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内存管理模拟
内存管理模拟算法：首次适应算法、最佳适应算法、最坏适应算法
此程序是参考别人的，因此也没有什么好说的，感觉写的不错就贴上来了
代码如下：
1 #include<stdio.h> 2 #include<malloc.h> 3 #include<stdlib.h> 4 5 #define PROCESS_NAME_LEN 32 //进程名字长度 6 #define MIN_SLICE 10 //最小碎片大小 7 #define DEFAULT_MEM_SIZE 1024 // 默认的内存大小 8 #define DEFAULT_MEM_START 0 //起始地址 9 10 #define MA_FF 1 //首次适应算法 11 #define MA_BF 2 //最佳适应算法 12 #define MA_WF 3 //最坏适应算法 13 14 15 //空闲分区的结构体 16 typedef struct free_block_type{ 17 int size; 18 int start_addr; 19 struct free_block_type *next; 20 }free_block_type; 21 free_block_type *free_block; 22 23 24 //已分配分区的结构体 25 typedef struct allocated_block{ 26 int pid; 27 int size; 28 int start_addr; 29 char process_name[PROCESS_NAME_LEN]; 30 struct allocated_block *next; 31 }allocated_block; 32 33 struct allocated_block *allocated_block_head = NULL; 34 35 int mem_size=DEFAULT_MEM_SIZE; 36 int ma_algorithm = MA_FF; 37 static int pid = 0; 38 int flag = 0; 39 40 //函数声明 41 void display_menu(); 42 int set_mem_size(); 43 void set_algorithm(); 44 void rearrange(int algorithm); 45 int new_process(); 46 int allocate_mem (struct allocated_block *ab); 47 void kill_process(); 48 int free_mem (struct allocated_block *ab); 49 int dispose (struct allocated_block *free_ab); 50 int display_mem_usage(); 51 allocated_block * find_process(int pid); 52 void rearrange_FF(); 53 void rearrange_BF(); 54 void rearrange_WF(); 55 56 //初始化空闲分区 57 free_block_type* init_free_block(int mem_size){ 58 free_block_type *fb; 59 fb=(free_block_type *)malloc(sizeof(free_block_type)); 60 if(fb==NULL){ 61 printf("No mem\n"); 62 return NULL; 63 } 64 fb->size = mem_size; 65 fb->start_addr = DEFAULT_MEM_START; 66 fb->next = NULL; 67 return fb; 68 } 69 70 //显示主菜单 71 void display_menu(){ 72 printf("\n"); 73 printf("1 - Set memory size (default=%d)\n", DEFAULT_MEM_SIZE); 74 printf("2 - Select memory allocation algorithm\n"); 75 printf("3 - New process \n"); 76 printf("4 - Terminate a process \n"); 77 printf("5 - Display memory usage \n"); 78 printf("0 - Exit\n"); 79 } 80 81 /*设置内存大小*/ 82 int set_mem_size(){ 83 int size; 84 if(flag!=0){ /*flag标志防止内存被再次设置*/ 85 printf("Cannot set memory size again\n"); 86 return 0; 87 } 88 printf("Total memory size ="); 89 scanf("%d", &size); 90 if(size>0) { 91 mem_size = size; 92 free_block->size = mem_size;/*设置初始大小为 1024*/ 93 } 94 flag=1; 95 return 1; 96 } 97 /*选择当前算法*/ 98 void set_algorithm(){ 99 int algorithm;100 printf("\t1 - First Fit\n");101 printf("\t2 - Best Fit \n");102 printf("\t3 - Worst Fit \n");103 printf("Please input your choice : ");104 scanf("%d", &algorithm);105 if(algorithm>=1 && algorithm <=3)106 ma_algorithm=algorithm;107 108 rearrange(ma_algorithm);109 }110 111 /*为每一个进程分配完内存以后重新按已选择的算法再次排序*/112 void rearrange(int algorithm){113 switch(algorithm){114 case MA_FF: rearrange_FF(); break;115 case MA_BF: rearrange_BF(); break;116 case MA_WF: rearrange_WF(); break;117 }118 }119 /*首次适应算法，按地址的大小由小到达排序*/120 void rearrange_FF(){121 free_block_type *temp,*p=NULL;122 free_block_type *head=NULL;123 int current_min_addr;124 125 if(free_block){126 temp=free_block;127 current_min_addr=free_block->start_addr;128 while(temp->next!=NULL){129 if(temp->next->start_addr<current_min_addr){130 current_min_addr=temp->next->start_addr;131 p=temp;132 }133 temp=temp->next;134 }135 if(p!=NULL){136 temp=p->next;137 p->next=p->next->next;138 temp->next=free_block;139 free_block=temp;140 }141 head=free_block;142 p=head;143 temp=head->next;144 while(head->next!=NULL){145 current_min_addr=head->next->start_addr;146 while(temp->next!=NULL){147 if(temp->next->start_addr<current_min_addr){148 current_min_addr=temp->next->start_addr;149 p=temp;150 }151 temp=temp->next;152 }153 if(p->next!=head->next){154 temp=p->next;155 p->next=p->next->next;156 temp->next=head->next;157 head->next=temp;158 }159 head=head->next;160 temp=head->next;161 p=head;162 }163 }164 return ;165 }166 167 /*最佳适应算法，按内存块的大小由小到大排序*/168 void rearrange_BF(){169 free_block_type *temp,*p=NULL;170 free_block_type *head=NULL;171 int current_min_size=free_block->size;172 173 temp=free_block;174 while(temp->next!=NULL){175 if(temp->next->size<current_min_size){176 current_min_size=temp->next->size;177 p=temp;178 }179 temp=temp->next;180 }181 if(p!=NULL){182 temp=p->next;183 p->next=p->next->next;184 temp->next=free_block;185 free_block=temp;186 }187 head=free_block;188 p=head;189 temp=head->next;190 while(head->next!=NULL){191 current_min_size=head->next->size;192 while(temp->next!=NULL){193 if(temp->next->size<current_min_size){194 current_min_size=temp->next->size;195 p=temp;196 }197 temp=temp->next;198 }199 if(p->next!=head->next){200 temp=p;201 p->next=p->next->next;202 temp->next=head->next;203 head->next=temp;204 }205 head=head->next;206 temp=head->next;207 p=head;208 }209 210 }211 212 /*最坏适应算法，按地址块的大小从大到小排序*/213 void rearrange_WF(){214 free_block_type *temp,*p=NULL;215 free_block_type *head=NULL;216 int current_max_size=free_block->size;217 temp=free_block;218 while(temp->next!=NULL){219 if(temp->next->size>current_max_size){220 current_max_size=temp->next->size;221 p=temp;222 }223 temp=temp->next;224 }225 if(p!=NULL){226 temp=p;227 p->next=p->next->next;228 temp->next=free_block;229 free_block=temp;230 }231 head=free_block;232 p=head;233 temp=head->next;234 while(head->next!=NULL){235 current_max_size=head->next->size;236 while(temp->next!=NULL){237 if(temp->next->size>current_max_size){238 current_max_size=temp->next->size;239 p=temp;240 }241 temp=temp->next;242 }243 if(p->next!=head->next){244 temp=p->next;245 p->next=p->next->next;246 temp->next=head->next;247 head->next=temp;248 }249 head=head->next;250 temp=head->next;251 p=head;252 }253 return ;254 }255 //创建一个新的进程256 int new_process(){257 struct allocated_block *ab;258 int size;259 int ret;260 ab=(struct allocated_block *)malloc(sizeof(struct allocated_block));261 if(!ab) exit(-5);262 ab->next = NULL;263 pid++;264 sprintf(ab->process_name, "PROCESS-%02d", pid);265 ab->pid = pid;266 printf("Memory for %s:", ab->process_name);267 printf("Please input you want to allocate process‘ size : ");268 scanf("%d", &size);269 if(size>0) {270 271 ab->size=size;272 }273 ret = allocate_mem(ab);274 if((ret==1) &&(allocated_block_head == NULL)){275 allocated_block_head=ab;276 return 1; }277 278 else if (ret==1) {279 ab->next=allocated_block_head;280 allocated_block_head=ab;281 return 2; }282 else if(ret==-1){283 printf("Allocation fail\n");284 pid--;285 free(ab);286 return -1;287 }288 return 3;289 }290 291 //内存分配292 int allocate_mem(struct allocated_block *ab){293 free_block_type *fbt, *pre;294 free_block_type *temp,*p,*p1;295 allocated_block *q;296 int request_size=ab->size;297 int sum=0;298 int max;299 fbt = pre = free_block;300 if(fbt){301 if(ma_algorithm==MA_WF){302 if(fbt==NULL||fbt->size<request_size)303 return -1;304 }305 else{306 while(fbt!=NULL&&fbt->size<request_size){307 pre=fbt;308 fbt=fbt->next;309 }310 }311 if(fbt==NULL||fbt->size<request_size){312 if(free_block->next!=NULL){313 sum=free_block->size;314 temp=free_block->next;315 while(temp!=NULL){316 sum+=temp->size;317 if(sum>=request_size)318 break;319 temp=temp->next;320 }321 if(temp==NULL)322 return -1;323 else{324 pre=free_block;325 max=free_block->start_addr;326 fbt=free_block;327 while(temp->next!=pre){328 if(max<pre->start_addr){329 max=pre->start_addr;330 fbt=pre;331 }332 pre=pre->next;333 }334 pre=free_block;335 336 while(pre!=temp->next)337 {338 q=allocated_block_head;339 p=free_block;340 341 while(q!=NULL)342 {343 if(q->start_addr>pre->start_addr)344 q->start_addr=q->start_addr-pre->size;345 q=q->next;346 }347 while(p!=NULL)348 {349 if(p->start_addr>pre->start_addr)350 p->start_addr=p->start_addr-pre->size;351 p=p->next;352 353 }354 355 pre=pre->next;356 }357 358 pre=free_block;359 while(pre!=temp->next){360 361 p1=pre->next;362 if(pre==fbt)363 break;364 free(pre);365 pre=p1;366 367 }368 q=allocated_block_head;369 free_block=fbt;370 free_block->start_addr=q->start_addr+q->size;371 372 free_block->size=sum;373 free_block->next=temp->next;374 if(free_block->size-request_size<MIN_SLICE){375 ab->size=free_block->size;376 ab->start_addr=free_block->start_addr;377 pre=free_block;378 free_block=free_block->next;379 free(pre);380 }381 else{382 ab->start_addr=free_block->start_addr;383 free_block->start_addr=free_block->start_addr+request_size;384 free_block->size=free_block->size-request_size;385 }386 387 }388 }389 else390 return -1;391 }392 else{393 if(fbt->size-request_size<MIN_SLICE){394 ab->size=fbt->size;395 ab->start_addr=fbt->start_addr;396 if(pre->next==free_block){397 free_block=fbt->next;398 }399 else{400 pre->next=fbt->next;401 }402 free_block=fbt->next;403 free(fbt);404 }405 else{406 ab->start_addr=fbt->start_addr;407 fbt->start_addr=fbt->start_addr+request_size;408 fbt->size=fbt->size-request_size;409 }410 }411 rearrange(ma_algorithm);412 return 1;413 }414 else415 {416 printf("Free Memory already has been allocated over: ");417 return -1;418 }419 420 }421 422 //选择杀死一个进程423 424 void kill_process(){425 struct allocated_block *ab;426 int pid;427 printf("Kill Process, pid=");428 scanf("%d", &pid);429 ab=find_process(pid);430 if(ab!=NULL){431 free_mem(ab);432 dispose(ab);433 }434 }435 //找到要杀死的进程的标号436 allocated_block * find_process(int pid){437 allocated_block *abb;438 abb=allocated_block_head;439 if(abb->pid==pid)440 {441 return abb;442 }443 abb=allocated_block_head->next;444 while(abb->next!=NULL){445 if(abb->pid==pid)446 return abb;447 abb=abb->next;448 }449 return abb;450 }451 452 //释放杀死进程的内存块453 int free_mem(struct allocated_block *ab){454 int algorithm = ma_algorithm;455 struct free_block_type *fbt, *pre;456 fbt=(struct free_block_type*) malloc(sizeof(struct free_block_type));457 pre=(struct free_block_type*) malloc(sizeof(struct free_block_type));458 if(!fbt) return -1;459 460 fbt->start_addr=ab->start_addr;461 fbt->size=ab->size;462 fbt->next=free_block;463 free_block=fbt;464 rearrange_FF();465 pre->next=free_block;466 pre->size=0;467 while(pre->next&&(pre->next->start_addr!=fbt->start_addr))468 pre=pre->next;469 if(pre->size!=0&&fbt->next!=NULL){470 if(((pre->start_addr+pre->size)==fbt->start_addr)&&((fbt->start_addr+fbt->size)==fbt->next->start_addr)){471 pre->size=pre->size+fbt->size+fbt->next->size;472 pre->next=fbt->next->next;473 free(fbt->next);474 free(fbt);475 }476 else if((pre->start_addr+pre->size)==fbt->start_addr){477 pre->size=pre->size+fbt->size;478 pre->next=fbt->next;479 free(fbt);480 }481 else if(fbt->start_addr+fbt->size==fbt->next->start_addr){482 fbt->size=fbt->size+fbt->next->size;483 fbt->next=fbt->next->next;484 free(fbt->next);485 }486 }487 else if((pre->size==0)&&fbt->next){488 if((fbt->start_addr+fbt->size)==fbt->next->start_addr){489 fbt->size=fbt->size+fbt->next->size;490 fbt->next=fbt->next->next;491 free_block=fbt;492 free(fbt->next);493 }494 }495 else if(fbt->next==NULL){496 if((pre->start_addr+pre->size)==fbt->start_addr){497 pre->size=pre->size+fbt->size;498 pre->next=fbt->next;499 free(fbt);500 }501 }502 rearrange(algorithm);503 504 return 1;505 }506 507 //销毁杀死进程的结点508 int dispose(struct allocated_block *free_ab){509 struct allocated_block *pre,*ab;510 511 if(free_ab == allocated_block_head) {512 allocated_block_head = allocated_block_head->next;513 free(free_ab);514 return 1;515 }516 pre = allocated_block_head;517 ab = allocated_block_head->next;518 while(ab!=free_ab)519 {520 pre = ab;521 ab = ab->next;522 }523 pre->next = ab->next;524 free(ab);525 return 2;526 }527 528 //显示内存使用情况529 530 int display_mem_usage(){531 struct free_block_type *fbt=free_block;532 struct allocated_block *ab=allocated_block_head;533 printf("----------------------------------------------------------\n");534 535 if(fbt==NULL)536 {537 printf("Free Memory already used over !\n");538 }539 printf("----------------------------------------------------------\n");540 541 542 if(fbt)543 {544 printf("Free Memory:\n");545 printf("%20s %20s\n", " start_addr", " size");546 while(fbt!=NULL){547 printf("%20d %20d\n", fbt->start_addr, fbt->size);548 fbt=fbt->next;549 }550 }551 552 printf("\nUsed Memory:\n");553 printf("%10s %20s %10s %10s\n", "PID", "ProcessName", "start_addr", " size");554 while(ab!=NULL){555 printf("%10d %20s %10d %10d\n", ab->pid, ab->process_name, ab->start_addr, ab->size);556 ab=ab->next;557 }558 printf("----------------------------------------------------------\n");559 return 0;560 }561 562 //退出，销毁所有链表563 void do_exit()564 {565 free_block_type *temp;566 allocated_block *temp1;567 temp=free_block->next;568 while(temp!=NULL)569 {570 free_block->next=temp->next;571 free(temp);572 temp=free_block->next;573 }574 free(free_block);575 temp1=allocated_block_head->next;576 while(temp1!=NULL)577 {578 allocated_block_head->next=temp1->next;579 free(temp1);580 temp1=allocated_block_head->next;581 }582 free(allocated_block_head->next);583 584 }585 //主函数586 int main(){587 char choice;588 pid=0;589 free_block=init_free_block(mem_size);590 while(1) {591 display_menu();592 fflush(stdin);593 594 choice=getchar();595 switch(choice){596 case ‘1‘: set_mem_size(); break;597 case ‘2‘: set_algorithm();flag=1; break;598 case ‘3‘: new_process(); flag=1; break;599 case ‘4‘: kill_process(); flag=1; break;600 case ‘5‘: display_mem_usage(); flag=1; break;601 case ‘0‘: do_exit();exit(0);602 default: break;603 }604 }605 return 0;606 }
内存管理模拟
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