wtf/symbian/BlockAllocatorSymbian.h

   1 /*
   2  * Copyright (C) 2010 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 BlockAllocatorSymbian_h
  30 #define BlockAllocatorSymbian_h
  31
  32 #include <e32cmn.h>
  33 #include <e32std.h>
  34 #include <hal.h>
  35
  36
  37 #define SYMBIAN_PAGESIZE(x) (HAL::Get(HALData::EMemoryPageSize, x));
  38 #define SYMBIAN_FREERAM(x)  (HAL::Get(HALData::EMemoryRAMFree, x));
  39 #define SYMBIAN_ROUNDUPTOMULTIPLE(x, multipleof)    ( (x + multipleof - 1) & ~(multipleof - 1) )
  40
  41 // Set sane defaults if -D<flagname=value> wasn't provided via compiler args
  42 #ifndef JSCCOLLECTOR_VIRTUALMEM_RESERVATION
  43 #if defined(__WINS__)
  44     // Emulator has limited virtual address space
  45     #define JSCCOLLECTOR_VIRTUALMEM_RESERVATION (4*1024*1024)
  46 #else
  47     // HW has plenty of virtual addresses
  48     #define JSCCOLLECTOR_VIRTUALMEM_RESERVATION (128*1024*1024)
  49 #endif
  50 #endif
  51
  52 namespace WTF {
  53
  54 /**
  55  *  Allocates contiguous region of size blockSize with blockSize-aligned address.
  56  *  blockSize must be a multiple of system page size (typically 4K on Symbian/ARM)
  57  *
  58  *  @param reservationSize Virtual address range to be reserved upon creation of chunk (bytes).
  59  *  @param blockSize Size of a single allocation. Returned address will also be blockSize-aligned.
  60  */
  61 class AlignedBlockAllocator {
  62     public:
  63         AlignedBlockAllocator(TUint32 reservationSize, TUint32 blockSize);
  64         ~AlignedBlockAllocator();
  65         void destroy();
  66         void* alloc();
  67         void free(void* data);
  68
  69     private:
  70         RChunk   m_chunk; // Symbian chunk that lets us reserve/commit/decommit
  71         TUint    m_offset; // offset of first committed region from base
  72         TInt     m_pageSize; // cached value of system page size, typically 4K on Symbian
  73         TUint32  m_reservation;
  74         TUint32  m_blockSize;
  75
  76         // Tracks comitted/decommitted state of a blockSize region
  77         struct {
  78
  79             TUint32 *bits; // array of bit flags
  80             TUint32  numBits; // number of regions to keep track of
  81
  82             bool get(TUint32 n) const
  83             {
  84                 return !!(bits[n >> 5] & (1 << (n & 0x1F)));
  85             }
  86
  87             void set(TUint32 n)
  88             {
  89                 bits[n >> 5] |= (1 << (n & 0x1F));
  90             }
  91
  92             void clear(TUint32 n)
  93             {
  94                 bits[n >> 5] &= ~(1 << (n & 0x1F));
  95             }
  96
  97             void clearAll()
  98             {
  99                for (TUint32 i = 0; i < numBits; i++)
 100                     clear(i);
 101             }
 102
 103             TInt findFree() const
 104             {
 105                 for (TUint32 i = 0; i < numBits; i++) {
 106                     if (!get(i))
 107                         return i;
 108                 }
 109                 return -1;
 110             }
 111
 112         } m_map;
 113
 114 };
 115
 116 }
 117
 118 #endif // end of BlockAllocatorSymbian_h
 119
 120