Changeset 21029 in webkit for trunk/JavaScriptCore/kjs/array_instance.h

Timestamp:

Apr 23, 2007, 1:53:41 AM (18 years ago)

Author:

mjs

Message:

Reviewed by Darin.

• shrink ArrayInstance objects by 4 bytes ​http://bugs.webkit.org/show_bug.cgi?id=13386

I did this by storing the capacity before the beginning of the storage array. It turns out
it is rarely needed and is by definition 0 when the storage array is null.

• kjs/array_instance.h: (KJS::ArrayInstance::capacity): Get it from the secret stash
• kjs/array_object.cpp: (allocateStorage): New function to encapsulate allocating the storage with extra space ahead for the capacity. (reallocateStorage): ditto for realloc (ArrayInstance::ArrayInstance): (ArrayInstance::~ArrayInstance): (ArrayInstance::resizeStorage):

File:

• trunk/JavaScriptCore/kjs/array_instance.h (modified) (1 diff)

trunk/JavaScriptCore/kjs/array_instance.h

@@ -62 +62 @@
     void resizeStorage(unsigned);
 
+    // store capacity in extra space at the beginning of the storage array to save space
+    size_t capacity() { return storage ? reinterpret_cast<size_t>(storage[-1]) : 0; }
+
     unsigned length;
     unsigned storageLength;
-    unsigned capacity;
     JSValue **storage;
   };