src/3rdparty/webkit/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp
changeset 22 79de32ba3296
child 30 5dc02b23752f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/3rdparty/webkit/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp	Fri May 14 16:40:13 2010 +0300
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include "config.h"
+
+#if PLATFORM(SYMBIAN)
+
+#include "BlockAllocatorSymbian.h"
+
+
+namespace WTF {
+
+/** Efficiently allocates blocks of size blockSize with blockSize alignment. 
+ * Primarly designed for JSC Collector's needs. 
+ * Not thread-safe.    
+ */
+AlignedBlockAllocator::AlignedBlockAllocator(TUint32 reservationSize, TUint32 blockSize )
+    : m_reservation(reservationSize), 
+      m_blockSize(blockSize)
+{
+
+     // Get system's page size value.
+     SYMBIAN_PAGESIZE(m_pageSize); 
+     
+     // We only accept multiples of system page size for both initial reservation and the alignment/block size
+     m_reservation = SYMBIAN_ROUNDUPTOMULTIPLE(m_reservation, m_pageSize);
+     __ASSERT_ALWAYS(SYMBIAN_ROUNDUPTOMULTIPLE(m_blockSize, m_pageSize), User::Panic(_L("AlignedBlockAllocator1"), KErrArgument));
+     
+     // Calculate max. bit flags we need to carve a reservationSize range into blockSize-sized blocks
+     m_map.numBits = m_reservation / m_blockSize;   
+     const TUint32 bitsPerWord = 8*sizeof(TUint32); 
+     const TUint32 numWords = (m_map.numBits + bitsPerWord -1) / bitsPerWord; 
+   
+     m_map.bits = new TUint32[numWords];
+     __ASSERT_ALWAYS(m_map.bits, User::Panic(_L("AlignedBlockAllocator2"), KErrNoMemory));
+     m_map.clearAll();
+     
+     // Open a Symbian RChunk, and reserve requested virtual address range   
+     // Any thread in this process can operate this rchunk due to EOwnerProcess access rights. 
+     TInt ret = m_chunk.CreateDisconnectedLocal(0 , 0, (TInt)m_reservation , EOwnerProcess);  
+     if (ret != KErrNone) 
+         User::Panic(_L("AlignedBlockAllocator3"), ret);
+       
+     // This is the offset to m_chunk.Base() required to make it m_blockSize-aligned
+     m_offset = SYMBIAN_ROUNDUPTOMULTIPLE(TUint32(m_chunk.Base()), m_blockSize) - TUint(m_chunk.Base()); 
+
+}
+
+void* AlignedBlockAllocator::alloc()
+{
+
+    TInt  freeRam = 0; 
+    void* address = 0;
+    
+    // Look up first free slot in bit map
+    const TInt freeIdx = m_map.findFree();
+        
+    // Pseudo OOM: We ate up the address space we reserved..
+    // ..even though the device may have free RAM left
+    if (freeIdx < 0)
+        return 0;
+        
+    TInt ret = m_chunk.Commit(m_offset + (m_blockSize * freeIdx), m_blockSize);
+    if (ret != KErrNone)  
+        return 0; // True OOM: Device didn't have physical RAM to spare
+        
+    // Updated bit to mark region as in use. 
+    m_map.set(freeIdx); 
+    
+    // Calculate address of committed region (block)
+    address = (void*)( (m_chunk.Base() + m_offset) + (TUint)(m_blockSize * freeIdx) );
+    
+    return address;
+}
+
+void AlignedBlockAllocator::free(void* block)
+{
+    // Calculate index of block to be freed
+    TInt idx = TUint(static_cast<TUint8*>(block) - m_chunk.Base() - m_offset) / m_blockSize;
+    
+    __ASSERT_DEBUG(idx >= 0 && idx < m_map.numBits, User::Panic(_L("AlignedBlockAllocator4"), KErrCorrupt)); // valid index check
+    __ASSERT_DEBUG(m_map.get(idx), User::Panic(_L("AlignedBlockAllocator5"), KErrCorrupt)); // in-use flag check    
+    
+    // Return committed region to system RAM pool (the physical RAM becomes usable by others)
+    TInt ret = m_chunk.Decommit(m_offset + m_blockSize * idx, m_blockSize);
+            
+    // mark this available again
+    m_map.clear(idx); 
+}
+
+void AlignedBlockAllocator::destroy() 
+{
+    // release everything!
+    m_chunk.Decommit(0, m_chunk.MaxSize());
+    m_map.clearAll();
+}
+
+AlignedBlockAllocator::~AlignedBlockAllocator()
+{
+    destroy();
+    m_chunk.Close();
+    delete [] m_map.bits;
+}
+
+} // end of namespace
+
+#endif // SYMBIAN