On 2014-06-17 09.34, Jeremiah Mahler wrote: > Add a strnncmp() function which behaves like strncmp() except it takes > the length of both strings instead of just one. > > Then simplify tree-walk.c and unpack-trees.c using this new function. > Replace all occurrences of name_compare() with strnncmp(). Remove > name_compare(), which they both had identical copies of. > > Version 2 includes suggestions from Jonathan Neider : > > - Fix the logic which caused the new strnncmp() to behave differently > from the old version. Now it is identical to strncmp(). > > - Improve description of strnncmp(). > > Also, strnncmp() was switched from using memcmp() to strncmp() > internally to make it clear that this is meant for strings, not > general buffers. I don't think this is a good change, for 2 reasons: - It changes the semantics of existing code, which should be carefully reviewed, documented and may be put into a seperate commit. - Looking into the code for memcmp() and strncmp() in libc, I can see that memcmp() is written in 13 lines of assembler, (on a 386 system) with a fast repz cmpsb %es:(%edi),%ds:(%esi) working as the core engine. strncmp() uses 83 lines of assembler, because after each comparison the code needs to check of the '\0' in both strings. - I can't see a reason to replace efficient code with less efficient code, so moving the old function "as is" into a include file, and declare it "static inline" could be the first step.
Having code inline may open the door for the compiler to decide, "Oh, I know exactly what memcmp() does, so I through in a handfull of lines assembly code, instead of calling memcmp() from libc". And another thing: What does cache_name_compare(name, namelen, ce->name, len)) in name-hash.c do? Isn't that the same function ? I like strnncmp() better than cache_name_compare() or name_compare(), but I agree with Erik here that strnncmp() has the potential to become a name clash some day, so that git_strnncmp() may be better. Thanks for the effort, cleaning up is needed. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html