It took a really long time - three months minus one day - but I have finally finished version 0.4 of foonathan/memory. The release contains a lot of changes and has more than doubled the number of commits.
The interface is completely cleaned and I’ve got rid of the historically grown stuff. This required renaming or moving a lot of stuff, in particular:
std_allocatorand moved to the new header
raw_allocator_deleterare now simply
allocator_deallocatorin new hader
raw_allocate_deleteare likewise renamed into
allocate_deletesince they can also handle normal Allocators
- the jungle of
raw_allocatortypedefs are all
allocator_type, likewise for the getter, they’re all
stack_allocator.hppare now named after their classes:
memory_stack.hpprespectively; the other pool headers have gotten the
memory_-prefix as well
allocator_storage.hppfor a similar reason as the other headers
I’ve also added some missing features I’ve noticed while writing the documentation.
They are many tiny things like the ability to specify a
Mutex at almost every class or alias or more default template arguments for other classes.
Another thing polished are the error handling facilites.
Before they were a mess of various exceptions and calls to
Now they use a well-defined interface and exception types.
But those facilites are customizable using handler functions. This allows a user-defined error handling even if exception support is disabled.
Allocator storage and traits improvement
The old allocator adapters are completely changed in the implementation.
allocator_storage class template takes a
StoragePolicy and stores a
RawAllocator using it.
The adapters like
allocator_reference are now simply aliases for the
allocator_storage template with a given policy.
Type-erased storage has been added as well, the tag type
any_allocator can be specified as
RawAllocator everywhere it is stored by an
It activates a specialization of
allocator_reference that uses type-erasure to store a generic reference to any
The default template specialization of
allocator_traits has been overhauled, too.
It is now able to handle a broader range of types including all
The minimum required interface for it has been reduced to
the defaults in case of missing member functions are improved and there are better error messages if a type does not fulfill the criteria.
The addition of supporting the
Allocator concept allows passing an
Allocator anywhere a
RawAllocator is required.
The problem with pool allocators are that they require a node size.
For example, if you want to use a
std::list with a
memory::memory_pool you write:
memory::memory_pool<> pool(???, 4096); memory::list<int, decltype(pool)> list(pool);
At the point of
??? belongs the size of each node in the pool.
But what should it be? 16? 32? It depends on the size of each node in the
But the internal node size is not accessible, so there is no easy and portable way to get its size.
So I’ve added the
This tool debugs the node sizes of STL containers by passing them a custom allocator that tracks the size of the type it is rebound too.
It automatically generates constants in the header
container.hpp that contains the appropriate node sizes, allowing us to write:
memory::memory_pool<> pool(memory::list_node_size<int>::value, 4096); memory::list<int, decltype(pool)> list(pool);
Other things worth mentioning
- new documentation and tutorial hosted here, at http://foonathan.github.io/doc/memory/
- all functionality except those that is an explicit wrapper around the standard library - like
container.hpp- can work on a freestanding implementation
- the compatibility checks are outsourced to foonathan/compatibility
- bugfixes, bugfixes and bugfixes, most notably regarding alignment issues with activated fence memory
This blog post was written for my old blog design and ported over. If there are any issues, please let me know.