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  1. #include <iostream>
  2.  
  3. using namespace std;
  4.  
  5. template<class type, int blockSize>
  6. class idBlockAlloc {
  7. public:
  8.               idBlockAlloc( void );
  9.               ~idBlockAlloc( void );
  10.  
  11.   void          Shutdown( void );
  12.  
  13.   type *          Alloc( void );
  14.   void          Free( type *element );
  15.  
  16.   int            GetTotalCount( void ) const { return total; }
  17.   int            GetAllocCount( void ) const { return active; }
  18.   int            GetFreeCount( void ) const { return total - active; }
  19.  
  20. private:
  21.   typedef struct element_s {
  22.     struct element_s *  next;
  23.     type        t;
  24.   } element_t;
  25.   typedef struct block_s {
  26.     element_t      elements[blockSize];
  27.     struct block_s *  next;
  28.   } block_t;
  29.  
  30.   block_t *        blocks;
  31.   element_t *        free;
  32.   int            total;
  33.   int            active;
  34. };
  35.  
  36. template<class type, int blockSize>
  37. idBlockAlloc<type,blockSize>::idBlockAlloc( void ) {
  38.   blocks = NULL;
  39.   free = NULL;
  40.   total = active = 0;
  41. }
  42.  
  43. template<class type, int blockSize>
  44. idBlockAlloc<type,blockSize>::~idBlockAlloc( void ) {
  45.   Shutdown();
  46. }
  47.  
  48. template<class type, int blockSize>
  49. type *idBlockAlloc<type,blockSize>::Alloc( void ) {
  50.   if ( !free ) {
  51.     block_t *block = new block_t;
  52.     block->next = blocks;
  53.     blocks = block;
  54.     for ( int i = 0; i < blockSize; i++ ) {
  55.       block->elements[i].next = free;
  56.       free = &block->elements[i];
  57.     }
  58.     total += blockSize;
  59.   }
  60.   active++;
  61.   element_t *element = free;
  62.   free = free->next;
  63.   element->next = NULL;
  64.   return &element->t;
  65. }
  66.  
  67. template<class type, int blockSize>
  68. void idBlockAlloc<type,blockSize>::Free( type *t ) {
  69.   element_t *element = (element_t *)( ( (unsigned char *) t ) - ( (int) &((element_t *)0)->t ) );
  70.   element->next = free;
  71.   free = element;
  72.   active--;
  73. }
  74.  
  75. template<class type, int blockSize>
  76. void idBlockAlloc<type,blockSize>::Shutdown( void ) {
  77.   while( blocks ) {
  78.     block_t *block = blocks;
  79.     blocks = blocks->next;
  80.     delete block;
  81.   }
  82.   blocks = NULL;
  83.   free = NULL;
  84.   total = active = 0;
  85. }
  86.  
  87. struct SomeClass{
  88.   SomeClass(){
  89.     cout << "SomeClass()" << endl;
  90.     }
  91.  
  92.   };
  93.  
  94. int main() {
  95.   idBlockAlloc<SomeClass,32>  eventAllocator;
  96.   SomeClass* event = eventAllocator.Alloc();
  97.  
  98.   eventAllocator.Free( event );
  99.   }
  100.  
Success #stdin #stdout 0.01s 2812KB
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Standard input is empty
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SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
SomeClass()
https://ideone.com/EXX91
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
public

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