mem.c File Reference

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

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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
	LWIP_DECLARE_MEMORY_ALIGNED (ram_heap, MEM_SIZE_ALIGNED+(2U *SIZEOF_STRUCT_MEM))
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)

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 MEMP_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 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 296 of file mem.c.

Function Documentation

LWIP_DECLARE_MEMORY_ALIGNED	(	ram_heap	,
		MEM_SIZE_ALIGNED+	2U *SIZEOF_STRUCT_MEM
	)

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

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 784 of file mem.c.

References mem_malloc().

Referenced by mem_malloc().

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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 438 of file mem.c.

References LWIP_DBG_LEVEL_SERIOUS, LWIP_DBG_LEVEL_SEVERE, LWIP_DBG_TRACE, LWIP_DEBUGF, MEM_DEBUG, mem::next, SYS_ARCH_DECL_PROTECT, and mem::used.

Referenced by mem_free_callback(), memp_malloc(), pbuf_free(), and slipif_init().

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void mem_init

(

void

)

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

Definition at line 401 of file mem.c.

References ERR_OK, LWIP_MEM_ALIGN, mem::next, mem::prev, sys_mutex_new(), and mem::used.

Referenced by lwip_init().

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void* mem_malloc

(

mem_size_t

size

)

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 622 of file mem.c.

References LWIP_DBG_LEVEL_SERIOUS, LWIP_DEBUGF, LWIP_MEM_ALIGN_SIZE, mem_calloc(), MEM_DEBUG, mem::next, mem::prev, sys_mutex_lock(), sys_mutex_unlock(), and mem::used.

Referenced by mem_calloc(), memp_init(), pbuf_alloc(), and slipif_init().

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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 497 of file mem.c.

References LWIP_DBG_LEVEL_SEVERE, LWIP_DEBUGF, LWIP_MEM_ALIGN_SIZE, MEM_DEBUG, mem::next, mem::prev, SYS_ARCH_DECL_PROTECT, and mem::used.

Referenced by pbuf_realloc().

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