delphij's Chaos


08 Feb 2009

memchr(3) rewrite

I have taken some time to rewrite memchr(3) to utilize similiar algorithm as my strlen(3) did. Two different formular, however, would have a roughly 1/3 difference.

Currently I have taken an approach that when memchr(3) is trying to match a pattern of 8-bit, then consider the string as 8-bit, which uses the first formular which is expected to have uniform O(n) time complexity by reducing unnecessary branches.

This approach, however, might be bogus since if you find 7-bit character within a 8-bit string, in that case, memchr(3) would perform poorly, if there are a lot of characters having their MSB as 1.

I’m thinking about how to deal this in a more reasonable way.

Archived: 1 Comment

d4m* | February 10, 2009 4:45 PM

btw, 现在的人wifi router都怎么设置的。。。

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