From dbc540c7a5827529a3f58befc9e5b81a31ec8fab Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= Date: Thu, 29 Sep 2016 17:23:43 +0200 Subject: add QSORT Add the macro QSORT, a convenient wrapper for qsort(3) that infers the size of the array elements and supports the convention of initializing empty arrays with a NULL pointer, which we use in some places. Calling qsort(3) directly with a NULL pointer is undefined -- even with an element count of zero -- and allows the compiler to optimize away any following NULL checks. Using the macro avoids such surprises. Add a semantic patch as well to demonstrate the macro's usage and to automate the transformation of trivial cases. Signed-off-by: Rene Scharfe Signed-off-by: Junio C Hamano --- git-compat-util.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'git-compat-util.h') diff --git a/git-compat-util.h b/git-compat-util.h index 8aab0c3047..544db2ae65 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -977,6 +977,14 @@ void git_qsort(void *base, size_t nmemb, size_t size, #define qsort git_qsort #endif +#define QSORT(base, n, compar) sane_qsort((base), (n), sizeof(*(base)), compar) +static inline void sane_qsort(void *base, size_t nmemb, size_t size, + int(*compar)(const void *, const void *)) +{ + if (nmemb > 1) + qsort(base, nmemb, size, compar); +} + #ifndef REG_STARTEND #error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd" #endif -- cgit v1.2.3