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# ArenaBlock.hpp

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    00001 /*
    00002  * The Apache Software License, Version 1.1
    00003  *
    00004  *
    00005  * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
    00006  * reserved.
    00007  *
    00008  * Redistribution and use in source and binary forms, with or without
    00009  * modification, are permitted provided that the following conditions
    00010  * are met:
    00011  *
    00012  * 1. Redistributions of source code must retain the above copyright
    00013  *    notice, this list of conditions and the following disclaimer.
    00014  *
    00015  * 2. Redistributions in binary form must reproduce the above copyright
    00016  *    notice, this list of conditions and the following disclaimer in
    00017  *    the documentation and/or other materials provided with the
    00018  *    distribution.
    00019  *
    00020  * 3. The end-user documentation included with the redistribution,
    00021  *    if any, must include the following acknowledgment:
    00022  *       "This product includes software developed by the
    00023  *        Apache Software Foundation (http://www.apache.org/)."
    00024  *    Alternately, this acknowledgment may appear in the software itself,
    00025  *    if and wherever such third-party acknowledgments normally appear.
    00026  *
    00027  * 4. The names "Xalan" and "Apache Software Foundation" must
    00028  *    not be used to endorse or promote products derived from this
    00029  *    software without prior written permission. For written
    00030  *    permission, please contact apache@apache.org.
    00031  *
    00032  * 5. Products derived from this software may not be called "Apache",
    00033  *    nor may "Apache" appear in their name, without prior written
    00034  *    permission of the Apache Software Foundation.
    00035  *
    00036  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    00037  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    00038  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    00039  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
    00040  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    00041  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    00042  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    00043  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    00044  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    00045  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    00046  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    00047  * SUCH DAMAGE.
    00048  * ====================================================================
    00049  *
    00050  * This software consists of voluntary contributions made by many
    00051  * individuals on behalf of the Apache Software Foundation and was
    00052  * originally based on software copyright (c) 1999, International
    00053  * Business Machines, Inc., http://www.ibm.com.  For more
    00054  * information on the Apache Software Foundation, please see
    00055  * <http://www.apache.org/>.
    00056  */
    00057
    00058 #if !defined(ARENABLOCK_INCLUDE_GUARD_1357924680)
    00059 #define ARENABLOCK_INCLUDE_GUARD_1357924680
    00060
    00061
    00062
    00063 #include <algorithm>
    00064 #include <cassert>
    00065 #include <set>
    00066 #include <memory>
    00067
    00068
    00069
    00070 #if defined(XALAN_NO_STD_ALLOCATORS) && !defined(XALAN_NO_SELECTIVE_TEMPLATE_INSTANTIATION)
    00071 #include <PlatformSupport/XalanAllocator.hpp>
    00072 #endif
    00073
    00074
    00075
    00076 XALAN_CPP_NAMESPACE_BEGIN
    00077
    00078
    00079
    00080 #if defined(XALAN_NO_SELECTIVE_TEMPLATE_INSTANTIATION)
    00081
    00082 template <class Type>
    00083 class ArenaBlockAllocator
    00084 {
    00085 public:
    00086
    00087     typedef size_t          size_type;
    00088     typedef ptrdiff_t       difference_type;
    00089     typedef Type*           pointer;
    00090     typedef const Type*     const_pointer;
    00091     typedef Type&           reference;
    00092     typedef const Type&     const_reference;
    00093     typedef Type            value_type;
    00094
    00095     ArenaBlockAllocator()
    00096     {
    00097     }
    00098
    00099     ArenaBlockAllocator(const ArenaBlockAllocator<Type>&)
    00100     {
    00101     };
    00102
    00103     ~ArenaBlockAllocator()
    00104     {
    00105     }
    00106
    00107     pointer
    00108     allocate(
    00109             size_type       size,
    00110             const void*     /* hint */ = 0)
    00111     {
    00112         return (pointer)operator new(size * sizeof(Type));
    00113     }
    00114
    00115     void
    00116     deallocate(
    00117                 pointer     p,
    00118                 size_type   /* n */)
    00119     {
    00120         operator delete(p);
    00121     }
    00122 };
    00123 #endif
    00124
    00125
    00126
    00127 template<class ObjectType>
    00128 class ArenaBlockDestroy
    00129 {
    00130 public:
    00131
    00132     void
    00133     operator()(ObjectType&  theObject) const
    00134     {
    00135 #if defined(XALAN_EXPLICIT_SCOPE_IN_TEMPLATE_BUG)
    00136         theObject.~ObjectType();
    00137 #else
    00138         theObject.ObjectType::~ObjectType();
    00139 #endif
    00140     }
    00141 };
    00142
    00143
    00144
    00145 template<class ObjectType>
    00146 class ArenaBlock
    00147 {
    00148 public:
    00149
    00150 #if defined(XALAN_NO_SELECTIVE_TEMPLATE_INSTANTIATION)
    00151     typedef ArenaBlockAllocator<ObjectType>     AllocatorType;
    00152 #elif defined(XALAN_NO_STD_ALLOCATORS)
    00153     typedef XalanAllocator<ObjectType>          AllocatorType;
    00154 #else
    00155     typedef std::allocator<ObjectType>          AllocatorType;
    00156 #endif
    00157
    00158     typedef ArenaBlockDestroy<ObjectType>       DestroyFunctionType;
    00159
    00160     typedef typename AllocatorType::size_type   size_type;
    00161
    00162     /*
    00163      * Construct an ArenaBlock of the specified size
    00164      * of objects.
    00165      *
    00166      * @param theBlockSize The size of the block (the number of objects it can contain).
    00167      */
    00168     ArenaBlock(size_type    theBlockSize) :
    00169         m_destroyFunction(DestroyFunctionType()),
    00170         m_objectCount(0),
    00171         m_blockSize(theBlockSize),
    00172         m_objectBlock(0),
    00173         m_allocator()
    00174     {
    00175         assert(theBlockSize > 0);
    00176     }
    00177
    00178     virtual
    00179     ~ArenaBlock()
    00180     {
    00181         destroyAll();
    00182
    00183         // Release the memory...
    00184         m_allocator.deallocate(m_objectBlock, m_blockSize);
    00185     }
    00186
    00187     /*
    00188      * Allocate a block.  Once the object is constructed, you must call
    00189      * commitAllocation().
    00190      *
    00191      * @return a pointer to the new block.
    00192      */
    00193     virtual ObjectType*
    00194     allocateBlock()
    00195     {
    00196         // Any space left?
    00197         if (m_objectCount == m_blockSize)
    00198         {
    00199             return 0;
    00200         }
    00201         else
    00202         {
    00203             // If no memory has yet been allocated, then allocate it...
    00204             if (m_objectBlock == 0)
    00205             {
    00206 #if defined(XALAN_NEW_STD_ALLOCATOR)
    00207                 m_objectBlock = m_allocator.allocate(m_blockSize);
    00208 #else
    00209                 m_objectBlock = m_allocator.allocate(m_blockSize, 0);
    00210 #endif
    00211             }
    00212             assert(m_objectBlock != 0);
    00213
    00214             return m_objectBlock + m_objectCount;
    00215         }
    00216     }
    00217
    00218     /*
    00219      * Commit the previous allocation.
    00220      *
    00221      * @param theBlock the address that was returned by allocateBlock()
    00222      */
    00223     virtual void
    00224 #if defined (NDEBUG)
    00225     commitAllocation(ObjectType*    /* theBlock */)
    00226 #else
    00227     commitAllocation(ObjectType*    theBlock)
    00228 #endif
    00229     {
    00230         assert(theBlock == m_objectBlock + m_objectCount);
    00231         assert(m_objectCount < m_blockSize);
    00232
    00233         m_objectCount++;
    00234     }
    00235
    00236     /*
    00237      * Find out if there is a block available.
    00238      *
    00239      * @return true if one is available, false if not.
    00240      */
    00241     virtual bool
    00242     blockAvailable() const
    00243     {
    00244         return m_objectCount < m_blockSize ? true : false;
    00245     }
    00246
    00247     /*
    00248      * Get the number of objects currently allocated in the
    00249      * block.
    00250      *
    00251      * @return The number of objects allocated.
    00252      */
    00253     virtual size_type
    00254     getCountAllocated() const
    00255     {
    00256         return m_objectCount;
    00257     }
    00258
    00259     /*
    00260      * Get the block size, that is, the number
    00261      * of objects in each block.
    00262      *
    00263      * @return The size of the block
    00264      */
    00265     size_type
    00266     getBlockSize() const
    00267     {
    00268         return m_blockSize;
    00269     }
    00270
    00271     /*
    00272      * Determine if this block owns the specified object.  Note
    00273      * that even if the object address is within our block, this
    00274      * call will return false if no object currently occupies the
    00275      * block.  See also ownsBlock().
    00276      *
    00277      * @param theObject the address of the object.
    00278      * @return true if we own the object, false if not.
    00279      */
    00280     virtual bool
    00281     ownsObject(const ObjectType*    theObject) const
    00282     {
    00283         // Use less<>, since it's guaranteed to do pointer
    00284         // comparisons correctly...
    00285         XALAN_STD_QUALIFIER less<const ObjectType*>     functor;
    00286
    00287         if (functor(theObject, m_objectBlock) == false &&
    00288             functor(theObject, m_objectBlock + m_objectCount) == true)
    00289         {
    00290             return true;
    00291         }
    00292         else
    00293         {
    00294             return false;
    00295         }
    00296     }
    00297
    00298     /*
    00299      * Determine if this block owns the specified object block.
    00300      * Note that, unlike ownsObject(), there does not need to
    00301      * be an object at the address.
    00302      *
    00303      * @param theObject the address of the object
    00304      * @return true if we own the object block, false if not.
    00305      */
    00306     bool
    00307     ownsBlock(const ObjectType*     theObject) const
    00308     {
    00309         // Use less<>, since it's guaranteed to do pointer
    00310         // comparisons correctly...
    00311         XALAN_STD_QUALIFIER less<const ObjectType*>     functor;
    00312
    00313         if (functor(theObject, m_objectBlock) == false &&
    00314             functor(theObject, m_objectBlock + m_blockSize) == true)
    00315         {
    00316             return true;
    00317         }
    00318         else
    00319         {
    00320             return false;
    00321         }
    00322     }
    00323
    00324     /*
    00325      * Destroy all objects in the block.  You can then reuse the
    00326      * block.
    00327      */
    00328     void
    00329     destroyAll()
    00330     {
    00331         // Destroy all existing objects...
    00332         XALAN_STD_QUALIFIER for_each(m_objectBlock,
    00333                  m_objectBlock + m_objectCount,
    00334                  DeleteFunctor(*this, m_destroyFunction));
    00335
    00336         m_objectCount = 0;
    00337     }
    00338
    00339 protected:
    00340
    00341     /*
    00342      * Determine if the block should be destroyed.  Called by
    00343      * an instance of DeleteFunctor, this function is for
    00344      * deriving classes that might want to control the destruction
    00345      * of things.
    00346      *
    00347      * @param theObject the address of the object
    00348      * @return true if block should be destroyed, false if not.
    00349      */
    00350     virtual bool
    00351     shouldDestroyBlock(const ObjectType*    /* theObject */) const
    00352     {
    00353         return true;
    00354     }
    00355
    00356     /*
    00357      * Determine the offset into the block for the given address.
    00358      * Behavior is undefined if the address is not within our
    00359      * block
    00360      *
    00361      * @param theObject the address of the object
    00362      * @return the offset
    00363      */
    00364     size_type
    00365     getBlockOffset(const ObjectType*    theObject) const
    00366     {
    00367         assert(size_type(theObject - m_objectBlock) < m_blockSize);
    00368
    00369         return theObject - m_objectBlock;
    00370     }
    00371
    00372     /*
    00373      * Determine the address within our block of the object
    00374      * at the specified offset.
    00375      * Behavior is undefined if the offset is greater than the
    00376      * block size.
    00377      *
    00378      * @param theObject the address of the object
    00379      * @return the offset
    00380      */
    00381     ObjectType*
    00382     getBlockAddress(size_type   theOffset) const
    00383     {
    00384         assert(theOffset < m_blockSize);
    00385
    00386         return m_objectBlock + theOffset;
    00387     }
    00388
    00389     struct DeleteFunctor
    00390     {
    00391         DeleteFunctor(
    00392                 const ArenaBlock<ObjectType>&   theArenaBlock,
    00393                 const DestroyFunctionType&      theDestroyFunction) :
    00394             m_arenaBlock(theArenaBlock),
    00395             m_destroyFunction(theDestroyFunction)
    00396         {
    00397         }
    00398
    00399         void
    00400         operator()(ObjectType&  theObject) const
    00401         {
    00402             if (m_arenaBlock.shouldDestroyBlock(&theObject) == true)
    00403             {
    00404                 m_destroyFunction(theObject);
    00405             }
    00406         }
    00407
    00408     private:
    00409
    00410         const ArenaBlock<ObjectType>&   m_arenaBlock;
    00411         const DestroyFunctionType&      m_destroyFunction;
    00412     };
    00413
    00414     friend struct DeleteFunctor;
    00415
    00416     const DestroyFunctionType   m_destroyFunction;
    00417
    00418 private:
    00419
    00420     // Not implemented...
    00421     ArenaBlock(const ArenaBlock<ObjectType>&);
    00422
    00423     ArenaBlock<ObjectType>&
    00424     operator=(const ArenaBlock<ObjectType>&);
    00425
    00426     bool
    00427     operator==(const ArenaBlock<ObjectType>&) const;
    00428
    00429
    00430     // data members...
    00431     size_type           m_objectCount;
    00432
    00433     const size_type     m_blockSize;
    00434
    00435     ObjectType*         m_objectBlock;
    00436
    00437     AllocatorType       m_allocator;
    00438 };
    00439
    00440
    00441
    00442 XALAN_CPP_NAMESPACE_END
    00443
    00444
    00445
    00446 #endif  // !defined(ARENABLOCK_INCLUDE_GUARD_1357924680)

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