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Diffstat (limited to 'core/lwip/src/core/mem.c')
| -rw-r--r-- | core/lwip/src/core/mem.c | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/core/lwip/src/core/mem.c b/core/lwip/src/core/mem.c new file mode 100644 index 00000000..2934e5a9 --- /dev/null +++ b/core/lwip/src/core/mem.c @@ -0,0 +1,642 @@ +/** + * @file + * 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 + */ + +/* + * Copyright (c) 2001-2004 Swedish Institute of Computer Science. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without modification, + * are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT + * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY + * OF SUCH DAMAGE. + * + * This file is part of the lwIP TCP/IP stack. + * + * Author: Adam Dunkels <adam@sics.se> + * Simon Goldschmidt + * + */ + +#include "lwip/opt.h" + +#if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */ + +#include "lwip/def.h" +#include "lwip/mem.h" +#include "lwip/sys.h" +#include "lwip/stats.h" +#include "lwip/err.h" + +#include <string.h> + +#if MEM_USE_POOLS +/* lwIP head implemented with different sized pools */ + +/** + * Allocate memory: determine the smallest pool that is big enough + * to contain an element of 'size' and get an element from that pool. + * + * @param size the size in bytes of the memory needed + * @return a pointer to the allocated memory or NULL if the pool is empty + */ +void * +mem_malloc(mem_size_t size) +{ + struct memp_malloc_helper *element; + memp_t poolnr; + mem_size_t required_size = size + sizeof(struct memp_malloc_helper); + + for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr = (memp_t)(poolnr + 1)) { +#if MEM_USE_POOLS_TRY_BIGGER_POOL +again: +#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ + /* is this pool big enough to hold an element of the required size + plus a struct memp_malloc_helper that saves the pool this element came from? */ + if (required_size <= memp_sizes[poolnr]) { + break; + } + } + if (poolnr > MEMP_POOL_LAST) { + LWIP_ASSERT("mem_malloc(): no pool is that big!", 0); + return NULL; + } + element = (struct memp_malloc_helper*)memp_malloc(poolnr); + if (element == NULL) { + /* No need to DEBUGF or ASSERT: This error is already + taken care of in memp.c */ +#if MEM_USE_POOLS_TRY_BIGGER_POOL + /** Try a bigger pool if this one is empty! */ + if (poolnr < MEMP_POOL_LAST) { + poolnr++; + goto again; + } +#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ + return NULL; + } + + /* save the pool number this element came from */ + element->poolnr = poolnr; + /* and return a pointer to the memory directly after the struct memp_malloc_helper */ + element++; + + return element; +} + +/** + * Free memory previously allocated by mem_malloc. Loads the pool number + * and calls memp_free with that pool number to put the element back into + * its pool + * + * @param rmem the memory element to free + */ +void +mem_free(void *rmem) +{ + struct memp_malloc_helper *hmem = (struct memp_malloc_helper*)rmem; + + LWIP_ASSERT("rmem != NULL", (rmem != NULL)); + LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem))); + + /* get the original struct memp_malloc_helper */ + hmem--; + + LWIP_ASSERT("hmem != NULL", (hmem != NULL)); + LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem))); + LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX)); + + /* and put it in the pool we saved earlier */ + memp_free(hmem->poolnr, hmem); +} + +#else /* MEM_USE_POOLS */ +/* lwIP replacement for your libc malloc() */ + +/** + * The heap is made up as a list of structs of this type. + * This does not have to be aligned since for getting its size, + * we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes. + */ +struct mem { + /** index (-> ram[next]) of the next struct */ + mem_size_t next; + /** index (-> ram[prev]) of the previous struct */ + mem_size_t prev; + /** 1: this area is used; 0: this area is unused */ + u8_t used; +}; + +/** 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. */ +#ifndef MIN_SIZE +#define MIN_SIZE 12 +#endif /* MIN_SIZE */ +/* some alignment macros: we define them here for better source code layout */ +#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) + +/** 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). */ +#ifndef LWIP_RAM_HEAP_POINTER +/** the heap. we need one struct mem at the end and some room for alignment */ +u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT]; +#define LWIP_RAM_HEAP_POINTER ram_heap +#endif /* LWIP_RAM_HEAP_POINTER */ + +/** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */ +static u8_t *ram; +/** the last entry, always unused! */ +static struct mem *ram_end; +/** pointer to the lowest free block, this is used for faster search */ +static struct mem *lfree; + +/** concurrent access protection */ +static sys_mutex_t mem_mutex; + +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + +static volatile u8_t mem_free_count; + +/* Allow mem_free from other (e.g. interrupt) context */ +#define LWIP_MEM_FREE_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_free) +#define LWIP_MEM_FREE_PROTECT() SYS_ARCH_PROTECT(lev_free) +#define LWIP_MEM_FREE_UNPROTECT() SYS_ARCH_UNPROTECT(lev_free) +#define LWIP_MEM_ALLOC_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_alloc) +#define LWIP_MEM_ALLOC_PROTECT() SYS_ARCH_PROTECT(lev_alloc) +#define LWIP_MEM_ALLOC_UNPROTECT() SYS_ARCH_UNPROTECT(lev_alloc) + +#else /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + +/* Protect the heap only by using a semaphore */ +#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) +/* mem_malloc is protected using semaphore AND LWIP_MEM_ALLOC_PROTECT */ +#define LWIP_MEM_ALLOC_DECL_PROTECT() +#define LWIP_MEM_ALLOC_PROTECT() +#define LWIP_MEM_ALLOC_UNPROTECT() + +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + + +/** + * "Plug holes" by combining adjacent empty struct mems. + * After this function is through, there should not exist + * one empty struct mem pointing to another empty struct mem. + * + * @param mem this points to a struct mem which just has been freed + * @internal this function is only called by mem_free() and mem_trim() + * + * This assumes access to the heap is protected by the calling function + * already. + */ +static void +plug_holes(struct mem *mem) +{ + struct mem *nmem; + struct mem *pmem; + + LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram); + LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end); + LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0); + + /* plug hole forward */ + LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", mem->next <= MEM_SIZE_ALIGNED); + + nmem = (struct mem *)(void *)&ram[mem->next]; + if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) { + /* if mem->next is unused and not end of ram, combine mem and mem->next */ + if (lfree == nmem) { + lfree = mem; + } + mem->next = nmem->next; + ((struct mem *)(void *)&ram[nmem->next])->prev = (mem_size_t)((u8_t *)mem - ram); + } + + /* plug hole backward */ + pmem = (struct mem *)(void *)&ram[mem->prev]; + if (pmem != mem && pmem->used == 0) { + /* if mem->prev is unused, combine mem and mem->prev */ + if (lfree == mem) { + lfree = pmem; + } + pmem->next = mem->next; + ((struct mem *)(void *)&ram[mem->next])->prev = (mem_size_t)((u8_t *)pmem - ram); + } +} + +/** + * Zero the heap and initialize start, end and lowest-free + */ +void +lwip_mem_init(void) +{ + struct mem *mem; + + LWIP_ASSERT("Sanity check alignment", + (SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT-1)) == 0); + + /* align the heap */ + ram = (u8_t *)LWIP_MEM_ALIGN(LWIP_RAM_HEAP_POINTER); + /* initialize the start of the heap */ + mem = (struct mem *)(void *)ram; + mem->next = MEM_SIZE_ALIGNED; + mem->prev = 0; + mem->used = 0; + /* initialize the end of the heap */ + ram_end = (struct mem *)(void *)&ram[MEM_SIZE_ALIGNED]; + ram_end->used = 1; + ram_end->next = MEM_SIZE_ALIGNED; + ram_end->prev = MEM_SIZE_ALIGNED; + + /* initialize the lowest-free pointer to the start of the heap */ + lfree = (struct mem *)(void *)ram; + + MEM_STATS_AVAIL(avail, MEM_SIZE_ALIGNED); + + if(sys_mutex_new(&mem_mutex) != ERR_OK) { + LWIP_ASSERT("failed to create mem_mutex", 0); + } +} + +/** + * Put a struct mem back on the heap + * + * @param rmem is the data portion of a struct mem as returned by a previous + * call to mem_malloc() + */ +void +mem_free(void *rmem) +{ + struct mem *mem; + LWIP_MEM_FREE_DECL_PROTECT(); + + if (rmem == NULL) { + LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("mem_free(p == NULL) was called.\n")); + return; + } + LWIP_ASSERT("mem_free: sanity check alignment", (((mem_ptr_t)rmem) & (MEM_ALIGNMENT-1)) == 0); + + LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram && + (u8_t *)rmem < (u8_t *)ram_end); + + if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { + SYS_ARCH_DECL_PROTECT(lev); + LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory\n")); + /* protect mem stats from concurrent access */ + SYS_ARCH_PROTECT(lev); + MEM_STATS_INC(illegal); + SYS_ARCH_UNPROTECT(lev); + return; + } + /* protect the heap from concurrent access */ + LWIP_MEM_FREE_PROTECT(); + /* Get the corresponding struct mem ... */ + mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); + /* ... which has to be in a used state ... */ + LWIP_ASSERT("mem_free: mem->used", mem->used); + /* ... and is now unused. */ + mem->used = 0; + + if (mem < lfree) { + /* the newly freed struct is now the lowest */ + lfree = mem; + } + + MEM_STATS_DEC_USED(used, mem->next - (mem_size_t)(((u8_t *)mem - ram))); + + /* finally, see if prev or next are free also */ + plug_holes(mem); +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + mem_free_count = 1; +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + LWIP_MEM_FREE_UNPROTECT(); +} + +/** + * Shrink memory returned by mem_malloc(). + * + * @param rmem pointer to memory allocated by mem_malloc the is to be shrinked + * @param newsize required size after shrinking (needs to be smaller than or + * equal to the previous size) + * @return 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! + */ +void * +mem_trim(void *rmem, mem_size_t newsize) +{ + mem_size_t size; + mem_size_t ptr, ptr2; + struct mem *mem, *mem2; + /* use the FREE_PROTECT here: it protects with sem OR SYS_ARCH_PROTECT */ + LWIP_MEM_FREE_DECL_PROTECT(); + + /* Expand the size of the allocated memory region so that we can + adjust for alignment. */ + newsize = LWIP_MEM_ALIGN_SIZE(newsize); + + if(newsize < MIN_SIZE_ALIGNED) { + /* every data block must be at least MIN_SIZE_ALIGNED long */ + newsize = MIN_SIZE_ALIGNED; + } + + if (newsize > MEM_SIZE_ALIGNED) { + return NULL; + } + + LWIP_ASSERT("mem_trim: legal memory", (u8_t *)rmem >= (u8_t *)ram && + (u8_t *)rmem < (u8_t *)ram_end); + + if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { + SYS_ARCH_DECL_PROTECT(lev); + LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_trim: illegal memory\n")); + /* protect mem stats from concurrent access */ + SYS_ARCH_PROTECT(lev); + MEM_STATS_INC(illegal); + SYS_ARCH_UNPROTECT(lev); + return rmem; + } + /* Get the corresponding struct mem ... */ + mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); + /* ... and its offset pointer */ + ptr = (mem_size_t)((u8_t *)mem - ram); + + size = mem->next - ptr - SIZEOF_STRUCT_MEM; + LWIP_ASSERT("mem_trim can only shrink memory", newsize <= size); + if (newsize > size) { + /* not supported */ + return NULL; + } + if (newsize == size) { + /* No change in size, simply return */ + return rmem; + } + + /* protect the heap from concurrent access */ + LWIP_MEM_FREE_PROTECT(); + + mem2 = (struct mem *)(void *)&ram[mem->next]; + if(mem2->used == 0) { + /* The next struct is unused, we can simply move it at little */ + mem_size_t next; + /* remember the old next pointer */ + next = mem2->next; + /* create new struct mem which is moved directly after the shrinked mem */ + ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; + if (lfree == mem2) { + lfree = (struct mem *)(void *)&ram[ptr2]; + } + mem2 = (struct mem *)(void *)&ram[ptr2]; + mem2->used = 0; + /* restore the next pointer */ + mem2->next = next; + /* link it back to mem */ + mem2->prev = ptr; + /* link mem to it */ + mem->next = ptr2; + /* last thing to restore linked list: as we have moved mem2, + * let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not + * the end of the heap */ + if (mem2->next != MEM_SIZE_ALIGNED) { + ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; + } + MEM_STATS_DEC_USED(used, (size - newsize)); + /* no need to plug holes, we've already done that */ + } else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) { + /* Next struct is used but there's room for another struct mem with + * at least MIN_SIZE_ALIGNED of data. + * Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem + * ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED'). + * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty + * region that couldn't hold data, but when mem->next gets freed, + * the 2 regions would be combined, resulting in more free memory */ + ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; + mem2 = (struct mem *)(void *)&ram[ptr2]; + if (mem2 < lfree) { + lfree = mem2; + } + mem2->used = 0; + mem2->next = mem->next; + mem2->prev = ptr; + mem->next = ptr2; + if (mem2->next != MEM_SIZE_ALIGNED) { + ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; + } + MEM_STATS_DEC_USED(used, (size - newsize)); + /* the original mem->next is used, so no need to plug holes! */ + } + /* else { + next struct mem is used but size between mem and mem2 is not big enough + to create another struct mem + -> don't do anyhting. + -> the remaining space stays unused since it is too small + } */ +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + mem_free_count = 1; +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + LWIP_MEM_FREE_UNPROTECT(); + return rmem; +} + +/** + * Adam's mem_malloc() plus solution for bug #17922 + * Allocate a block of memory with a minimum of 'size' bytes. + * + * @param size is the minimum size of the requested block in bytes. + * @return 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). + */ +void * +mem_malloc(mem_size_t size) +{ + mem_size_t ptr, ptr2; + struct mem *mem, *mem2; +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + u8_t local_mem_free_count = 0; +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + LWIP_MEM_ALLOC_DECL_PROTECT(); + + if (size == 0) { + return NULL; + } + + /* Expand the size of the allocated memory region so that we can + adjust for alignment. */ + size = LWIP_MEM_ALIGN_SIZE(size); + + if(size < MIN_SIZE_ALIGNED) { + /* every data block must be at least MIN_SIZE_ALIGNED long */ + size = MIN_SIZE_ALIGNED; + } + + if (size > MEM_SIZE_ALIGNED) { + return NULL; + } + + /* protect the heap from concurrent access */ + sys_mutex_lock(&mem_mutex); + LWIP_MEM_ALLOC_PROTECT(); +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + /* run as long as a mem_free disturbed mem_malloc */ + do { + local_mem_free_count = 0; +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + + /* Scan through the heap searching for a free block that is big enough, + * beginning with the lowest free block. + */ + for (ptr = (mem_size_t)((u8_t *)lfree - ram); ptr < MEM_SIZE_ALIGNED - size; + ptr = ((struct mem *)(void *)&ram[ptr])->next) { + mem = (struct mem *)(void *)&ram[ptr]; +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + mem_free_count = 0; + LWIP_MEM_ALLOC_UNPROTECT(); + /* allow mem_free to run */ + LWIP_MEM_ALLOC_PROTECT(); + if (mem_free_count != 0) { + local_mem_free_count = mem_free_count; + } + mem_free_count = 0; +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + + if ((!mem->used) && + (mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) { + /* mem is not used and at least perfect fit is possible: + * mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */ + + if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) { + /* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing + * at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem') + * -> split large block, create empty remainder, + * remainder must be large enough to contain MIN_SIZE_ALIGNED data: if + * mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size, + * struct mem would fit in but no data between mem2 and mem2->next + * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty + * region that couldn't hold data, but when mem->next gets freed, + * the 2 regions would be combined, resulting in more free memory + */ + ptr2 = ptr + SIZEOF_STRUCT_MEM + size; + /* create mem2 struct */ + mem2 = (struct mem *)(void *)&ram[ptr2]; + mem2->used = 0; + mem2->next = mem->next; + mem2->prev = ptr; + /* and insert it between mem and mem->next */ + mem->next = ptr2; + mem->used = 1; + + if (mem2->next != MEM_SIZE_ALIGNED) { + ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; + } + MEM_STATS_INC_USED(used, (size + SIZEOF_STRUCT_MEM)); + } else { + /* (a mem2 struct does no fit into the user data space of mem and mem->next will always + * be used at this point: if not we have 2 unused structs in a row, plug_holes should have + * take care of this). + * -> near fit or excact fit: do not split, no mem2 creation + * also can't move mem->next directly behind mem, since mem->next + * will always be used at this point! + */ + mem->used = 1; + MEM_STATS_INC_USED(used, mem->next - (mem_size_t)((u8_t *)mem - ram)); + } + + if (mem == lfree) { + /* Find next free block after mem and update lowest free pointer */ + while (lfree->used && lfree != ram_end) { + LWIP_MEM_ALLOC_UNPROTECT(); + /* prevent high interrupt latency... */ + LWIP_MEM_ALLOC_PROTECT(); + lfree = (struct mem *)(void *)&ram[lfree->next]; + } + LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used))); + } + LWIP_MEM_ALLOC_UNPROTECT(); + sys_mutex_unlock(&mem_mutex); + LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.", + (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end); + LWIP_ASSERT("mem_malloc: allocated memory properly aligned.", + ((mem_ptr_t)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0); + LWIP_ASSERT("mem_malloc: sanity check alignment", + (((mem_ptr_t)mem) & (MEM_ALIGNMENT-1)) == 0); + + return (u8_t *)mem + SIZEOF_STRUCT_MEM; + } + } +#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT + /* if we got interrupted by a mem_free, try again */ + } while(local_mem_free_count != 0); +#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ + LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size)); + MEM_STATS_INC(err); + LWIP_MEM_ALLOC_UNPROTECT(); + sys_mutex_unlock(&mem_mutex); + return NULL; +} + +#endif /* MEM_USE_POOLS */ +/** + * 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. + * + * @param count number of objects to allocate + * @param size size of the objects to allocate + * @return pointer to allocated memory / NULL pointer if there is an error + */ +void *mem_calloc(mem_size_t count, mem_size_t size) +{ + void *p; + + /* allocate 'count' objects of size 'size' */ + p = mem_malloc(count * size); + if (p) { + /* zero the memory */ + memset(p, 0, count * size); + } + return p; +} + +#endif /* !MEM_LIBC_MALLOC */ |