C语言实现 操作系统 银行家算法

/****************************************************银行家算法算法思想：1. 在多个进程中，挑选资源需求最小的进程Pmin，可能存在多类资源，这时暂取第一类资源作为基准2. 验证剩余的资源能否满足进程Pmin各类资源的最大资源需求，若满足，意味着进程能够运行完毕，最后释放占有着的资源，此时回收Pmin占有的资源，将此进程标志为FINISH,并唤醒那些等待的进程（实际就是改变等待进程的状态标志）若不满足，表明资源不够，将此进程标志为WAIT3. 循环整个过程，当检测到进程全部为FINISH时，表明是安全状态检测到全部的进程为WAIT时，表明可能死锁了，是一个非安全状态林育彬2014/10/17*****************************************************/#include <stdio.h>#include <malloc.h>#include <string.h>// 安全状态标志#define TRUE0#define FALSE-1// 进程状态标志#define FINISH1#define READY0#define WAIT-1// 为了在函数调用的时候，减少参数的个数，这里将声明一些变量为全局变量int *Available = NULL;// 剩余资源可用数量int *Max = NULL;// 每个进程最大的需求量int *Allocation = NULL;// 每个进程已经分配的资源数int *Need = NULL;// 每个进程还需要的资源数int *SafeList = NULL;// 存储一个安全序列int initData(const int pCount, const int rCount){int i = 0;Available =(int*)malloc(rCount * sizeof(int));Max =(int*)malloc(rCount*pCount * sizeof(int));Allocation =(int*)malloc(rCount*pCount * sizeof(int));Need =(int*)malloc(rCount*pCount * sizeof(int));SafeList =(int*)malloc((pCount+1) * sizeof(int));// SafeList[0] 作为一个安全标志位if (Available == NULL || Max == NULL || Allocation == NULL || Need == NULL || SafeList == NULL){printf("out of space\n");return FALSE;}SafeList[0] = 0;// 初始化，表明不存在安全序列// 最大需求量for(i=0; i<rCount*pCount; ++i){scanf("%d", &Max[i]);}// 已分配资源数量for(i=0; i<rCount*pCount; ++i){scanf("%d", &Allocation[i]);}// 剩余资源量for(i=0; i<rCount; ++i){scanf("%d", &Available[i]);}// 计算需求数for(i=0; i<rCount*pCount; ++i){Need[i] = Max[i] - Allocation[i];}return TRUE;}// 测试此时的进程状态int testStatus(const int pCount, const int rCount){int pMin = 0;// 最小需求进程IDint pWait = 0;// 等待进程数int pFinish = 0;// 完成进程数int p = 0;int r = 0;int posList = 1;// 安全序列下标int *pStatus   = (int*)malloc(pCount * sizeof(int));// 进程的标志状态int *pAvai_cpy = (int*)malloc(rCount * sizeof(int));// Available 的一份拷贝，避免破坏数据int *safeList_tmp = (int*)malloc((pCount+1) * sizeof(int));if (pStatus == NULL || pAvai_cpy == NULL || safeList_tmp == NULL){printf("out of space\n");return FALSE;}// 初始化所有的进程为就绪状态memset(pStatus, READY, pCount * sizeof(int));// 拷贝 Availablememcpy(pAvai_cpy, Available, rCount * sizeof(int));while(pFinish != pCount && pWait != pCount){// 以第一类资源为基准，挑选资源需求最小的进程int needMin = -1;pMin = 0;for (p=0; p<pCount; ++p){if (pStatus[p] != READY)continue;if (needMin == -1 || Need[p*rCount + 0] < needMin)  // 第一类需求资源, needMin == -1 初次取值{needMin = Need[p*rCount + 0];pMin = p;}}// 验证剩余资源能否满足最小资源进程的需求for (r=0; r<rCount; ++r){if (Need[pMin*rCount + r]> pAvai_cpy[r]){// 满足不了break;}}if (r == rCount){// 增加到安全序列中safeList_tmp[posList++] = pMin+1;// 满足各类资源需求pStatus[pMin] = FINISH;pFinish++;// 回收资源for (r=0; r<rCount; ++r){pAvai_cpy[r] += Allocation[pMin*rCount + r];  }// 唤醒等待的进程for (p=0; p<pCount; ++p){if (pStatus[p] == WAIT){pStatus[p] = READY;pWait--;}}}else{// 表明无法满足，进程等待pStatus[pMin] = WAIT;pWait++;}}free(pStatus);free(pAvai_cpy);// 验证状态if (pFinish == pCount){// 更新安全序列safeList_tmp[0] = 1;// 安全标志位置1，表明存在安全序列memcpy(SafeList, safeList_tmp, (pCount+1) * sizeof(int) );free(safeList_tmp);return TRUE;}else{free(safeList_tmp);return FALSE;}}void showSafeList(const int pCount){if (SafeList != NULL){int i = 0;if (SafeList[i] != 1){printf("不存在安全序列\n");}else{++i;printf("安全序列：");while(i <= pCount){printf("p%d  ", SafeList[i++]);}printf("\n");}}else{printf("不存在安全序列\n");}}// 测试资源请求，如果满足，则分配，不满足，则不分配资源   modify 2014/11/2int request(const int pId, const int pCount, const int rCount, const int *reqList){int *Avai_cpy = (int*)malloc(rCount * sizeof(int));int *pId_Allo = (int*)malloc(rCount * sizeof(int));// 保存当前进程的一条分配情况, int *pId_Need = (int*)malloc(rCount * sizeof(int));// 保存当前进程的一条需求情况int r = 0;const int locate = pId*rCount;// 定位到进程的位置if (Avai_cpy == NULL || pId_Allo == NULL || pId_Need == NULL){printf("out of space\n");return FALSE;}// 做数据备份for(r=0; r<rCount; ++r){pId_Allo[r] = Allocation[locate + r];pId_Need[r] = Need[locate + r];Avai_cpy[r] = Available[r];}// 资源分配for (r=0; r<rCount; ++r){if (reqList[r] > Available[r])   {return FALSE;}Allocation[locate + r] += reqList[r];Available[r] -= reqList[r];Need[locate + r] -= reqList[r];}// testif (testStatus(pCount, rCount) != TRUE){// 分配之后处于非安全状态，数据还原for(r=0; r<rCount; ++r){Allocation[locate + r] = pId_Allo[r];Need[locate + r]       = pId_Need[r];Available[r]           = Avai_cpy[r];}free(Avai_cpy);free(pId_Allo);free(pId_Need);Avai_cpy = pId_Allo = pId_Need = NULL;return FALSE;}else{// 成功分配free(Avai_cpy);free(pId_Allo);free(pId_Need);Avai_cpy = pId_Allo = pId_Need = NULL;return TRUE;}return TRUE;}// 清理空间void destory(){if (Available != NULL){free(Available);}if (Max != NULL){free(Max);}if (Allocation != NULL){free(Allocation);}if (Need != NULL){free(Need);}if (SafeList != NULL){free(SafeList);}Available = NULL;Max = NULL;Allocation = NULL;Need = NULL;SafeList = NULL;//printf("destory\n");}int main(){int rCount = 0;int pCount = 0;// request int pId = 2;int reqList[] = {0, 3, 4};freopen("data.txt", "r", stdin);// 为了测试的方便，这里使用重定位// read datascanf("%d %d", &pCount, &rCount);initData(pCount, rCount);// test statusif (testStatus(pCount, rCount) == TRUE){printf("是安全状态\n");}else{printf("非安全状态\n");}showSafeList(pCount);//请求资源    p2 请求资源 0 3 4if (request(pId, pCount, rCount, reqList) == TRUE){printf("资源成功分配\n");}else{printf("该请求无法满足安全状态\n");}destory();return 0;}/********************************************data.txt5 35 5 95 3 64 0 114 2 54 2 4 2 1 24 0 24 0 52 0 43 1 42 3 3********************************************/