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1.3.3
by David MartÃnez Moreno
Import upstream version 1.4.0 |
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/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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#ifndef CACHE_H
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#define CACHE_H
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#include <pthread.h> |
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#ifdef HAVE_UMEM_H
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#include <umem.h> |
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#define cache_t umem_cache_t
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#define cache_alloc(a) umem_cache_alloc(a, UMEM_DEFAULT)
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#define cache_free(a, b) umem_cache_free(a, b)
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#define cache_create(a,b,c,d,e) umem_cache_create((char*)a, b, c, d, e, NULL, NULL, NULL, 0)
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#define cache_destroy(a) umem_cache_destroy(a);
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#else
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#ifndef NDEBUG
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/* may be used for debug purposes */
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extern int cache_error; |
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#endif
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/**
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* Constructor used to initialize allocated objects
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*
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* @param obj pointer to the object to initialized.
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* @param notused1 This parameter is currently not used.
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* @param notused2 This parameter is currently not used.
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* @return you should return 0, but currently this is not checked
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*/
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typedef int cache_constructor_t(void* obj, void* notused1, int notused2); |
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/**
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* Destructor used to clean up allocated objects before they are
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* returned to the operating system.
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*
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* @param obj pointer to the object to initialized.
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* @param notused1 This parameter is currently not used.
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* @param notused2 This parameter is currently not used.
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* @return you should return 0, but currently this is not checked
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*/
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typedef void cache_destructor_t(void* obj, void* notused); |
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/**
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* Definition of the structure to keep track of the internal details of
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* the cache allocator. Touching any of these variables results in
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* undefined behavior.
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*/
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typedef struct { |
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/** Mutex to protect access to the structure */
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pthread_mutex_t mutex; |
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/** Name of the cache objects in this cache (provided by the caller) */
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char *name; |
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/** List of pointers to available buffers in this cache */
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void **ptr; |
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/** The size of each element in this cache */
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size_t bufsize; |
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/** The capacity of the list of elements */
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int freetotal; |
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/** The current number of free elements */
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int freecurr; |
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/** The constructor to be called each time we allocate more memory */
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cache_constructor_t* constructor; |
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/** The destructor to be called each time before we release memory */
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cache_destructor_t* destructor; |
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} cache_t; |
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/**
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* Create an object cache.
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*
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* The object cache will let you allocate objects of the same size. It is fully
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* MT safe, so you may allocate objects from multiple threads without having to
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* do any syncrhonization in the application code.
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*
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* @param name the name of the object cache. This name may be used for debug purposes
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* and may help you track down what kind of object you have problems with
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* (buffer overruns, leakage etc)
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* @param bufsize the size of each object in the cache
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* @param align the alignment requirements of the objects in the cache.
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* @param constructor the function to be called to initialize memory when we need
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* to allocate more memory from the os.
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* @param destructor the function to be called before we release the memory back
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* to the os.
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* @return a handle to an object cache if successful, NULL otherwise.
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*/
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cache_t* cache_create(const char* name, size_t bufsize, size_t align, |
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cache_constructor_t* constructor, |
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cache_destructor_t* destructor); |
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/**
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* Destroy an object cache.
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*
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* Destroy and invalidate an object cache. You should return all buffers allocated
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* with cache_alloc by using cache_free before calling this function. Not doing
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* so results in undefined behavior (the buffers may or may not be invalidated)
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*
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* @param handle the handle to the object cache to destroy.
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*/
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void cache_destroy(cache_t* handle); |
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/**
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* Allocate an object from the cache.
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*
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* @param handle the handle to the object cache to allocate from
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* @return a pointer to an initialized object from the cache, or NULL if
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* the allocation cannot be satisfied.
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*/
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void* cache_alloc(cache_t* handle); |
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/**
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* Return an object back to the cache.
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*
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* The caller should return the object in an initialized state so that
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* the object may be returned in an expected state from cache_alloc.
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*
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* @param handle handle to the object cache to return the object to
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* @param ptr pointer to the object to return.
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*/
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void cache_free(cache_t* handle, void* ptr); |
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#endif
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#endif
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