Strlen

New strlen(3) committed

Finally, I got my strlen(3) [1] committed against -HEAD. This is a long story, to put it short, I had proposed assembly version of some string operations at the point of 2005, but these was never committed due to a hard disk failure, and as Bruce pointed out, having the hand optimized assembly code use a different algorithm is not good in general.

Therefore, I have take some time on it and reimplemented the idea in C, resulting in a portable (say, you can use it on any 32-bit or 64-bit processors, and it can be easily extended to 128-bit) version.

So, is it important for *YOU*?

Generally speaking, it should not. Performance sensitive programs should, by all means, avoid C style string operations. Think a 5x better strlen(3) would boost performance of your application since it uses strlen(3) in critical path? Think again!

However, I found it valuable. There is difference in worldstone, where I saw some minor improvements. Micro-benchmark indicates that this version is at most 2x slower when the string is very short, but 5x faster for strings that is at least word-length long.

[1] Note: the version has been further revised to provide better comment and match style(9).