Seems reasonable. Good idea to try join(). Why the question about
Number.toString()?
-Alex
On 10/17/13 6:17 PM, "Justin Mclean" <jus...@classsoftware.com> wrote:
>Hi,
>
>This is about 2/3rds to twice as fast by my measurements (in Scout). Any
>one confirm?
>
>Changes include.
>- Use a string to store hex digits and charAt rather than array of ascii
>- Use Array.join rather than String.fromCharCode
>- Remove Math.floor as they are not required
>- Set up static array and reuse that rather than creating new array each
>time
>
>The timeString could probably be improved to remove the string
>manipulation but put the digits directly into the correct place into the
>array to save another 5% or so.
>
>BYW any see where Number.toString is being called in there?
>
>Any feedback?
>
>Thanks,
>Justin
>
>diff --git a/frameworks/projects/framework/src/mx/utils/UIDUtil.as
>b/frameworks/projects/framework/src/mx/utils/UIDUtil.as
>index 4993563..576b598 100644
>--- a/frameworks/projects/framework/src/mx/utils/UIDUtil.as
>+++ b/frameworks/projects/framework/src/mx/utils/UIDUtil.as
>@@ -61,10 +61,16 @@ public class UIDUtil
>
> /**
> * @private
>- * Char codes for 0123456789ABCDEF
> */
>- private static const ALPHA_CHAR_CODES:Array = [48, 49, 50, 51, 52,
>53, 54,
>- 55, 56, 57, 65, 66, 67, 68, 69, 70];
>+ private static const CHAR_CODES:String = "0123456789ABCDEF";
>+
>+ private static var EMPTYUID:Array = [
>+ '0','0','0','0','0','0','0','0',
>+ '-','0','0','0','0',
>+ '-','0','0','0','0',
>+ '-','0','0','0','0',
>+ '0','0','0','0','0','0','0','0','0','0','0','0'
>+ ];
>
>
>//------------------------------------------------------------------------
>--
> //
>@@ -106,53 +112,53 @@ public class UIDUtil
> * @playerversion AIR 1.1
> * @productversion Flex 3
> */
>- public static function createUID():String
>- {
>- var uid:Array = new Array(36);
>- var index:int = 0;
>-
>- var i:int;
>- var j:int;
>-
>- for (i = 0; i < 8; i++)
>- {
>- uid[index++] = ALPHA_CHAR_CODES[Math.floor(Math.random() *
>16)];
>- }
>-
>- for (i = 0; i < 3; i++)
>- {
>- uid[index++] = 45; // charCode for "-"
>-
>- for (j = 0; j < 4; j++)
>- {
>- uid[index++] = ALPHA_CHAR_CODES[Math.floor(Math.random()
>* 16)];
>- }
>- }
>-
>- uid[index++] = 45; // charCode for "-"
>-
>- var time:Number = new Date().getTime();
>- // Note: time is the number of milliseconds since 1970,
>- // which is currently more than one trillion.
>- // We use the low 8 hex digits of this number in the UID.
>- // Just in case the system clock has been reset to
>- // Jan 1-4, 1970 (in which case this number could have only
>- // 1-7 hex digits), we pad on the left with 7 zeros
>- // before taking the low digits.
>- var timeString:String = ("0000000" +
>time.toString(16).toUpperCase()).substr(-8);
>-
>- for (i = 0; i < 8; i++)
>- {
>- uid[index++] = timeString.charCodeAt(i);
>- }
>-
>- for (i = 0; i < 4; i++)
>- {
>- uid[index++] = ALPHA_CHAR_CODES[Math.floor(Math.random() *
>16)];
>- }
>-
>- return String.fromCharCode.apply(null, uid);
>- }
>+ public static function createUID():String
>+ {
>+ var uid:Array = EMPTYUID;
>+ var index:int = 0;
>+
>+ var i:int;
>+ var j:int;
>+
>+ for (i = 0; i < 8; i++)
>+ {
>+ uid[index++] = CHAR_CODES.charAt(Math.random() * 16);
>+ }
>+
>+ for (i = 0; i < 3; i++)
>+ {
>+ index++; // skip "-"
>+
>+ for (j = 0; j < 4; j++)
>+ {
>+ uid[index++] = CHAR_CODES.charAt(Math.random()
>* 16);
>+ }
>+ }
>+
>+ index++; // skip "-"
>+
>+ var time:Number = new Date().getTime();
>+ // Note: time is the number of milliseconds since 1970,
>+ // which is currently more than one trillion.
>+ // We use the low 8 hex digits of this number in the UID.
>+ // Just in case the system clock has been reset to
>+ // Jan 1-4, 1970 (in which case this number could have only
>+ // 1-7 hex digits), we pad on the left with 7 zeros
>+ // before taking the low digits.
>+ var timeString:String = ("0000000" +
>time.toString(16).toUpperCase()).substr(-8);
>+
>+ for (i = 0; i < 8; i++)
>+ {
>+ uid[index++] = timeString.charAt(i);
>+ }
>+
>+ for (i = 0; i < 4; i++)
>+ {
>+ uid[index++] = CHAR_CODES.charAt(Math.random() * 16);
>+ }
>+
>+ return uid.join("");
>+ }
>
>
