Bitwise operations and md4digest function
Hi all, i've been porting this md4digest function from Macromedia Director to Runtime Revolution: http://www.isometrik.org/md5/lingo_md4_fastest.txt Some differences i had noticed while handling numbers are: Numeric Arrays in Director starts from 0 (zero) Numeric Arrays in Runrev starts from 1 (one) In Director: put (24 + 64) / 512 * 16 + 16 results in 16 In RunRev put (24 + 64) / 512 * 16 + 16 results in 18.75 To get the same result in RunRev i had to rewrite the operation like this: put round((24 + 64)/( 512 * 16)) + 16 More problematic is that bitwise operations do not return the same results in Director and Runrev... for example in Director put bitAnd(-271733879,-1732584194) returns -2004318072 in RunRev put -271733879 bitand -1732584194 returns 0 (zero) How could i get the same the result in RunRev as this bitAnd operation made in Director? Thanks in advance. alejandro Visit my site: http://www.geocities.com/capellan2000/ __ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Bitwise operations and md4digest function
Alejandro Tejada wrote: Hi all, i've been porting this md4digest function from Macromedia Director to Runtime Revolution: http://www.isometrik.org/md5/lingo_md4_fastest.txt Some differences i had noticed while handling numbers are: Numeric Arrays in Director starts from 0 (zero) Numeric Arrays in Runrev starts from 1 (one) In Director: put (24 + 64) / 512 * 16 + 16 results in 16 In RunRev put (24 + 64) / 512 * 16 + 16 results in 18.75 To get the same result in RunRev i had to rewrite the operation like this: put round((24 + 64)/( 512 * 16)) + 16 Right. Director is using all integer arithmetic, so 88/512 gives 0, multiply by 16 is still 0, and add 16 is 16. Rev uses dynamic typing, so 88/512 gives some small fraction, multiply by 16 gives 2.75m and add 16 gives you the 18.75 More problematic is that bitwise operations do not return the same results in Director and Runrev... for example in Director put bitAnd(-271733879,-1732584194) returns -2004318072 in RunRev put -271733879 bitand -1732584194 returns 0 (zero) How could i get the same the result in RunRev as this bitAnd operation made in Director? The problem here is that Rev's bitand operator is defined to work for positive numbers only. From the docs: Parameters: The number1 and number2 are numbers, or expressions that evaluate to numbers, between zero and 4,294,967,295 (2^32 - 1). Because your values are less than 0, it gives wrong answer - they appear to be 0 because the top bit is set - the original code probably had them defined as unsigned integers (which Director probably doesn't support). You can get the right result with function mybitand p1, p2 if p1 0 then add 2^32 to p1 if p2 0 then add 2^32 to p2 return p1 bitand p2 end mybitand but you may be able to avoid the need for this depending on how the input values here are built-up. If they are the results of other bit operators, then in Rev it ought to be possible to keep everything as positive values, and then just use the standard bitand operator. If the code isn't too long, I'd be happy to take a look -- Alex Tweedly http://www.tweedly.net -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.4/176 - Release Date: 20/11/2005 ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Bitwise operations and md4digest function
Alejandro, if you are using Rev 2.5.x or lower, Rev can't do any math with numbers larger than 0xFFF (7 F's) Rev 2.6 and greater can (I don't know the limits as I only needed 0x (8 F's)) I'm having similiar problems with bit math and am looking at rolling my own.. _ Is your PC infected? Get a FREE online computer virus scan from McAfee® Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Bitwise operations and md4digest function
Sean Shao wrote: Alejandro, if you are using Rev 2.5.x or lower, Rev can't do any math with numbers larger than 0xFFF (7 F's) Rev 2.6 and greater can (I don't know the limits as I only needed 0x (8 F's)) I'm having similiar problems with bit math and am looking at rolling my own.. It can do some arithmetic above 0xFFF (7 Fs) For instance, in 2.5 and 2.2.1 I can do put format(%x, 2^31 + 5) 8005 (i.e. it has successfully taken an addition into the range above INT32) or even put format(%08x %u, 2^32 / 2^30, 2^32 / 2^30) --- 0004 4 I'd be interested to hear what things you had trouble with ... -- Alex Tweedly http://www.tweedly.net -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.4/176 - Release Date: 20/11/2005 ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Bitwise operations and md4digest function
Alex Tweedly wrote: It can do some arithmetic above 0xFFF (7 Fs) For instance, in 2.5 and 2.2.1 I can do put format(%x, 2^31 + 5) 8005 (i.e. it has successfully taken an addition into the range above INT32) or even put format(%08x %u, 2^32 / 2^30, 2^32 / 2^30) --- 0004 4 I'd be interested to hear what things you had trouble with ... Not to worry - I found some that fail, so I'm now happy to not use it. Haven't figured out the pattern yet - but have found enough to convince me it's not usable without great care - and possible not even *with* care. -- Alex Tweedly http://www.tweedly.net -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.4/176 - Release Date: 20/11/2005 ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
