bdlma_multipool.h

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/// @file bdlma_multipool.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdlma_multipool.h                                                  -*-C++-*-
#ifndef INCLUDED_BDLMA_MULTIPOOL
#define INCLUDED_BDLMA_MULTIPOOL
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bdlma_multipool bdlma_multipool
/// @brief  Provide a memory manager to manage pools of varying block sizes.
/// @addtogroup bdl
/// @{
/// @addtogroup bdlma
/// @{
/// @addtogroup bdlma_multipool
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdlma_multipool-purpose"> Purpose</a>
/// * <a href="#bdlma_multipool-classes"> Classes </a>
/// * <a href="#bdlma_multipool-description"> Description </a>
///   * <a href="#bdlma_multipool-configuration-at-construction"> Configuration at Construction </a>
///   * <a href="#bdlma_multipool-usage"> Usage </a>
///     * <a href="#bdlma_multipool-example-1-using-a-bdlma-multipool-directly"> Example 1: Using a bdlma::Multipool Directly </a>
///     * <a href="#bdlma_multipool-example-2-implementing-an-allocator-using-bdlma-multipool"> Example 2: Implementing an Allocator Using bdlma::Multipool </a>
///
/// # Purpose {#bdlma_multipool-purpose}
/// Provide a memory manager to manage pools of varying block sizes.
///
/// # Classes {#bdlma_multipool-classes}
///
/// -  bdlma::Multipool: memory manager that manages pools of varying block sizes
///
/// @see  bdlma_pool, bdlma_multipoolallocator
///
/// # Description {#bdlma_multipool-description}
/// This component implements a memory manager, `bdlma::Multipool`,
/// that maintains a configurable number of `bdlma::Pool` objects, each
/// dispensing maximally-aligned memory blocks of a unique size.  The
/// `bdlma::Pool` objects are placed in an array, starting at index 0, with each
/// successive pool managing memory blocks of a size twice that of the previous
/// pool.  Each multipool allocation (deallocation) request allocates memory
/// from (returns memory to) the internal pool managing memory blocks of the
/// smallest size not less than the requested size, or else from a separately
/// managed list of memory blocks, if no internal pool managing memory blocks of
/// sufficient size exists.  Both the `release` method and the destructor of a
/// `bdlma::Multipool` release all memory currently allocated via the object.
///
/// A `bdlma::Multipool` can be depicted visually:
/// @code
///                   +-----+--- memory blocks of 8 bytes
///                   |     |
///  ========       ----- ----- ------------
/// |8 bytes |---->|     |     |     ...    |
/// >========<      =====^=====^============
/// |16 bytes|
/// >========<      \___________ __________/
/// |32 bytes|                  V
/// >========<              a "chunk"
/// |        |
/// |  ...   |
/// |        |
///  ========
///     |
///     +------- array of 'bdlma::Pool'
/// @endcode
/// Note that a "chunk" is a large, contiguous block of memory, internal to a
/// `bdlma::Pool` maintained by the multipool, from which memory blocks of
/// uniform size are dispensed to users.
///
/// ## Configuration at Construction {#bdlma_multipool-configuration-at-construction}
///
///
/// When creating a `bdlma::Multipool`, clients can optionally configure:
///
/// 1. NUMBER OF POOLS -- the number of internal pools (the block size managed
///    by the first pool is eight bytes, with each successive pool managing
///    blocks of a size twice that of the previous pool).
/// 2. GROWTH STRATEGY -- geometrically growing chunk size starting from 1 (in
///    terms of the number of memory blocks per chunk), or fixed chunk size,
///    specified as either:
///   - the unique growth strategy for all pools, or
///   - (if the number of pools is specified) an array of growth strategies
///     corresponding to each individual pool.
///   If the growth strategy is not specified, geometric growth is used for all
///   pools.
/// 3. MAX BLOCKS PER CHUNK -- the maximum number of memory blocks within a
///    chunk, specified as either:
///     - the unique maximum-blocks-per-chunk value for all of the pools, or
///     - an array of maximum-blocks-per-chunk values corresponding to each
///       individual pool.
///   If the maximum blocks per chunk is not specified, an
///   implementation-defined default value is used.  Note that the maximum
///   blocks per chunk can be configured only if the number of pools is also
///   configured.
/// 4. BASIC ALLOCATOR -- the allocator used to supply memory (to replenish an
///    internal pool, or directly if the maximum block size is exceeded).  If
///    not specified, the currently installed default allocator is used (see
///    @ref bslma_default ).
///
/// A default-constructed multipool has a relatively small,
/// implementation-defined number of pools, `N`, with respective block sizes
/// ranging from `2^3 = 8` to `2^(N+2)`.  By default, the initial chunk size,
/// (i.e., the number of blocks of a given size allocated at once to replenish a
/// pool's memory) is 1, and each pool's chunk size grows geometrically until it
/// reaches an implementation-defined maximum, at which it is capped.  Finally,
/// unless otherwise specified, all memory comes from the allocator that was the
/// currently installed default allocator at the time the `bdlma::Multipool` was
/// created.
///
/// Using the various pooling options described above, we can configure the
/// number of pools maintained, whether replenishment should be adaptive (i.e.,
/// geometric starting with 1) or fixed at a maximum chunk size, what that
/// maximum chunk size should be (which need not be an integral power of 2), and
/// the underlying allocator used to supply memory.  Note that both GROWTH
/// STRATEGY and MAX BLOCKS PER CHUNK can be specified separately either as a
/// single value applying to all of the maintained pools, or as an array of
/// values, with the elements applying to each individually maintained pool.
///
/// ## Usage {#bdlma_multipool-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Using a bdlma::Multipool Directly {#bdlma_multipool-example-1-using-a-bdlma-multipool-directly}
///
///
/// A `bdlma::Multipool` can be used by containers that hold different types of
/// elements, each of uniform size, for efficient memory allocation of new
/// elements.  Suppose we have a factory class, `my_MessageFactory`, that
/// creates messages based on user requests.  Each message is created with the
/// most efficient memory storage possible, using predefined 8-byte, 16-byte,
/// and 32-byte buffers.  If the message size exceeds the three predefined
/// values, a generic message is used.  For efficient memory allocation of
/// messages, we use a `bdlma::Multipool`.
///
/// First, we define our message types as follows:
/// @code
/// class my_MessageFactory;
///
/// class my_Message {
///     // This class represents a general message interface that provides a
///     // 'getMessage' method for clients to retrieve the underlying message.
///
///   public:
///     // CREATORS
///     virtual ~my_Message() {}
///         // Destroy this object.
///
///     // ACCESSORS
///     virtual const char *getMessage() = 0;
///         // Return the null-terminated message string.
/// };
///
/// class my_SmallMessage : public my_Message {
///     // This class represents an 8-byte message (including null terminator).
///
///     // DATA
///     char d_buffer[8];
///
///     // FRIEND
///     friend class my_MessageFactory;
///
///   private:
///     // NOT IMPLEMENTED
///     my_SmallMessage(const my_SmallMessage&);
///     my_SmallMessage& operator=(const my_SmallMessage&);
///
///     // PRIVATE CREATORS
///     my_SmallMessage(const char *msg, int length)
///     {
///         assert(length <= 7);
///
///         bsl::memcpy(d_buffer, msg, length);
///         d_buffer[length] = '\0';
///     }
///
///     virtual ~my_SmallMessage() {}
///         // Destroy this object.
///
///     // PRIVATE ACCESSORS
///     virtual const char *getMessage()
///     {
///         return d_buffer;
///     }
/// };
///
/// class my_MediumMessage : public my_Message {
///     // This class represents a 16-byte message (including null
///     // terminator).
///
///     // DATA
///     char d_buffer[16];
///
///     // FRIEND
///     friend class my_MessageFactory;
///
///   private:
///     // NOT IMPLEMENTED
///     my_MediumMessage(const my_MediumMessage&);
///     my_MediumMessage& operator=(const my_MediumMessage&);
///
///     // PRIVATE CREATORS
///     my_MediumMessage(const char *msg, int length)
///     {
///         assert(length <= 15);
///
///         bsl::memcpy(d_buffer, msg, length);
///         d_buffer[length] = '\0';
///     }
///
///     virtual ~my_MediumMessage() {}
///         // Destroy this object.
///
///     // PRIVATE ACCESSORS
///     virtual const char *getMessage()
///     {
///         return d_buffer;
///     }
/// };
///
/// class my_LargeMessage : public my_Message {
///     // This class represents a 32-byte message (including null
///     // terminator).
///
///     // DATA
///     char d_buffer[32];
///
///     // FRIEND
///     friend class my_MessageFactory;
///
///   private:
///     // NOT IMPLEMENTED
///     my_LargeMessage(const my_LargeMessage&);
///     my_LargeMessage& operator=(const my_LargeMessage&);
///
///     // PRIVATE CREATORS
///     my_LargeMessage(const char *msg, int length)
///     {
///         assert(length <= 31);
///
///         bsl::memcpy(d_buffer, msg, length);
///         d_buffer[length] = '\0';
///     }
///
///     virtual ~my_LargeMessage() {}
///         // Destroy this object.
///
///     // PRIVATE ACCESSORS
///     virtual const char *getMessage()
///     {
///         return d_buffer;
///     }
/// };
///
/// class my_GenericMessage : public my_Message {
///     // This class represents a generic message.
///
///     // DATA
///     char *d_buffer;
///
///     // FRIEND
///     friend class my_MessageFactory;
///
///   private:
///     // NOT IMPLEMENTED
///     my_GenericMessage(const my_GenericMessage&);
///     my_GenericMessage& operator=(const my_GenericMessage&);
///
///     // PRIVATE CREATORS
///     my_GenericMessage(char *msg) : d_buffer(msg)
///     {
///     }
///
///     virtual ~my_GenericMessage() {}
///         // Destroy this object.
///
///     // PRIVATE ACCESSORS
///     virtual const char *getMessage()
///     {
///         return d_buffer;
///     }
/// };
/// @endcode
/// Then, we define our factory class, `my_MessageFactory`, as follows:
/// @code
/// class my_MessageFactory {
///     // This class implements an efficient message factory that builds and
///     // returns messages.  The life-time of the messages created by this
///     // factory is the same as this factory.
///
///     // DATA
///     bdlma::Multipool d_multipool;  // multipool used to supply memory
///
///   private:
///     // Not implemented:
///     my_MessageFactory(const my_MessageFactory&);
///
///   public:
///     // CREATORS
///     my_MessageFactory(bslma::Allocator *basicAllocator = 0);
///         // Create a message factory.  Optionally specify a 'basicAllocator'
///         // used to supply memory.  If 'basicAllocator' is 0, the currently
///         // installed default allocator is used.
///
///     ~my_MessageFactory();
///         // Destroy this factory and reclaim all messages created by it.
///
///     // MANIPULATORS
///     my_Message *createMessage(const char *data);
///         // Create a message storing the specified 'data'.  The behavior is
///         // undefined unless 'data' is null-terminated.
///
///     void disposeAllMessages();
///         // Dispose of all created messages.
///
///     void disposeMessage(my_Message *message);
///         // Dispose of the specified 'message'.  The behavior is undefined
///         // unless 'message' was created by this factory, and has not
///         // already been disposed.
/// };
/// @endcode
/// Next, we define the `inline` methods of `my_MessageFactory`.
///
/// In calling the multipool's `release` method, `disposeAllMessages` quickly
/// deallocates all memory blocks that were used to create messages currently
/// outstanding from the factory.  Following the call to `release`, *all* memory
/// that had been allocated from the multipool is available for reuse:
/// @code
/// // MANIPULATORS
/// inline
/// void my_MessageFactory::disposeAllMessages()
/// {
///     d_multipool.release();
/// }
/// @endcode
/// Similarly, the call to the multipool's `deleteObject` method in
/// `disposeMessage` first destroys the message, then releases the memory that
/// had been allocated for it back to the multipool for use in creating another
/// message having the same size:
/// @code
/// inline
/// void my_MessageFactory::disposeMessage(my_Message *message)
/// {
///     d_multipool.deleteObject(message);
/// }
/// @endcode
/// A multipool optimizes the allocation of memory by using
/// dynamically-allocated buffers (also known as chunks) to supply memory.  As
/// each chunk can satisfy multiple memory block requests before requiring
/// additional dynamic memory allocation, the number of dynamic allocation
/// requests needed is greatly reduced.
///
/// For the number of pools managed by the multipool, we chose to use the
/// implementation-defined default value instead of calculating and specifying a
/// value.  If users instead want to specify the number of pools, the value can
/// be calculated as the smallest value, `N`, such that the following
/// relationship holds:
/// @code
/// N > log2(sizeof(Object Type)) - 2
/// @endcode
/// Next, we define the creators of `my_MessageFactory`:
/// @code
/// // CREATORS
/// my_MessageFactory::my_MessageFactory(bslma::Allocator *basicAllocator)
/// : d_multipool(basicAllocator)
/// {
/// }
/// @endcode
/// Note that in the destructor, all outstanding messages are reclaimed
/// automatically when `d_multipool` is destroyed:
/// @code
/// my_MessageFactory::~my_MessageFactory()
/// {
/// }
/// @endcode
/// Finally, we define the `createMessage` factory method that actually creates
/// the messages using memory provided by the multipool.  A `bdlma::Multipool`
/// is ideal for allocating the different sized messages since repeated
/// deallocations might be necessary, which renders a `bdlma::SequentialPool`
/// unsuitable:
/// @code
/// // MANIPULATORS
/// my_Message *my_MessageFactory::createMessage(const char *data)
/// {
///     enum { k_SMALL = 8, k_MEDIUM = 16, k_LARGE = 32 };
///
///     const int length = static_cast<int>(bsl::strlen(data));
///
///     if (length < k_SMALL) {
///         return new(d_multipool.allocate(sizeof(my_SmallMessage)))
///                                   my_SmallMessage(data, length);  // RETURN
///     }
///
///     if (length < k_MEDIUM) {
///         return new(d_multipool.allocate(sizeof(my_MediumMessage)))
///                                  my_MediumMessage(data, length);  // RETURN
///     }
///
///     if (length < k_LARGE) {
///         return new(d_multipool.allocate(sizeof(my_LargeMessage)))
///                                   my_LargeMessage(data, length);  // RETURN
///     }
///
///     char *buffer = (char *)d_multipool.allocate(length + 1);
///     bsl::memcpy(buffer, data, length + 1);
///
///     return new(d_multipool.allocate(sizeof(my_GenericMessage)))
///                                                  my_GenericMessage(buffer);
/// }
/// @endcode
///
/// ### Example 2: Implementing an Allocator Using bdlma::Multipool {#bdlma_multipool-example-2-implementing-an-allocator-using-bdlma-multipool}
///
///
/// Suppose that we want to create a multipool allocator (i.e., that implements
/// the `bslma::Allocator` interface) that allocates memory from multiple
/// `bdlma::Pool` objects in a similar fashion to `bdlma::Multipool`.  In this
/// example, we create just such a multipool allocator, `my_MultipoolAllocator`,
/// that uses a `bdlma::Multipool` to manage the multiple pools.
///
/// First, we define the interface of `my_MultipoolAllocator`:
/// @code
/// class my_MultipoolAllocator : public bslma::Allocator {
///     // This class implements the 'bslma::Allocator' protocol to provide an
///     // allocator that manages a set of memory pools, each dispensing memory
///     // blocks of a unique size, with each successive pool's block size
///     // being twice that of the previous one.
///
///     // DATA
///     bdlma::Multipool d_multiPool;  // memory manager for allocated memory
///                                    // blocks
///
///   public:
///     // CREATORS
///     my_MultipoolAllocator(bslma::Allocator *basicAllocator = 0);
///         // Create a multipool allocator.  Optionally specify a
///         // 'basicAllocator' used to supply memory.  If 'basicAllocator' is
///         // 0, the currently installed default allocator is used.
///
///     // ...
///
///     virtual ~my_MultipoolAllocator();
///         // Destroy this multipool allocator.  All memory allocated from
///         // this memory pool is released.
///
///     // MANIPULATORS
///     virtual void *allocate(bsls::Types::size_type size);
///         // Return the address of a contiguous block of maximally-aligned
///         // memory of (at least) the specified 'size' (in bytes).  If 'size'
///         // is 0, no memory is allocated and 0 is returned.
///
///     virtual void deallocate(void *address);
///         // Relinquish the memory block at the specified 'address' back to
///         // this multipool allocator for reuse.  The behavior is undefined
///         // unless 'address' is non-zero, was allocated by this multipool
///         // allocator, and has not already been deallocated.
/// };
/// @endcode
/// Note that the interface and documentation for this class is simplified for
/// this usage example.  Please see @ref bdlma_multipoolallocator  for a similar
/// class meant for production use.
///
/// Finally, we provide the trivial implementation of `my_MultipoolAllocator`:
/// @code
/// // CREATORS
/// inline
/// my_MultipoolAllocator::my_MultipoolAllocator(
///                                           bslma::Allocator *basicAllocator)
/// : d_multiPool(basicAllocator)
/// {
/// }
///
/// my_MultipoolAllocator::~my_MultipoolAllocator()
/// {
/// }
///
/// // MANIPULATORS
/// inline
/// void *my_MultipoolAllocator::allocate(bsls::Types::size_type size)
/// {
///     if (0 == size) {
///         return 0;                                                 // RETURN
///     }
///
///     return d_multiPool.allocate(size);
/// }
///
/// inline
/// void my_MultipoolAllocator::deallocate(void *address)
/// {
///     d_multiPool.deallocate(address);
/// }
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdlma
 * @{
 */
/** @addtogroup bdlma_multipool
 * @{
 */
 
#include <bdlscm_version.h>
 
#include <bdlma_blocklist.h>
#include <bdlma_pool.h>
 
#include <bslma_allocator.h>
#include <bslma_deleterhelper.h>
 
#include <bsls_alignmentutil.h>
#include <bsls_blockgrowth.h>
#include <bsls_types.h>
 
 
namespace bdlma {
 
                             // ===============
                             // class Multipool
                             // ===============
 
/// This class implements a memory manager that maintains a configurable
/// number of `bdlma::Pool` objects, each dispensing memory blocks of a
/// unique size.  The `bdlma::Pool` objects are placed in an array, with
/// each successive pool managing memory blocks of size twice that of the
/// previous pool.  Each multipool allocation (deallocation) request
/// allocates memory from (returns memory to) the internal pool having the
/// smallest block size not less than the requested size, or, if no pool
/// manages memory blocks of sufficient size, from a separately managed list
/// of memory blocks.  Both the `release` method and the destructor of a
/// `bdlma::Multipool` release all memory currently allocated via the
/// object.
///
/// See @ref bdlma_multipool 
class Multipool {
 
    // PRIVATE TYPES
 
    /// This `struct` provides header information for each allocated memory
    /// block.  The header stores the index to the pool used for the memory
    /// allocation.
    struct Header {
 
        union {
            int                    d_poolIdx;  // index to pool used for this
                                               // memory block, or -1 if from
                                               // 'd_blockList'
 
            bsls::AlignmentUtil::MaxAlignedType
                                   d_dummy;    // force maximum alignment
        } d_header;
    };
 
    // DATA
    Pool                   *d_pools_p;       // array of memory pools, each
                                             // dispensing fixed-size memory
                                             // blocks
 
    int                     d_numPools;      // number of memory pools
 
    bsls::Types::size_type  d_maxBlockSize;  // largest memory block size;
                                             // dispensed by the
                                             // 'd_numPools - 1'th pool; always
                                             // a power of 2
 
    BlockList               d_blockList;     // memory manager for "large"
                                             // memory blocks
 
    bslma::Allocator       *d_allocator_p;   // holds (but does not own)
                                             // allocator
 
  private:
    // PRIVATE MANIPULATORS
 
    void initialize(bsls::BlockGrowth::Strategy growthStrategy,
                    int                         maxBlocksPerChunk);
    void initialize(const bsls::BlockGrowth::Strategy *growthStrategyArray,
                    int                                maxBlocksPerChunk);
    void initialize(bsls::BlockGrowth::Strategy  growthStrategy,
                    const int                   *maxBlocksPerChunkArray);
    /// Initialize this multipool with the specified `growthStrategy[Array]`
    /// and `maxBlocksPerChunk[Array]`.  If an array is used, each
    /// individual `bdlma::Pool` maintained by this multipool is initialized
    /// with the corresponding growth strategy or max blocks per chunk entry
    /// within the array.
    void initialize(const bsls::BlockGrowth::Strategy *growthStrategyArray,
                    const int                         *maxBlocksPerChunkArray);
 
    // PRIVATE ACCESSORS
 
    /// Return the index of the memory pool in this multipool for an
    /// allocation request of the specified `size` (in bytes).  The behavior
    /// is undefined unless `size <= maxPooledBlockSize()`.  Note that the
    /// index of the memory pool managing memory blocks having the minimum
    /// block size is 0.
    int findPool(bsls::Types::size_type size) const;
 
  private:
    // NOT IMPLEMENTED
    Multipool(const Multipool&);
    Multipool& operator=(const Multipool&);
 
  public:
    // CREATORS
 
    explicit
    Multipool(bslma::Allocator *basicAllocator = 0);
    explicit
    Multipool(int numPools, bslma::Allocator *basicAllocator = 0);
    explicit
    Multipool(bsls::BlockGrowth::Strategy  growthStrategy,
              bslma::Allocator            *basicAllocator = 0);
    Multipool(int                          numPools,
              bsls::BlockGrowth::Strategy  growthStrategy,
              bslma::Allocator            *basicAllocator = 0);
    /// Create a multipool memory manager.  Optionally specify `numPools`,
    /// indicating the number of internally created `bdlma::Pool` objects;
    /// the block size of the first pool is 8 bytes, with the block size of
    /// each additional pool successively doubling.  If `numPools` is not
    /// specified, an implementation-defined number of pools `N` -- covering
    /// memory blocks ranging in size from `2^3 = 8` to `2^(N+2)` -- are
    /// created.  Optionally specify a `growthStrategy` indicating whether
    /// the number of blocks allocated at once for every internally created
    /// `bdlma::Pool` should be either fixed or grow geometrically, starting
    /// with 1.  If `growthStrategy` is not specified, the allocation
    /// strategy for each internally created `bdlma::Pool` object is
    /// geometric, starting from 1.  If `numPools` and `growthStrategy` are
    /// specified, optionally specify a `maxBlocksPerChunk`, indicating the
    /// maximum number of blocks to be allocated at once when a pool must be
    /// replenished.  If `maxBlocksPerChunk` is not specified, an
    /// implementation-defined value is used.  Optionally specify a
    /// `basicAllocator` used to supply memory.  If `basicAllocator` is 0,
    /// the currently installed default allocator is used.  Memory
    /// allocation (and deallocation) requests will be satisfied using the
    /// internally maintained pool managing memory blocks of the smallest
    /// size not less than the requested size, or directly from the
    /// underlying allocator (supplied at construction), if no internal pool
    /// managing memory blocks of sufficient size exists.  The behavior is
    /// undefined unless `1 <= numPools` and `1 <= maxBlocksPerChunk`.  Note
    /// that, on platforms where
    /// `8 < bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT`, excess memory may be
    /// allocated for pools managing smaller blocks.  Also note that
    /// `maxBlocksPerChunk` need not be an integral power of 2; if geometric
    /// growth would exceed the maximum value, the chunk size is capped at
    /// that value.
    Multipool(int                          numPools,
              bsls::BlockGrowth::Strategy  growthStrategy,
              int                          maxBlocksPerChunk,
              bslma::Allocator            *basicAllocator = 0);
 
    Multipool(int                                numPools,
              const bsls::BlockGrowth::Strategy *growthStrategyArray,
              bslma::Allocator                  *basicAllocator = 0);
    Multipool(int                                numPools,
              const bsls::BlockGrowth::Strategy *growthStrategyArray,
              int                                maxBlocksPerChunk,
              bslma::Allocator                  *basicAllocator = 0);
    Multipool(int                          numPools,
              bsls::BlockGrowth::Strategy  growthStrategy,
              const int                   *maxBlocksPerChunkArray,
              bslma::Allocator            *basicAllocator = 0);
    /// Create a multipool memory manager having the specified `numPools`,
    /// indicating the number of internally created `bdlma::Pool` objects;
    /// the block size of the first pool is 8 bytes, with the block size of
    /// each additional pool successively doubling.  Optionally specify a
    /// `growthStrategy` indicating whether the number of blocks allocated
    /// at once for every internally created `bdlma::Pool` should be either
    /// fixed or grow geometrically, starting with 1.  If `growthStrategy`
    /// is not specified, optionally specify a `growthStrategyArray`,
    /// indicating the strategies for each individual `bdlma::Pool` created
    /// by this object.  If neither `growthStrategy` nor
    /// `growthStrategyArray` is specified, the allocation strategy for each
    /// internally created `bdlma::Pool` object will grow geometrically,
    /// starting from 1.  Optionally specify a `maxBlocksPerChunk`,
    /// indicating the maximum number of blocks to be allocated at once when
    /// a pool must be replenished.  If `maxBlocksPerChunk` is not
    /// specified, optionally specify a `maxBlocksPerChunkArray`, indicating
    /// the maximum number of blocks to allocate at once for each
    /// individually created `bdlma::Pool` object.  If neither
    /// `maxBlocksPerChunk` nor `maxBlocksPerChunkArray` is specified, an
    /// implementation-defined value is used.  Optionally specify a
    /// `basicAllocator` used to supply memory.  If `basicAllocator` is 0,
    /// the currently installed default allocator is used.  Memory
    /// allocation (and deallocation) requests will be satisfied using the
    /// internally maintained pool managing memory blocks of the smallest
    /// size not less than the requested size, or directly from the
    /// underlying allocator (supplied at construction), if no internal pool
    /// managing memory blocks of sufficient size exists.  The behavior is
    /// undefined unless `1 <= numPools`, `growthStrategyArray` has at least
    /// `numPools` strategies, `1 <= maxBlocksPerChunk`, and
    /// `maxBlocksPerChunkArray` has at least `numPools` positive values.
    /// Note that, on platforms where
    /// `8 < bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT`, excess memory may be
    /// allocated for pools managing smaller blocks.  Also note that the
    /// maximum need not be an integral power of 2; if geometric growth
    /// would exceed a maximum value, the chunk size is capped at that
    /// value.
    Multipool(int                                numPools,
              const bsls::BlockGrowth::Strategy *growthStrategyArray,
              const int                         *maxBlocksPerChunkArray,
              bslma::Allocator                  *basicAllocator = 0);
 
    /// Destroy this multipool.  All memory allocated from this memory pool
    /// is released.
    ~Multipool();
 
    // MANIPULATORS
 
    /// Return the address of a contiguous block of maximally-aligned memory
    /// of (at least) the specified `size` (in bytes).  If `size` is 0, no
    /// memory is allocated and 0 is returned.  If
    /// `size > maxPooledBlockSize()`, the memory allocation is managed
    /// directly by the underlying allocator, and will not be pooled, but
    /// will be deallocated when the `release` method is called, or when
    /// this object is destroyed.
    void *allocate(bsls::Types::size_type size);
 
    /// Relinquish the memory block at the specified `address` back to this
    /// multipool object for reuse.  The behavior is undefined unless
    /// `address` is non-zero, was allocated by this multipool object, and
    /// has not already been deallocated.
    void deallocate(void *address);
 
    /// Destroy the specified `object` based on its dynamic type and then
    /// use this multipool object to deallocate its memory footprint.  This
    /// method has no effect if `object` is 0.  The behavior is undefined
    /// unless `object`, when cast appropriately to `void *`, was allocated
    /// using this multipool object and has not already been deallocated.
    /// Note that `dynamic_cast<void *>(object)` is applied if `TYPE` is
    /// polymorphic, and `static_cast<void *>(object)` is applied otherwise.
    template <class TYPE>
    void deleteObject(const TYPE *object);
 
    /// Destroy the specified `object` and then use this multipool to
    /// deallocate its memory footprint.  This method has no effect if
    /// `object` is 0.  The behavior is undefined unless `object` is **not** a
    /// secondary base class pointer (i.e., the address is (numerically) the
    /// same as when it was originally dispensed by this multipool), was
    /// allocated using this multipool, and has not already been
    /// deallocated.
    template <class TYPE>
    void deleteObjectRaw(const TYPE *object);
 
    /// Relinquish all memory currently allocated via this multipool object.
    void release();
 
    /// Reserve memory from this multipool to satisfy memory requests for at
    /// least the specified `numBlocks` having the specified `size` (in
    /// bytes) before the pool replenishes.  If `size` is 0, this method has
    /// no effect.  The behavior is undefined unless
    /// `size <= maxPooledBlockSize()` and `0 <= numBlocks`.
    void reserveCapacity(bsls::Types::size_type size, int numBlocks);
 
    // ACCESSORS
 
    /// Return the number of pools managed by this multipool object.
    int numPools() const;
 
    /// Return the maximum size of memory blocks that are pooled by this
    /// multipool object.  Note that the maximum value is defined as:
    /// @code
    /// 2 ^ (numPools + 2)
    /// @endcode
    /// where `numPools` is either specified at construction, or an
    /// implementation-defined value.
    bsls::Types::size_type maxPooledBlockSize() const;
 
                                  // Aspects
 
    /// 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.
    bslma::Allocator *allocator() const;
};
 
// ============================================================================
//                             INLINE DEFINITIONS
// ============================================================================
 
                             // ---------------
                             // class Multipool
                             // ---------------
 
// MANIPULATORS
template <class TYPE>
inline
void Multipool::deleteObject(const TYPE *object)
{
    bslma::DeleterHelper::deleteObject(object, this);
}
 
template <class TYPE>
inline
void Multipool::deleteObjectRaw(const TYPE *object)
{
    bslma::DeleterHelper::deleteObjectRaw(object, this);
}
 
// ACCESSORS
inline
int Multipool::numPools() const
{
    return d_numPools;
}
 
inline
bsls::Types::size_type Multipool::maxPooledBlockSize() const
{
    return d_maxBlockSize;
}
 
// Aspects
 
inline
bslma::Allocator *Multipool::allocator() const
{
    return d_allocator_p;
}
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2016 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */