[操作系统]课程设计源码2
作者:互联网
#include <unistd.h> #define COLLISIONFACTOR 0.5 //Hash函数冲突因子 struct HashFileHeader { int sig; //Hash文件印鉴 int reclen; //记录长度 int total_rec_num; //总记录数 int current_rec_num; //当前记录数 }; struct CFTag { char collision; //冲突计数 char free; //空闲标志 }; int hashfile_creat(const char *filename,mode_t mode,int reclen,int recnum); //int hashfile_open(const char *filename,int flags); int hashfile_open(const char *filename,int flags, mode_t mode); int hashfile_close(int fd); int hashfile_read(int fd,int keyoffset,int keylen,void *buf); int hashfile_write(int fd,int keyoffset,int keylen,void *buf); int hashfile_delrec(int fd,int keyoffset,int keylen,void *buf); int hashfile_findrec(int fd,int keyoffset,int keylen,void *buf); int hashfile_saverec(int fd,int keyoffset,int keylen,void *buf); int hash(int keyoffset,int keylen,void *buf,int recnum); int checkHashFileFull(int fd); int readHashFileHeader(int fd,struct HashFileHeader *hfh ) #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <stdio.h> #include "HashFile.h" int hashfile_creat(const char *filename,mode_t mode,int reclen,int total_rec_num) { struct HashFileHeader hfh; int fd; int rtn; char *buf; int i=0; hfh.sig=31415926; hfh.reclen=reclen; hfh.total_rec_num=total_rec_num; hfh.current_rec_num=0; //fd=open(filename,mode); fd=creat(filename,mode); if(fd!=-1) { rtn=write(fd,&hfh,sizeof(struct HashFileHeader)); //lseek(fd,sizeof(struct HashFileHeader),SEEK_SET); if(rtn!=-1) { buf=(char*)malloc((reclen+sizeof(struct CFTag))*total_rec_num); memset(buf,0,(reclen+sizeof(struct CFTag))*total_rec_num); rtn=write(fd,buf,(reclen+sizeof(struct CFTag))*total_rec_num); free(buf); } close(fd); return rtn; } else { close(fd); return -1; } } int hashfile_open(const char *filename,int flags, mode_t mode) { int fd=open(filename,flags,mode); struct HashFileHeader hfh; if(read(fd,&hfh,sizeof(struct HashFileHeader))!=-1) { lseek(fd,0,SEEK_SET); if(hfh.sig==31415926) return fd; else return -1; } else return -1; } int hashfile_close(int fd) { return close(fd); } int hashfile_read(int fd,int keyoffset,int keylen,void *buf) { struct HashFileHeader hfh; readHashFileHeader(fd,&hfh); int offset=hashfile_findrec(fd,keyoffset,keylen,buf); if(offset!=-1) { lseek(fd,offset+sizeof(struct CFTag),SEEK_SET); return read(fd,buf,hfh.reclen); } else { return -1; } } int hashfile_write(int fd,int keyoffset,int keylen,void *buf) { return hashfile_saverec(fd,keyoffset,keylen,buf); //return -1; } int hashfile_delrec(int fd,int keyoffset,int keylen,void *buf) { int offset; offset=hashfile_findrec(fd,keyoffset,keylen,buf); if(offset!=-1) { struct CFTag tag; read(fd,&tag,sizeof(struct CFTag)); tag.free=0; //置空闲标志 lseek(fd,offset,SEEK_SET); write(fd,&tag,sizeof(struct CFTag)); struct HashFileHeader hfh; readHashFileHeader(fd,&hfh); int addr=hash(keyoffset,keylen,buf,hfh.total_rec_num); offset=sizeof(struct HashFileHeader)+addr*(hfh.reclen+sizeof(struct CFTag)); if(lseek(fd,offset,SEEK_SET)==-1) return -1; read(fd,&tag,sizeof(struct CFTag)); tag.collision--; //冲突记数减1 lseek(fd,offset,SEEK_SET); // write(fd,&tag,sizeof(struct CFTag)); hfh.current_rec_num--; //当前记录数减1 lseek(fd,0,SEEK_SET); write(fd,&hfh,sizeof(struct HashFileHeader)); } else { return -1; } } int hashfile_findrec(int fd,int keyoffset,int keylen,void *buf) { struct HashFileHeader hfh; readHashFileHeader(fd,&hfh); int addr=hash(keyoffset,keylen,buf,hfh.total_rec_num); int offset=sizeof(struct HashFileHeader)+addr*(hfh.reclen+sizeof(struct CFTag)); if(lseek(fd,offset,SEEK_SET)==-1) return -1; struct CFTag tag; read(fd,&tag,sizeof(struct CFTag)); char count=tag.collision; if(count==0) return -1; //不存在 recfree: if(tag.free==0) { offset+=hfh.reclen+sizeof(struct CFTag); if(lseek(fd,offset,SEEK_SET)==-1) return -1; read(fd,&tag,sizeof(struct CFTag)); goto recfree; } else { char *p=(char*)malloc(hfh.reclen*sizeof(char)); read(fd,p,hfh.reclen); //printf("Record is {%d,%s}\n",((struct jtRecord*)p)->key,((struct jtRecord*)p)->other); char *p1,*p2; p1=(char*)buf+keyoffset; p2=p+keyoffset; int j=0; while((*p1==*p2)&&(j<keylen)) { p1++; p2++; j++; } if(j==keylen) { free(p); p=NULL; return (offset); //找到,返回偏移值 } else { if(addr==hash(keyoffset,keylen,p,hfh.total_rec_num)) { count--; //hash值相等而key值不等 if(count==0) { free(p); p=NULL; return -1; //不存在 } } free(p); p=NULL; offset+=hfh.reclen+sizeof(struct CFTag); if(lseek(fd,offset,SEEK_SET)==-1) return -1; read(fd,&tag,sizeof(struct CFTag)); goto recfree; } } } int hashfile_saverec(int fd,int keyoffset,int keylen,void *buf) { if(checkHashFileFull(fd)) { return -1; } struct HashFileHeader hfh; readHashFileHeader(fd,&hfh); int addr=hash(keyoffset,keylen,buf,hfh.total_rec_num); int offset=sizeof(struct HashFileHeader)+addr*(hfh.reclen+sizeof(struct CFTag)); if(lseek(fd,offset,SEEK_SET)==-1) return -1; struct CFTag tag; read(fd,&tag,sizeof(struct CFTag)); tag.collision++; lseek(fd,sizeof(struct CFTag)*(-1),SEEK_CUR); write(fd,&tag,sizeof(struct CFTag)); while(tag.free!=0) //冲突,顺序探查 { offset+=hfh.reclen+sizeof(struct CFTag); if(offset>=lseek(fd,0,SEEK_END)) offset=sizeof(struct HashFileHeader);//reach at end,then rewind if(lseek(fd,offset,SEEK_SET)==-1) return -1; read(fd,&tag,sizeof(struct CFTag)); } tag.free=1; lseek(fd,sizeof(struct CFTag)*(-1),SEEK_CUR); write(fd,&tag,sizeof(struct CFTag)); write(fd,buf,hfh.reclen); hfh.current_rec_num++; //当前记录数加1 lseek(fd,0,SEEK_SET); return write(fd,&hfh,sizeof(struct HashFileHeader)); //存入记录 } int hash(int keyoffset,int keylen,void *buf,int total_rec_num) { int i=0; char *p=(char *)buf+keyoffset; int addr=0; for(i=0;i<keylen;i++) { addr+=(int)(*p); p++; } return addr%(int)(total_rec_num*COLLISIONFACTOR); } int readHashFileHeader(int fd,struct HashFileHeader *hfh ) { lseek(fd,0,SEEK_SET); return read(fd,hfh,sizeof(struct HashFileHeader)); } int checkHashFileFull(int fd) { struct HashFileHeader hfh; readHashFileHeader(fd,&hfh); if(hfh.current_rec_num<hfh.total_rec_num) return 0; else return 1; #define RECORDLEN 32 struct jtRecord { int key; char other[RECORDLEN-sizeof(int)]; }; #ifdef HAVE_CONFIG_H #include <config.h> #endif #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <stdio.h> #include <stdlib.h> #include <stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #include "HashFile.h" #include "jtRecord.h" #define KEYOFFSET 0 #define KEYLEN sizeof(int) #define FILENAME "jing.hash" void showHashFile(); int main(int argc, char *argv[]) { struct jtRecord rec[6]= { { 1,"jing" } ,{2,"wang"},{3,"li"},{4,"zhang"},{5,"qing"},{6,"yuan"} }; int j=0; for(j=0;j<6;j++) { printf("<%d,%d>\t",rec[j].key,hash(KEYOFFSET,KEYLEN,&rec[j],6)); } int fd=hashfile_creat(FILENAME,O_RDWR|O_CREAT,RECORDLEN,6); int i=0; printf("\nOpen ans Save Record...\n"); fd=hashfile_open(FILENAME,O_RDWR,0); for(i=0;i<6;i++) { hashfile_saverec(fd,KEYOFFSET,KEYLEN,&rec[i]); } hashfile_close(fd); showHashFile(); //Demo find Rec printf("\nFind Record..."); fd=hashfile_open(FILENAME,O_RDWR,0); int offset=hashfile_findrec(fd,KEYOFFSET,KEYLEN,&rec[4]); printf("\noffset is %d\n",offset); hashfile_close(fd); struct jtRecord jt; struct CFTag tag; fd=open(FILENAME,O_RDWR); lseek(fd,offset,SEEK_SET); read(fd,&tag,sizeof(struct CFTag)); printf("Tag is <%d,%d>\t",tag.collision,tag.free); read(fd,&jt,sizeof(struct jtRecord)); printf("Record is {%d,%s}\n",jt.key,jt.other); //Demo Delete Rec printf("\nDelete Record..."); fd=hashfile_open(FILENAME,O_RDWR,0); hashfile_delrec(fd,KEYOFFSET,KEYLEN,&rec[2]); hashfile_close(fd); showHashFile(); //Demo Read fd=hashfile_open(FILENAME,O_RDWR,0); char buf[32]; memcpy(buf,&rec[1],KEYLEN); hashfile_read(fd,KEYOFFSET,KEYLEN,buf); printf("\nRead Record is {%d,%s}\n",((struct jtRecord*)buf)->key,((struct jtRecord*)buf)->other); hashfile_close(fd); //Demo Write printf("\nWrite Record..."); fd=hashfile_open(FILENAME,O_RDWR,0); hashfile_write(fd,KEYOFFSET,KEYLEN,&rec[3]); hashfile_close(fd); showHashFile(); return 0; } void showHashFile() { int fd; printf("\n"); fd=open(FILENAME,O_RDWR); lseek(fd,sizeof(struct HashFileHeader),SEEK_SET); struct jtRecord jt; struct CFTag tag; while(1) { if (read(fd,&tag,sizeof(struct CFTag))<=0) break; printf("Tag is <%d,%d>\t",tag.collision,tag.free); if(read(fd,&jt,sizeof(struct jtRecord))<=0) break; printf("Record is {%d,%s}\n",jt.key,jt.other); } close(fd); }
标签:课程设计,操作系统,int,源码,fd,hashfile,buf,sizeof,struct 来源: https://www.cnblogs.com/cckong/p/13091133.html