[gaowei@localhost memory]$ ls
display_menu.c main.c Makefile2 memory.h
上面是代码的目录
编译后的目录如下：
[gaowei@localhost memory]$ ls
display_menu.c display_menu.o main.o Makefile2 memory memory.h
再详细看看我的代码
头文件在memory.h中！
#include <stdio.h>
#include <stdlib.h>/*会引起警告：隐式声明与内建函数 “malloc” "exit“ 不兼容*/
#include <unistd.h>
/*memory.c:331: 警告：隐式声明与内建函数 ‘_exit’ 不兼容*/
#define PROCESS_NAME_LEN 32 /*进程名称的最大长度*/
#define MIN_SLICE 10 /*最小碎片的大小*/
#define DEFAULT_MEM_SIZE 1024 /*默认内存的大小*/
#define DEFAULT_MEM_START 0 /*默认内存的起始位置*/
/* 内存分配算法 */
#define MA_FF 1
#define MA_BF 2
#define MA_WF 3
在看看我的Makefile的文件：
memory: main.o display_menu.o
gcc -o memory main.o display_menu.o
main.o: main.c memory.h
gcc -c main.c
display_memu.o: display_memu.c memory.h
gcc -c display_memu.c
在看看我的菜单的文件，现在由于要考试了，时间紧张，所以只是完成了老师规定的内容，我想用把他做成图形界面的，用#include <curses.h>
所以我的菜单文件是
#include "memory.h"
int display_menu(void){
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");
}
我的主函数的代码是
#include "memory.h"
extern void display_menu();
struct allocated_block *find_process(int pid);
/*描述每一个空闲块的数据结构*/
struct free_block_type{
int size;
int start_addr;
struct free_block_type *next;
};
/*指向内存中空闲块链表的首指针*/
struct free_block_type *free_block;
/*每个进程分配到的内存块的描述*/
struct allocated_block{
int pid;
int size;
int start_addr;
char process_name[PROCESS_NAME_LEN];
struct allocated_block *next;
};
/*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; /*当前分配算法*/
static int pid = 0; /*初始pid*/
int flag = 0;/* 设置内存大小标志*/
/*初始化空闲块，默认为一块，可以指定大小及起始地址*/
struct free_block_type* init_free_block(int mem_size){
struct free_block_type *fb;
fb=(struct free_block_type *)malloc(sizeof(struct 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;
}
/*设置内存的大小*/
set_mem_size() {
int size;
if(flag!=0){ /*防止重复设置*/
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;
}
flag=1;
return 1;
}
/* 设置当前的分配算法 */
set_algorithm(){
int algorithm;
printf("\t1 - First Fit\n");
printf("\t2 - Best Fit \n");
printf("\t3 - Worst Fit \n");
scanf("%d", &algorithm);
if(algorithm>=1 && algorithm <=3)
ma_algorithm=algorithm; /*按指定算法重新排列空闲区链表*/
rearrange(ma_algorithm); }
/*按指定的算法整理内存空闲块链表*/
rearrange(int algorithm){
switch(algorithm){
case MA_FF: rearrange_FF(); break;
case MA_BF: rearrange_BF(); break;
case MA_WF: rearrange_WF(); break;
}
}
void swap(int *p1,int *p2) {
int temp; temp=*p1; *p1=*p2; *p2=temp;
}
/*按FF算法重新整理内存空闲块链表*/
rearrange_FF(){
struct free_block_type *tmp, *work;
printf("Rearrange free blocks for FF \n");
tmp = free_block; while(tmp!=NULL) {
work = tmp->next;
while(work!=NULL){
if( work->start_addr <>start_addr) { /*地址递增*/
swap(&work->start_addr, &tmp->start_addr);
swap(&work->size, &tmp->size);
}
work=work->next;
}
tmp=tmp->next;
}
}
/*按BF算法重新整理内存空闲块链表*/
rearrange_BF(){
struct free_block_type *tmp, *work;
printf("Rearrange free blocks for BF \n");
tmp = free_block;
while(tmp->next!=NULL) {
work = tmp->next;
while(work!=NULL) {
if(work->size > tmp->size) { /*大小递减*/
swap(&work->start_addr,&tmp->start_addr);
swap(&work->size,&tmp->size);
}
work = work->next;
}
tmp = tmp->next;
}
return 0;
}
/*按WF算法重新整理内存空闲块链表*/
rearrange_WF(){
struct free_block_type *tmp, *work;
printf("Rearrange free blocks for WF \n");
tmp = free_block;
while(tmp->next!=NULL) {
work = tmp->next;
while(work!=NULL) {
if(work->size <>size) { /*大小递增*/
swap(&work->start_addr,&tmp->start_addr);
swap(&work->size,&tmp->size);
}
work = work->next;
}
tmp = tmp->next;
}
return 0;
}
/*创建新的进程，主要是获取内存的申请数量*/
int new_process(void) {
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);
scanf("%d", &size);
if(size>0) ab->size = size;
ret = allocate_mem(ab); /* 从空闲区分配内存，ret==1表示分配ok*/
/*如果此时allocated_block_head尚未赋值，则赋值*/
if((ret==1) &&(allocated_block_head == NULL)){
allocated_block_head=ab;
return 1;
}
/*分配成功，将该已分配块的描述插入已分配链表*/
else if (ret==1) {
ab->next=allocated_block_head;
allocated_block_head=ab;
return 2;
}
else if(ret==-1){ /*分配不成功*/
printf("Allocation fail\n");
free(ab);
return -1;
}
return 3;
}
/*分配内存模块*/
int allocate_mem(struct allocated_block *ab) {
struct free_block_type *fbt, *pre;
int request_size = ab->size;
fbt = pre = free_block;
printf("%d", fbt->start_addr);
while(fbt!=NULL) {
if(fbt->size>=request_size){/*分配后空闲空间足够大，则分割*/
if((fbt->size-request_size)>MIN_SLICE) {
ab->size = request_size;
ab->start_addr = fbt->start_addr;
fbt->size -= request_size;
fbt->start_addr += request_size;
}
else {/*分割后空闲区成为小碎片，一起分配*/
ab->size = fbt->size;
ab->start_addr = fbt->start_addr;
if (fbt == free_block)
free_block = fbt->next;
else {
pre->next = fbt->next;
free(fbt);
}
}
return 1;
}
pre = fbt;
fbt = fbt->next;
}
return 0;
}
/*删除进程，归还分配的存储空间，并删除描述该进程内存分配的节点*/
kill_process(void){
struct allocated_block *ab;
int pid;
printf("Kill Process, pid=");
scanf("%d", &pid);
ab=find_process(pid);
if(ab!=NULL){
free_mem(ab); /*释放ab所表示的分配区*/
dispose(ab); /*释放ab数据结构节点*/
}
}
/*struct free_block_type* find_process(int pid) */
struct allocated_block *find_process(int pid)
{
struct allocated_block *ab=allocated_block_head;
while(ab!=NULL) {
if(pid != ab->pid) {
ab=ab->next;
}
else return ab;
}
}
/*将ab所表示的已分配区归还，并进行可能的合并*/
int free_mem(struct allocated_block *ab){
int algorithm = ma_algorithm;
struct free_block_type *fbt, *pre, *work;
fbt=(struct free_block_type*) malloc(sizeof(struct free_block_type));
if(!fbt) return -1;
fbt->size = ab->size;
fbt->start_addr = ab->start_addr;
/*插入到空闲区链表的头部并将空闲区按地址递增的次序排列*/
fbt->next = free_block;
free_block=fbt;
rearrange(MA_FF);/*默认是FF算法*/
fbt=free_block;
while(fbt!=NULL){
work = fbt->next;
if(work!=NULL){
/*如果当前空闲区与后面的空闲区相连，则合并*/
if(fbt->start_addr+fbt->size == work->start_addr){
fbt->size += work->size;
fbt->next = work->next;
free(work);
continue;
}
}
fbt = fbt->next;
}
rearrange(algorithm); /*重新按当前的算法排列空闲区*/
return 1;
}
/*释放ab数据结构节点*/
int dispose(struct allocated_block *free_ab) {
struct allocated_block *pre, *ab;
if(free_ab == allocated_block_head) { /*如果要释放第一个节点*/
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;
}
/* 显示当前内存的使用情况，包括空闲区的情况和已经分配的情况 */
int display_mem_usage(void) {
struct free_block_type *fbt = free_block;
struct allocated_block *ab = allocated_block_head;
if(fbt==NULL) return(-1);
printf("----------------------------------------------------------\n");
/* 显示空闲区 */
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;
}
/* 显示已分配区 */
printf("\nUsed Memory:\n");
printf("%10s %20s %10s %10s\n", "PID", "ProcessName", "start_addr", " size");
while(ab!=NULL){
printf("%10d %20s %10d %10d\n", ab->pid, ab->process_name, ab->start_addr, ab->size);
ab=ab->next;
}
printf("----------------------------------------------------------\n");
return 0;
}
do_exit()
{
/* exit(0); */
_exit(0);
return 0;
}
int main(void)
{
char choice;
pid=0;
free_block = init_free_block(mem_size); /*初始化空闲区*/
for(;;) {
display_menu(); //显示菜单
fflush(stdin);
scanf("%s", &choice);
switch(choice) {
case '1': set_mem_size();break; /*设置内存大小*/
case '2': set_algorithm();flag=1;break;/*设置分配算法*/
case '3': new_process(); flag=1;break; /*创建新进程*/
case '4': kill_process(); flag=1;break;/*删除进程*/
case '5': display_mem_usage();flag=1;break;/*显示内存使用*/
case '0': do_exit(); exit(0); /*释放链表并退出*/
default: break;
}
}
}
