(svn_txdelta_next_window): Improve our windowing algorithm performance by padding the source view with half a target view's worth of data on each side.  This change doesn't appreciably slow down delta generation in my tests, even though we're passing twice as much source data to the vdelta engine. (svn_txdelta_stream_t, svn_txdelta): Add new fields sbuf and sbuf_len to stash source data in between calls to svn_txdelta_next_window.
(svn_txdelta_next_window): Improve our windowing algorithm performance
by padding the source view with half a target view's worth of data on
each side.  This change doesn't appreciably slow down delta generation
in my tests, even though we're passing twice as much source data to
the vdelta engine.
(svn_txdelta_stream_t, svn_txdelta): Add new fields sbuf and sbuf_len
to stash source data in between calls to svn_txdelta_next_window.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion