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- Method comments.

Browse Source 
- Track the size of non-simple keys separately so that we really know when
  to resize the map.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4121 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Ray Greenwell
2006-05-16 20:41:04 +00:00
parent f778c1e518
commit 4aa8f5a5d5
2 changed files with 70 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/as/com/threerings/util/Hashtable.as
+43 -24
View File
@@ -46,22 +46,22 @@ public class Hashtable
_hashFn = hashFn;
}
// documentation inherited from interface Map
public function clear () :void
{
_simpleData = null;
_simpleSize = 0;
_entries = null;
_size = 0;
_entriesSize = 0;
}
// documentation inherited from interface Map
public function containsKey (key :Object) :Boolean
{
return (undefined !== get(key));
}
/**
* Get the value stored in the map for the specified key, or
* <code>undefined</code> if there is no value for that key.
*/
// documentation inherited from interface Map
public function get (key :Object) :*
{
if (isSimple(key)) {
@@ -87,11 +87,13 @@ public class Hashtable
}
}
// documentation inherited from interface Map
public function isEmpty () :Boolean
{
return (_size == 0);
return (size() == 0);
}
// documentation inherited from interface Map
public function put (key :Object, value :Object) :*
{
if (isSimple(key)) {
@@ -102,7 +104,7 @@ public class Hashtable
var oldValue :* = _simpleData[key];
_simpleData[key] = value;
if (oldValue === undefined) {
_size++;
_simpleSize++;
}
return oldValue;
}
@@ -126,15 +128,16 @@ public class Hashtable
}
_entries[index] = new Entry(hash, hkey, value, firstEntry);
_size++;
_entriesSize++;
// check to see if we should grow the map
if (_size > _entries.length * _loadFactor) {
if (_entriesSize > _entries.length * _loadFactor) {
resize(2 * _entries.length);
}
// indicate that there was no value previously stored for the key
return undefined;
}
// documentation inherited from interface Map
public function remove (key :Object) :*
{
if (isSimple(key)) {
@@ -144,7 +147,7 @@ public class Hashtable
var oldValue :* = _simpleData[key];
if (oldValue !== undefined) {
_size--;
_simpleSize--;
}
delete _simpleData[key];
return oldValue;
@@ -168,10 +171,10 @@ public class Hashtable
} else {
prev.next = next;
}
_size--;
_entriesSize--;
// check to see if we should shrink the map
if ((_entries.length > DEFAULT_BUCKETS) &&
(_size < _entries.length * _loadFactor * .125)) {
(_entriesSize < _entries.length * _loadFactor * .125)) {
resize(Math.max(DEFAULT_BUCKETS, _entries.length / 2));
}
return e.value;
@@ -183,9 +186,10 @@ public class Hashtable
return undefined; // never found
}
// documentation inherited from interface Map
public function size () :int
{
return _size;
return _simpleSize + _entriesSize;
}
public function keys () :Array
@@ -241,6 +245,9 @@ public class Hashtable
return vals;
}
/**
* Return a Hashable that represents the key.
*/
protected function keyFor (key :Object) :Hashable
{
if (key is Hashable) {
@@ -255,16 +262,27 @@ public class Hashtable
}
}
/**
* Return an index for the specified hashcode.
*/
protected function indexFor (hash :int) :int
{
return Math.abs(hash % _entries.length);
return Math.abs(hash) % _entries.length;
}
/**
* Return true if the specified key may be used to store values in a
* Dictionary object.
*/
protected function isSimple (key :Object) :Boolean
{
return (key is String) || (key is Number) || (key is Boolean);
}
/**
* Resize the entries with Hashable keys to optimize
* the memory/performance tradeoff.
*/
protected function resize (newSize :int) :void
{
var oldEntries :Array = _entries;
@@ -274,20 +292,21 @@ public class Hashtable
// place all the old entries in the new map
for (var ii :int = 0; ii < oldEntries.length; ii++) {
var e :Entry = (oldEntries[ii] as Entry);
if (e != null) {
do {
var next :Entry = e.next;
var index :int = indexFor(e.hash);
e.next = _entries[index];
_entries[index] = e;
e = next;
} while (e != null);
while (e != null) {
var next :Entry = e.next;
var index :int = indexFor(e.hash);
e.next = (_entries[index] as Entry);
_entries[index] = e;
e = next;
}
}
}
/** The current number of key/value pairs stored in the map. */
protected var _size :int = 0;
/** The current number of key/value pairs stored in the Dictionary. */
protected var _simpleSize :int = 0;
/** The current number of key/value pairs stored in the _entries. */
protected var _entriesSize :int = 0;
/** The load factor. */
protected var _loadFactor :Number;
src/as/com/threerings/util/Map.as
+27
View File
@@ -1,19 +1,46 @@
package com.threerings.util {
/**
* A Map is an object that maps keys to values.
*/
public interface Map
{
/**
* Clear this map, removing all stored elements.
*/
function clear () :void;
/**
* Returns true if the specified key exists in the map.
*/
function containsKey (key :Object) :Boolean;
/**
* Retrieve the value stored in this map for the specified key.
* Returns the value, or undefined if there is no mapping for the key.
*/
function get (key :Object) :*;
/**
* Returns true if this map contains no elements.
*/
function isEmpty () :Boolean;
/**
* Store a value in the map associated with the specified key.
* Returns the previous value stored for that key, or undefined.
*/
function put (key :Object, value :Object) :*;
/**
* Removes the mapping for the specified key.
* Returns the value that had been stored, or undefined.
*/
function remove (key :Object) :*;
/**
* Return the current size of the map.
*/
function size () :int;
}