Donatien Garnier
NetServices Stack source
Dependents: HelloWorld ServoInterfaceBoardExample1 4180_Lab4
Dynamic memory manager. More...
Go to the source code of this file.
Functions | |
| void * | mem_malloc (mem_size_t size) |
| Allocate memory: determine the smallest pool that is big enough to contain an element of 'size' and get an element from that pool. | |
| void | mem_free (void *rmem) |
| Free memory previously allocated by mem_malloc. | |
| static void | plug_holes (struct mem *mem) |
| "Plug holes" by combining adjacent empty struct mems. | |
| void | mem_init (void) |
| Zero the heap and initialize start, end and lowest-free. | |
| void * | mem_trim (void *rmem, mem_size_t newsize) |
| Shrink memory returned by mem_malloc(). | |
| void * | mem_calloc (mem_size_t count, mem_size_t size) |
| Contiguously allocates enough space for count objects that are size bytes of memory each and returns a pointer to the allocated memory. | |
Variables | |
| u8_t | ram_heap [MEM_SIZE_ALIGNED+(2 *SIZEOF_STRUCT_MEM)+MEM_ALIGNMENT] |
| If you want to relocate the heap to external memory, simply define LWIP_RAM_HEAP_POINTER as a void-pointer to that location. | |
| static u8_t * | ram |
| pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array | |
| static struct mem * | ram_end |
| the last entry, always unused! | |
| static struct mem * | lfree |
| pointer to the lowest free block, this is used for faster search | |
| static sys_mutex_t | mem_mutex |
| concurrent access protection | |
Detailed Description
Dynamic memory manager.
This is a lightweight replacement for the standard C library malloc().
If you want to use the standard C library malloc() instead, define MEM_LIBC_MALLOC to 1 in your lwipopts.h
To let mem_malloc() use pools (prevents fragmentation and is much faster than a heap but might waste some memory), define MEM_USE_POOLS to 1, define MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list of pools like this (more pools can be added between _START and _END):
Define three pools with sizes 256, 512, and 1512 bytes LWIP_MALLOC_MEMPOOL_START LWIP_MALLOC_MEMPOOL(20, 256) LWIP_MALLOC_MEMPOOL(10, 512) LWIP_MALLOC_MEMPOOL(5, 1512) LWIP_MALLOC_MEMPOOL_END
Definition in file mem.c.
Function Documentation
| void* mem_calloc | ( | mem_size_t | count, |
| mem_size_t | size | ||
| ) |
Contiguously allocates enough space for count objects that are size bytes of memory each and returns a pointer to the allocated memory.
The allocated memory is filled with bytes of value zero.
- Parameters:
-
count number of objects to allocate size size of the objects to allocate
- Returns:
- pointer to allocated memory / NULL pointer if there is an error
| void mem_free | ( | void * | rmem ) |
Free memory previously allocated by mem_malloc.
Put a struct mem back on the heap.
Loads the pool number and calls memp_free with that pool number to put the element back into its pool
- Parameters:
-
rmem the memory element to free rmem is the data portion of a struct mem as returned by a previous call to mem_malloc()
| void mem_init | ( | void | ) |
| void * mem_malloc | ( | mem_size_t | size ) |
Allocate memory: determine the smallest pool that is big enough to contain an element of 'size' and get an element from that pool.
Adam's mem_malloc() plus solution for bug #17922 Allocate a block of memory with a minimum of 'size' bytes.
- Parameters:
-
size the size in bytes of the memory needed
- Returns:
- a pointer to the allocated memory or NULL if the pool is empty
- Parameters:
-
size is the minimum size of the requested block in bytes.
- Returns:
- pointer to allocated memory or NULL if no free memory was found.
Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT).
Try a bigger pool if this one is empty!
| void* mem_trim | ( | void * | rmem, |
| mem_size_t | newsize | ||
| ) |
Shrink memory returned by mem_malloc().
- Parameters:
-
rmem pointer to memory allocated by mem_malloc the is to be shrinked newsize required size after shrinking (needs to be smaller than or equal to the previous size)
- Returns:
- for compatibility reasons: is always == rmem, at the moment or NULL if newsize is > old size, in which case rmem is NOT touched or freed!
| static void plug_holes | ( | struct mem * | mem ) | [static] |
Variable Documentation
struct mem* lfree [static] |
u8_t* ram [static] |
| u8_t ram_heap[MEM_SIZE_ALIGNED+(2 *SIZEOF_STRUCT_MEM)+MEM_ALIGNMENT] |
If you want to relocate the heap to external memory, simply define LWIP_RAM_HEAP_POINTER as a void-pointer to that location.
If so, make sure the memory at that location is big enough (see below on how that space is calculated). the heap. we need one struct mem at the end and some room for alignment
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