/** @file * * Dynamic memory manager * *//*  * 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> * */#include <string.h>#include "lwip/arch.h"#include "lwip/opt.h"#include "lwip/def.h"#include "lwip/mem.h"#include "lwip/sys.h"#include "lwip/stats.h"struct mem {  mem_size_t next, prev;#if MEM_ALIGNMENT == 1  u8_t used;#elif MEM_ALIGNMENT == 2  u16_t used;#elif MEM_ALIGNMENT == 4  u32_t used;#elif MEM_ALIGNMENT == 8  u64_t used;#else#error "unhandled MEM_ALIGNMENT size"#endif /* MEM_ALIGNMENT */}; static struct mem *ram_end;static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT];#define MIN_SIZE 12#if 0 /* this one does not align correctly for some, resulting in crashes */#define SIZEOF_STRUCT_MEM (unsigned int)MEM_ALIGN_SIZE(sizeof(struct mem))#else#define SIZEOF_STRUCT_MEM (sizeof(struct mem) + \                          (((sizeof(struct mem) % MEM_ALIGNMENT) == 0)? 0 : \                          (4 - (sizeof(struct mem) % MEM_ALIGNMENT))))#endifstatic struct mem *lfree;   /* pointer to the lowest free block */static sys_sem_t mem_sem;static voidplug_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", mem->next <= MEM_SIZE);    nmem = (struct mem *)&ram[mem->next];  if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) {    if (lfree == nmem) {      lfree = mem;    }    mem->next = nmem->next;    ((struct mem *)&ram[nmem->next])->prev = (u8_t *)mem - ram;  }  /* plug hole backward */  pmem = (struct mem *)&ram[mem->prev];  if (pmem != mem && pmem->used == 0) {    if (lfree == mem) {      lfree = pmem;    }    pmem->next = mem->next;    ((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram;  }}voidmem_init(void){  struct mem *mem;  memset(ram, 0, MEM_SIZE);  mem = (struct mem *)ram;  mem->next = MEM_SIZE;  mem->prev = 0;  mem->used = 0;  ram_end = (struct mem *)&ram[MEM_SIZE];  ram_end->used = 1;  ram_end->next = MEM_SIZE;  ram_end->prev = MEM_SIZE;  mem_sem = sys_sem_new(1);  lfree = (struct mem *)ram;#if MEM_STATS  lwip_stats.mem.avail = MEM_SIZE;#endif /* MEM_STATS */}voidmem_free(void *rmem){  struct mem *mem;  if (rmem == NULL) {    LWIP_DEBUGF(MEM_DEBUG | DBG_TRACE | 2, ("mem_free(p == NULL) was called.\n"));    return;  }    sys_sem_wait(mem_sem);  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) {    LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n"));#if MEM_STATS    ++lwip_stats.mem.err;#endif /* MEM_STATS */    sys_sem_signal(mem_sem);    return;  }  mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);  LWIP_ASSERT("mem_free: mem->used", mem->used);    mem->used = 0;  if (mem < lfree) {    lfree = mem;  }  #if MEM_STATS  lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram);  #endif /* MEM_STATS */  plug_holes(mem);  sys_sem_signal(mem_sem);}void *mem_reallocm(void *rmem, mem_size_t newsize){  void *nmem;  nmem = mem_malloc(newsize);  if (nmem == NULL) {    return mem_realloc(rmem, newsize);  }  memcpy(nmem, rmem, newsize);  mem_free(rmem);  return nmem;}void *mem_realloc(void *rmem, mem_size_t newsize){  mem_size_t size;  mem_size_t ptr, ptr2;  struct mem *mem, *mem2;  /* Expand the size of the allocated memory region so that we can     adjust for alignment. */  if ((newsize % MEM_ALIGNMENT) != 0) {   newsize += MEM_ALIGNMENT - ((newsize + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);  }    if (newsize > MEM_SIZE) {    return NULL;  }    sys_sem_wait(mem_sem);    LWIP_ASSERT("mem_realloc: 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) {    LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n"));    return rmem;  }  mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);  ptr = (u8_t *)mem - ram;  size = mem->next - ptr - SIZEOF_STRUCT_MEM;#if MEM_STATS  lwip_stats.mem.used -= (size - newsize);#endif /* MEM_STATS */    if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE < size) {    ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;    mem2 = (struct mem *)&ram[ptr2];    mem2->used = 0;    mem2->next = mem->next;    mem2->prev = ptr;    mem->next = ptr2;    if (mem2->next != MEM_SIZE) {      ((struct mem *)&ram[mem2->next])->prev = ptr2;    }    plug_holes(mem2);  }  sys_sem_signal(mem_sem);    return rmem;}void *mem_malloc(mem_size_t size){  mem_size_t ptr, ptr2;  struct mem *mem, *mem2;  if (size == 0) {    return NULL;  }  /* Expand the size of the allocated memory region so that we can     adjust for alignment. */  if ((size % MEM_ALIGNMENT) != 0) {    size += MEM_ALIGNMENT - ((size + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);  }    if (size > MEM_SIZE) {    return NULL;  }    sys_sem_wait(mem_sem);  for (ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE; ptr = ((struct mem *)&ram[ptr])->next) {    mem = (struct mem *)&ram[ptr];    if (!mem->used &&       mem->next - (ptr + SIZEOF_STRUCT_MEM) >= size + SIZEOF_STRUCT_MEM) {      ptr2 = ptr + SIZEOF_STRUCT_MEM + size;      mem2 = (struct mem *)&ram[ptr2];      mem2->prev = ptr;            mem2->next = mem->next;      mem->next = ptr2;            if (mem2->next != MEM_SIZE) {        ((struct mem *)&ram[mem2->next])->prev = ptr2;      }            mem2->used = 0;            mem->used = 1;#if MEM_STATS      lwip_stats.mem.used += (size + SIZEOF_STRUCT_MEM);      /*      if (lwip_stats.mem.max < lwip_stats.mem.used) {        lwip_stats.mem.max = lwip_stats.mem.used;  } */      if (lwip_stats.mem.max < ptr2) {        lwip_stats.mem.max = ptr2;      }      #endif /* MEM_STATS */      if (mem == lfree) {  /* Find next free block after mem */        while (lfree->used && lfree != ram_end) {    lfree = (struct mem *)&ram[lfree->next];        }        LWIP_ASSERT("mem_malloc: !lfree->used", !lfree->used);      }      sys_sem_signal(mem_sem);      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.",       (unsigned long)((u8_t *)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);      return (u8_t *)mem + SIZEOF_STRUCT_MEM;    }      }  LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %d bytes\n", (int)size));#if MEM_STATS  ++lwip_stats.mem.err;#endif /* MEM_STATS */    sys_sem_signal(mem_sem);  return NULL;}