JavaScriptCore-903.tar.gz

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

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+/*
+ * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer. 
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution. 
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef PageAllocatorSymbian_h
+#define PageAllocatorSymbian_h
+
+#include <e32std.h>
+#include <wtf/Bitmap.h>
+
+namespace WTF { 
+
+size_t pageSize();
+
+// Convenience wrapper around an RChunk
+class SymbianChunk : public RChunk {
+   
+public:   
+    SymbianChunk(TInt handle) 
+    {
+        SetHandle(handle);
+        // prevent kernel calls by caching these
+        m_base = reinterpret_cast<char*>(Base()); 
+        m_maxSize = MaxSize();
+    }
+    
+    ~SymbianChunk() 
+    { 
+        Decommit(0, m_maxSize);
+        Close();
+    }
+     
+    // checks if address is in chunk's virtual address space
+    bool contains(const void* address) const 
+    {
+        return (static_cast<const char*>(address) >= m_base && static_cast<const char*>(address) < (m_base + m_maxSize));  
+    }
+    
+    char* m_base; 
+    size_t m_maxSize; 
+    
+};
+
+// Size of the large up-front reservation
+#if defined(__WINS__) 
+// Emulator has limited virtual address space
+const size_t largeReservationSize = 96*1024*1024;
+#else
+// HW has plenty of virtual addresses
+const size_t largeReservationSize = 256*1024*1024;
+#endif
+
+class PageAllocatorSymbian { 
+
+public:     
+    PageAllocatorSymbian();
+    ~PageAllocatorSymbian();
+    
+    void* reserve(size_t);
+    void release(void*, size_t);
+    bool commit(void*, size_t);
+    bool decommit(void*, size_t);
+    
+    bool contains(const void*) const; 
+    
+private:     
+    static const size_t m_pageSize = 4096; 
+    SymbianChunk* m_chunk; 
+    Bitmap<largeReservationSize / m_pageSize> m_map;
+    
+};
+
+} // namespace WTF
+
+#endif // PageAllocatorSymbian_h
+