一個(gè)簡(jiǎn)單而強(qiáng)大的單片機(jī)內(nèi)存管理器

作者：piaolingtear

來(lái)源：http://blog.csdn.net/u011833609/article/details/46834203

本代碼基于無(wú)操作系統(tǒng)的STM32單片機(jī)開(kāi)發(fā)，功能強(qiáng)大，可申請(qǐng)到地址空間連續(xù)的不同大小的內(nèi)存空間，且用戶(hù)接口簡(jiǎn)單，使用方便。直接貼代碼：

memory.h：

#ifndef?__MEMORY_H__
#define?__MEMORY_H__
?
#include?"stdio.h"
#include?"string.h"
#include?"includes.h"
//用戶(hù)使用
typedef?struct
{
????void????*addr;??????//申請(qǐng)到的內(nèi)存的起始地址
????uint32_t?size;??????//申請(qǐng)到的內(nèi)存的大小，按照塊大小分配，大于等于申請(qǐng)大小
????uint16_t??tb;???????//申請(qǐng)表序號(hào)，申請(qǐng)內(nèi)存時(shí)分配，釋放內(nèi)存時(shí)使用，用戶(hù)不使用
}DMEM;
?
//若返回空，則申請(qǐng)失敗
DMEM?*DynMemGet(uint32_t?size);
void?DynMemPut(DMEM?*pDmem);
?
#endif?//__MEMORY_H__

memory.c：

#include?"memory.h"
?
#define?DMEM_BLOCK_SIZE?????????256??????//內(nèi)存塊大小為128字節(jié)
#define?DMEM_BLOCK_NUM??????????20???????//內(nèi)存塊個(gè)數(shù)為40個(gè)
#define?DMEM_TOTAL_SIZE?????????(DMEM_BLOCK_SIZE*DMEM_BLOCK_NUM)????//內(nèi)存總大小
?
typedef?enum
{
????DMEM_FREE???=?0,
????DMEM_USED???=?1,
}DMEM_USED_ITEM;
?
typedef?struct
{
????DMEM_USED_ITEM???used;???????//使用狀態(tài)
????uint16_t?????????blk_s;??????//起始?jí)K序號(hào)
????uint16_t?????????blk_num;????//塊個(gè)數(shù)
}DMEM_APPLY;
?
typedef?struct
{
????DMEM_USED_ITEM??tb_blk[DMEM_BLOCK_NUM];
????DMEM????????????tb_user[DMEM_BLOCK_NUM];????????//用戶(hù)申請(qǐng)內(nèi)存信息
????DMEM_APPLY??????tb_apply[DMEM_BLOCK_NUM];???????//系統(tǒng)分配內(nèi)存信息
????uint16_t????????apply_num;??????//內(nèi)存申請(qǐng)表占用數(shù)目
????uint16_t????????blk_num;????????//內(nèi)存塊占用數(shù)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;
????
????//申請(qǐng)內(nèi)存大小不能為0
????if(size?==?0)???????????????{???return?NULL;????}
????//申請(qǐng)內(nèi)存不可超過(guò)總內(nèi)存大小
????if(size?>?DMEM_TOTAL_SIZE)??{???return?NULL;????}
????//申請(qǐng)內(nèi)存不可超過(guò)剩余內(nèi)存大小
????if(size?>?(DMEM_BLOCK_NUM?-?DMEMS.blk_num)?*?DMEM_BLOCK_SIZE)???{???return?NULL;????}
????//申請(qǐng)表必須有空余
????if(DMEMS.apply_num?>=?DMEM_BLOCK_NUM)???{???return?NULL;????}
????
????//計(jì)算所需連續(xù)塊的個(gè)數(shù)
????blk_num_want?=?(size?+?DMEM_BLOCK_SIZE?-?1)?/?DMEM_BLOCK_SIZE;
????
????//尋找申請(qǐng)表
????for(loop?=?0;?loop?????{
????????if(DMEMS.tb_apply[loop].used?==?DMEM_FREE)
????????{
????????????apply?=?&DMEMS.tb_apply[loop];??????????????????//申請(qǐng)表已找到
????????????user?=?&DMEMS.tb_user[loop];????????????????????//用戶(hù)表對(duì)應(yīng)找到
????????????user->tb?=?loop;????????????????????????????????//申請(qǐng)表編號(hào)記錄
????????????user->size?=?blk_num_want?*?DMEM_BLOCK_SIZE;????//分配大小計(jì)算
????????????break;
????????}
????}
????
????//沒(méi)有找到可用申請(qǐng)表，理論上是不會(huì)出現(xiàn)此現(xiàn)象的，申請(qǐng)表剩余已在上面校驗(yàn)
????if(loop?==?DMEM_BLOCK_NUM)??{???return?NULL;????}
????
????//尋找連續(xù)內(nèi)存塊
????for(loop?=?0;?loop?????{
????????if(DMEMS.tb_blk[loop]?==?DMEM_FREE)
????????{//找到第一個(gè)空閑內(nèi)存塊
????????????for(find?=?1;?(find?????????????{//找到下一個(gè)空閑內(nèi)存塊
????????????????if(DMEMS.tb_blk[loop?+?find]?!=?DMEM_FREE)
????????????????{//發(fā)現(xiàn)已使用內(nèi)存塊
????????????????????break;
????????????????}
????????????}
????????????if(find?>=?blk_num_want)
????????????{//尋找到的空閑內(nèi)存塊數(shù)目已經(jīng)夠用
????????????????user->addr?=?DMEMORY?+?loop?*?DMEM_BLOCK_SIZE;??//計(jì)算申請(qǐng)到的內(nèi)存的地址
????????????????apply->blk_s?=?loop;????????????????????????????//記錄申請(qǐng)到的內(nèi)存塊首序號(hào)
????????????????apply->blk_num?=?blk_num_want;??????????????????//記錄申請(qǐng)到的內(nèi)存塊數(shù)目
????????????????for(find?=?0?;?find?blk_num;?find++)
????????????????{
????????????????????DMEMS.tb_blk[loop?+?find]?=?DMEM_USED;
????????????????}
????????????????apply->used?=?DMEM_USED;????????????????????????//標(biāo)記申請(qǐng)表已使用
????????????????DMEMS.apply_num?+=?1;
????????????????DMEMS.blk_num?+=?blk_num_want;
????????????????
????????????????return?user;
????????????}
????????????else
????????????{//尋找到的空閑內(nèi)存塊不夠用，從下一個(gè)開(kāi)始找
????????????????loop?+=?find;
????????????}
????????}
????}
????
????//搜索整個(gè)內(nèi)存塊，未找到大小適合的空間
????return?NULL;
}
?
void?DynMemPut(DMEM?*user)
{
????uint16_t?loop?=?0;
????//若參數(shù)為空，直接返回
????if(NULL?==?user)????{???return;?}
????
????//釋放內(nèi)存空間
????for(loop?=?DMEMS.tb_apply[user->tb].blk_s;?loop?tb].blk_s?+?DMEMS.tb_apply[user->tb].blk_num;?loop++)
????{
????????DMEMS.tb_blk[loop]?=?DMEM_FREE;
????????DMEMS.blk_num?-=?1;
????}
????//釋放申請(qǐng)表
????DMEMS.tb_apply[user->tb].used?=?DMEM_FREE;
????DMEMS.apply_num?-=?1;
}