2.4.9.3 The fixed allocator

The fixed allocator is used in those resource containers that cannot grow. Its length is fixed once given at instantiation time.

<Off fixed allocator. >= (U->)
// A software-table fixed-size allocator.
//
class off_FixedAllocator: public off_SwAllocator {
public:
  // Allows declarations of uninitialized fixed allocators.
  off_FixedAllocator(void){;}

  //Creates a sw. fixed allocator.
  off_FixedAllocator(off_Exhausted *r, const off_Indexable *i,
                     void *first, natural_t len ) :
    off_SwAllocator(r,i,first,len)
  { ;  }

};

Defines off_FixedAllocator (links are to index).

<Off fixed allocator dependencies. >= (U->)
#include <klib/SwAllocator.h>   // for off_SwAllocator

A fixed allocator can be instantiated, so we provide a type-safe interface for it.

<Off type safe fixed allocator. >= (U->)
// A software-table fixed-size allocator.
//
template <class T>
class off_TFixedAllocator : private off_FixedAllocator {
public:
  // Allows declarations of uninitialized fixed allocators.
  off_TFixedAllocator(void) : off_FixedAllocator() {;}

  //Creates a sw. fixed allocator.
  off_TFixedAllocator(off_Exhausted *r, const off_Indexable *i,
                      T *first, natural_t len ) :
    off_FixedAllocator(r, i, (void *)first, len )
  { ;  }

  // Allocate (deallocate) units. 
  // Return NULL when allocation failed. 
  T *allocate(boolean_t use_revocation=FALSE ) { 
    return (T*)off_FixedAllocator::allocate(use_revocation);
  }
  T *allocate(natural_t at, boolean_t use_revocation=FALSE) {
    return (T*) off_FixedAllocator::allocate(at,use_revocation);
  }

  void  deallocate(T *p) { off_FixedAllocator::deallocate((void*)p); }

  off_FixedAllocator::is_free;

  T *operator +(natural_t at) {
    return (T*)(this->off_KernAllocator::operator+(at));
  }

  natural_t pos(T *p) { return off_KernAllocator::pos((void*)p);  }
  off_BKAllocator::get_nfree;
  off_BKAllocator::get_nalloc;
  off_BKAllocator::get_maxalloc;
  off_BKAllocator::get_num_allocrq;
  off_BKAllocator::get_num_freerq;
  off_BKAllocator::get_length;

  <Other public methods of off_TFixedAllocator. >

};

Defines off_TFixedAllocator (links are to index).

To allow initialization of pre-allocated TFixedAllocators an operator new is provided.

<Other public methods of off_TFixedAllocator. >= (<-U) [D->]
void * operator new(size_t s, void *p) { (void)s; return p; }