主存空间的分配与回收.docVIP

1.采用可变分区管理，使用首次适应算法实现主存的分配与回收

#includeiostream

#includememory.h

#includevector

#includealgorithm

#includetime.h

usingnamespacestd;

structblock{ //定义空闲块的记录表;

intbegin;

intlength;

};

boolcmp(constblockp1,constblockp2){

if(p1.beginp2.begin)

returntrue;

returnfalse;

}

vectorblockmem_table; //内存使用表;

vectorblockfree_table; //空闲分区表;

voidinit(){ //初始化空闲块,并将空闲信息记录到空闲分区说明表中;

blocknow;

while(cinnow.beginnow.length,now.begin=0){

mem_table.push_back(now);

}

sort(mem_table.begin(),mem_table.end(),cmp);

if(mem_table[0].begin0){

now.begin=0;

now.length=mem_table[0].begin;

free_table.push_back(now);

}

vectorblock::iteratorp=mem_table.begin();

while(p!=mem_table.end()p+1!=mem_table.end()){

if(p-begin+p-length(p+1)-begin){

now.begin=p-begin+p-length;

now.length=(p+1)-begin-now.begin;

free_table.push_back(now);

}

p++;

}

if(mem_table[mem_table.size()-1].begin+mem_table[mem_table.size()-1].length256){

now.begin=mem_table[mem_table.size()-1].begin+mem_table[mem_table.size()-1].length;

now.length=256-now.begin;

free_table.push_back(now);

}

sort(free_table.begin(),free_table.end(),cmp);

}

voidapplacation(constintlenght){ //内存申请操作;

vectorblock::iteratorp=free_table.begin();

while(p!=free_table.end()){ //利用FF查找适宜的空闲块；

if(p-length=lenght){

blocknow;

now.begin=p-begin;

now.length=lenght;

mem_table.push_back(now);

if(p-length==lenght) //查找成功就将内存分配出去;

free_table.erase(p);

else{

p-begin+=lenght;

p-length-=lenght;

}

cout分配成功!endl;

return;

}

p++;

}

cout内存不够,无法分配endl;

exit(0);

}

voidprint(){ //主存空间占用表和空闲分区说明表的打印;

cout主存空间占用情况endl

起始地址 长度endlendl;

for(inti=0;imem_table.size();i++)

coutmem_table[i].begin mem_table[i].lengthendl;

coutendl

空闲区表endl

起始地址 长度endl;

for(inti=0;ifree_table.size();i++)

coutfree_table[i].begin free_table[i].lengthendl;

}

voidrecover(){ //内存的回收;

intt;

t=rand()%mem_table.size(); //随机选取一个非系统内存块进行回收;

w