commit 02f3a5b7e05122b18e9cda19f05914e8ebac3b0a
author Nick Kralevich <nnk@google.com> Thu Mar 28 14:04:15 2019 -0700
committer android-build-merger <android-build-merger@google.com> Thu Mar 28 14:04:15 2019 -0700
tree ca74385bbecd90dce0f8d1179b93eaa2549fe2f7
parent 9ad79795de539c321ee7daef364e45f15ccfcb55
parent 622f9b35cedfe56a7502f932aac60bea2d73da44

Merge "zip_writer.cc: update powerof2 and use it unconditionally" am: b86e248e8b am: 0fd9adf747
am: 707d0b6da5

Change-Id: Iac67cf33d1bd51920cd06741f9e39ab3ccabf3b8

zip_writer.cc

diff --git a/zip_writer.cc b/zip_writer.cc
index 981df3a..0df0fa5 100644
--- a/zip_writer.cc
+++ b/zip_writer.cc
@@ -30,9 +30,13 @@
 #include "entry_name_utils-inl.h"
 #include "zip_archive_common.h"
 
-#if !defined(powerof2)
-#define powerof2(x) ((((x)-1) & (x)) == 0)
-#endif
+#undef powerof2
+#define powerof2(x)                                               \
+  ({                                                              \
+    __typeof__(x) _x = (x);                                       \
+    __typeof__(x) _x2;                                            \
+    __builtin_add_overflow(_x, -1, &_x2) ? 1 : ((_x2 & _x) == 0); \
+  })
 
 /* Zip compression methods we support */
 enum {