This class implements the ManagedAllocator protocol to provide a fast allocator that dispenses heterogeneous blocks of memory (of varying, user-specified sizes) from an external buffer whose address and size (in bytes) are supplied at construction. If an allocation request exceeds the remaining free memory space in the external buffer, memory will be supplied by an (optional) allocator also supplied at construction; if no allocator is supplied, the currently installed default allocator is used. This class is exception neutral: If memory cannot be allocated, the behavior is defined by the (optional) allocator supplied at construction. Note that in no case will the buffered sequential allocator attempt to deallocate the external buffer.
Declared in <bdlma_bufferedsequentialallocator.h>
class BufferedSequentialAllocator
: public ManagedAllocator| Name | Description |
|---|---|
ManagedAllocator | This protocol class extends bslma::Allocator for allocators with the ability to release all memory currently allocated through the protocol back to the memory supplier of the derived concrete allocator object. |
| Name | Description |
|---|---|
size_type | Alias for an unsigned integral type capable of representing the number of bytes in this platform's virtual address space. |
| Name | Description |
|---|---|
BufferedSequentialAllocator [constructor] | Constructors |
~BufferedSequentialAllocator [destructor] [virtual] | Destroy this buffered sequential allocator. All memory allocated from this allocator is released. |
operator= | |
allocate | Return a block of memory of the specified size (in bytes). |
allocator | Return the allocator passed at construction. |
deallocate | This method has no effect on the specified memory block. |
deleteObject | deleteObject overloads |
deleteObjectRaw | deleteObjectRaw overloads |
is_equal | |
release [virtual] | Release all memory allocated through this allocator and return to the underlying allocator all memory except the external buffer supplied at construction. The allocator is reset to its default-constructed state, making the memory from the entire external buffer supplied at construction available for subsequent allocations, retaining the alignment and growth strategies, and the initial and maximum buffer sizes in effect following construction. The effect of subsequently - to this invokation of release - using a pointer obtained from this object prior to this call to release is undefined. |
rewind [virtual] | Release all memory allocated through this allocator and return to the underlying allocator only memory that was allocated outside of the typical internal buffer growth of this allocator (i.e., large blocks). All retained memory will be used to satisfy subsequent allocations. The effect of subsequently - to this invokation of rewind - using a pointer obtained from this object prior to this call to rewind is undefined. |
| Name | Description |
|---|---|
throwBadAlloc | Throw std::bad_alloc if exceptions are enabled or abort the program otherwise. Derived classes and helper functions will typically call this function when they are unable to satisfy an allocation request. This function never returns. |
| Name | Description |
|---|---|
do_allocate [virtual] | Return a newly allocated block of memory of (at least) the specified positive bytes and having at least the specified alignment. Unless overriden in a derived class, the return value is this->allocate(bytes). If this allocator cannot return the requested number of bytes or cannot satisfy the alignment request, then it will throw a std::bad_alloc exception in an exception-enabled build, or else will abort the program in a non-exception build. Unless overriden in a derived class, this function will forward the allocation request to the allocate virtual function, padding bytes and adjusting the return value as necessary to ensure sufficient alignment. Note that if bytes is 0, the same non-null value will be returned every time. |
do_deallocate [virtual] | Return the memory block at the specified p address, having the specified bytes and specified alignment, back to this allocator. Unless overriden in a derived class, this function will forward the deallocation request to the deallocate virtual function, padding bytes and adjusting p as necessary to account for alignment values other than the natural alignment for an object of size bytes. The behavior is undefined unless address is a block allocated from this allocator object using the same bytes and alignment and not already deallocated. |
do_is_equal [virtual] | Return true if this allocator is equal to the specified other allocator, meaning (at least) that a memory block allocated by one can be deallocated by the other; otherwise return false. Unless overriden, this method returns this == &other. |
| Name | Description |
|---|---|
LocalSequentialAllocator | This class implements the ManagedAllocator protocol to provide a fast allocator that dispenses heterogeneous blocks of memory (of varying, user-specified sizes) from a local buffer whose capacity is the specified t_SIZE (in bytes). If an allocation request exceeds the remaining free memory space in the local buffer, memory will be supplied by an (optional) allocator supplied at construction; if no allocator is supplied, the currently installed default allocator is used. This class is exception neutral; if memory cannot be allocated, the behavior is defined by the (optional) allocator supplied at construction. |