Fast strcmp() wanted.

[Ed Falk]

In article <6003 at hplabsz.HPL.HP.COM> sartin at hplabs.hp.com (Rob Sartin) writes:
>In article <CEDMAN.90Sep29091115 at lynx.ps.uci.edu> cedman at lynx.ps.uci.edu (Carl Edman) writes:
>>string structure (or better class, long live C++ ! :-) which calculates
>>a 32-bit CRC for each string the first time and stores it somewhere.
>>Then only 1 (inlined) longword-compare will do the stringcomparisons
>>for you.
>
>Afraid not.  It'll give you an estimate of whether the strings match
>(correctly identifying those that don't).  You will need to then
>actually compare the strings if they are the same.  This method will
>also be unable to reproduce strcmp's behavior (strcmp returns a signed
>result indicated the <, =, > by being negative, zero, positive), it will
>only return a boolean (match, no match).

Also, these two strings

	"ab\0x"
	"ab\0y"

(where x and y are any garbage that happens to be in memory after the
terminating '\0') will be evaluated as unequal.

There are workarounds for both problems, of course, but I think there
won't be much of a performance improvement after you've done all it
requires to get it right.

		-ed falk, sun microsystems
		 sun!falk, falk at sun.com
		 card-carrying ACLU member.