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- Created a Map interface.

Browse Source 
- Renamed HashMap Hashtable, because I wanted a version without ties to
  mx.* code. User-defined hashing functions may be specified.
- Created a subclass of Hashtable called HashMap which uses
  functions in mx.utils.ObjectUtil to hash non-Hashable complex keys.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4120 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Ray Greenwell
2006-05-16 19:02:24 +00:00
parent 470c46acf5
commit f778c1e518
3 changed files with 400 additions and 293 deletions
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src/as/com/threerings/util/HashMap.as
+9 -293
View File
@@ -1,305 +1,21 @@
package com.threerings.util { package com.threerings.util {
import flash.utils.Dictionary;
import mx.utils.ObjectUtil; import mx.utils.ObjectUtil;
/** /**
* An implementation of a HashMap in actionscript. * A Hashtable implementation that utilizes ObjectUtil.compare and
* ObjectUtil.toString for hashing keys that are non-simple and do
* not implement Hashable.
*/ */
public class HashMap public class HashMap extends Hashtable
{ {
public function HashMap (loadFactor :Number = 1.75) public function HashMap (loadFactor :Number = 1.75)
{ {
_loadFactor = loadFactor; super(loadFactor,
} function (o1 :Object, o2 :Object) :Boolean {
return (0 == ObjectUtil.compare(o1, o2));
public function clear () :void },
{ ObjectUtil.toString);
_simpleData = null;
_entries = null;
_size = 0;
}
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.
*/
public function get (key :Object) :*
{
if (ObjectUtil.isSimple(key)) {
return (_simpleData == null) ? undefined : _simpleData[key];
}
if (_entries == null) {
return undefined;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var e :Entry = (_entries[index] as Entry);
while (true) {
if (e == null) {
return null;
}
if (e.hash == hash && e.key.equals(hkey)) {
return e.value;
}
e = e.next;
}
}
public function isEmpty () :Boolean
{
return (_size == 0);
}
public function put (key :Object, value :Object) :*
{
if (ObjectUtil.isSimple(key)) {
if (_simpleData == null) {
_simpleData = new Dictionary();
}
var oldValue :* = _simpleData[key];
_simpleData[key] = value;
if (oldValue === undefined) {
_size++;
}
return oldValue;
}
// lazy-create the array holding other hashables
if (_entries == null) {
_entries = new Array();
_entries.length = DEFAULT_BUCKETS;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var firstEntry :Entry = (_entries[index] as Entry);
for (var e :Entry = firstEntry; e != null; e = e.next) {
if (e.hash == hash && e.key.equals(hkey)) {
var oldValue :* = e.value;
e.value = value;
return oldValue; // size did not change
}
}
_entries[index] = new Entry(hash, hkey, value, firstEntry);
_size++;
// check to see if we should grow the map
if (_size > _entries.length * _loadFactor) {
resize(2 * _entries.length);
}
// indicate that there was no value previously stored for the key
return undefined;
}
public function remove (key :Object) :*
{
if (ObjectUtil.isSimple(key)) {
if (_simpleData == null) {
return undefined;
}
var oldValue :* = _simpleData[key];
if (oldValue !== undefined) {
_size--;
}
delete _simpleData[key];
return oldValue;
}
if (_entries == null) {
return undefined;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var prev :Entry = (_entries[index] as Entry);
var e :Entry = prev;
while (e != null) {
var next :Entry = e.next;
if (e.hash == hash && e.key.equals(hkey)) {
if (prev == e) {
_entries[index] = next;
} else {
prev.next = next;
}
_size--;
// check to see if we should shrink the map
if ((_entries.length > DEFAULT_BUCKETS) &&
(_size < _entries.length * _loadFactor * .125)) {
resize(Math.max(DEFAULT_BUCKETS, _entries.length / 2));
}
return e.value;
}
prev = e;
e = next;
}
return undefined; // never found
}
public function size () :int
{
return _size;
}
public function keys () :Array
{
var keys :Array = new Array();
// get the simple keys first
if (_simpleData != null) {
for (var key :* in _simpleData) {
keys.push(key);
}
}
// get the more complex keys
if (_entries != null) {
for (var ii :int = _entries.length - 1; ii >= 0; ii--) {
for (var e :Entry = (_entries[ii] as Entry); e != null;
e = e.next) {
if (e.key is KeyWrapper) {
keys.push((e.key as KeyWrapper).key);
} else {
keys.push(e.key)
}
}
}
}
return keys;
}
public function values () :Array
{
var vals :Array = new Array();
// get the simple properties first
if (_simpleData != null) {
for each (var value :* in _simpleData) {
vals.push(value);
}
}
// get the more complex properties
if (_entries != null) {
for (var ii :int = _entries.length - 1; ii >= 0; ii--) {
for (var e :Entry = (_entries[ii] as Entry); e != null;
e = e.next) {
vals.push(e.value);
}
}
}
return vals;
}
protected function keyFor (key :Object) :Hashable
{
return (key is Hashable) ? (key as Hashable) : new KeyWrapper(key);
}
protected function indexFor (hash :int) :int
{
return Math.abs(hash % _entries.length);
}
protected function resize (newSize :int) :void
{
var oldEntries :Array = _entries;
_entries = new Array();
_entries.length = newSize;
// 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);
}
}
}
protected var _size :int = 0;
protected var _loadFactor :Number;
protected var _simpleData :Dictionary
protected var _entries :Array;
/** The default size for the bucketed hashmap. */
protected static const DEFAULT_BUCKETS :int = 16;
}
} // end: package
import com.threerings.util.Hashable;
class Entry
{
public var key :Hashable;
public var value :Object;
public var hash :int;
public var next :Entry;
public function Entry (hash :int, key :Hashable, value :Object, next :Entry)
{
this.hash = hash;
this.key = key;
this.value = value;
this.next = next;
} }
} }
import mx.utils.ObjectUtil;
class KeyWrapper
implements Hashable
{
public var key :Object;
public function KeyWrapper (key :Object)
{
this.key = key;
_hash = 0;
var uid :String = ObjectUtil.toString(key);
for (var ii :int = 0; ii < uid.length; ii++) {
_hash = (_hash << 1) ^ int(uid.charCodeAt(ii));
}
}
public function equals (other :Object) :Boolean
{
return (other is KeyWrapper) &&
(0 == ObjectUtil.compare(key, (other as KeyWrapper).key));
}
public function hashCode () :int
{
return _hash;
}
protected var _key :Object;
protected var _hash :int;
} }
src/as/com/threerings/util/Hashtable.as
+371
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@@ -0,0 +1,371 @@
package com.threerings.util {
import flash.errors.IllegalOperationError;
import flash.utils.Dictionary;
/**
* An implementation of a Hashtable in actionscript. Any object (and null) may
* be used as a key. Simple keys (Number, int, uint, Boolean, String) utilize
* a Dictionary internally for storage; keys that implement Hashable are
* stored efficiently, and any other key can also be used if the equalsFn
* and hashFn are specified to the constructor.
*/
public class Hashtable
implements Map
{
/**
* Construct a Hashtable
*
* @param loadFactor - A measure of how full the hashtable is allowed to
* get before it is automatically resized. The default
* value of 1.75 should be fine.
* @param equalsFn - (Optional) A function to use to compare object
* equality for keys that are neither simple nor
* implement Hashable. The signature should be
* "function (o1, o2) :Boolean".
* @param hashFn - (Optional) A function to use to generate a hash
* code for keys that are neither simple nor
* implement Hashable. The signature should be
* "function (obj) :*", where the return type is
* numeric or String. Two objects that are equals
* according to the specified equalsFn *must*
* generate equal values when passed to the hashFn.
*/
public function Hashtable (
loadFactor :Number = 1.75,
equalsFn :Function = null,
hashFn :Function = null)
{
if ((equalsFn != null) != (hashFn != null)) {
throw new ArgumentError("Both the equals and hash functions " +
"must be specified, or neither.");
}
_loadFactor = loadFactor;
_equalsFn = equalsFn;
_hashFn = hashFn;
}
public function clear () :void
{
_simpleData = null;
_entries = null;
_size = 0;
}
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.
*/
public function get (key :Object) :*
{
if (isSimple(key)) {
return (_simpleData == null) ? undefined : _simpleData[key];
}
if (_entries == null) {
return undefined;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var e :Entry = (_entries[index] as Entry);
while (true) {
if (e == null) {
return null;
}
if (e.hash == hash && e.key.equals(hkey)) {
return e.value;
}
e = e.next;
}
}
public function isEmpty () :Boolean
{
return (_size == 0);
}
public function put (key :Object, value :Object) :*
{
if (isSimple(key)) {
if (_simpleData == null) {
_simpleData = new Dictionary();
}
var oldValue :* = _simpleData[key];
_simpleData[key] = value;
if (oldValue === undefined) {
_size++;
}
return oldValue;
}
// lazy-create the array holding other hashables
if (_entries == null) {
_entries = new Array();
_entries.length = DEFAULT_BUCKETS;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var firstEntry :Entry = (_entries[index] as Entry);
for (var e :Entry = firstEntry; e != null; e = e.next) {
if (e.hash == hash && e.key.equals(hkey)) {
var oldValue :* = e.value;
e.value = value;
return oldValue; // size did not change
}
}
_entries[index] = new Entry(hash, hkey, value, firstEntry);
_size++;
// check to see if we should grow the map
if (_size > _entries.length * _loadFactor) {
resize(2 * _entries.length);
}
// indicate that there was no value previously stored for the key
return undefined;
}
public function remove (key :Object) :*
{
if (isSimple(key)) {
if (_simpleData == null) {
return undefined;
}
var oldValue :* = _simpleData[key];
if (oldValue !== undefined) {
_size--;
}
delete _simpleData[key];
return oldValue;
}
if (_entries == null) {
return undefined;
}
var hkey :Hashable = keyFor(key);
var hash :int = hkey.hashCode();
var index :int = indexFor(hash);
var prev :Entry = (_entries[index] as Entry);
var e :Entry = prev;
while (e != null) {
var next :Entry = e.next;
if (e.hash == hash && e.key.equals(hkey)) {
if (prev == e) {
_entries[index] = next;
} else {
prev.next = next;
}
_size--;
// check to see if we should shrink the map
if ((_entries.length > DEFAULT_BUCKETS) &&
(_size < _entries.length * _loadFactor * .125)) {
resize(Math.max(DEFAULT_BUCKETS, _entries.length / 2));
}
return e.value;
}
prev = e;
e = next;
}
return undefined; // never found
}
public function size () :int
{
return _size;
}
public function keys () :Array
{
var keys :Array = new Array();
// get the simple keys first
if (_simpleData != null) {
for (var key :* in _simpleData) {
keys.push(key);
}
}
// get the more complex keys
if (_entries != null) {
for (var ii :int = _entries.length - 1; ii >= 0; ii--) {
for (var e :Entry = (_entries[ii] as Entry); e != null;
e = e.next) {
if (e.key is KeyWrapper) {
keys.push((e.key as KeyWrapper).key);
} else {
keys.push(e.key)
}
}
}
}
return keys;
}
public function values () :Array
{
var vals :Array = new Array();
// get the simple properties first
if (_simpleData != null) {
for each (var value :* in _simpleData) {
vals.push(value);
}
}
// get the more complex properties
if (_entries != null) {
for (var ii :int = _entries.length - 1; ii >= 0; ii--) {
for (var e :Entry = (_entries[ii] as Entry); e != null;
e = e.next) {
vals.push(e.value);
}
}
}
return vals;
}
protected function keyFor (key :Object) :Hashable
{
if (key is Hashable) {
return (key as Hashable);
} else if (_hashFn == null) {
throw new IllegalOperationError("Illegal key specified " +
"for Hashtable created without hashing functions.");
} else {
return new KeyWrapper(key, _equalsFn, _hashFn);
}
}
protected function indexFor (hash :int) :int
{
return Math.abs(hash % _entries.length);
}
protected function isSimple (key :Object) :Boolean
{
return (key is String) || (key is Number) || (key is Boolean);
}
protected function resize (newSize :int) :void
{
var oldEntries :Array = _entries;
_entries = new Array();
_entries.length = newSize;
// 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);
}
}
}
/** The current number of key/value pairs stored in the map. */
protected var _size :int = 0;
/** The load factor. */
protected var _loadFactor :Number;
/** If non-null, contains simple key/value pairs. */
protected var _simpleData :Dictionary
/** If non-null, contains Hashable keys and their values. */
protected var _entries :Array;
/** The hashing function to use for non-Hashable complex keys. */
protected var _hashFn :Function;
/** The equality function to use for non-Hashable complex keys. */
protected var _equalsFn :Function;
/** The default size for the bucketed hashmap. */
protected static const DEFAULT_BUCKETS :int = 16;
}
} // end: package com.threerings.util
import com.threerings.util.Hashable;
class Entry
{
public var key :Hashable;
public var value :Object;
public var hash :int;
public var next :Entry;
public function Entry (hash :int, key :Hashable, value :Object, next :Entry)
{
this.hash = hash;
this.key = key;
this.value = value;
this.next = next;
}
}
class KeyWrapper
implements Hashable
{
public var key :Object;
public function KeyWrapper (
key :Object, equalsFn :Function, hashFn :Function)
{
this.key = key;
_equalsFn = equalsFn;
var hashValue :* = hashFn(key);
if (hashValue is String) {
var uid :String = (hashValue as String);
// examine at most 32 characters of the string
var inc :int = int(Math.max(1, Math.ceil(uid.length / 32)));
for (var ii :int = 0; ii < uid.length; ii += inc) {
_hash = (_hash << 1) ^ int(uid.charCodeAt(ii));
}
} else {
_hash = int(hashValue);
}
}
// documentation inherited from interface Hashable
public function equals (other :Object) :Boolean
{
return (other is KeyWrapper) &&
Boolean(_equalsFn(key, (other as KeyWrapper).key));
}
// documentation inherited from interface Hashable
public function hashCode () :int
{
return _hash;
}
protected var _key :Object;
protected var _hash :int;
protected var _equalsFn :Function;
}
src/as/com/threerings/util/Map.as
+20
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@@ -0,0 +1,20 @@
package com.threerings.util {
public interface Map
{
function clear () :void;
function containsKey (key :Object) :Boolean;
function get (key :Object) :*;
function isEmpty () :Boolean;
function put (key :Object, value :Object) :*;
function remove (key :Object) :*;
function size () :int;
}
}