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authorRené Scharfe <l.s.r@web.de>2017-01-28 21:38:21 (GMT)
committerJunio C Hamano <gitster@pobox.com>2017-01-30 22:07:45 (GMT)
commit568edcb95a8b86ffd0d267b124896df8ea81307c (patch)
treee0701b31ed1e8e7d0a628757d84cd7f236060654 /contrib/coccinelle
parent4e59582ff70d299f5a88449891e78d15b4b3fabe (diff)
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add SWAP macro
Add a macro for exchanging the values of variables. It allows users to avoid repetition and takes care of the temporary variable for them. It also makes sure that the storage sizes of its two parameters are the same. Its memcpy(1) calls are optimized away by current compilers. Also add a conservative semantic patch for transforming only swaps of variables of the same type. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'contrib/coccinelle')
-rw-r--r--contrib/coccinelle/swap.cocci28
1 files changed, 28 insertions, 0 deletions
diff --git a/contrib/coccinelle/swap.cocci b/contrib/coccinelle/swap.cocci
new file mode 100644
index 0000000..a0934d1
--- /dev/null
+++ b/contrib/coccinelle/swap.cocci
@@ -0,0 +1,28 @@
+@ swap_with_declaration @
+type T;
+identifier tmp;
+T a, b;
+@@
+- T tmp = a;
++ T tmp;
++ tmp = a;
+ a = b;
+ b = tmp;
+
+@ swap @
+type T;
+T tmp, a, b;
+@@
+- tmp = a;
+- a = b;
+- b = tmp;
++ SWAP(a, b);
+
+@ extends swap @
+identifier unused;
+@@
+ {
+ ...
+- T unused;
+ ... when != unused
+ }