sdbm.h
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/*
* sdbm - ndbm work-alike hashed database library
* based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
* author: oz@nexus.yorku.ca
* status: public domain.
*/
#ifndef _SDBM_H_
#define _SDBM_H_
#include <stdio.h>
#define DBLKSIZ 4096
#define PBLKSIZ 1024
#define PAIRMAX 1008 /* arbitrary on PBLKSIZ-N */
#define SPLTMAX 10 /* maximum allowed splits */
/* for a single insertion */
#define DIRFEXT ".dir"
#define PAGFEXT ".pag"
typedef struct {
int dirf; /* directory file descriptor */
int pagf; /* page file descriptor */
int flags; /* status/error flags, see below */
int keyptr; /* current key for nextkey */
off_t maxbno; /* size of dirfile in bits */
long curbit; /* current bit number */
long hmask; /* current hash mask */
long blkptr; /* current block for nextkey */
long blkno; /* current page to read/write */
long pagbno; /* current page in pagbuf */
char pagbuf[PBLKSIZ]; /* page file block buffer */
long dirbno; /* current block in dirbuf */
char dirbuf[DBLKSIZ]; /* directory file block buffer */
} DBM;
#define DBM_RDONLY 0x1 /* data base open read-only */
#define DBM_IOERR 0x2 /* data base I/O error */
/*
* utility macros
*/
#define sdbm_rdonly(db) ((db)->flags & DBM_RDONLY)
#define sdbm_error(db) ((db)->flags & DBM_IOERR)
#define sdbm_clearerr(db) ((db)->flags &= ~DBM_IOERR) /* ouch */
#define sdbm_dirfno(db) ((db)->dirf)
#define sdbm_pagfno(db) ((db)->pagf)
typedef struct {
char *dptr;
int dsize;
} datum;
extern datum nullitem;
#if defined(__STDC__)
#define proto(p) p
#else
#define proto(p) ()
#endif
/*
* flags to sdbm_store
*/
#define DBM_INSERT 0
#define DBM_REPLACE 1
/*
* ndbm interface
*/
extern DBM *sdbm_open proto((char *, int, int));
extern void sdbm_close proto((DBM *));
extern datum sdbm_fetch proto((DBM *, datum));
extern int sdbm_delete proto((DBM *, datum));
extern int sdbm_store proto((DBM *, datum, datum, int));
extern datum sdbm_firstkey proto((DBM *));
extern datum sdbm_nextkey proto((DBM *));
/*
* other
*/
extern DBM *sdbm_prep proto((char *, char *, int, int));
extern long sdbm_hash proto((char *, int));
#endif /* _SDBM_H_ */