compat: add qsort_s()

The function qsort_s() was introduced with C11 Annex K; it provides the
ability to pass a context pointer to the comparison function, supports
the convention of using a NULL pointer for an empty array and performs a
few safety checks.

Add an implementation based on compat/qsort.c for platforms that lack a
native standards-compliant qsort_s() (i.e. basically everyone).  It
doesn't perform the full range of possible checks: It uses size_t
instead of rsize_t and doesn't check nmemb and size against RSIZE_MAX
because we probably don't have the restricted size type defined.  For
the same reason it returns int instead of errno_t.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/git-compat-util.h b/git-compat-util.h
index 87237b092b..f706744e6a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -988,6 +988,12 @@ static inline void sane_qsort(void *base, size_t nmemb, size_t size,
 		qsort(base, nmemb, size, compar);
 }
 
+#ifndef HAVE_ISO_QSORT_S
+int git_qsort_s(void *base, size_t nmemb, size_t size,
+		int (*compar)(const void *, const void *, void *), void *ctx);
+#define qsort_s git_qsort_s
+#endif
+
 #ifndef REG_STARTEND
 #error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
 #endif