ldm.rar_LDM_just5gn_动态内存

#include "iostream.h" #include "iomanip.h" #define ERR_NOFREEAREA 1 #define ERR_NOADEQUACYAREA 2 #define ERR_ALLOCATED 4 #define ERR_NOJOBS 1 #define ERR_NOSUCHJOB 2 #define ERR_RECLAIMED 4 typedef struct tagUsedNode { long address; long length; int flag; struct tagUsedNode *next; } USED_AREA , *USED_TABLE; typedef struct tagFreeNode { long address; long length; struct tagFreeNode *next; } FREE_AREA , *FREE_TABLE; //空闲区、作业区链表 USED_TABLE usedTable = NULL; FREE_TABLE freeTable = NULL; //给作业分配空间 //jobname: 作业名 //jobsize: 作业所需空间大小 //-------------------------------------------------------------------------- int Allocate( int jobname , long jobsize ) { //如果没有空闲区 if( freeTable == NULL ) return ERR_NOFREEAREA; FREE_TABLE p = freeTable; FREE_TABLE q = p; //找首次适应空闲区 while( p != NULL && p->length < jobsize ) { q = p; p = p->next; } //如果找不到有足够空间的分区 if( p == NULL ) return ERR_NOADEQUACYAREA; USED_TABLE x = new USED_AREA; x->address = p->address; x->length = jobsize; x->flag = jobname; x->next = NULL; //如果该分区大于作业需求，空间大小减去作业大小 if( p->length > jobsize ) { p->length -= jobsize; p->address += jobsize; } //如果该分区等于作业大小，删除该分区 else { if( p == freeTable ) freeTable = NULL; else q->next = p->next; delete p; } //作业加入“作业表”中 USED_TABLE r = usedTable; USED_TABLE t = r; while( r != NULL && r->address < x->address ) { t = r; r = r->next; } if( usedTable == NULL ) usedTable = x; else { x->next = r; t->next = x; } return ERR_ALLOCATED; } //--------------------------------------------------------------------------------- //回收作业空间 //jobname: 作业名 //--------------------------------------------------------------------------------- int Reclaim( int jobname ) { if( usedTable == NULL ) return ERR_NOJOBS; USED_TABLE p = usedTable; USED_TABLE q = p; while( p != NULL && p->flag != jobname ) { q = p; p = p->next; } //如果没有该作业 if( p == NULL ) return ERR_NOSUCHJOB; //回收后的空间加入到空闲区 FREE_TABLE r = freeTable; FREE_TABLE t = r; FREE_TABLE x; while( r != NULL && r->address < p->address ) { t = r; r = r->next; } x = new FREE_AREA; x->address = p->address; x->length = p->length; x->next = NULL; if( r == freeTable ) { x->next = r; freeTable = x; t = freeTable; if( t->next != NULL && t->address + t->length == t->next->address) { t->length += t->next->length; r = t->next; t->next = t->next->next; delete r; } } else { x->next = r; t->next = x; if( t->next != NULL && t->address + t->length == t->next->address) { t->length += t->next->length; r = t->next; t->next = t->next->next; delete r; } t = t->next; if( t->next != NULL && t->address + t->length == t->next->address) { t->length += t->next->length; r = t->next; t->next = t->next->next; delete r; t = t->next; } } //合并分区 //删除该作业 if( p == usedTable ) { usedTable = usedTable->next; } else q->next = p->next; delete p; return ERR_RECLAIMED; } //------------------------------------------------------------------------------- int Init() { freeTable = new FREE_AREA; freeTable->address = 0; freeTable->length = 64; freeTable->next = NULL; return 1; } //------------------------------------------------------------------------------- void jobrequest() { int jobname; int jobsize; cout<<"作业名: "; cin >> jobname; cout<<"作业长度: "; cin >> jobsize; if( Allocate( jobname , jobsize ) == ERR_ALLOCATED ) cout<<"该作业已成功获得所需空间"<<endl; else cout<<"该作业没有获得所需空间"<<endl; } //--------------------------------------------------------------------------------- void jobreclaim() { int jobname; cout<<"需要回收的作业名: "; cin >>jobname; int result = Reclaim( jobname ); if( result == ERR_RECLAIMED ) cout<<"作业"<<jobname<<"已成功回收"<<endl; else if( result == ERR_NOSUCHJOB || result == ERR_NOJOBS ) cout<<"系统没有作业"<<jobname<<"或该作业"<<jobname<<"不存在"<<endl; } //--------------------------------------------------------------------------------- void freeTablePrint() { cout<<"..............................................................."<<endl; cout<<setw(10)<<"address"<<setw(15)<<"length"<<setw(15)<<"state"<<setw(15)<<"jobname"<<endl<<endl; FREE_TABLE p = freeTable; USED_TABLE q = usedTable; int x , y; while( p || q ) { if( p ) x = p->address; else x = 0x7fffffff; if( q ) y = q->address; else y = 0x7fffffff; if( x < y ) { cout<<setw(10)<<p->address<<setw(15)<<p->length<<setw(15)<<"空闲"<<endl; p = p->next; } if( x > y ) { cout<<setw(10)<<q->address<<setw(15)<<q->length<<setw(15)<<"已分配"<<setw(15)<<"jobname="<<q->flag<<endl; q = q->next; } } cout<<".............................................................."<<endl; cout<<endl; } void main() { cout<<"--------------------------------------------------------------------"<<endl; cout<<" 操作系统课程设计实验：连续动态内存管理模拟实现 "<<endl; cout<<" 计算机科学与技术学院 "<<endl; cout<<"--------------------------------------------------------------------"<<endl; Init(); int choose; bool exitFlag = false; cout<<"输入功能项: 0 -　退出 1 - 分配主存 2 - 回收主存 3 - 显示主存 "<<endl; while( !exitFlag ) { cout<<"输入:"; cin>>choose; switch( choose ) { case 0: exitFlag = true; break; case 1: jobrequest(); break; case 2: jobreclaim(); break; case 3: freeTablePrint(); break; } } }