JavaScriptCore-721.26.tar.gz

[apple/javascriptcore.git] / wtf / StdLibExtras.h

diff --git a/wtf/StdLibExtras.h b/wtf/StdLibExtras.h
index 14227abb30b2e0c1d198f0a5da0ceafecb44757b..96a929c7ed03d065b88b72551334d821605d1009 100644 (file)
--- a/wtf/StdLibExtras.h
+++ b/wtf/StdLibExtras.h
@@ -26,12 +26,12 @@
 #ifndef WTF_StdLibExtras_h
 #define WTF_StdLibExtras_h
 
-#include <wtf/Platform.h>
 #include <wtf/Assertions.h>
 
 // Use these to declare and define a static local variable (static T;) so that
 //  it is leaked so that its destructors are not called at exit. Using this
 //  macro also allows workarounds a compiler bug present in Apple's version of GCC 4.0.1.
+#ifndef DEFINE_STATIC_LOCAL
 #if COMPILER(GCC) && defined(__APPLE_CC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 1
 #define DEFINE_STATIC_LOCAL(type, name, arguments) \
     static type* name##Ptr = new type arguments; \
@@ -40,6 +40,16 @@
 #define DEFINE_STATIC_LOCAL(type, name, arguments) \
     static type& name = *new type arguments
 #endif
+#endif
+
+// OBJECT_OFFSETOF: Like the C++ offsetof macro, but you can use it with classes.
+// The magic number 0x4000 is insignificant. We use it to avoid using NULL, since
+// NULL can cause compiler problems, especially in cases of multiple inheritance.
+#define OBJECT_OFFSETOF(class, field) (reinterpret_cast<ptrdiff_t>(&(reinterpret_cast<class*>(0x4000)->field)) - 0x4000)
+
+// STRINGIZE: Can convert any value to quoted string, even expandable macros
+#define STRINGIZE(exp) #exp
+#define STRINGIZE_VALUE_OF(exp) STRINGIZE(exp)
 
 namespace WTF {
 
@@ -47,17 +57,25 @@ namespace WTF {
      * C++'s idea of a reinterpret_cast lacks sufficient cojones.
      */
     template<typename TO, typename FROM>
-    TO bitwise_cast(FROM in)
+    TO bitwise_cast(FROM from)
     {
-        COMPILE_ASSERT(sizeof(TO) == sizeof(FROM), WTF_wtf_reinterpret_cast_sizeof_types_is_equal);
+        COMPILE_ASSERT(sizeof(TO) == sizeof(FROM), WTF_bitwise_cast_sizeof_casted_types_is_equal);
         union {
             FROM from;
             TO to;
         } u;
-        u.from = in;
+        u.from = from;
         return u.to;
     }
 
+    // Returns a count of the number of bits set in 'bits'.
+    inline size_t bitCount(unsigned bits)
+    {
+        bits = bits - ((bits >> 1) & 0x55555555);
+        bits = (bits & 0x33333333) + ((bits >> 2) & 0x33333333);
+        return (((bits + (bits >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
+    }
+
 } // namespace WTF
 
 #endif