wenjuno / memory_management

Memory management in C

Memory management (v1.1.0)

Memory management in C

Global typedef

CMM_free_func is defined as a type of function pointer taking a void pointer and return void. It is used as a type for free() function.

CMM_handle is defined as a type for memory management handle.

Global interfaces (recommended)

int CMM_Init(size_t buckets)

This is the initialization function that should be called before using the memory management. The parameter specifies the number of buckets used for hash table. More buckets can decrease the probability of conflict but incur more memory overhead. In the case of allocation failure, the function returns 1.

void CMM_Finalize()

This is the finalization function that clean up the memory that managed by the handle and the handle itself.

void* CMM_Malloc(size_t)

Basically, this function calls malloc for the memory and register the memory in the management unit. In case the malloc returns NULL, this function returns NULL. This function is recommended for basic use.

int CMM_Register_memory(void*)

Manually register the memory to the management unit. The return codes and their meaning are as follows:

• 0 - successful
• 1 - failed because insufficient memory
• 2 = called before CMM_Init or after CMM_Finalize

int CMM_Register_special_memory(void*, CMM_free_func)

Manually register the memory to the management unit. The only difference between this function and the previous function is that custom free function can be specified to free this chunk memory. The return code is the same as previous function.

void CMM_Set_free_func(CMM_free_func)

This function set the default free function.

int CMM_Free(void*)

This function free the specified memory in the management unit. The return codes and their meaning are as follows:

• 0 - successful
• 1 - the memory pointed by the pointer is not found in the management unit
• 2 - pointer is NULL
• 3 - called before CMM_Init or after CMM_Finalize

Local interfaces (expert interfaces)

CMM_handle* CMM_init(size_t buckets)

This is the initialization function that should be called before using the memory management. The parameter specifies the number of buckets used for hash table. More buckets can decrease the probability of conflict but incur more memory overhead. The return handle should be check against NULL. In the case of allocation failure, the function returns NULL pointer.

void CMM_finalize(CMM_handle*)

This is the finalization function that clean up the memory that managed by the handle and the handle itself. This function must be call before the handle variable becomes out of scope otherwise memory leak is ensure (even user manually free the memory, the internal memory in the memory management unit will certainly leak).

void* CMM_malloc(CMM_handle*, size_t)

Basically, this function calls malloc for the memory and register the memory in the management unit. In case the malloc returns NULL, this function returns NULL. This function is recommended for basic use.

int CMM_register_memory(CMM_handle*, void*)

Manually register the memory to the management unit. The return codes and their meaning are as follows:

• 0 - successful
• 1 - failed because insufficient memory
• 2 = CMM_handle is NULL

int CMM_register_special_memory(CMM_handle*, void*, CMM_free_func)

Manually register the memory to the management unit. The only difference between this function and the previous function is that custom free function can be specified to free this chunk memory. The return code is the same as previous function.

void CMM_set_free_func(CMM_handle*, CMM_free_func)

This function set the default free function.

int CMM_free(CMM_handle*, void*)

This function free the specified memory in the management unit. The return codes and their meaning are as follows:

• 0 - successful
• 1 - the memory pointed by the pointer is not found in the management unit
• 2 - pointer is NULL
• 3 - CMM_handle is NULL

Usage tips (expert interfaces)

• Initialize a management unit at the beginning of the function.
• Use CMM_malloc to ease the way to get and register the memory.
• Call CMM_finalize at the end of the function to clean up.
• CMM_free is totally optional.