Linux操作系统实验（3）（模拟实现请求分页虚存页面替换算法）

数据结构：

typedef struct _Page{ // 页面    int pageID;     //页号}Page;typedef struct _PageQueue{ //页面队列    Page page;    struct _PageQueue* next; //下一页面}PageQueue;typedef struct _Block{ //块记录结构    Page *page; //页面    long time; //最后访问时间    int state; //页块是否空闲}Block;typedef struct _BlockQueue{ //块队列    Block block;    struct _BlockQueue *next;}BlockQueue;typedef struct process{ // 进程结构    PageQueue pages; //页面    unsigned int pageLength; // 页面数}process;//进程

函数：

BlockQueue* InitializeBlockQueue(unsigned int size); //初始化主存块，把首地址返回，如果分配失败返回NULLint GetBlockQueueSize(BlockQueue *blockQueue);    //获取块长度void ResetBlockQueue(BlockQueue *blockQueue);    //清空块内容void PrintBlockList(BlockQueue *blockQueue, int pageID, int color);   //打印块信息PageQueue* InitializePageQueue(unsigned int pageLength, int maxPageID);    //初始化页面void InitializeProcess(process *proc, unsigned int pageSize, unsigned int maxPageID);   //初始化进程BlockQueue* SearchPage(BlockQueue *blockQueue, Page page);   //搜索特定页面BlockQueue* SearchIdleBlock(BlockQueue *blockQueue);  //搜索空闲块BlockQueue* GetOldestBlock(BlockQueue *blockQueue);   //取得主存中停留最久的页面，返回它的地址void FIFO(BlockQueue *blockQueue, process *proc);   //先进先出算法

代码：

#include<stdio.h>#include<stdlib.h>#include<ctype.h>#include<sys/time.h>#include<unistd.h>#define BUSY 1#define IDLE 0#define blockNumber 3#define n 10int Time = 0;typedef struct _Page{ // 页面    int pageID;     //页号}Page;typedef struct _PageQueue{ //页面队列    Page page;    struct _PageQueue* next; //下一页面}PageQueue;typedef struct _Block{ //块记录结构    Page *page; //页面    long time; //最后访问时间    int state; //页块是否空闲}Block;typedef struct _BlockQueue{ //块队列    Block block;    struct _BlockQueue *next;}BlockQueue;typedef struct process{ // 进程结构    PageQueue pages; //页面    unsigned int pageLength; // 页面数}process;//进程BlockQueue* InitializeBlockQueue(unsigned int size){     //初始化主存块，把首地址返回，如果分配失败返回NULL    BlockQueue *p1, *p2;    BlockQueue *block;    block = NULL;    for(int i = 0; i < size; ++i){        p1 = (BlockQueue*)malloc(sizeof(BlockQueue));        p1->block.time = 0;        p1->block.state = 0;        p1->block.page = NULL;        p1->next = NULL;        if(block == NULL) block = p1;        else p2->next = p1;        p2 = p1;    }    return block;}int GetBlockQueueSize(BlockQueue *blockQueue){    //获取块长度    BlockQueue *presentBlock;    presentBlock = blockQueue;    int blockQueueSize = 0;    while(presentBlock != NULL){        blockQueueSize++;        presentBlock = presentBlock->next;    }    return blockQueueSize;}void ResetBlockQueue(BlockQueue *blockQueue){    //清空块内容    BlockQueue *presentBlock;    presentBlock = blockQueue;    while(presentBlock != NULL){        presentBlock->block.page = NULL;        presentBlock->block.state = IDLE;        presentBlock->block.time = 0;        presentBlock = presentBlock->next;    }}void PrintBlockList(BlockQueue *blockQueue, int pageID, int color){    //打印块信息    BlockQueue *presentBlock;    char strl[5], *str2;    presentBlock = blockQueue;    while(presentBlock != NULL){        if(presentBlock->block.state == IDLE)            printf("|    |\n");        else{            printf("| %d  |\n", presentBlock->block.page->pageID);        }        presentBlock = presentBlock->next;    }    printf("\n");}PageQueue* InitializePageQueue(unsigned int pageLength, int maxPageID){    //初始化页面    srand(100);    PageQueue *head;    head = NULL;    PageQueue *p, *q;    for(int i = 0; i < pageLength; ++i){        p = (PageQueue*)malloc(sizeof(PageQueue));        p->page.pageID = (int)(rand() % (maxPageID + 1));        printf("%d ", p->page.pageID);        p->next = NULL;        if(head == NULL) head = p;        else q->next = p;        q = p;    }    printf("\n");    return head;}void InitializeProcess(process *proc, unsigned int pageSize, unsigned int maxPageID){    //初始化进程    printf("进程初始化：\n");    proc->pageLength = pageSize;    proc->pages.next = InitializePageQueue(pageSize, maxPageID);}BlockQueue* SearchPage(BlockQueue *blockQueue, Page page){    //搜索特定页面    BlockQueue *p;    int blockSize;    p = blockQueue;    while(p != NULL){        if(p->block.page != NULL){            if(p->block.page->pageID == page.pageID)                return p;        }    }    return NULL;}BlockQueue* SearchIdleBlock(BlockQueue *blockQueue){    //搜索空闲块    BlockQueue *p;    p = blockQueue;    while(p != NULL){        if(p->block.state == IDLE)            return p;        else p = p->next;    }    return NULL;}BlockQueue* GetOldestBlock(BlockQueue *blockQueue){    //取得主存中停留最久的页面，返回它的地址    BlockQueue *p;    p = blockQueue;    if(p == NULL) return p;    int cnt = 0, cur = 0;    int t = p->block.time;    while(p != NULL){        if(t > p->block.time){            t = p->block.time;            cur = cnt;        }        p = p->next;        cnt++;    }    BlockQueue *q;    q = blockQueue;    cnt = 0;    while(q != NULL){        if(cnt == cur) return q;        q = q->next;        cnt++;    }}void FIFO(BlockQueue *blockQueue, process *proc){    //先进先出算法    int blockQueueSize = GetBlockQueueSize(blockQueue);    PageQueue *currentPage;    currentPage = proc->pages.next;    BlockQueue *p;    p = blockQueue;    int count = 0, cnt = 0;    while(currentPage != NULL){        int ok = 0;        p = blockQueue;        Time++;        while(p != NULL){            if(p->block.page !=NULL && p->block.page->pageID == currentPage->page.pageID){                ok = 1;                break;            }            p = p->next;        }        if(ok){            PrintBlockList(blockQueue, currentPage->page.pageID, 0);        }        else{            BlockQueue *block;            block = SearchIdleBlock(blockQueue);            if(block != NULL){                block->block.state = BUSY;                block->block.time = Time;                block->block.page = (Page*)malloc(sizeof(Page));                block->block.page->pageID = currentPage->page.pageID;                PrintBlockList(blockQueue, currentPage->page.pageID, 1);            }            else{                BlockQueue *block;                block = GetOldestBlock(blockQueue);                block->block.time = Time;                block->block.page->pageID = currentPage->page.pageID;                PrintBlockList(blockQueue, currentPage->page.pageID, 2);            }        }        currentPage = currentPage->next;        cnt++;    }    printf("%d\n", cnt);}int main(){    int pageNumber;    scanf("%d", &pageNumber);    printf("Block Number : %d, Page Number : %d\n", blockNumber, pageNumber);    BlockQueue *blocks;    process proc;    InitializeProcess(&proc, pageNumber, n);    blocks = InitializeBlockQueue(blockNumber);    FIFO(blocks, &proc);    ResetBlockQueue(blocks);    return 0;}