#ifndef __MEMORY_H__#define __MEMORY_H__
#include "stdio.h"#include "string.h"#include "includes.h"//用戶使用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__

#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
static uint8_t DMEMORY[DMEM_TOTAL_SIZE];static DMEM_STATE DMEMS = {0};
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;

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 < DMEM_BLOCK_NUM; 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 < DMEM_BLOCK_NUM; loop++) { if(DMEMS.tb_blk[loop] == DMEM_FREE) {//找到第一個(gè)空閑內(nèi)存塊 for(find = 1; (find < blk_num_want) && (loop + find < DMEM_BLOCK_NUM); 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 < apply->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 < 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; } //釋放申請(qǐng)表 DMEMS.tb_apply[user->tb].used = DMEM_FREE; DMEMS.apply_num -= 1;}