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| author | René Scharfe <l.s.r@web.de> | 2016-09-29 17:23:43 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2016-09-29 15:42:18 -0700 |
| commit | dbc540c7a5827529a3f58befc9e5b81a31ec8fab (patch) | |
| tree | cd2c485c62e68411e418616c6ca26923e24b3e1b | |
| parent | 21f862b498925194f8f1ebe8203b7a7df756555b (diff) | |
| download | git-dbc540c7a5827529a3f58befc9e5b81a31ec8fab.tar.gz git-dbc540c7a5827529a3f58befc9e5b81a31ec8fab.tar.xz | |
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 <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | contrib/coccinelle/qsort.cocci | 19 | ||||
| -rw-r--r-- | git-compat-util.h | 8 |
2 files changed, 27 insertions, 0 deletions
diff --git a/contrib/coccinelle/qsort.cocci b/contrib/coccinelle/qsort.cocci new file mode 100644 index 000000000..a094e7c5e --- /dev/null +++ b/contrib/coccinelle/qsort.cocci @@ -0,0 +1,19 @@ +@@ +expression base, nmemb, compar; +@@ +- qsort(base, nmemb, sizeof(*base), compar); ++ QSORT(base, nmemb, compar); + +@@ +expression base, nmemb, compar; +@@ +- qsort(base, nmemb, sizeof(base[0]), compar); ++ QSORT(base, nmemb, compar); + +@@ +type T; +T *base; +expression nmemb, compar; +@@ +- qsort(base, nmemb, sizeof(T), compar); ++ QSORT(base, nmemb, compar); diff --git a/git-compat-util.h b/git-compat-util.h index 8aab0c304..544db2ae6 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 |