Changeset 31032 in webkit for trunk/JavaScriptCore

Timestamp:

Mar 13, 2008, 11:32:07 AM (17 years ago)

Author:

Beth Dakin

Message:

Reviewed by Geoff.

Adding new functionality to Vector. Currently all of the shrink and
resize functions on Vector only shrink the size of the Vector, not
the capacity. For the Vector to take up as little memory as
possible, though, it is necessary to be able to shrink the capacity
as well. So this patch adds that functionality.

I need this for a speed up I am working on, and Geoff wants to use
it in a speed up he is working on also, so he asked me to commit it
now.

• wtf/Vector.h: (WTF::VectorBufferBase::allocateBuffer): (WTF::::shrinkCapacity):

Location:

trunk/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• wtf/Vector.h (modified) (3 diffs)

trunk/JavaScriptCore/ChangeLog

@@ +1 @@
+2008-03-13  Beth Dakin  <[email protected]>
+
+        Reviewed by Geoff.
+
+        Adding new functionality to Vector. Currently all of the shrink and 
+        resize functions on Vector only shrink the size of the Vector, not 
+        the capacity. For the Vector to take up as little memory as 
+        possible, though, it is necessary to be able to shrink the capacity 
+        as well. So this patch adds that functionality. 
+
+        I need this for a speed up I am working on, and Geoff wants to use 
+        it in a speed up he is working on also, so he asked me to commit it 
+        now. 
+
+        * wtf/Vector.h:
+        (WTF::VectorBufferBase::allocateBuffer):
+        (WTF::::shrinkCapacity):
+
 2008-03-13  Simon Hausmann  <[email protected]>
 

trunk/JavaScriptCore/wtf/Vector.h

@@ -246 +246 @@
         void allocateBuffer(size_t newCapacity)
         {
-            ASSERT(newCapacity >= m_capacity);
             m_capacity = newCapacity;
             if (newCapacity > std::numeric_limits<size_t>::max() / sizeof(T))
@@ -456 +455 @@
         void resize(size_t size);
         void reserveCapacity(size_t newCapacity);
+        void shrinkCapacity(size_t newCapacity);
 
         void clear() { if (m_size) shrink(0); }
@@ -657 +657 @@
         m_buffer.allocateBuffer(newCapacity);
         TypeOperations::move(oldBuffer, oldEnd, begin());
+        m_buffer.deallocateBuffer(oldBuffer);
+    }
+    
+    template<typename T, size_t inlineCapacity>
+    void Vector<T, inlineCapacity>::shrinkCapacity(size_t newCapacity)
+    {
+        if (newCapacity >= capacity())
+            return;
+
+        T* oldBuffer = begin();
+        if (newCapacity > 0) {
+            T* oldEnd = end();
+            m_buffer.allocateBuffer(newCapacity);
+            TypeOperations::move(oldBuffer, oldEnd, begin());
+        }
+        m_size = min(m_size, newCapacity);
         m_buffer.deallocateBuffer(oldBuffer);
     }