Reviewers: Mads Ager, danno,
Message:
A small & independent patch, just to keep the upcoming ToBoolean patch
manageable.
Description:
Introduce a poor man's version of STL's bitset.
Used in a separate upcoming patch...
Please review this at http://codereview.chromium.org/7472029/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/utils.h
Index: src/utils.h
===================================================================
--- src/utils.h (revision 8701)
+++ src/utils.h (working copy)
@@ -30,6 +30,7 @@
#include <stdlib.h>
#include <string.h>
+#include <climits>
#include "globals.h"
#include "checks.h"
@@ -885,6 +886,30 @@
DISALLOW_IMPLICIT_CONSTRUCTORS(SimpleStringBuilder);
};
+
+// A poor man's version of STL's bitset: A bit set of enums E (without
explicit
+// values), fitting into an integral type T.
+template <class E, class T = int>
+class EnumSet {
+ public:
+ explicit EnumSet(T bits = 0) : bits_(bits) {}
+ bool IsEmpty() const { return bits_ == 0; }
+ bool Contains(E element) const { return (bits_ & Mask(element)) != 0; }
+ void Add(E element) { bits_ |= Mask(element); }
+ void Remove(E element) { bits_ &= ~Mask(element); }
+ T ToIntegral() const { return bits_; }
+
+ private:
+ T Mask(E element) const {
+ // The strange typing in ASSERT is necessary to avoid stupid warnings,
see:
+ // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43680
+ ASSERT(element < static_cast<int>(sizeof(T) * CHAR_BIT));
+ return 1 << element;
+ }
+
+ T bits_;
+};
+
} } // namespace v8::internal
#endif // V8_UTILS_H_
--
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