зеркало из https://github.com/github/ruby.git
85 строки
2.2 KiB
C
85 строки
2.2 KiB
C
/*
|
|
* 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_
|
|
|
|
#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 */
|
|
long maxbno; /* size of dirfile in bits */
|
|
long curbit; /* current bit number */
|
|
long hmask; /* current hash mask */
|
|
long blkptr; /* current block for nextkey */
|
|
int keyptr; /* current key 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__) || defined(MSDOS)
|
|
#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_ */
|