1 /****************************************************************************

     2 **

     3 ** Copyright (C) 2001-2004 Roberto Raggi

     4 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

     5 ** All rights reserved.

     6 ** Contact: Nokia Corporation (qt-info@nokia.com)

     7 **

     8 ** This file is part of the qt3to4 porting application of the Qt Toolkit.

     9 **

    10 ** $QT_BEGIN_LICENSE:LGPL$

    11 ** No Commercial Usage

    12 ** This file contains pre-release code and may not be distributed.

    13 ** You may use this file in accordance with the terms and conditions

    14 ** contained in the Technology Preview License Agreement accompanying

    15 ** this package.

    16 **

    17 ** GNU Lesser General Public License Usage

    18 ** Alternatively, this file may be used under the terms of the GNU Lesser

    19 ** General Public License version 2.1 as published by the Free Software

    20 ** Foundation and appearing in the file LICENSE.LGPL included in the

    21 ** packaging of this file.  Please review the following information to

    22 ** ensure the GNU Lesser General Public License version 2.1 requirements

    23 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

    24 **

    25 ** In addition, as a special exception, Nokia gives you certain additional

    26 ** rights.  These rights are described in the Nokia Qt LGPL Exception

    27 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

    28 **

    29 ** If you have questions regarding the use of this file, please contact

    30 ** Nokia at qt-info@nokia.com.

    31 **

    32 **

    33 **

    34 **

    35 **

    36 **

    37 **

    38 **

    39 ** $QT_END_LICENSE$

    40 **

    41 ****************************************************************************/

    42 

    43 #ifndef SMALLOBJECT_H

    44 #define SMALLOBJECT_H

    45 

    46 #include <QList>

    47 

    48 #include <assert.h>

    49 #include <stdlib.h>

    50 #include <string.h>

    51 

    52 QT_BEGIN_NAMESPACE

    53 

    54 struct block_t

    55 {

    56     static int N;

    57 

    58     block_t *chain;

    59     char *data;

    60     char *ptr;

    61     char *end;

    62 

    63     inline void init(int block_size = 256)

    64     {

    65         ++N;

    66         chain = 0;

    67         data = (char*) malloc(block_size);

    68         ptr = data;

    69         end = data + block_size;

    70     }

    71 

    72     inline void init0(int block_size)

    73     {

    74         init();

    75         memset(data, '0', block_size);

    76     }

    77 

    78     inline void destroy()

    79     {

    80         --N;

    81         if (chain) {

    82             chain->destroy();

    83             free(chain);

    84         }

    85 

    86         free(data);

    87     }

    88 

    89     inline void *allocate(size_t size, block_t **right_most)

    90     {

    91         const unsigned int block_size = 1 << 16;

    92         if (end < ptr + size) {

    93             assert( size < block_size );

    94 

    95             if (!chain) {

    96                 chain = (block_t*) malloc(sizeof(block_t));

    97                 Q_ASSERT(chain);

    98                 chain->init(block_size);

    99             }

   100 

   101             return chain->allocate(size, right_most);

   102         }

   103 

   104         char *r = ptr;

   105         ptr += size;

   106 

   107         if (right_most)

   108             *right_most = this;

   109 

   110         return r;

   111     }

   112 

   113 };

   114 

   115 // a stupid memory pool

   116 struct pool

   117 {

   118     block_t blk;

   119     block_t *right_most;

   120 

   121     inline pool() { blk.init(); right_most = &blk; }

   122     inline ~pool() { blk.destroy(); }

   123 

   124     inline void *allocate(size_t size)

   125     {

   126         void *ptr = right_most->allocate(size, &right_most);

   127         Q_ASSERT(ptr);

   128         return ptr;

   129 

   130     }

   131     inline void *reallocate(void *old, size_t old_size, size_t size)

   132     {

   133         void *alloc = right_most->allocate(size, &right_most);

   134         memcpy(alloc, old, old_size);

   135         return alloc;

   136     }

   137 private:

   138    Q_DISABLE_COPY(pool)

   139 };

   140 

   141 /*

   142     A memory pool that calls the destructor for each stored item when memory is

   143     freed, at the expence storing one BaseType* per item.

   144 

   145     Note that allocations for types that does not inherit BaseType

   146     is not allowed and will result in a crash when the memory is freed.

   147 */

   148 template <typename BaseType>

   149 class TypedPool

   150 {

   151 public:

   152     inline TypedPool() { blk.init(); right_most = &blk; }

   153     inline ~TypedPool()

   154     {

   155         foreach(BaseType *item, allocated)

   156             item->~BaseType();

   157         blk.destroy();

   158     }

   159 

   160     inline void *allocate(size_t size)

   161     {

   162         void *memory = right_most->allocate(size, &right_most);

   163         allocated.append(reinterpret_cast<BaseType *>(memory));

   164         Q_ASSERT(memory);

   165         return memory;

   166     }

   167 private:

   168     Q_DISABLE_COPY(TypedPool)

   169     block_t blk;

   170     block_t *right_most;

   171     QList<BaseType *> allocated;

   172 };

   173 

   174 struct SmallObject

   175 {

   176     static void *operator new(size_t size);

   177     static void operator delete(void *p);

   178 };

   179 

   180 QT_END_NAMESPACE

   181 

   182 #endif