【操作系统】课程设计源码2

#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);
}