store(i, new HashMapNode[K, V](key, v))
- end
- end
+ redef fun is_empty do return self.map.is_empty
+ redef fun length do return self.map.length
+
+ redef fun iterator do return new MapValuesIterator[K, V](self.map.iterator)
+
+ redef fun clear do self.map.clear
redef fun remove(item)
do
- var i = 0
- while i < _capacity do
- var c = _array[i]
- if c != null and c._value == item then
- remove_index(i)
+ var map = self.map
+ var c = map._first_item
+ while c != null do
+ if c._value == item then
+ map.remove_node(c._key)
return
end
- i += 1
+ c = c._next_item
end
end
- redef fun remove_at(key) do remove_index(index_at(key))
-
- redef fun clear do raz
-
- fun couple_at(key: K): nullable HashMapNode[K, V] do return _array[index_at(key)]
-
- init
+ redef fun remove_all(item)
do
- _capacity = 0
- _length = 0
- enlarge(0)
+ var map = self.map
+ var c = map._first_item
+ while c != null do
+ if c._value == item then
+ map.remove_node(c._key)
+ end
+ c = c._next_item
+ end
end
end
-class HashMapNode[K, V]
-special HashNode[K]
+private class HashMapNode[K, V]
+ super HashNode[K]
redef type N: HashMapNode[K, V]
- var _value: V
-
- init(k: K, v: V)
- do
- super(k)
- _value = v
- end
+ var value: V
end
+# A `MapIterator` over a `HashMap`.
class HashMapIterator[K, V]
-special MapIterator[K, V]
+ super MapIterator[K, V]
redef fun is_ok do return _node != null
redef fun item
end
# The map to iterate on
- var _map: HashMap[K, V]
+ private var map: HashMap[K, V]
# The current node
- var _node: nullable HashMapNode[K, V]
+ private var node: nullable HashMapNode[K, V] = null
- init(map: HashMap[K, V])
+ init
do
_map = map
- _node = map.first_item
+ _node = _map._first_item
end
end
-class HashSet[E]
-special Set[E]
-special HashCollection[E, HashSetNode[E], E]
+# A `Set` implemented with a hash table.
+# Keys of such a map cannot be null and require a working `hash` method
+class HashSet[E: Object]
+ super Set[E]
+ super HashCollection[E]
+
+ redef type N: HashSetNode[E] is fixed
- redef fun is_empty do return _length == 0
+ redef fun length do return _the_length
+
+ redef fun is_empty do return _the_length == 0
redef fun first
do
- assert _length > 0
+ assert _the_length > 0
return _first_item._key
end
redef fun has(item)
do
- return _array[index_at(item)] != null
+ return node_at(item) != null
end
redef fun add(item)
do
var i = index_at(item)
- var c = _array[i]
+ var c = node_at_idx(i, item)
if c != null then
c._key = item
else
end
end
- redef fun remove(item) do remove_index(index_at(item))
+ redef fun remove(item) do remove_node(item)
redef fun clear do raz
init
do
_capacity = 0
- _length = 0
+ _the_length = 0
enlarge(0)
end
+
+ # Build a list filled with the items of `coll`.
+ init from(coll: Collection[E]) do
+ init
+ add_all(coll)
+ end
+
+ redef fun new_set do return new HashSet[E]
end
-class HashSetNode[E]
-special HashNode[E]
+private class HashSetNode[E: Object]
+ super HashNode[E]
redef type N: HashSetNode[E]
-
- init(e: E)
- do
- _key = e
- end
end
-class HashSetIterator[E]
-special Iterator[E]
+private class HashSetIterator[E: Object]
+ super Iterator[E]
redef fun is_ok do return _node != null
redef fun item
end
# The set to iterate on
- var _set: HashSet[E]
+ var set: HashSet[E]
# The position in the internal map storage
- var _node: nullable HashSetNode[E]
+ var node: nullable HashSetNode[E] = null
- init(set: HashSet[E])
+ init
do
- _set = set
- _node = set._first_item
+ _node = _set._first_item
end
end
nitlanguage / nit.git / blobdiff