hashfile.h

操作系统课程设计 有进程同步问题 内存管理 设备管理

/***************************************************************************
 *   Copyright (C) 2004 by root                                            *
 *   root@simplemepis                                                      *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <unistd.h>
#define COLLISIONFACTOR 0.5
struct HashFileHeader
{
    int sig;//file signature
    int reclen;//record length
    int total_rec_num;//total record num;
    int current_rec_num;//current record num,if current_record_num<total_rec_num,there are free record
};
struct CFTag
{
    char collision;//collision count
    char free;//free tag,0 is free,1 is occupied
};
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 );