Comments on: Calculating Elf-32 in C# and .NET http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net?utm_source=rss&utm_medium=rss&utm_campaign=calculating-elf-32-in-c-and-net A .NET developer in Redmond Fri, 23 Jul 2010 04:45:33 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Damien Guard http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-9753 Damien Guard Mon, 20 Oct 2008 17:09:13 +0000 http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-9753 All hash functions can return the same hash code for a different input sets. If they didn't they would instead be very effective compression algorithms. [)amien All hash functions can return the same hash code for a different input sets. If they didn’t they would instead be very effective compression algorithms.

[)amien

]]> By: QuangCanh http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-9748 QuangCanh Mon, 20 Oct 2008 09:33:15 +0000 http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-9748 hi Damien, Can this algorithm duplicate? private static uint GetELF(string str) { int i; uint x; uint result = 10; byte[] b = ASCIIEncoding.Unicode.GetBytes(str); for (i = 0; i < b.Length; i++) { unchecked { result = (result <> 24); result &= ~x; } } return result; } hash code of "mj9d" and "oj9f" is the same. regards, Canh hi Damien,

Can this algorithm duplicate?

private static uint GetELF(string str)
{
int i;
uint x;
uint result = 10;
byte[] b = ASCIIEncoding.Unicode.GetBytes(str);
for (i = 0; i < b.Length; i++)
{
unchecked
{
result = (result <> 24);
result &= ~x;
}
}
return result;
}

hash code of “mj9d” and “oj9f” is the same.

regards,
Canh

]]> By: Damien Guard http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-5837 Damien Guard Wed, 09 Jan 2008 00:30:27 +0000 http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-5837 Yeah you are probably right. I will revise it. [)amien Yeah you are probably right. I will revise it.

[)amien

]]> By: bitRAKE http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-5400 bitRAKE Tue, 04 Dec 2007 08:04:06 +0000 http://damieng.com/blog/2007/11/24/calculating-elf-32-in-c-and-net#comment-5400 if (work != 0) hash ^= (work >> 24); Makes me wonder if it costs more to avoid this than to just do it anyway when work==0? As it has no effect on hash when work==0, and I'm almost certain it'll always be slower to branch. if (work != 0) hash ^= (work >> 24);

Makes me wonder if it costs more to avoid this than to just do it anyway when work==0? As it has no effect on hash when work==0, and I’m almost certain it’ll always be slower to branch.

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