Web server based weather station using Sparkfun Weather Meters.
Dependencies: FatFileSystem mbed WeatherMeters SDFileSystem
mem.c
00001 #pragma diag_remark 177 00002 /** 00003 * @file 00004 * Dynamic memory manager 00005 * 00006 * This is a lightweight replacement for the standard C library malloc(). 00007 * 00008 * If you want to use the standard C library malloc() instead, define 00009 * MEM_LIBC_MALLOC to 1 in your lwipopts.h 00010 * 00011 * To let mem_malloc() use pools (prevents fragmentation and is much faster than 00012 * a heap but might waste some memory), define MEM_USE_POOLS to 1, define 00013 * MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list 00014 * of pools like this (more pools can be added between _START and _END): 00015 * 00016 * Define three pools with sizes 256, 512, and 1512 bytes 00017 * LWIP_MALLOC_MEMPOOL_START 00018 * LWIP_MALLOC_MEMPOOL(20, 256) 00019 * LWIP_MALLOC_MEMPOOL(10, 512) 00020 * LWIP_MALLOC_MEMPOOL(5, 1512) 00021 * LWIP_MALLOC_MEMPOOL_END 00022 */ 00023 00024 /* 00025 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00026 * All rights reserved. 00027 * 00028 * Redistribution and use in source and binary forms, with or without modification, 00029 * are permitted provided that the following conditions are met: 00030 * 00031 * 1. Redistributions of source code must retain the above copyright notice, 00032 * this list of conditions and the following disclaimer. 00033 * 2. Redistributions in binary form must reproduce the above copyright notice, 00034 * this list of conditions and the following disclaimer in the documentation 00035 * and/or other materials provided with the distribution. 00036 * 3. The name of the author may not be used to endorse or promote products 00037 * derived from this software without specific prior written permission. 00038 * 00039 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00040 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00041 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00042 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00043 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00044 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00045 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00046 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00047 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00048 * OF SUCH DAMAGE. 00049 * 00050 * This file is part of the lwIP TCP/IP stack. 00051 * 00052 * Author: Adam Dunkels <adam@sics.se> 00053 * Simon Goldschmidt 00054 * 00055 */ 00056 00057 #include "lwip/opt.h" 00058 00059 #if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */ 00060 00061 #include "lwip/def.h" 00062 #include "lwip/mem.h" 00063 #include "lwip/sys.h" 00064 #include "lwip/stats.h" 00065 #include "lwip/err.h" 00066 00067 #include <string.h> 00068 00069 #if MEM_USE_POOLS 00070 /* lwIP head implemented with different sized pools */ 00071 00072 /** 00073 * Allocate memory: determine the smallest pool that is big enough 00074 * to contain an element of 'size' and get an element from that pool. 00075 * 00076 * @param size the size in bytes of the memory needed 00077 * @return a pointer to the allocated memory or NULL if the pool is empty 00078 */ 00079 void * 00080 mem_malloc(mem_size_t size) 00081 { 00082 struct memp_malloc_helper *element; 00083 memp_t poolnr; 00084 mem_size_t required_size = size + sizeof(struct memp_malloc_helper); 00085 00086 for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr = (memp_t)(poolnr + 1)) { 00087 #if MEM_USE_POOLS_TRY_BIGGER_POOL 00088 again: 00089 #endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ 00090 /* is this pool big enough to hold an element of the required size 00091 plus a struct memp_malloc_helper that saves the pool this element came from? */ 00092 if (required_size <= memp_sizes[poolnr]) { 00093 break; 00094 } 00095 } 00096 if (poolnr > MEMP_POOL_LAST) { 00097 LWIP_ASSERT("mem_malloc(): no pool is that big!", 0); 00098 return NULL; 00099 } 00100 element = (struct memp_malloc_helper*)memp_malloc(poolnr); 00101 if (element == NULL) { 00102 /* No need to DEBUGF or ASSERT: This error is already 00103 taken care of in memp.c */ 00104 #if MEM_USE_POOLS_TRY_BIGGER_POOL 00105 /** Try a bigger pool if this one is empty! */ 00106 if (poolnr < MEMP_POOL_LAST) { 00107 poolnr++; 00108 goto again; 00109 } 00110 #endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ 00111 return NULL; 00112 } 00113 00114 /* save the pool number this element came from */ 00115 element->poolnr = poolnr; 00116 /* and return a pointer to the memory directly after the struct memp_malloc_helper */ 00117 element++; 00118 00119 return element; 00120 } 00121 00122 /** 00123 * Free memory previously allocated by mem_malloc. Loads the pool number 00124 * and calls memp_free with that pool number to put the element back into 00125 * its pool 00126 * 00127 * @param rmem the memory element to free 00128 */ 00129 void 00130 mem_free(void *rmem) 00131 { 00132 struct memp_malloc_helper *hmem = (struct memp_malloc_helper*)rmem; 00133 00134 LWIP_ASSERT("rmem != NULL", (rmem != NULL)); 00135 LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem))); 00136 00137 /* get the original struct memp_malloc_helper */ 00138 hmem--; 00139 00140 LWIP_ASSERT("hmem != NULL", (hmem != NULL)); 00141 LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem))); 00142 LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX)); 00143 00144 /* and put it in the pool we saved earlier */ 00145 memp_free(hmem->poolnr, hmem); 00146 } 00147 00148 #else /* MEM_USE_POOLS */ 00149 /* lwIP replacement for your libc malloc() */ 00150 00151 /** 00152 * The heap is made up as a list of structs of this type. 00153 * This does not have to be aligned since for getting its size, 00154 * we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes. 00155 */ 00156 struct mem { 00157 /** index (-> ram[next]) of the next struct */ 00158 mem_size_t next; 00159 /** index (-> ram[prev]) of the previous struct */ 00160 mem_size_t prev; 00161 /** 1: this area is used; 0: this area is unused */ 00162 u8_t used; 00163 }; 00164 00165 /** All allocated blocks will be MIN_SIZE bytes big, at least! 00166 * MIN_SIZE can be overridden to suit your needs. Smaller values save space, 00167 * larger values could prevent too small blocks to fragment the RAM too much. */ 00168 #ifndef MIN_SIZE 00169 #define MIN_SIZE 12 00170 #endif /* MIN_SIZE */ 00171 /* some alignment macros: we define them here for better source code layout */ 00172 #define MIN_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MIN_SIZE) 00173 #define SIZEOF_STRUCT_MEM LWIP_MEM_ALIGN_SIZE(sizeof(struct mem)) 00174 #define MEM_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MEM_SIZE) 00175 00176 /** If you want to relocate the heap to external memory, simply define 00177 * LWIP_RAM_HEAP_POINTER as a void-pointer to that location. 00178 * If so, make sure the memory at that location is big enough (see below on 00179 * how that space is calculated). */ 00180 #ifndef LWIP_RAM_HEAP_POINTER 00181 /** the heap. we need one struct mem at the end and some room for alignment */ 00182 u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT] MEM_POSITION; 00183 #define LWIP_RAM_HEAP_POINTER ram_heap 00184 #endif /* LWIP_RAM_HEAP_POINTER */ 00185 00186 /** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */ 00187 static u8_t *ram; 00188 /** the last entry, always unused! */ 00189 static struct mem *ram_end; 00190 /** pointer to the lowest free block, this is used for faster search */ 00191 static struct mem *lfree; 00192 00193 /** concurrent access protection */ 00194 static sys_mutex_t mem_mutex; 00195 00196 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00197 00198 static volatile u8_t mem_free_count; 00199 00200 /* Allow mem_free from other (e.g. interrupt) context */ 00201 #define LWIP_MEM_FREE_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_free) 00202 #define LWIP_MEM_FREE_PROTECT() SYS_ARCH_PROTECT(lev_free) 00203 #define LWIP_MEM_FREE_UNPROTECT() SYS_ARCH_UNPROTECT(lev_free) 00204 #define LWIP_MEM_ALLOC_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_alloc) 00205 #define LWIP_MEM_ALLOC_PROTECT() SYS_ARCH_PROTECT(lev_alloc) 00206 #define LWIP_MEM_ALLOC_UNPROTECT() SYS_ARCH_UNPROTECT(lev_alloc) 00207 00208 #else /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00209 00210 /* Protect the heap only by using a semaphore */ 00211 #define LWIP_MEM_FREE_DECL_PROTECT() 00212 #define LWIP_MEM_FREE_PROTECT() sys_mutex_lock(&mem_mutex) 00213 #define LWIP_MEM_FREE_UNPROTECT() sys_mutex_unlock(&mem_mutex) 00214 /* mem_malloc is protected using semaphore AND LWIP_MEM_ALLOC_PROTECT */ 00215 #define LWIP_MEM_ALLOC_DECL_PROTECT() 00216 #define LWIP_MEM_ALLOC_PROTECT() 00217 #define LWIP_MEM_ALLOC_UNPROTECT() 00218 00219 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00220 00221 00222 /** 00223 * "Plug holes" by combining adjacent empty struct mems. 00224 * After this function is through, there should not exist 00225 * one empty struct mem pointing to another empty struct mem. 00226 * 00227 * @param mem this points to a struct mem which just has been freed 00228 * @internal this function is only called by mem_free() and mem_trim() 00229 * 00230 * This assumes access to the heap is protected by the calling function 00231 * already. 00232 */ 00233 static void 00234 plug_holes(struct mem *mem) 00235 { 00236 struct mem *nmem; 00237 struct mem *pmem; 00238 00239 LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram); 00240 LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end); 00241 LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0); 00242 00243 /* plug hole forward */ 00244 LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", mem->next <= MEM_SIZE_ALIGNED); 00245 00246 nmem = (struct mem *)(void *)&ram[mem->next]; 00247 if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) { 00248 /* if mem->next is unused and not end of ram, combine mem and mem->next */ 00249 if (lfree == nmem) { 00250 lfree = mem; 00251 } 00252 mem->next = nmem->next; 00253 ((struct mem *)(void *)&ram[nmem->next])->prev = (mem_size_t)((u8_t *)mem - ram); 00254 } 00255 00256 /* plug hole backward */ 00257 pmem = (struct mem *)(void *)&ram[mem->prev]; 00258 if (pmem != mem && pmem->used == 0) { 00259 /* if mem->prev is unused, combine mem and mem->prev */ 00260 if (lfree == mem) { 00261 lfree = pmem; 00262 } 00263 pmem->next = mem->next; 00264 ((struct mem *)(void *)&ram[mem->next])->prev = (mem_size_t)((u8_t *)pmem - ram); 00265 } 00266 } 00267 00268 /** 00269 * Zero the heap and initialize start, end and lowest-free 00270 */ 00271 void 00272 mem_init(void) 00273 { 00274 struct mem *mem; 00275 00276 LWIP_ASSERT("Sanity check alignment", 00277 (SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT-1)) == 0); 00278 00279 /* align the heap */ 00280 ram = (u8_t *)LWIP_MEM_ALIGN(LWIP_RAM_HEAP_POINTER); 00281 /* initialize the start of the heap */ 00282 mem = (struct mem *)(void *)ram; 00283 mem->next = MEM_SIZE_ALIGNED; 00284 mem->prev = 0; 00285 mem->used = 0; 00286 /* initialize the end of the heap */ 00287 ram_end = (struct mem *)(void *)&ram[MEM_SIZE_ALIGNED]; 00288 ram_end->used = 1; 00289 ram_end->next = MEM_SIZE_ALIGNED; 00290 ram_end->prev = MEM_SIZE_ALIGNED; 00291 00292 /* initialize the lowest-free pointer to the start of the heap */ 00293 lfree = (struct mem *)(void *)ram; 00294 00295 MEM_STATS_AVAIL(avail, MEM_SIZE_ALIGNED); 00296 00297 if(sys_mutex_new(&mem_mutex) != ERR_OK) { 00298 LWIP_ASSERT("failed to create mem_mutex", 0); 00299 } 00300 } 00301 00302 /** 00303 * Put a struct mem back on the heap 00304 * 00305 * @param rmem is the data portion of a struct mem as returned by a previous 00306 * call to mem_malloc() 00307 */ 00308 void 00309 mem_free(void *rmem) 00310 { 00311 struct mem *mem; 00312 LWIP_MEM_FREE_DECL_PROTECT(); 00313 00314 if (rmem == NULL) { 00315 LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("mem_free(p == NULL) was called.\n")); 00316 return; 00317 } 00318 LWIP_ASSERT("mem_free: sanity check alignment", (((mem_ptr_t)rmem) & (MEM_ALIGNMENT-1)) == 0); 00319 00320 LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram && 00321 (u8_t *)rmem < (u8_t *)ram_end); 00322 00323 if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { 00324 SYS_ARCH_DECL_PROTECT(lev); 00325 LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory\n")); 00326 /* protect mem stats from concurrent access */ 00327 SYS_ARCH_PROTECT(lev); 00328 MEM_STATS_INC(illegal); 00329 SYS_ARCH_UNPROTECT(lev); 00330 return; 00331 } 00332 /* protect the heap from concurrent access */ 00333 LWIP_MEM_FREE_PROTECT(); 00334 /* Get the corresponding struct mem ... */ 00335 mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); 00336 /* ... which has to be in a used state ... */ 00337 LWIP_ASSERT("mem_free: mem->used", mem->used); 00338 /* ... and is now unused. */ 00339 mem->used = 0; 00340 00341 if (mem < lfree) { 00342 /* the newly freed struct is now the lowest */ 00343 lfree = mem; 00344 } 00345 00346 MEM_STATS_DEC_USED(used, mem->next - (mem_size_t)(((u8_t *)mem - ram))); 00347 00348 /* finally, see if prev or next are free also */ 00349 plug_holes(mem); 00350 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00351 mem_free_count = 1; 00352 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00353 LWIP_MEM_FREE_UNPROTECT(); 00354 } 00355 00356 /** 00357 * Shrink memory returned by mem_malloc(). 00358 * 00359 * @param rmem pointer to memory allocated by mem_malloc the is to be shrinked 00360 * @param newsize required size after shrinking (needs to be smaller than or 00361 * equal to the previous size) 00362 * @return for compatibility reasons: is always == rmem, at the moment 00363 * or NULL if newsize is > old size, in which case rmem is NOT touched 00364 * or freed! 00365 */ 00366 void * 00367 mem_trim(void *rmem, mem_size_t newsize) 00368 { 00369 mem_size_t size; 00370 mem_size_t ptr, ptr2; 00371 struct mem *mem, *mem2; 00372 /* use the FREE_PROTECT here: it protects with sem OR SYS_ARCH_PROTECT */ 00373 LWIP_MEM_FREE_DECL_PROTECT(); 00374 00375 /* Expand the size of the allocated memory region so that we can 00376 adjust for alignment. */ 00377 newsize = LWIP_MEM_ALIGN_SIZE(newsize); 00378 00379 if(newsize < MIN_SIZE_ALIGNED) { 00380 /* every data block must be at least MIN_SIZE_ALIGNED long */ 00381 newsize = MIN_SIZE_ALIGNED; 00382 } 00383 00384 if (newsize > MEM_SIZE_ALIGNED) { 00385 return NULL; 00386 } 00387 00388 LWIP_ASSERT("mem_trim: legal memory", (u8_t *)rmem >= (u8_t *)ram && 00389 (u8_t *)rmem < (u8_t *)ram_end); 00390 00391 if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { 00392 SYS_ARCH_DECL_PROTECT(lev); 00393 LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_trim: illegal memory\n")); 00394 /* protect mem stats from concurrent access */ 00395 SYS_ARCH_PROTECT(lev); 00396 MEM_STATS_INC(illegal); 00397 SYS_ARCH_UNPROTECT(lev); 00398 return rmem; 00399 } 00400 /* Get the corresponding struct mem ... */ 00401 mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); 00402 /* ... and its offset pointer */ 00403 ptr = (mem_size_t)((u8_t *)mem - ram); 00404 00405 size = mem->next - ptr - SIZEOF_STRUCT_MEM; 00406 LWIP_ASSERT("mem_trim can only shrink memory", newsize <= size); 00407 if (newsize > size) { 00408 /* not supported */ 00409 return NULL; 00410 } 00411 if (newsize == size) { 00412 /* No change in size, simply return */ 00413 return rmem; 00414 } 00415 00416 /* protect the heap from concurrent access */ 00417 LWIP_MEM_FREE_PROTECT(); 00418 00419 mem2 = (struct mem *)(void *)&ram[mem->next]; 00420 if(mem2->used == 0) { 00421 /* The next struct is unused, we can simply move it at little */ 00422 mem_size_t next; 00423 /* remember the old next pointer */ 00424 next = mem2->next; 00425 /* create new struct mem which is moved directly after the shrinked mem */ 00426 ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; 00427 if (lfree == mem2) { 00428 lfree = (struct mem *)(void *)&ram[ptr2]; 00429 } 00430 mem2 = (struct mem *)(void *)&ram[ptr2]; 00431 mem2->used = 0; 00432 /* restore the next pointer */ 00433 mem2->next = next; 00434 /* link it back to mem */ 00435 mem2->prev = ptr; 00436 /* link mem to it */ 00437 mem->next = ptr2; 00438 /* last thing to restore linked list: as we have moved mem2, 00439 * let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not 00440 * the end of the heap */ 00441 if (mem2->next != MEM_SIZE_ALIGNED) { 00442 ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; 00443 } 00444 MEM_STATS_DEC_USED(used, (size - newsize)); 00445 /* no need to plug holes, we've already done that */ 00446 } else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) { 00447 /* Next struct is used but there's room for another struct mem with 00448 * at least MIN_SIZE_ALIGNED of data. 00449 * Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem 00450 * ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED'). 00451 * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty 00452 * region that couldn't hold data, but when mem->next gets freed, 00453 * the 2 regions would be combined, resulting in more free memory */ 00454 ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; 00455 mem2 = (struct mem *)(void *)&ram[ptr2]; 00456 if (mem2 < lfree) { 00457 lfree = mem2; 00458 } 00459 mem2->used = 0; 00460 mem2->next = mem->next; 00461 mem2->prev = ptr; 00462 mem->next = ptr2; 00463 if (mem2->next != MEM_SIZE_ALIGNED) { 00464 ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; 00465 } 00466 MEM_STATS_DEC_USED(used, (size - newsize)); 00467 /* the original mem->next is used, so no need to plug holes! */ 00468 } 00469 /* else { 00470 next struct mem is used but size between mem and mem2 is not big enough 00471 to create another struct mem 00472 -> don't do anyhting. 00473 -> the remaining space stays unused since it is too small 00474 } */ 00475 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00476 mem_free_count = 1; 00477 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00478 LWIP_MEM_FREE_UNPROTECT(); 00479 return rmem; 00480 } 00481 00482 /** 00483 * Adam's mem_malloc() plus solution for bug #17922 00484 * Allocate a block of memory with a minimum of 'size' bytes. 00485 * 00486 * @param size is the minimum size of the requested block in bytes. 00487 * @return pointer to allocated memory or NULL if no free memory was found. 00488 * 00489 * Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT). 00490 */ 00491 void * 00492 mem_malloc(mem_size_t size) 00493 { 00494 mem_size_t ptr, ptr2; 00495 struct mem *mem, *mem2; 00496 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00497 u8_t local_mem_free_count = 0; 00498 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00499 LWIP_MEM_ALLOC_DECL_PROTECT(); 00500 00501 if (size == 0) { 00502 return NULL; 00503 } 00504 00505 /* Expand the size of the allocated memory region so that we can 00506 adjust for alignment. */ 00507 size = LWIP_MEM_ALIGN_SIZE(size); 00508 00509 if(size < MIN_SIZE_ALIGNED) { 00510 /* every data block must be at least MIN_SIZE_ALIGNED long */ 00511 size = MIN_SIZE_ALIGNED; 00512 } 00513 00514 if (size > MEM_SIZE_ALIGNED) { 00515 return NULL; 00516 } 00517 00518 /* protect the heap from concurrent access */ 00519 sys_mutex_lock(&mem_mutex); 00520 LWIP_MEM_ALLOC_PROTECT(); 00521 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00522 /* run as long as a mem_free disturbed mem_malloc */ 00523 do { 00524 local_mem_free_count = 0; 00525 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00526 00527 /* Scan through the heap searching for a free block that is big enough, 00528 * beginning with the lowest free block. 00529 */ 00530 for (ptr = (mem_size_t)((u8_t *)lfree - ram); ptr < MEM_SIZE_ALIGNED - size; 00531 ptr = ((struct mem *)(void *)&ram[ptr])->next) { 00532 mem = (struct mem *)(void *)&ram[ptr]; 00533 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00534 mem_free_count = 0; 00535 LWIP_MEM_ALLOC_UNPROTECT(); 00536 /* allow mem_free to run */ 00537 LWIP_MEM_ALLOC_PROTECT(); 00538 if (mem_free_count != 0) { 00539 local_mem_free_count = mem_free_count; 00540 } 00541 mem_free_count = 0; 00542 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00543 00544 if ((!mem->used) && 00545 (mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) { 00546 /* mem is not used and at least perfect fit is possible: 00547 * mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */ 00548 00549 if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) { 00550 /* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing 00551 * at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem') 00552 * -> split large block, create empty remainder, 00553 * remainder must be large enough to contain MIN_SIZE_ALIGNED data: if 00554 * mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size, 00555 * struct mem would fit in but no data between mem2 and mem2->next 00556 * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty 00557 * region that couldn't hold data, but when mem->next gets freed, 00558 * the 2 regions would be combined, resulting in more free memory 00559 */ 00560 ptr2 = ptr + SIZEOF_STRUCT_MEM + size; 00561 /* create mem2 struct */ 00562 mem2 = (struct mem *)(void *)&ram[ptr2]; 00563 mem2->used = 0; 00564 mem2->next = mem->next; 00565 mem2->prev = ptr; 00566 /* and insert it between mem and mem->next */ 00567 mem->next = ptr2; 00568 mem->used = 1; 00569 00570 if (mem2->next != MEM_SIZE_ALIGNED) { 00571 ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2; 00572 } 00573 MEM_STATS_INC_USED(used, (size + SIZEOF_STRUCT_MEM)); 00574 } else { 00575 /* (a mem2 struct does no fit into the user data space of mem and mem->next will always 00576 * be used at this point: if not we have 2 unused structs in a row, plug_holes should have 00577 * take care of this). 00578 * -> near fit or excact fit: do not split, no mem2 creation 00579 * also can't move mem->next directly behind mem, since mem->next 00580 * will always be used at this point! 00581 */ 00582 mem->used = 1; 00583 MEM_STATS_INC_USED(used, mem->next - (mem_size_t)((u8_t *)mem - ram)); 00584 } 00585 00586 if (mem == lfree) { 00587 /* Find next free block after mem and update lowest free pointer */ 00588 while (lfree->used && lfree != ram_end) { 00589 LWIP_MEM_ALLOC_UNPROTECT(); 00590 /* prevent high interrupt latency... */ 00591 LWIP_MEM_ALLOC_PROTECT(); 00592 lfree = (struct mem *)(void *)&ram[lfree->next]; 00593 } 00594 LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used))); 00595 } 00596 LWIP_MEM_ALLOC_UNPROTECT(); 00597 sys_mutex_unlock(&mem_mutex); 00598 LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.", 00599 (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end); 00600 LWIP_ASSERT("mem_malloc: allocated memory properly aligned.", 00601 ((mem_ptr_t)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0); 00602 LWIP_ASSERT("mem_malloc: sanity check alignment", 00603 (((mem_ptr_t)mem) & (MEM_ALIGNMENT-1)) == 0); 00604 00605 return (u8_t *)mem + SIZEOF_STRUCT_MEM; 00606 } 00607 } 00608 #if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 00609 /* if we got interrupted by a mem_free, try again */ 00610 } while(local_mem_free_count != 0); 00611 #endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 00612 LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size)); 00613 MEM_STATS_INC(err); 00614 LWIP_MEM_ALLOC_UNPROTECT(); 00615 sys_mutex_unlock(&mem_mutex); 00616 return NULL; 00617 } 00618 00619 #endif /* MEM_USE_POOLS */ 00620 /** 00621 * Contiguously allocates enough space for count objects that are size bytes 00622 * of memory each and returns a pointer to the allocated memory. 00623 * 00624 * The allocated memory is filled with bytes of value zero. 00625 * 00626 * @param count number of objects to allocate 00627 * @param size size of the objects to allocate 00628 * @return pointer to allocated memory / NULL pointer if there is an error 00629 */ 00630 void *mem_calloc(mem_size_t count, mem_size_t size) 00631 { 00632 void *p; 00633 00634 /* allocate 'count' objects of size 'size' */ 00635 p = mem_malloc(count * size); 00636 if (p) { 00637 /* zero the memory */ 00638 memset(p, 0, count * size); 00639 } 00640 return p; 00641 } 00642 00643 #endif /* !MEM_LIBC_MALLOC */
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