These functions provide some helper for a pseudo Copy On Write mechanism. More...
Macros | |
#define | EINA_COW_WRITE_BEGIN(Cow, Read, Write_Type, Write) |
This macro setup a writable pointer from a const one. More... | |
#define | EINA_COW_WRITE_END(Cow, Read, Write) |
This macro close the writable pointer. More... | |
Typedefs | |
typedef struct _Eina_Cow | Eina_Cow |
Type for Eina_Cow pool. | |
typedef void | Eina_Cow_Data |
Type of the returned pointer to simplify some reading. | |
Functions | |
Eina_Cow * | eina_cow_add (const char *name, unsigned int struct_size, unsigned int step, const void *default_value, Eina_Bool gc) |
Instantiate a new Eina_Cow pool. More... | |
void | eina_cow_del (Eina_Cow *cow) |
Destroy an Eina_Cow pool and all the allocated memory. More... | |
const Eina_Cow_Data * | eina_cow_alloc (Eina_Cow *cow) |
Return an initialized pointer from the pool. More... | |
void | eina_cow_free (Eina_Cow *cow, const Eina_Cow_Data **data) |
Free a pointer from the pool. More... | |
void * | eina_cow_write (Eina_Cow *cow, const Eina_Cow_Data *const *src) |
Get a writable pointer from a const pointer. More... | |
void | eina_cow_done (Eina_Cow *cow, const Eina_Cow_Data *const *dst, const void *data, Eina_Bool needed_gc) |
Set back a pointer into read only. More... | |
void | eina_cow_memcpy (Eina_Cow *cow, const Eina_Cow_Data *const *dst, const Eina_Cow_Data *src) |
Make the destination contain the same thing as the source pointer. More... | |
Eina_Bool | eina_cow_gc (Eina_Cow *cow) |
Try to find entries that have the same content and update them. More... | |
These functions provide some helper for a pseudo Copy On Write mechanism.
Eina_Cow will return const memory pointer to some default value that you will be able to change only by requesting a writable pointer. Later on a garbage collector can come online and try to merge back some of those pointer.
#define EINA_COW_WRITE_BEGIN | ( | Cow, | |
Read, | |||
Write_Type, | |||
Write | |||
) |
This macro setup a writable pointer from a const one.
Cow | The Eina_Cow where the const pointer come from. |
Read | The const pointer to get a writable handler from. |
Write_Type | The type of the pointer you want to write to. |
Write | The name of the variable where to put the writeable pointer to. |
Be careful this macro opens a C scope that is expected to be closed by EINA_COW_WRITE_END().
#define EINA_COW_WRITE_END | ( | Cow, | |
Read, | |||
Write | |||
) |
This macro close the writable pointer.
Cow | The Eina_Cow where the const pointer come from. |
Read | The const pointer to get a writable handler from. |
Write | The name of the variable where to put the writeable pointer to. |
Be careful this macro close the scope opened by EINA_COW_WRITE_BEGIN().
Eina_Cow* eina_cow_add | ( | const char * | name, |
unsigned int | struct_size, | ||
unsigned int | step, | ||
const void * | default_value, | ||
Eina_Bool | gc | ||
) |
Instantiate a new Eina_Cow pool.
name | The name of this pool, used for debug. |
struct_size | The size of the object from this pool. |
step | How many objects to allocate when the pool gets empty. |
default_value | The default value returned by this pool. |
gc | Is it possible to run garbage collection on this pool. |
NULL
on error. References eina_hash_new(), eina_hash_pointer_new(), and EINA_MAGIC_SET.
Referenced by edje_init().
void eina_cow_del | ( | Eina_Cow * | cow | ) |
Destroy an Eina_Cow pool and all the allocated memory.
cow | The pool to destroy |
References eina_hash_free().
Referenced by evas_shutdown().
const Eina_Cow_Data* eina_cow_alloc | ( | Eina_Cow * | cow | ) |
Return an initialized pointer from the pool.
cow | The pool to take things from. |
void eina_cow_free | ( | Eina_Cow * | cow, |
const Eina_Cow_Data ** | data | ||
) |
Free a pointer from the pool.
cow | The pool to gave back memory to. |
data | The data to give back. |
References EINA_MAGIC_NONE, and EINA_MAGIC_SET.
Referenced by eina_cow_memcpy().
void* eina_cow_write | ( | Eina_Cow * | cow, |
const Eina_Cow_Data *const * | src | ||
) |
Get a writable pointer from a const pointer.
cow | The pool the pointer come from. |
src | The pointer you want to write to. |
NOTE: this function is not thread safe, be careful.
References EINA_FALSE, EINA_MAGIC_SET, and EINA_TRUE.
void eina_cow_done | ( | Eina_Cow * | cow, |
const Eina_Cow_Data *const * | dst, | ||
const void * | data, | ||
Eina_Bool | needed_gc | ||
) |
Set back a pointer into read only.
cow | The pool the pointer come from. |
dst | The read only version of the pointer. |
data | The pointer to which data was written to. |
NOTE: this function is not thread safe, be careful.
References EINA_FALSE.
void eina_cow_memcpy | ( | Eina_Cow * | cow, |
const Eina_Cow_Data *const * | dst, | ||
const Eina_Cow_Data * | src | ||
) |
Make the destination contain the same thing as the source pointer.
cow | The pool the pointers come from. |
dst | The destination to update. |
src | The source of information to copy. |
References eina_cow_free().
Try to find entries that have the same content and update them.
cow | The cow to try to compact. |
There is no guaranty in the time it will require, but should remain low. It does run a hash function on all possible common structures trying to find the one that match and merge them into one pointer.
References EINA_FALSE, eina_hash_iterator_data_new(), eina_hash_population(), eina_iterator_free(), eina_iterator_next(), and EINA_TRUE.