Now that all of its callers are gone, remove llist_mergesort().
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the macros DECLARE_LIST_SORT and DEFINE_LIST_SORT for building
type-specific functions for sorting linked lists. The generated
function expects a typed comparison function.
The programmer provides full type information (no void pointers). This
allows the compiler to check whether the comparison function matches the
list type. It can also inline the "next" pointer accessor functions and
even the comparison function to get rid of the calling overhead.
Also provide a DECLARE_LIST_SORT_DEBUG macro that allows executing
custom code whenever the accessor functions are used. It's intended to
be used by test-mergesort, which counts these operations.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even though the function is generic enough, <anything>sort() inherits
connotations from the standard function qsort() that sorts an array.
Rename it to llist_mergesort() and describe the external interface in
its header file.
This incidentally avoids name clashes with mergesort() some platforms
declare in, and contaminate user namespace with, their <stdlib.h>.
Reported-by: Brian Gernhardt
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds a generic bottom-up mergesort implementation for singly linked
lists. It was inspired by Simon Tatham's webpage on the topic[1], but
not so much by his implementation -- for no good reason, really, just a
case of NIH.
[1] http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
