mem.c File Reference

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/sys.h"
#include "lwip/stats.h"
#include "lwip/err.h"
#include <string.h>

Go to the source code of this file.

Classes
struct	mem

Macros
#define	MIN_SIZE   12
#define	MIN_SIZE_ALIGNED   LWIP_MEM_ALIGN_SIZE(MIN_SIZE)
#define	SIZEOF_STRUCT_MEM   LWIP_MEM_ALIGN_SIZE(sizeof(struct mem))
#define	MEM_SIZE_ALIGNED   LWIP_MEM_ALIGN_SIZE(MEM_SIZE)
#define	LWIP_RAM_HEAP_POINTER   ram_heap
#define	LWIP_MEM_FREE_DECL_PROTECT()
#define	LWIP_MEM_FREE_PROTECT()   sys_mutex_lock(&mem_mutex)
#define	LWIP_MEM_FREE_UNPROTECT()   sys_mutex_unlock(&mem_mutex)
#define	LWIP_MEM_ALLOC_DECL_PROTECT()
#define	LWIP_MEM_ALLOC_PROTECT()
#define	LWIP_MEM_ALLOC_UNPROTECT()

Functions
void	mem_init (void)
void	mem_free (void *rmem)
void *	mem_trim (void *rmem, mem_size_t newsize)
void *	mem_malloc (mem_size_t size)
void *	mem_calloc (mem_size_t count, mem_size_t size)

Variables
u8_t	ram_heap [MEM_SIZE_ALIGNED+(2 *SIZEOF_STRUCT_MEM)+MEM_ALIGNMENT]

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.

Macro Definition Documentation

#define LWIP_MEM_ALLOC_DECL_PROTECT

(

)

Definition at line 214 of file mem.c.

#define LWIP_MEM_ALLOC_PROTECT

(

)

Definition at line 215 of file mem.c.

#define LWIP_MEM_ALLOC_UNPROTECT

(

)

Definition at line 216 of file mem.c.

#define LWIP_MEM_FREE_DECL_PROTECT

(

)

concurrent access protection

Definition at line 210 of file mem.c.

#define LWIP_MEM_FREE_PROTECT

(

)

sys_mutex_lock(&mem_mutex)

Definition at line 211 of file mem.c.

#define LWIP_MEM_FREE_UNPROTECT

(

)

sys_mutex_unlock(&mem_mutex)

Definition at line 212 of file mem.c.

#define LWIP_RAM_HEAP_POINTER   ram_heap

Definition at line 182 of file mem.c.

#define MEM_SIZE_ALIGNED   LWIP_MEM_ALIGN_SIZE(MEM_SIZE)

Definition at line 173 of file mem.c.

#define MIN_SIZE   12

All allocated blocks will be MIN_SIZE bytes big, at least! MIN_SIZE can be overridden to suit your needs. Smaller values save space, larger values could prevent too small blocks to fragment the RAM too much.

Definition at line 168 of file mem.c.

#define MIN_SIZE_ALIGNED   LWIP_MEM_ALIGN_SIZE(MIN_SIZE)

Definition at line 171 of file mem.c.

#define SIZEOF_STRUCT_MEM   LWIP_MEM_ALIGN_SIZE(sizeof(struct mem))

Definition at line 172 of 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

Definition at line 629 of file mem.c.

void mem_free

(

void *

rmem)

Put a struct mem back on the heap

Parameters

rmem	is the data portion of a struct mem as returned by a previous call to mem_malloc()

Definition at line 308 of file mem.c.

void mem_init

(

void

)

Zero the heap and initialize start, end and lowest-free

Definition at line 271 of file mem.c.

void* mem_malloc

(

mem_size_t

size)

Adam's mem_malloc() plus solution for bug #17922 Allocate a block of memory with a minimum of 'size' bytes.

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).

Definition at line 491 of file mem.c.

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!

Definition at line 366 of file mem.c.

Variable Documentation

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

Definition at line 181 of file mem.c.