X-Git-Url: http://nitlanguage.org

diff --git a/lib/standard/collection/hash_collection.nit b/lib/standard/collection/hash_collection.nit
index 13d5a7a..7c90189 100644
--- a/lib/standard/collection/hash_collection.nit
+++ b/lib/standard/collection/hash_collection.nit
@@ -11,27 +11,26 @@
 # another product.
 
 # Introduce Hashmap and Hashset.
-package hash_collection
+module hash_collection
 
 import array
-import hash
 
 # A HashCollection is an array of HashNode[K] indexed by the K hash value
-private class HashCollection[K: Object, N: HashNode[K], E]
-	super Collection[E]
+private abstract class HashCollection[K: Object, N: HashNode[Object]]
 	super 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
 
-	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)
+	private var array: nullable NativeArray[nullable N] = null # Used to store items
+	private var capacity: Int = 0 # Size of _array
+	private var the_length: Int = 0 # Number of items in the map
+
+	private var first_item: nullable N = null # First added item (used to visit items in nice order)
+	private var last_item: nullable N = null # Last added item (same)
 
 	# The last key accessed (used for cache)
-	var _last_accessed_key: nullable K = null
+	private var last_accessed_key: nullable K = null
 
 	# The last node accessed (used for cache)
-	var _last_accessed_node: nullable N = null
+	private var last_accessed_node: nullable N = null
 
 	# Return the index of the key k
 	fun index_at(k: K): Int
@@ -44,8 +43,8 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 	# Return the node assosiated 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 _last_accessed_key then return _last_accessed_node
+		# 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
@@ -59,7 +58,7 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 		var c = _array[i]
 		while c != null do
 			var ck = c._key
-			if ck is k or ck == k then # prefilter with `is' because the compiler is not smart enought yet
+			if ck.is_same_instance(k) or ck == k then # FIXME prefilter because the compiler is not smart enought yet
 				break
 			end
 			c = c._next_in_bucklet
@@ -90,11 +89,15 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 		_last_accessed_node = node
 
 		# Enlarge if needed
-		var l = _length
-		_length = l + 1
-		l = (l + 5) * 3 / 2
+		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
 
@@ -120,7 +123,7 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 		end
 
 		# Remove the item in the array
-		_length -= 1
+		_the_length -= 1
 		prev = node._prev_in_bucklet
 		next = node._next_in_bucklet
 		if prev != null then
@@ -135,6 +138,7 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 		_last_accessed_key = null
 	end
 
+	# Clear the whole structure
 	fun raz
 	do
 		var i = _capacity - 1
@@ -142,17 +146,18 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 			_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
-		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
@@ -177,6 +182,7 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 			# 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
@@ -184,69 +190,108 @@ private class HashCollection[K: Object, N: HashNode[K], E]
 	end
 end
 
-private class HashNode[K: Object]
-	var _key: K
+private abstract class HashNode[K: Object]
+	private var key: K
 	type N: HashNode[K]
-	readable writable var _next_item: nullable N = null
-	readable writable var _prev_item: nullable N = null
-	var _prev_in_bucklet: nullable N = null
-	var _next_in_bucklet: nullable N = null
+	private var next_item: nullable N = null
+	private var prev_item: nullable N = null
+	private var prev_in_bucklet: nullable N = null
+	private var next_in_bucklet: nullable N = null
 	init(k: K)
 	do
 		_key = k
 	end
 end
 
+# A map implemented with a hash table.
+# Keys of such a map cannot be null and require a working `hash` method
 class HashMap[K: Object, V]
 	super Map[K, V]
-	super HashCollection[K, HashMapNode[K, V], V]
+	super HashCollection[K, HashMapNode[K, V]]
 
 	redef fun [](key)
 	do
 		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 node_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: Object, 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: Object, V]
+	super RemovableCollection[V]
+	# The original map
+	var map: HashMap[K, V]
 
 	redef fun count(item)
 	do
 		var nb = 0
-		var c = _first_item
+		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 c = _first_item
+		var c = self.map._first_item
 		while c != null do
 			if c._value == item then return true
 			c = c._next_item
@@ -256,7 +301,7 @@ class HashMap[K: Object, V]
 
 	redef fun has_only(item)
 	do
-		var c = _first_item
+		var c = self.map._first_item
 		while c != null do
 			if c._value != item then return false
 			c = c._next_item
@@ -264,46 +309,43 @@ class HashMap[K: Object, V]
 		return true
 	end
 
-	redef fun []=(key, v)
-	do
-		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 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 c = _first_item
+		var map = self.map
+		var c = map._first_item
 		while c != null do
 			if c._value == item then
-				remove_node(c._key)
+				map.remove_node(c._key)
 				return
 			end
 			c = c._next_item
 		end
 	end
 
-	redef fun remove_at(key) do remove_node(key)
-
-	redef fun clear do raz
-
-	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: Object, V]
+private class HashMapNode[K: Object, V]
 	super HashNode[K]
 	redef type N: HashMapNode[K, V]
-	var _value: V
+	private var value: V
 
 	init(k: K, v: V)
 	do
@@ -341,27 +383,31 @@ class HashMapIterator[K: Object, V]
 	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]
 
 	init(map: HashMap[K, V])
 	do
 		_map = map
-		_node = map.first_item
+		_node = map._first_item
 	end
 end
 
+# 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, HashSetNode[E], E]
+	super HashCollection[E, HashSetNode[E]]
+
+	redef fun length do return _the_length
 
-	redef fun is_empty do return _length == 0
+	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
 
@@ -390,12 +436,20 @@ class HashSet[E: Object]
 	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: Object]
+private class HashSetNode[E: Object]
 	super HashNode[E]
 	redef type N: HashSetNode[E]
 
@@ -405,7 +459,7 @@ class HashSetNode[E: Object]
 	end
 end
 
-class HashSetIterator[E: Object]
+private class HashSetIterator[E: Object]
 	super Iterator[E]
 	redef fun is_ok do return _node != null
 
@@ -422,10 +476,10 @@ class HashSetIterator[E: Object]
 	end
 
 	# The set to iterate on
-	var _set: HashSet[E]
+	private var set: HashSet[E]
 
 	# The position in the internal map storage
-	var _node: nullable HashSetNode[E]
+	private var node: nullable HashSetNode[E]
 
 	init(set: HashSet[E])
 	do