no commit message

source/com/hurlant/crypto/prng/Random.as

@@ -0,0 +1,119 @@
+/**
+ * Random
+ * 
+ * An ActionScript 3 implementation of a Random Number Generator
+ * Copyright (c) 2007 Henri Torgemane
+ * 
+ * Derived from:
+ * 		The jsbn library, Copyright (c) 2003-2005 Tom Wu
+ * 
+ * See LICENSE.txt for full license information.
+ */
+package com.hurlant.crypto.prng
+{
+	import flash.utils.ByteArray;
+	import com.hurlant.util.Memory;
+	import flash.system.System;
+	import flash.system.Capabilities;
+	import flash.accessibility.AccessibilityProperties;
+	import flash.display.SWFVersion;
+	import flash.display.Stage;
+	import flash.utils.getTimer;
+	import flash.text.Font;
+	
+	public class Random
+	{
+		private var state:IPRNG;
+		private var ready:Boolean = false;
+		private var pool:ByteArray;
+		private var psize:int;
+		private var pptr:int;
+		private var seeded:Boolean = false;
+		
+		public function Random(prng:Class = null) {
+			if (prng==null) prng = ARC4;
+			state = new prng as IPRNG;
+			psize= state.getPoolSize();
+			pool = new ByteArray;
+			pptr = 0;
+			while (pptr <psize) {
+				var t:uint = 65536*Math.random();
+				pool[pptr++] = t >>> 8;
+				pool[pptr++] = t&255;
+			}
+			pptr=0;
+			seed();
+		}
+		
+		public function seed(x:int = 0):void {
+			if (x==0) {
+				x = new Date().getTime();
+			}
+			pool[pptr++] ^= x & 255;
+			pool[pptr++] ^= (x>>8)&255;
+			pool[pptr++] ^= (x>>16)&255;
+			pool[pptr++] ^= (x>>24)&255;
+			pptr %= psize;
+			seeded = true;
+		}
+		
+		/**
+		 * Gather anything we have that isn't entirely predictable:
+		 *  - memory used
+		 *  - system capabilities
+		 *  - timing stuff
+		 *  - installed fonts
+		 */
+		public function autoSeed():void {
+			var b:ByteArray = new ByteArray;
+			b.writeUnsignedInt(System.totalMemory);
+			b.writeUTF(Capabilities.serverString);
+			b.writeUnsignedInt(getTimer());
+			b.writeUnsignedInt((new Date).getTime());
+			var a:Array = Font.enumerateFonts(true);
+			for each (var f:Font in a) {
+				b.writeUTF(f.fontName);
+				b.writeUTF(f.fontStyle);
+				b.writeUTF(f.fontType);
+			}
+			b.position=0;
+			while (b.bytesAvailable>=4) {
+				seed(b.readUnsignedInt());
+			}
+		}
+		
+		
+		public function nextBytes(buffer:ByteArray, length:int):void {
+			while (length--) {
+				buffer.writeByte(nextByte());
+			}
+		}
+		public function nextByte():int {
+			if (!ready) {
+				if (!seeded) {
+					autoSeed();
+				}
+				state.init(pool);
+				pool.length = 0;
+				pptr = 0;
+				ready = true;
+			}
+			return state.next();
+		}
+		public function dispose():void {
+			for (var i:uint=0;i<pool.length;i++) {
+				pool[i] = Math.random()*256;
+			}
+			pool.length=0;
+			pool = null;
+			state.dispose();
+			state = null;
+			psize = 0;
+			pptr = 0;
+			Memory.gc();
+		}
+		public function toString():String {
+			return "random-"+state.toString();
+		}
+	}
+}