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