wtf/PageAllocatorSymbian.h

   1 /*
   2  * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies)
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef PageAllocatorSymbian_h
  30 #define PageAllocatorSymbian_h
  31
  32 #include <e32std.h>
  33 #include <wtf/Bitmap.h>
  34
  35 namespace WTF {
  36
  37 size_t pageSize();
  38
  39 // Convenience wrapper around an RChunk
  40 class SymbianChunk : public RChunk {
  41
  42 public:
  43     SymbianChunk(TInt handle)
  44     {
  45         SetHandle(handle);
  46         // prevent kernel calls by caching these
  47         m_base = reinterpret_cast<char*>(Base());
  48         m_maxSize = MaxSize();
  49     }
  50
  51     ~SymbianChunk()
  52     {
  53         Decommit(0, m_maxSize);
  54         Close();
  55     }
  56
  57     // checks if address is in chunk's virtual address space
  58     bool contains(const void* address) const
  59     {
  60         return (static_cast<const char*>(address) >= m_base && static_cast<const char*>(address) < (m_base + m_maxSize));
  61     }
  62
  63     char* m_base;
  64     size_t m_maxSize;
  65
  66 };
  67
  68 // Size of the large up-front reservation
  69 #if defined(__WINS__)
  70 // Emulator has limited virtual address space
  71 const size_t largeReservationSize = 96*1024*1024;
  72 #else
  73 // HW has plenty of virtual addresses
  74 const size_t largeReservationSize = 256*1024*1024;
  75 #endif
  76
  77 class PageAllocatorSymbian {
  78
  79 public:
  80     PageAllocatorSymbian();
  81     ~PageAllocatorSymbian();
  82
  83     void* reserve(size_t);
  84     void release(void*, size_t);
  85     bool commit(void*, size_t);
  86     bool decommit(void*, size_t);
  87
  88     bool contains(const void*) const;
  89
  90 private:
  91     static const size_t m_pageSize = 4096;
  92     SymbianChunk* m_chunk;
  93     Bitmap<largeReservationSize / m_pageSize> m_map;
  94
  95 };
  96
  97 } // namespace WTF
  98
  99 #endif // PageAllocatorSymbian_h
 100