内存管理伙伴算法 模拟程序

#include <stdio.h>#include<iostream>using namespace std;#include<list>#include<math.h>#include<string>#include<ctype.h>struct Block{int start;int end;Block(){start=0;end =0;}int operator<(Block b){return this->end < b.start;}};#define BLOCKTYPE 10struct MemBlock{int num;int base;list<Block> memBlockList;MemBlock(){num = 0;base = 0;memBlockList.clear();}};struct Job{int start;int end;int index;Job(){start=0;end =0;}};list<Job> jobList;int jobindex = 0;MemBlock arr[BLOCKTYPE];bool isMemInit = false;//是否初始化过内存//回收所有内存void MemEnd(){int i = 0;for(i = 0;i<BLOCKTYPE;i++){arr[i].base = 0;arr[i].memBlockList.clear();}jobList.clear();jobindex = 0;isMemInit = false;}//初始化分配内存void MemInit( int PoolSize ){int i = BLOCKTYPE - 1;int n = 0;int j = 0;int base;for(;PoolSize >=8 && i>=0;i--){base = (int)pow(2.0,i+3);arr[i].num = 0;n = PoolSize/base;PoolSize = PoolSize%base;if(n > 0){arr[i].num = n;for(j = n;j>0;j--){Block block;arr[i].memBlockList.push_back(block);}}}int start = 0;int end = 0;list<Block>::iterator it;for(i = 0;i<BLOCKTYPE;i++){base = (int)pow(2.0,i+3);arr[i].base = base;if(arr[i].num>0){it = arr[i].memBlockList.begin();while(it != arr[i].memBlockList.end()){end = start+base-1;(*it).start = start;(*it).end = end;start = end+1;it++;}}}isMemInit = true;}//合并连续内存void mergeMem(int index){int i = index;if(i>=BLOCKTYPE -1)//超过最大了{return;}if(arr[i].num > 1){list<Block>::iterator it1 = arr[i].memBlockList.begin();list<Block>::iterator it2 = arr[i].memBlockList.begin();it2++;while(it2 != arr[i].memBlockList.end()){if(it1->end == it2->start-1){Block block;block.start = it1->start;block.end = it2->end;arr[i+1].memBlockList.push_back(block);arr[i+1].num++;arr[i].memBlockList.erase(it1);arr[i].memBlockList.erase(it2);arr[i+1].memBlockList.sort();arr[i].num--;arr[i].num--;break;}it1++;it2++;}}mergeMem(i+1);}//分割多余内存void divdeMem(int start,int end,int index){int i = index;if(start > end){//合并内存mergeMem(i+1);return;}Block block;block.end = end;block.start = end - arr[i].base+1;end = block.start -1;arr[i].memBlockList.push_back(block);arr[i].memBlockList.sort();arr[i].num++;divdeMem(start,end,i-1);}//申请内存bool MemAlloc( int MemSize ){if(MemSize > 4096 || MemSize < 1){return false;}int size = 0;int i = 0;int n = 0;for(;i<BLOCKTYPE;i++){if(MemSize <= arr[i].base){if(0 == size){size = arr[i].base;//实际分配的大小}//有空闲块if(arr[i].num > 0){//空闲块链表应该是有序的Block block = arr[i].memBlockList.front();jobList.back().start = block.start;jobList.back().end = block.start+size-1;//分配了一块内存 arr[i].memBlockList.pop_front();arr[i].num--;//分割多余内存int start = block.start + size;int end = block.end;divdeMem(start,end,i-1);return true;}}}return false;}//释放指定内存void MemFree( int start,int end ){int size = end - start +1;int i = 0;for(;i<BLOCKTYPE;i++){if(arr[i].base == size){Block block;block.start = start;block.end = end;arr[i].memBlockList.push_back(block);arr[i].memBlockList.sort();arr[i].num++;mergeMem(i);}}}void menu(){cout <<"空闲内存伙伴算法程序模拟" << endl;cout <<"1.初始化内存分配" << endl;cout <<"2.作业分配申请内存" << endl;cout <<"3.作业释放内存" << endl;cout <<"4.查看当前内存使用情况" << endl;cout <<"0.退出模拟程序" << endl;}//获得要初始化的内存大小bool getRequestMem(int &n){if(isMemInit){cout << "内存已经被初始化,将重新初始化分配内存,所有数据将会丢失,确定要继续吗,Y/N?" << endl;char c;cin >> c;if(toupper(c) == 'Y'){}else if(toupper(c) == 'N'){return false;}else{cout << "非法输入,返回主程序" << endl;return false;} MemEnd();}cout << "请输入分配的内存大小" << endl;cin >> n;return true;}//为作业分配内存void assignMemForJob(){Job job;job.index = jobindex++;jobList.push_back(job);cout << "请输入申请内存大小" << endl;int n;cin >> n;if(MemAlloc(n)){cout << "作业申请内存成功,起始地址为job" << job.index << ":" << jobList.back().start << "~" << jobList.back().end << endl;}else{jobindex--;jobList.pop_back();cout << "当前没有足够内存,请释放一定内存后再试" << endl;}}void checkMem(){cout << "内存空闲块:" << endl;int i = 0;list<Block>::iterator it;for(;i< BLOCKTYPE;i++){printf("%d : 有%d个空闲内存块    起始地址分别为:",arr[i].base,arr[i].num);for(it = arr[i].memBlockList.begin();it!=arr[i].memBlockList.end();it++){printf("%d~%d ",it->start,it->end);}printf("\n");}cout << "作业占用内存:" << endl;list<Job>::iterator job = jobList.begin();while(job != jobList.end()){printf("作业%d 大小:%d 内存地址:%d~%d\n",job->index,job->end - job->start+1,job->start,job->end);job++;}}//释放作业内存void retrieveMemFromJob(){cout << "请输入要释放的作业编号" << endl;int n = -1;cin >> n;if(n < 0){cout << "不存在该编号的作业,作业释放内存失败" << endl;}else{list<Job>::iterator it = jobList.begin();while(it != jobList.end()){if(it->index == n){Job job = *it;jobList.erase(it);//释放作业内存MemFree(job.start,job.end);break;}it++;}cout << "作业释放内存成功" << endl;}}int main(){int choice = -1;int size = 0;while(1){menu();cin >> choice;if(0 == choice){break;}switch(choice){case 1:if(getRequestMem(size)){MemInit(size);cout << "初始化内存成功" << endl;}else{cout << "初始化内存失败" << endl;}break;case 2:assignMemForJob();break;case 3:retrieveMemFromJob();break;case 4:checkMem();break;default:cout << "非法选项" << endl;break;}}cout << "退出模拟程序" << endl;return 0;}