单片机简单内存管理器

本代码基于无操作系统的STM32单片机开发。功能强大。可申请到地址空间连续的不同大小的内存空间，且用户接口简单，使用方便

转载请注明出处：http://blog.csdn.net/u011833609/article/details/46834203

memory.h

#ifndef __MEMORY_H__
#define __MEMORY_H__#include "stdio.h"
#include "string.h"
#include "includes.h"
//用户使用
typedef struct
{void    *addr;      //申请到的内存的起始地址uint32_t size;      //申请到的内存的大小，依照块大小分配。大于等于申请大小uint16_t  tb;        //申请表序号，申请内存时分配，释放内存时使用。用户不使用
}DMEM;//若返回空。则申请失败
DMEM *DynMemGet(uint32_t size);void DynMemPut(DMEM *pDmem);#endif //__MEMORY_H__

memory.c

#include "memory.h"#define DMEM_BLOCK_SIZE         256      //内存块大小为128字节
#define DMEM_BLOCK_NUM          20       //内存块个数为40个
#define DMEM_TOTAL_SIZE         (DMEM_BLOCK_SIZE*DMEM_BLOCK_NUM)    //内存总大小typedef enum
{DMEM_FREE   = 0,DMEM_USED   = 1,
}DMEM_USED_ITEM;typedef struct
{DMEM_USED_ITEM   used;       //使用状态uint16_t         blk_s;      //起始块序号uint16_t         blk_num;    //块个数
}DMEM_APPLY;typedef struct
{DMEM_USED_ITEM  tb_blk[DMEM_BLOCK_NUM];DMEM            tb_user[DMEM_BLOCK_NUM];        //用户申请内存信息DMEM_APPLY      tb_apply[DMEM_BLOCK_NUM];       //系统分配内存信息uint16_t        apply_num;      //内存申请表占用数目uint16_t        blk_num;        //内存块占用数目
}DMEM_STATE;static uint8_t DMEMORY[DMEM_TOTAL_SIZE];
static DMEM_STATE DMEMS = {0};

DMEM *DynMemGet(uint32_t size)
{uint16_t loop = 0;uint16_t find = 0;uint16_t blk_num_want = 0;DMEM * user = NULL;DMEM_APPLY *apply = NULL;//申请内存大小不能为0if(size == 0)               {   return NULL;    }//申请内存不可超过总内存大小if(size > DMEM_TOTAL_SIZE)  {   return NULL;    }//申请内存不可超过剩余内存大小if(size > (DMEM_BLOCK_NUM - DMEMS.blk_num) * DMEM_BLOCK_SIZE)   {   return NULL;    }//申请表必须有空余if(DMEMS.apply_num >= DMEM_BLOCK_NUM)   {   return NULL;    }//计算所需连续块的个数blk_num_want = (size + DMEM_BLOCK_SIZE - 1) / DMEM_BLOCK_SIZE;//寻找申请表for(loop = 0; loop < DMEM_BLOCK_NUM; loop++){if(DMEMS.tb_apply[loop].used == DMEM_FREE){apply = &DMEMS.tb_apply[loop];                  //申请表已找到user = &DMEMS.tb_user[loop];                    //用户表相应找到user->tb = loop;                                //申请表编号记录user->size = blk_num_want * DMEM_BLOCK_SIZE;    //分配大小计算break;}}//没有找到可用申请表，理论上是不会出现此现象的，申请表剩余已在上面校验if(loop == DMEM_BLOCK_NUM)  {   return NULL;    }//寻找连续内存块for(loop = 0; loop < DMEM_BLOCK_NUM; loop++){if(DMEMS.tb_blk[loop] == DMEM_FREE){//找到第一个空暇内存块for(find = 1; (find < blk_num_want) && (loop + find < DMEM_BLOCK_NUM); find ++){//找到下一个空暇内存块if(DMEMS.tb_blk[loop + find] != DMEM_FREE){//发现已使用内存块break;}}if(find >= blk_num_want){//寻找到的空暇内存块数目已经够用user->addr = DMEMORY + loop * DMEM_BLOCK_SIZE;  //计算申请到的内存的地址apply->blk_s = loop;                            //记录申请到的内存块首序号apply->blk_num = blk_num_want;                  //记录申请到的内存块数目for(find = 0 ; find < apply->blk_num; find++){DMEMS.tb_blk[loop + find] = DMEM_USED;}apply->used = DMEM_USED;                        //标记申请表已使用DMEMS.apply_num += 1;DMEMS.blk_num += blk_num_want;return user;}else{//寻找到的空暇内存块不够用，从下一个開始找loop += find;}}}//搜索整个内存块，未找到大小适合的空间return NULL;
}void DynMemPut(DMEM *user)
{uint16_t loop = 0;//若參数为空，直接返回if(NULL == user)    {   return; }//释放内存空间for(loop = DMEMS.tb_apply[user->tb].blk_s; loop < DMEMS.tb_apply[user->tb].blk_s + DMEMS.tb_apply[user->tb].blk_num; loop++){DMEMS.tb_blk[loop] = DMEM_FREE;DMEMS.blk_num -= 1;}//释放申请表DMEMS.tb_apply[user->tb].used = DMEM_FREE;DMEMS.apply_num -= 1;
}