今天上机要求Linux下实现动态分区存储管理的内存分别配回收现在把源码贡献出来
#include<stdlib.h>
#include <stdio.h>
#include <string.h>
#define MAX 600 //设置总内存大小为512k
struct partition {
char pn[10];//分区名字
int begin;//起始地址
int size;//分区大小
int end;//结束地址
char status;//分区状态
};
struct partition part[MAX];
int p = 0; //标记上次扫描结束处
void Init()//初始化分区地址、大小以及状态
{
int i;
for ( i = 0; i < MAX; i++ )
part[i].status = '-';
strcpy( part[0].pn, "SYSTEM" );
part[0].begin = 0;
part[0].size = 100;
part[0].status = 'u';
strcpy( part[1].pn, "-----" );
part[1].begin = 100;
part[1].size = 100;
part[1].status = 'f';
strcpy( part[2].pn, "A" );
part[2].begin = 200;
part[2].size = 50;
part[2].status = 'u';
strcpy( part[3].pn, "-----" );
part[3].begin = 250;
part[3].size = 50;
part[3].status = 'f';
strcpy( part[4].pn, "B" );
part[4].begin = 300;
part[4].size = 100;
part[4].status = 'u';
strcpy( part[5].pn, "-----" );
part[5].begin = 400;
part[5].size = 200;
part[5].status = 'f';
for ( i = 0; i < MAX; i++ )
part[i].end = part[i].begin + part[i].size-1;
}
void Output( int i ) //以行的形式输出结构体的数据
{
printf( "\t%s", part[i].pn );
printf( "\t%d", part[i].begin );
printf( "\t%d", part[i].size );
printf( "\t%d", part[i].end );
printf( "\t%c", part[i].status );
}
void display() //显示分区
{
int i;
int n; //用n来记录分区的个数
printf("\n");
printf( "\n 已分配分区表Used:" );
printf( "\n\tNo.\tproname\tbegin\tsize\tend\tstatus" );
printf("\n");
n = 1;
for ( i = 0; i < MAX; i++ )
{
if ( part[i].status == '-' )
break;
if ( part[i].status == 'u' )
{
printf( "\n\tNo.%d", n );
Output( i );
n++;// 记录已分配使用的分区个数
}
}
printf("\n");
printf( "\n 空闲分区表Free:" );
printf( "\n\tNo.\tproname\tbegin\tsize\tend\tstatus" );
printf("\n");
n = 1;
for ( i = 0; i < MAX; i++ )
{
if ( part[i].status == '-' )
break;
if ( part[i].status == 'f' )
{
printf( "\n\tNo.%d", n );
Output( i );
n++; //记录空闲分区的个数
}
}
// printf( "\n" );
printf("\n");
printf( "\n 内存使用情况，按起始址增长的排:" );
//printf( "\n printf sorted by address:" );
printf( "\n\tNo.\tproname\tbegin\tsize\tend\tstatus" );
printf("\n");
n = 1;
for ( i = 0; i < MAX; i++ )
{
if ( part[i].status == '-' )
break;
printf( "\n\tNo.%d", n );
Output( i );
n++;//记录已分配分区以及空闲分区之和的总个数
}
getc;
}
void Fit( int a, char workName[], int workSize ) //新作业把一个分区分配成两个分区：已使用分区和空闲分区
{
int i;
for ( i = MAX; i > a + 1; i-- )
{
//通过逆向遍历，把在a地址后的所有分区往后退一个分区，目的在于增加一个分区
if ( part[i - 1].status == '-' )
continue;
part[i]=part[i-1];
}
strcpy( part[a + 1].pn, "-----" );
part[a + 1].begin = part[a].begin + workSize;
part[a + 1].size = part[a].size - workSize;
part[a + 1].end = part[a].end-1;
part[a + 1].status = 'f';
strcpy( part[a].pn, workName );
part[a].size = workSize;
part[a].end = part[a].begin + part[a].size-1;
part[a].status = 'u';
}
void fenpei() // 分配
{
int i;
int a;
int workSize;
char workName[10];
int pFree;
printf( "\n请输入作业名称：" );
scanf( "%s", &workName );
for(i=0;i<MAX;i++)
{
if(!strcmp(part[i].pn,workName))//判断作业名称是否已经存在
{
printf("\n作业已经存在，不必再次分配！\n");
return;
}
}
printf( "请输入作业大小(k)：" );
scanf( "%d", &workSize );
for ( i = 0; i < MAX; i++ )//通过循环在空闲区找是否有适合区间存储作业
{
if ( part[i].status == 'f' && part[i].size >= workSize )
{
pFree = i;
break;
}
}
if ( i == MAX )
{
printf( "\n该作业大小超出最大可分配空间" );
getc;
return;
}
for ( i = 0; i < MAX; i++ )//最佳适应算法
if ( part[i].status == 'f' && part[i].size >= workSize )
if ( part[pFree].size > part[i].size )
pFree = i;//通过遍历所有区间，每次都找到最小空闲分区进行分配
Fit( pFree, workName, workSize );
printf( "\n分配成功！" );
getc;
}
void hebing() //合并连续的空闲分区
{
int i = 0;
while ( i != MAX - 1 )
{
for ( i = 0; i < MAX - 1; i++ )
{
if ( part[i].status == 'f' )
if ( part[i + 1].status == 'f' )
{
part[i].size = part[i].size + part[i + 1].size;
part[i].end = part[i].begin + part[i].size-1;
i++;
for ( i; i < MAX - 1; i++ )
{
if ( part[i + 1].status == '-' )
{
part[i].status = '-';
break;
}
part[i]=part[i+1];
}
part[MAX - 1].status = '-';
break;
}
}
}
}
void huishou() // 回收分区
{
int i;
int number;
int n=0;
printf( "\n请输入回收的分区号：" );
scanf( "%d", &number );
if ( number == 1 )
{
printf( "\n系统分区无法回收" );
return;
}
for ( i = 0; i < MAX; i++ )//通过循环查找要回收的已使用分区区号
{
if ( part[i].status == 'u' )
{
n++;
if ( n == number )
{
strcpy( part[i].pn, "-----" );
part[i].status = 'f';
}
}
}
if ( i == MAX - 1 )
{
printf( "\n找不到分区" );
return;
}
hebing();//合并连续的空闲分区
printf( "\n回收成功！" );
getc;
}
void main()
{
int selection;
Init();
printf( "初始化完成，设内存容量%dk", MAX );
printf( "\n系统文件从低址存储，占%dk", part[0].size );
while ( 1 )
{
printf( "\n----------选择----------" );
printf( "\n| 0、退出系统 |" );
printf( "\n| 1、显示分区 |" );
printf( "\n| 2、分配分区 |" );
printf( "\n| 3、回收分区 |" );
printf( "\n------------------------");
printf( "\n请选择 > " );
while ( 1 )
{
scanf( "%d", &selection );
if ( selection == 0 ||selection == 1 || selection == 2 || selection == 3 )
break;
printf( "输入错误，请重新输入：" );
}
switch ( selection )
{
case 0:
exit(0); //退出系统
break;
case 1:
display(); //显示分区
break;
case 2:
fenpei(); //分配作业
break;
case 3:
huishou(); //回收分区
break;
default:
break;
}
}
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