This class implements a fast memory pool that efficiently dispenses heterogeneous blocks of memory (of varying, user‐specified sizes) from a sequence of dynamically‐allocated internal buffers. Memory for the internal buffers is supplied by an (optional) allocator supplied at construction; if no allocator is supplied, the currently installed default allocator is used. If an allocation exceeds the remaining free memory space in the current buffer, the pool replenishes its internal buffer with new memory to satisfy the request. This class is exception neutral: If memory cannot be allocated, the behavior is defined by the (optional) allocator specified at construction.

Synopsis

Declared in <bdlma_sequentialpool.h>

class SequentialPool;

Member Functions

Name

Description

SequentialPool [constructor]

Constructors

~SequentialPool [destructor]

Destroy this sequential pool. All memory allocated by this pool is released.

allocate

Return the address of a contiguous block of memory of the specified size (in bytes) according to the alignment strategy specified at construction. If size is 0, no memory is allocated and 0 is returned. If the allocation request exceeds the remaining free memory space in the current internal buffer, use the allocator supplied at construction to allocate a new internal buffer, then allocate memory from the new buffer.

allocateAndExpand

Return the address of a contiguous block of memory of at least the specified *size (in bytes), and load the actual amount of memory allocated in *size. If *size is 0, return 0 with no effect. If the allocation request exceeds the remaining free memory space in the current internal buffer, use the allocator supplied at construction to allocate a new internal buffer, then allocate memory from the new buffer.

allocator

Return the allocator used by this object to allocate memory. Note that this allocator can not be used to deallocate memory allocated through this pool.

deleteObject

Destroy the specified object. Note that this method has the same effect as the deleteObjectRaw method (since no deallocation is involved), and exists for consistency across pools.

deleteObjectRaw

Destroy the specified object. Note that memory associated with object is not deallocated because there is no deallocate method in SequentialPool.

release

Release all memory allocated through this pool and return to the underlying allocator all memory. The pool is reset to its default‐constructed state, retaining the alignment and growth strategies, and the initial and maximum buffer sizes in effect following construction. The effect of subsequently ‐ to this invocation of release ‐ using a pointer obtained from this object prior to this call to release is undefined.

reserveCapacity

Reserve sufficient memory to satisfy allocation requests for at least the specified numBytes without replenishment (i.e., without dynamic allocation). If numBytes is 0, no memory is reserved. Note that, when the numBytes is distributed over multiple allocate requests ‐ due to alignment effects ‐ it is possible that not all numBytes of memory will be used for allocation before triggering dynamic allocation.

rewind

Release all memory allocated through this pool and return to the underlying allocator only memory that was allocated outside of the typical internal buffer growth of this pool (i.e., large blocks). All retained memory will be used to satisfy subsequent allocations. The effect of subsequently ‐ to this invocation of rewind ‐ using a pointer obtained from this object prior to this call to rewind is undefined.

truncate

Reduce the amount of memory allocated at the specified address of the specified originalSize (in bytes) to the specified newSize. Return newSize after truncating, or originalSize if the memory block at address cannot be truncated. This method can only truncate the memory block returned by the most recent allocate request from this memory pool, and otherwise has no effect. The behavior is undefined unless the memory block at address was originally allocated by this memory pool, the size of the memory block at address is originalSize, newSize <= originalSize, and release was not called after allocating the memory block at address.

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