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|
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>
#define PROCESS_NAME_LEN 32 //进程名字长度
#define MIN_SLICE 10 //最小碎片大小
#define DEFAULT_MEM_SIZE 1024 // 默认的内存大小
#define DEFAULT_MEM_START 0 //起始地址
#define MA_FF 1 //首次适应算法
#define MA_BF 2 //最佳适应算法
#define MA_WF 3 //最坏适应算法
#define MA_NF 4 //临近适应算法（循环首次适应算法）
//空闲分区的结构体
typedef struct free_block_type {
int size;
int start_addr;
struct free_block_type *next;
} free_block_type;
/*指向内存中空闲块链表的首指针*/
free_block_type *free_block;
//已分配分区的结构体
typedef struct allocated_block {
int pid;
int size;
int start_addr;
char process_name[PROCESS_NAME_LEN];
struct allocated_block *next;
} allocated_block;
//进程分配内存块链表的首指针
struct allocated_block *allocated_block_head = NULL;
int mem_size = DEFAULT_MEM_SIZE; // 内存大小
int ma_algorithm = MA_FF; // 动态分区分配算法
static int pid = 0; // 进程号
int flag = 0; // 判断内存是否被修改标志
//函数声明
void display_menu(); // 显示主菜单
int set_mem_size(); // 设置内存大小
void set_algorithm(); // 选择当前算法
void rearrange(int algorithm); // 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
int new_process(); // 创建一个新的进程
int allocate_mem(struct allocated_block *ab); // 内存分配
void kill_process(); // 杀死进程
int free_mem(struct allocated_block *ab); // 释放杀死进程的内存块
int dispose(struct allocated_block *free_ab); // 销毁杀死进程的结点
int display_mem_usage(); // 显示内存使用情况
allocated_block *find_process(int pid); // 找到要杀死的进程的标号
void rearrange_FF(); // 首次适应算法
void rearrange_BF(); // 最佳适应算法
void rearrange_WF(); // 最坏适应算法
void rearrange_NF(); // 临近适应算法（循环首次适应算法）
//初始化空闲分区
free_block_type *init_free_block(int mem_size) {
free_block_type *fb;
fb = (free_block_type *)malloc(sizeof(free_block_type));
if (fb == NULL) {
printf("No mem\n");
return NULL;
}
fb->size = mem_size;
fb->start_addr = DEFAULT_MEM_START;
fb->next = NULL;
return fb;
}
//显示主菜单
void display_menu() {
printf("\n");
printf("1 - Set memory size (default=%d)\n", DEFAULT_MEM_SIZE);
printf("2 - Select memory allocation algorithm\n");
printf("3 - New process \n");
printf("4 - Terminate a process \n");
printf("5 - Display memory usage \n");
printf("0 - Exit\n");
}
/*设置内存大小*/
int set_mem_size() {
int size;
if (flag != 0) { /*flag标志防止内存被再次设置*/
printf("Cannot set memory size again\n");
return 0;
}
printf("Total memory size =");
scanf("%d", &size);
if (size > 0) {
mem_size = size;
free_block->size = mem_size; /*设置初始大小为 1024*/
}
flag = 1;
return 1;
}
/*选择当前算法*/
void set_algorithm() {
int algorithm;
printf("\t1 - First Fit\n");
printf("\t2 - Best Fit \n");
printf("\t3 - Worst Fit \n");
printf("\t4 - Next Fit\n");
printf("Please input your choice : ");
scanf("%d", &algorithm);
if (algorithm >= 1 && algorithm <= 4)
ma_algorithm = algorithm;
rearrange(ma_algorithm);
}
/*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*/
void rearrange(int algorithm) {
switch (algorithm) {
case MA_FF:
rearrange_FF();
break;
case MA_BF:
rearrange_BF();
break;
case MA_WF:
rearrange_WF();
break;
case MA_NF:
rearrange_NF();
break;
}
}
/*首次适应算法，按地址的大小由小到大排序*/
void rearrange_FF() {
free_block_type *temp, *p = NULL;
free_block_type *head = NULL;
int current_min_addr;
if (free_block) {
temp = free_block;
current_min_addr = free_block->start_addr;
while (temp->next != NULL) {
if (temp->next->start_addr < current_min_addr) {
current_min_addr = temp->next->start_addr;
p = temp;
}
temp = temp->next;
}
if (p != NULL) {
temp = p->next;
p->next = p->next->next;
temp->next = free_block;
free_block = temp;
}
head = free_block;
p = head;
temp = head->next;
while (head->next != NULL) {
current_min_addr = head->next->start_addr;
while (temp->next != NULL) {
if (temp->next->start_addr < current_min_addr) {
current_min_addr = temp->next->start_addr;
p = temp;
}
temp = temp->next;
}
if (p->next != head->next) {
temp = p->next;
p->next = p->next->next;
temp->next = head->next;
head->next = temp;
}
head = head->next;
temp = head->next;
p = head;
}
}
return;
}
/*最佳适应算法，按内存块的大小由小到大排序*/
void rearrange_BF() {
free_block_type *temp, *p = NULL;
free_block_type *head = NULL;
int current_min_size = free_block->size;
temp = free_block;
while (temp->next != NULL) {
if (temp->next->size < current_min_size) {
current_min_size = temp->next->size;
p = temp;
}
temp = temp->next;
}
if (p != NULL) {
temp = p->next;
p->next = p->next->next;
temp->next = free_block;
free_block = temp;
}
head = free_block;
p = head;
temp = head->next;
while (head->next != NULL) {
current_min_size = head->next->size;
while (temp->next != NULL) {
if (temp->next->size < current_min_size) {
current_min_size = temp->next->size;
p = temp;
}
temp = temp->next;
}
if (p->next != head->next) {
temp = p;
p->next = p->next->next;
temp->next = head->next;
head->next = temp;
}
head = head->next;
temp = head->next;
p = head;
}
}
/*最坏适应算法，按地址块的大小从大到小排序*/
void rearrange_WF() {
free_block_type *temp, *p = NULL;
free_block_type *head = NULL;
int current_max_size = free_block->size;
temp = free_block;
while (temp->next != NULL) {
if (temp->next->size > current_max_size) {
current_max_size = temp->next->size;
p = temp;
}
temp = temp->next;
}
if (p != NULL) {
temp = p;
p->next = p->next->next;
temp->next = free_block;
free_block = temp;
}
head = free_block;
p = head;
temp = head->next;
while (head->next != NULL) {
current_max_size = head->next->size;
while (temp->next != NULL) {
if (temp->next->size > current_max_size) {
current_max_size = temp->next->size;
p = temp;
}
temp = temp->next;
}
if (p->next != head->next) {
temp = p->next;
p->next = p->next->next;
temp->next = head->next;
head->next = temp;
}
head = head->next;
temp = head->next;
p = head;
}
return;
}
// 临近适应算法（循环首次适应算法）
struct free_block_type *NF_tmp = NULL;
void rearrange_NF(){
free_block_type *temp, *p = NULL;
free_block_type *head = NULL;
int current_min_addr;
if (free_block) {
temp = free_block;
current_min_addr = free_block->start_addr;
// 找到最小的地址
while (temp->next != NULL) {
if (temp->next->start_addr < current_min_addr) {
current_min_addr = temp->next->start_addr;
p = temp;
}
temp = temp->next;
} // 让最小的地址成为空闲内存链表头
if (p != NULL) {
temp = p->next;
p->next = p->next->next;
temp->next = free_block;
free_block = temp;
}
head = free_block;
p = head;
temp = head->next;
while (head->next != NULL) { // 从头开始向后遍历，把最小的地址的内存逐次接起来
current_min_addr = head->next->start_addr;
while (temp->next != NULL) { // 找到剩余最小的地址的内存
if (temp->next->start_addr < current_min_addr) {
current_min_addr = temp->next->start_addr;
p = temp;
}
temp = temp->next;
}
if (p->next != head->next) { // 把找到的最小的接起来
temp = p->next;
p->next = p->next->next;
temp->next = head->next;
head->next = temp; // 接上新的较小的头
}
head = head->next; // 继续向后遍历
temp = head->next;
p = head;
}
}
return;
}
//创建一个新的进程
int new_process() {
struct allocated_block *ab;
int size;
int ret;
ab = (struct allocated_block *)malloc(sizeof(struct allocated_block));
if (!ab)
exit(-5);
ab->next = NULL;
pid++;
sprintf(ab->process_name, "PROCESS-%02d", pid);
ab->pid = pid;
printf("Memory for %s:", ab->process_name);
printf("Please input you want to allocate process' size : ");
scanf("%d", &size);
if (size > 0) {
ab->size = size;
}
ret = allocate_mem(ab);
if ((ret == 1) && (allocated_block_head == NULL)) {
allocated_block_head = ab;
return 1;
}
else if (ret == 1) {
ab->next = allocated_block_head;
allocated_block_head = ab;
return 2;
} else if (ret == -1) {
printf("Allocation fail\n");
pid--;
free(ab);
return -1;
}
return 3;
}
// NF专属内存分配
int allocate_mem_NF(struct allocated_block *ab, int ab_size) {
struct free_block_type *fbt, *pre, *temp, *work, *F = NULL;
int request_size = ab_size;
// 与上一次位置有关
if (NF_tmp == free_block || NF_tmp == NULL) { // 从头或者首次分配
F = NULL;
NF_tmp = free_block;
} else
F = NF_tmp; // F记录保存上次位置，作为循环判断条件
fbt = NF_tmp;
pre = fbt;
do {
if (F != NULL && fbt == NULL)
fbt = free_block;
if (fbt->size >= request_size) {
NF_tmp = fbt;
if (fbt->size - request_size >= MIN_SLICE) { /*分配后空闲空间足够大，则分割*/
// mem_size -= request_size;
fbt->size -= request_size;
ab->start_addr = fbt->start_addr;
fbt->start_addr += request_size;
NF_tmp = fbt; // 重新记录分配位置
} else if ((fbt->size - request_size) < MIN_SLICE) { /*分割后空闲区成为小碎片，一起分配*/
// mem_size -= fbt->size;
if (pre == free_block)
free_block = fbt->next;
else if (pre == fbt)
for (pre = free_block; pre->next != NULL; pre = pre->next)
if (pre->next == fbt)
break;
pre->next = fbt->next;
NF_tmp = fbt->next; // 重新记录分配位置
ab->start_addr = fbt->start_addr;
ab->size = fbt->size;
free(fbt);
} else {
temp = free_block;
while (temp != NULL) {
work = temp->next;
if (work != NULL) { /*如果当前空闲区与后面的空闲区相连，则合并*/
if (temp->start_addr + temp->size == work->start_addr) {
temp->size += work->size;
temp->next = work->next;
if (NF_tmp == work)
NF_tmp = temp;
free(work);
continue;
}
}
temp = temp->next;
}
rearrange(ma_algorithm); /*重新按当前的算法排列空闲区*/
}
return 1;
}
pre = fbt;
fbt = fbt->next;
} while (fbt != F); // 判断fbt是否循环完一圈
return -1;
}
//内存分配
int allocate_mem(struct allocated_block *ab) {
if(ma_algorithm == MA_NF) {
return allocate_mem_NF(ab, ab->size);
}
free_block_type *fbt, *pre;
free_block_type *temp, *p, *p1;
allocated_block *q;
int request_size = ab->size;
int sum = 0;
int max;
fbt = pre = free_block;
// 若有空闲内存
if (fbt) {
if (ma_algorithm == MA_WF) {
// 若是最坏适应算法且最大的空闲内存也不够
if (fbt == NULL || fbt->size < request_size)
return -1;
} else { // 若不是WF则是由小到大排列，遍历空闲内存寻找需要的大小
while (fbt != NULL && fbt->size < request_size) {
pre = fbt;
fbt = fbt->next;
}
} // 遍历完仍旧找不到
if (fbt == NULL || fbt->size < request_size) {
if (free_block->next != NULL) { // 将剩余内存空间相加看是否足够
sum = free_block->size;
temp = free_block->next;
while (temp != NULL) {
sum += temp->size;
if (sum >= request_size)
break;
temp = temp->next;
}
if (temp == NULL) // 还不够，退出
return -1;
else { // 足够
pre = free_block;
max = free_block->start_addr;
fbt = free_block;
while (temp->next != pre) { // 找到这些块的最大地址
if (max < pre->start_addr) {
max = pre->start_addr;
fbt = pre;
}
pre = pre->next;
}
pre = free_block;
while (pre != temp->next) {
q = allocated_block_head;
p = free_block;
while (q != NULL) { // 向前推
if (q->start_addr > pre->start_addr)
q->start_addr = q->start_addr - pre->size;
q = q->next;
}
while (p != NULL) {
if (p->start_addr > pre->start_addr)
p->start_addr = p->start_addr - pre->size;
p = p->next;
}
pre = pre->next;
}
pre = free_block;
while (pre != temp->next) {
p1 = pre->next;
if (pre == fbt) // 最大块
break;
free(pre);
pre = p1;
}
q = allocated_block_head;
free_block = fbt;
free_block->start_addr = q->start_addr + q->size;
free_block->size = sum;
free_block->next = temp->next;
if (free_block->size - request_size < MIN_SLICE) { // 分割后太小就一起分割
ab->size = free_block->size;
ab->start_addr = free_block->start_addr;
pre = free_block;
free_block = free_block->next;
free(pre);
} else { // 分割内存
ab->start_addr = free_block->start_addr;
free_block->start_addr =
free_block->start_addr + request_size;
free_block->size = free_block->size - request_size;
}
}
} else // 剩余空间相加仍旧不够
return -1;
} else { // 遍历空闲内存找到了足够大的
if (fbt->size - request_size < MIN_SLICE) { // 分割后太小就一起分割
ab->size = fbt->size;
ab->start_addr = fbt->start_addr;
if (pre->next == free_block) {
free_block = fbt->next;
} else {
pre->next = fbt->next;
}
free_block = fbt->next;
free(fbt);
} else { // 分割内存
ab->start_addr = fbt->start_addr;
fbt->start_addr = fbt->start_addr + request_size;
fbt->size = fbt->size - request_size;
}
}
rearrange(ma_algorithm);
return 1;
} else { // 无空闲内存
printf("Free Memory already has been allocated over: ");
return -1;
}
}
//选择杀死一个进程
void kill_process() {
struct allocated_block *ab;
int pid;
printf("Kill Process, pid=");
scanf("%d", &pid);
ab = find_process(pid);
if (ab != NULL) {
free_mem(ab);
dispose(ab);
}
}
//找到要杀死的进程的标号
allocated_block *find_process(int pid) {
allocated_block *abb;
abb = allocated_block_head;
if (abb->pid == pid) {
return abb;
}
abb = allocated_block_head->next;
while (abb->next != NULL) {
if (abb->pid == pid)
return abb;
abb = abb->next;
}
return abb;
}
//释放杀死进程的内存块
int free_mem(struct allocated_block *ab) {
int algorithm = ma_algorithm;
struct free_block_type *fbt, *pre;
fbt = (struct free_block_type *)malloc(sizeof(struct free_block_type));
pre = (struct free_block_type *)malloc(sizeof(struct free_block_type));
if (!fbt)
return -1;
fbt->start_addr = ab->start_addr;
fbt->size = ab->size;
fbt->next = free_block;
free_block = fbt;
rearrange_FF();
pre->next = free_block;
pre->size = 0;
while (pre->next && (pre->next->start_addr != fbt->start_addr))
pre = pre->next;
if (pre->size != 0 && fbt->next != NULL) {
if (((pre->start_addr + pre->size) == fbt->start_addr) &&
((fbt->start_addr + fbt->size) == fbt->next->start_addr)) {
pre->size = pre->size + fbt->size + fbt->next->size;
pre->next = fbt->next->next;
free(fbt->next);
free(fbt);
} else if ((pre->start_addr + pre->size) == fbt->start_addr) {
pre->size = pre->size + fbt->size;
pre->next = fbt->next;
free(fbt);
} else if (fbt->start_addr + fbt->size == fbt->next->start_addr) {
fbt->size = fbt->size + fbt->next->size;
fbt->next = fbt->next->next;
free(fbt->next);
}
} else if ((pre->size == 0) && fbt->next) {
if ((fbt->start_addr + fbt->size) == fbt->next->start_addr) {
fbt->size = fbt->size + fbt->next->size;
fbt->next = fbt->next->next;
free_block = fbt;
free(fbt->next);
}
} else if (fbt->next == NULL) {
if ((pre->start_addr + pre->size) == fbt->start_addr) {
pre->size = pre->size + fbt->size;
pre->next = fbt->next;
free(fbt);
}
}
rearrange(algorithm);
return 1;
}
//销毁杀死进程的结点
int dispose(struct allocated_block *free_ab) {
struct allocated_block *pre, *ab;
if (free_ab == allocated_block_head) {
allocated_block_head = allocated_block_head->next;
free(free_ab);
return 1;
}
pre = allocated_block_head;
ab = allocated_block_head->next;
while (ab != free_ab) {
pre = ab;
ab = ab->next;
}
pre->next = ab->next;
free(ab);
return 2;
}
//显示内存使用情况
int display_mem_usage() {
struct free_block_type *fbt = free_block;
struct allocated_block *ab = allocated_block_head;
printf("----------------------------------------------------------\n");
if (fbt == NULL) {
printf("Free Memory already used over !\n");
}
printf("----------------------------------------------------------\n");
if (fbt) {
printf("Free Memory:\n");
printf("%20s %20s\n", " start_addr", " size");
while (fbt != NULL) {
printf("%20d %20d\n", fbt->start_addr, fbt->size);
fbt = fbt->next;
}
}
printf("\nUsed Memory:\n");
printf("%10s %20s %15s %10s\n", "PID", "ProcessName", "start_addr",
" size");
while (ab != NULL) {
printf("%10d %20s %15d %10d\n", ab->pid, ab->process_name,
ab->start_addr, ab->size);
ab = ab->next;
}
printf("----------------------------------------------------------\n");
return 0;
}
//退出，销毁所有链表
void do_exit() {
free_block_type *temp;
allocated_block *temp1;
temp = free_block->next;
while (temp != NULL) {
free_block->next = temp->next;
free(temp);
temp = free_block->next;
}
free(free_block);
if(!allocated_block_head)
return;
temp1 = allocated_block_head->next;
while (temp1 != NULL) {
allocated_block_head->next = temp1->next;
free(temp1);
temp1 = allocated_block_head->next;
}
free(allocated_block_head->next);
}
//主函数
int main() {
char choice;
pid = 0;
free_block = init_free_block(mem_size);
while (1) {
display_menu();
fflush(stdin);
choice = getchar();
switch (choice) {
case '1':
set_mem_size();
break;
case '2':
set_algorithm();
flag = 1;
break;
case '3':
new_process();
flag = 1;
break;
case '4':
kill_process();
flag = 1;
break;
case '5':
display_mem_usage();
flag = 1;
break;
case '0':
do_exit();
exit(0);
default:
break;
}
}
return 0;
}
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