strbuf new semantics, let's give it a try

[Pierre Habouzit <madcoder@debian.org>]

  Allright, here is a proposal for a new strbuf semantics like the one I
proposed before. Like said, with this proposal, strbuf's always have a
'\0' at the end of the buffer, not accounted in its length, so that any
C str* function can still be used.

  The second patch demonstrate that strbufs makes the code smaller,
simpler to read, while keeping the exact same efficiency (as may
mallocs, memcpys, and fread's in that case).


  I've tried to keep the amount of inlines low. Though, I wonder if
strbuf_add shouldn't be inlined (so that memcpys could be even more
inlined/optmized by gcc). And strbuf_addstr is inlined so that the
strlen call is optimized when the argument is an immediate string.
Meaning that calling strbuf_addstr(sb, "foo") is not sloppy at all.

  I don't really like the buffer growth scheme right now, I just stick
with the one that was used in git before. Though I really belive it's
inelegant as is, and should be simplified (strbuf_extend).

Cheers,
-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org