wenjuno / c_mem_pool

Memory pool implemented in C

c_mem_pool (v1.2.0)

Fixed size memory pool implemented in C

Interfaces

Handle type

The type of the handle for the memory pool is MP_handle.

long mp_version();

Returns the version number. The version number is formatted as AABBCC (or ABBCC), in which AA is the major version number for major feature, BB is the minor version number for interfaces and CC is the micro version number for bug fixes.

MP_handle* MP_init(size_t size, size_t count);

Initialization routine that returns the handle for the memory pool. The first parameter is the size of the fixed size memory chunk that the memory pool will allocates and the second parameter is the number of memory chunk initially allocated internally. When allocation failed, this routine returns NULL.

void MP_finalize(MP_handle*);

Finalization routine that free all memory.

void* MP_alloc(MP_handle*);

Return a chunk of memory from memory pool.

int MP_free(MP_handle*, void*);

Recycle the memory that allocated by MP_alloc back to memory pool. When MP_DEBUG is defined, the memory address is checked for its validity. See Debug mode for more detail.

Notes

• User does not have to call MP_free for every chunk of memory allocated by MP_alloc. But user must call MP_finalize to actually free the memory otherwise memory leak is followed. However, memory pool will increase its pool size when memory pool is fully occupied, so calling MP_free to recycle unused memory can save actual memory allocation counts.

Debug mode

The debug mode can be activated by compiling with MP_DEBUG macro defined. In debug mode the MP_alloc routine will encode unique bookkeeping information after the end of the memory chunk for each memory of each memory pool instance. So when MP_free is called, it will check the bookkeeping information and refuse to recycle the memory if information is incorrect and returns 1. This error might usually happen in the following scenarios:

• Calling MP_free with memory allocated from MP_alloc of other memory pool.
• Memory is corrupted because of out-of-range access.
• Calling MP_free more than once on the same memory.