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This commit was manufactured by cvs2svn to create branch 'RUBY'.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/RUBY@9 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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981
win32/sdbm.c
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981
win32/sdbm.c
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/*
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* sdbm - ndbm work-alike hashed database library
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* based on Per-Aake 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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* core routines
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*/
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#ifndef lint
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/*char sdbm_rcsid[] = "$Id: sdbm.c,v 1.16 90/12/13 13:01:31 oz Exp $";*/
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#endif
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#include "sdbm.h"
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/*#include "tune.h"*/
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/*
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* sdbm - ndbm work-alike hashed database library
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* tuning and portability constructs [not nearly enough]
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* author: oz@nexus.yorku.ca
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*/
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#define BYTESIZ 8
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#ifdef SVID
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#include <unistd.h>
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#endif
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#ifdef __GO32__
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#include <unistd.h>
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#endif
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#ifdef BSD42
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#define SEEK_SET L_SET
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#define memset(s,c,n) bzero(s, n) /* only when c is zero */
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#define memcpy(s1,s2,n) bcopy(s2, s1, n)
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#define memcmp(s1,s2,n) bcmp(s1,s2,n)
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#endif
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/*
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* important tuning parms (hah)
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*/
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#define SEEDUPS /* always detect duplicates */
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#define BADMESS /* generate a message for worst case:
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cannot make room after SPLTMAX splits */
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/*
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* misc
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*/
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#ifdef DEBUG
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#define debug(x) printf x
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#else
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#define debug(x)
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#endif
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#ifdef BIG_E
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#define GET_SHORT(p, i) (((unsigned)((unsigned char *)(p))[(i)*2] << 8) + (((unsigned char *)(p))[(i)*2 + 1]))
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#define PUT_SHORT(p, i, s) (((unsigned char *)(p))[(i)*2] = (unsigned char)((s) >> 8), ((unsigned char *)(p))[(i)*2 + 1] = (unsigned char)(s))
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#else
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#define GET_SHORT(p, i) ((p)[i])
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#define PUT_SHORT(p, i, s) ((p)[i] = (s))
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#endif
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/*#include "pair.h"*/
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static int fitpair proto((char *, int));
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static void putpair proto((char *, datum, datum));
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static datum getpair proto((char *, datum));
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static int delpair proto((char *, datum));
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static int chkpage proto((char *));
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static datum getnkey proto((char *, int));
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static void splpage proto((char *, char *, long));
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#ifdef SEEDUPS
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static int duppair proto((char *, datum));
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#endif
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#ifdef MSDOS
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#include <stdio.h>
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#include <stdlib.h>
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#include <io.h>
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#endif
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#include <sys/types.h>
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#include <sys/stat.h>
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#ifdef BSD42
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#include <sys/file.h>
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#else
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#include <fcntl.h>
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/*#include <memory.h>*/
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#endif
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#ifndef O_BINARY
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#define O_BINARY 0
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#endif
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#include <errno.h>
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#ifndef EPERM
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#define EPERM EACCES
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#endif
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#include <string.h>
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#ifdef __STDC__
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#include <stddef.h>
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#endif
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#ifndef NULL
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#define NULL 0
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#endif
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/*
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* externals
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*/
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#ifndef sun
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#ifndef MSDOS
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extern int errno;
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#endif
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#endif
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/*
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* forward
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*/
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static int getdbit proto((DBM *, long));
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static int setdbit proto((DBM *, long));
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static int getpage proto((DBM *, long));
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static datum getnext proto((DBM *));
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static int makroom proto((DBM *, long, int));
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/*
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* useful macros
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*/
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#define bad(x) ((x).dptr == NULL || (x).dsize < 0)
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#define exhash(item) dbm_hash((item).dptr, (item).dsize)
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#define ioerr(db) ((db)->flags |= DBM_IOERR)
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#define OFF_PAG(off) (long) (off) * PBLKSIZ
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#define OFF_DIR(off) (long) (off) * DBLKSIZ
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static long masks[] = {
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000000000000L, 000000000001L, 000000000003L,
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000000000007L, 000000000017L, 000000000037L,
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000000000077L, 000000000177L, 000000000377L,
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000000000777L, 000000001777L, 000000003777L,
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000000007777L, 000000017777L, 000000037777L,
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000000077777L, 000000177777L, 000000377777L,
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000000777777L, 000001777777L, 000003777777L,
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000007777777L, 000017777777L, 000037777777L,
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000077777777L, 000177777777L, 000377777777L,
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000777777777L, 001777777777L, 003777777777L,
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007777777777L, 017777777777L
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};
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datum nullitem = {NULL, 0};
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DBM *
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dbm_open(file, flags, mode)
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register char *file;
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register int flags;
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register int mode;
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{
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register DBM *db;
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register char *dirname;
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register char *pagname;
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register int n;
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if (file == NULL || !*file)
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return errno = EINVAL, (DBM *) NULL;
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/*
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* need space for two seperate filenames
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*/
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n = strlen(file) * 2 + strlen(DIRFEXT) + strlen(PAGFEXT) + 2;
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if ((dirname = malloc((unsigned) n)) == NULL)
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return errno = ENOMEM, (DBM *) NULL;
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/*
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* build the file names
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*/
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dirname = strcat(strcpy(dirname, file), DIRFEXT);
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pagname = strcpy(dirname + strlen(dirname) + 1, file);
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pagname = strcat(pagname, PAGFEXT);
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db = dbm_prep(dirname, pagname, flags, mode);
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free((char *) dirname);
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return db;
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}
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DBM *
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dbm_prep(dirname, pagname, flags, mode)
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char *dirname;
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char *pagname;
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int flags;
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int mode;
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{
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register DBM *db;
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struct stat dstat;
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if ((db = (DBM *) malloc(sizeof(DBM))) == NULL)
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return errno = ENOMEM, (DBM *) NULL;
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db->flags = 0;
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db->hmask = 0;
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db->blkptr = 0;
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db->keyptr = 0;
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/*
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* adjust user flags so that WRONLY becomes RDWR,
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* as required by this package. Also set our internal
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* flag for RDONLY.
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*/
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if (flags & O_WRONLY)
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flags = (flags & ~O_WRONLY) | O_RDWR;
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if (flags & O_RDONLY)
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db->flags = DBM_RDONLY;
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/*
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* open the files in sequence, and stat the dirfile.
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* If we fail anywhere, undo everything, return NULL.
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*/
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#ifdef MSDOS
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flags |= O_BINARY;
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#endif
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if ((db->pagf = open(pagname, flags, mode)) > -1) {
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if ((db->dirf = open(dirname, flags, mode)) > -1) {
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/*
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* need the dirfile size to establish max bit number.
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*/
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if (fstat(db->dirf, &dstat) == 0) {
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/*
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* zero size: either a fresh database, or one with a single,
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* unsplit data page: dirpage is all zeros.
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*/
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db->dirbno = (!dstat.st_size) ? 0 : -1;
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db->pagbno = -1;
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db->maxbno = dstat.st_size * (long) BYTESIZ;
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(void) memset(db->pagbuf, 0, PBLKSIZ);
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(void) memset(db->dirbuf, 0, DBLKSIZ);
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/*
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* success
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*/
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return db;
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}
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(void) close(db->dirf);
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}
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(void) close(db->pagf);
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}
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free((char *) db);
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return (DBM *) NULL;
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}
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void
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dbm_close(db)
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register DBM *db;
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{
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if (db == NULL)
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errno = EINVAL;
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else {
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(void) close(db->dirf);
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(void) close(db->pagf);
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free((char *) db);
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}
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}
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datum
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dbm_fetch(db, key)
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register DBM *db;
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datum key;
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{
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if (db == NULL || bad(key))
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return errno = EINVAL, nullitem;
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if (getpage(db, exhash(key)))
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return getpair(db->pagbuf, key);
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return ioerr(db), nullitem;
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}
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int
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dbm_delete(db, key)
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register DBM *db;
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datum key;
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{
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if (db == NULL || bad(key))
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return errno = EINVAL, -1;
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if (dbm_rdonly(db))
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return errno = EPERM, -1;
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if (getpage(db, exhash(key))) {
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if (!delpair(db->pagbuf, key))
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return -1;
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/*
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* update the page file
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*/
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if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0
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|| write(db->pagf, db->pagbuf, PBLKSIZ) < 0)
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return ioerr(db), -1;
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return 0;
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}
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return ioerr(db), -1;
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}
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int
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dbm_store(db, key, val, flags)
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register DBM *db;
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datum key;
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datum val;
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int flags;
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{
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int need;
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register long hash;
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if (db == NULL || bad(key))
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return errno = EINVAL, -1;
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if (dbm_rdonly(db))
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return errno = EPERM, -1;
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need = key.dsize + val.dsize;
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/*
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* is the pair too big (or too small) for this database ??
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*/
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if (need < 0 || need > PAIRMAX)
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return errno = EINVAL, -1;
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if (getpage(db, (hash = exhash(key)))) {
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/*
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* if we need to replace, delete the key/data pair
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* first. If it is not there, ignore.
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*/
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if (flags == DBM_REPLACE)
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(void) delpair(db->pagbuf, key);
|
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#ifdef SEEDUPS
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else if (duppair(db->pagbuf, key))
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return 1;
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#endif
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/*
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* if we do not have enough room, we have to split.
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*/
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if (!fitpair(db->pagbuf, need))
|
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if (!makroom(db, hash, need))
|
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return ioerr(db), -1;
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/*
|
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* we have enough room or split is successful. insert the key,
|
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* and update the page file.
|
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*/
|
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(void) putpair(db->pagbuf, key, val);
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|
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if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0
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|| write(db->pagf, db->pagbuf, PBLKSIZ) < 0)
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return ioerr(db), -1;
|
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/*
|
||||
* success
|
||||
*/
|
||||
return 0;
|
||||
}
|
||||
|
||||
return ioerr(db), -1;
|
||||
}
|
||||
|
||||
/*
|
||||
* makroom - make room by splitting the overfull page
|
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* this routine will attempt to make room for SPLTMAX times before
|
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* giving up.
|
||||
*/
|
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static int
|
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makroom(db, hash, need)
|
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register DBM *db;
|
||||
long hash;
|
||||
int need;
|
||||
{
|
||||
long newp;
|
||||
char twin[PBLKSIZ];
|
||||
#ifdef MSDOS
|
||||
char zer[PBLKSIZ];
|
||||
#endif
|
||||
char *pag = db->pagbuf;
|
||||
char *new = twin;
|
||||
register int smax = SPLTMAX;
|
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long oldtail;
|
||||
|
||||
do {
|
||||
/*
|
||||
* split the current page
|
||||
*/
|
||||
(void) splpage(pag, new, db->hmask + 1);
|
||||
/*
|
||||
* address of the new page
|
||||
*/
|
||||
newp = (hash & db->hmask) | (db->hmask + 1);
|
||||
debug(("newp: %ld\n", newp));
|
||||
/*
|
||||
* write delay, read avoidence/cache shuffle:
|
||||
* select the page for incoming pair: if key is to go to the new page,
|
||||
* write out the previous one, and copy the new one over, thus making
|
||||
* it the current page. If not, simply write the new page, and we are
|
||||
* still looking at the page of interest. current page is not updated
|
||||
* here, as dbm_store will do so, after it inserts the incoming pair.
|
||||
*/
|
||||
|
||||
#ifdef MSDOS
|
||||
/*
|
||||
* Fill hole with 0 if made it.
|
||||
* (hole is NOT read as 0)
|
||||
*/
|
||||
oldtail = lseek(db->pagf, 0L, SEEK_END);
|
||||
memset(zer, 0, PBLKSIZ);
|
||||
while (OFF_PAG(newp) > oldtail) {
|
||||
if (lseek(db->pagf, 0L, SEEK_END) < 0 ||
|
||||
write(db->pagf, zer, PBLKSIZ) < 0) {
|
||||
|
||||
return 0;
|
||||
}
|
||||
oldtail += PBLKSIZ;
|
||||
}
|
||||
#endif
|
||||
|
||||
if (hash & (db->hmask + 1)) {
|
||||
if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0
|
||||
|| write(db->pagf, db->pagbuf, PBLKSIZ) < 0)
|
||||
return 0;
|
||||
db->pagbno = newp;
|
||||
(void) memcpy(pag, new, PBLKSIZ);
|
||||
}
|
||||
else if (lseek(db->pagf, OFF_PAG(newp), SEEK_SET) < 0
|
||||
|| write(db->pagf, new, PBLKSIZ) < 0)
|
||||
return 0;
|
||||
|
||||
if (!setdbit(db, db->curbit))
|
||||
return 0;
|
||||
/*
|
||||
* see if we have enough room now
|
||||
*/
|
||||
if (fitpair(pag, need))
|
||||
return 1;
|
||||
/*
|
||||
* try again... update curbit and hmask as getpage would have
|
||||
* done. because of our update of the current page, we do not
|
||||
* need to read in anything. BUT we have to write the current
|
||||
* [deferred] page out, as the window of failure is too great.
|
||||
*/
|
||||
db->curbit = 2 * db->curbit +
|
||||
((hash & (db->hmask + 1)) ? 2 : 1);
|
||||
db->hmask |= (db->hmask + 1);
|
||||
|
||||
if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0
|
||||
|| write(db->pagf, db->pagbuf, PBLKSIZ) < 0)
|
||||
return 0;
|
||||
|
||||
} while (--smax);
|
||||
/*
|
||||
* if we are here, this is real bad news. After SPLTMAX splits,
|
||||
* we still cannot fit the key. say goodnight.
|
||||
*/
|
||||
#ifdef BADMESS
|
||||
(void) write(2, "sdbm: cannot insert after SPLTMAX attempts.\n", 44);
|
||||
#endif
|
||||
return 0;
|
||||
|
||||
}
|
||||
|
||||
/*
|
||||
* the following two routines will break if
|
||||
* deletions aren't taken into account. (ndbm bug)
|
||||
*/
|
||||
datum
|
||||
dbm_firstkey(db)
|
||||
register DBM *db;
|
||||
{
|
||||
if (db == NULL)
|
||||
return errno = EINVAL, nullitem;
|
||||
/*
|
||||
* start at page 0
|
||||
*/
|
||||
(void) memset(db->pagbuf, 0, PBLKSIZ);
|
||||
if (lseek(db->pagf, OFF_PAG(0), SEEK_SET) < 0
|
||||
|| read(db->pagf, db->pagbuf, PBLKSIZ) < 0)
|
||||
return ioerr(db), nullitem;
|
||||
db->pagbno = 0;
|
||||
db->blkptr = 0;
|
||||
db->keyptr = 0;
|
||||
|
||||
return getnext(db);
|
||||
}
|
||||
|
||||
datum
|
||||
dbm_nextkey(db)
|
||||
register DBM *db;
|
||||
{
|
||||
if (db == NULL)
|
||||
return errno = EINVAL, nullitem;
|
||||
return getnext(db);
|
||||
}
|
||||
|
||||
/*
|
||||
* all important binary trie traversal
|
||||
*/
|
||||
static int
|
||||
getpage(db, hash)
|
||||
register DBM *db;
|
||||
register long hash;
|
||||
{
|
||||
register int hbit;
|
||||
register long dbit;
|
||||
register long pagb;
|
||||
|
||||
dbit = 0;
|
||||
hbit = 0;
|
||||
while (dbit < db->maxbno && getdbit(db, dbit))
|
||||
dbit = 2 * dbit + ((hash & ((long) 1 << hbit++)) ? 2 : 1);
|
||||
|
||||
debug(("dbit: %d...", dbit));
|
||||
|
||||
db->curbit = dbit;
|
||||
db->hmask = masks[hbit];
|
||||
|
||||
pagb = hash & db->hmask;
|
||||
/*
|
||||
* see if the block we need is already in memory.
|
||||
* note: this lookaside cache has about 10% hit rate.
|
||||
*/
|
||||
if (pagb != db->pagbno) {
|
||||
/*
|
||||
* note: here, we assume a "hole" is read as 0s.
|
||||
* if not, must zero pagbuf first.
|
||||
*/
|
||||
(void) memset(db->pagbuf, 0, PBLKSIZ);
|
||||
|
||||
if (lseek(db->pagf, OFF_PAG(pagb), SEEK_SET) < 0
|
||||
|| read(db->pagf, db->pagbuf, PBLKSIZ) < 0)
|
||||
return 0;
|
||||
if (!chkpage(db->pagbuf)) {
|
||||
return 0;
|
||||
}
|
||||
db->pagbno = pagb;
|
||||
|
||||
debug(("pag read: %d\n", pagb));
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
static int
|
||||
getdbit(db, dbit)
|
||||
register DBM *db;
|
||||
register long dbit;
|
||||
{
|
||||
register long c;
|
||||
register long dirb;
|
||||
|
||||
c = dbit / BYTESIZ;
|
||||
dirb = c / DBLKSIZ;
|
||||
|
||||
if (dirb != db->dirbno) {
|
||||
if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0
|
||||
|| read(db->dirf, db->dirbuf, DBLKSIZ) < 0)
|
||||
return 0;
|
||||
db->dirbno = dirb;
|
||||
|
||||
debug(("dir read: %d\n", dirb));
|
||||
}
|
||||
|
||||
return db->dirbuf[c % DBLKSIZ] & (1 << (dbit % BYTESIZ));
|
||||
}
|
||||
|
||||
static int
|
||||
setdbit(db, dbit)
|
||||
register DBM *db;
|
||||
register long dbit;
|
||||
{
|
||||
register long c;
|
||||
register long dirb;
|
||||
|
||||
c = dbit / BYTESIZ;
|
||||
dirb = c / DBLKSIZ;
|
||||
|
||||
if (dirb != db->dirbno) {
|
||||
if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0
|
||||
|| read(db->dirf, db->dirbuf, DBLKSIZ) < 0)
|
||||
return 0;
|
||||
db->dirbno = dirb;
|
||||
|
||||
debug(("dir read: %d\n", dirb));
|
||||
}
|
||||
|
||||
db->dirbuf[c % DBLKSIZ] |= (1 << (dbit % BYTESIZ));
|
||||
|
||||
if (dbit >= db->maxbno)
|
||||
db->maxbno += (long) DBLKSIZ * BYTESIZ;
|
||||
|
||||
if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0
|
||||
|| write(db->dirf, db->dirbuf, DBLKSIZ) < 0)
|
||||
return 0;
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* getnext - get the next key in the page, and if done with
|
||||
* the page, try the next page in sequence
|
||||
*/
|
||||
static datum
|
||||
getnext(db)
|
||||
register DBM *db;
|
||||
{
|
||||
datum key;
|
||||
|
||||
for (;;) {
|
||||
db->keyptr++;
|
||||
key = getnkey(db->pagbuf, db->keyptr);
|
||||
if (key.dptr != NULL)
|
||||
return key;
|
||||
/*
|
||||
* we either run out, or there is nothing on this page..
|
||||
* try the next one... If we lost our position on the
|
||||
* file, we will have to seek.
|
||||
*/
|
||||
db->keyptr = 0;
|
||||
if (db->pagbno != db->blkptr++)
|
||||
if (lseek(db->pagf, OFF_PAG(db->blkptr), SEEK_SET) < 0)
|
||||
break;
|
||||
db->pagbno = db->blkptr;
|
||||
if (read(db->pagf, db->pagbuf, PBLKSIZ) <= 0)
|
||||
break;
|
||||
if (!chkpage(db->pagbuf)) {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return ioerr(db), nullitem;
|
||||
}
|
||||
|
||||
/* pair.c */
|
||||
/*
|
||||
* sdbm - ndbm work-alike hashed database library
|
||||
* based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
|
||||
* author: oz@nexus.yorku.ca
|
||||
* status: public domain.
|
||||
*
|
||||
* page-level routines
|
||||
*/
|
||||
|
||||
#ifndef lint
|
||||
/*char pair_rcsid[] = "$Id: pair.c,v 1.10 90/12/13 13:00:35 oz Exp $";*/
|
||||
#endif
|
||||
|
||||
#ifndef BSD42
|
||||
/*#include <memory.h>*/
|
||||
#endif
|
||||
|
||||
#define exhash(item) dbm_hash((item).dptr, (item).dsize)
|
||||
|
||||
/*
|
||||
* forward
|
||||
*/
|
||||
static int seepair proto((char *, int, char *, int));
|
||||
|
||||
/*
|
||||
* page format:
|
||||
* +------------------------------+
|
||||
* ino | n | keyoff | datoff | keyoff |
|
||||
* +------------+--------+--------+
|
||||
* | datoff | - - - ----> |
|
||||
* +--------+---------------------+
|
||||
* | F R E E A R E A |
|
||||
* +--------------+---------------+
|
||||
* | <---- - - - | data |
|
||||
* +--------+-----+----+----------+
|
||||
* | key | data | key |
|
||||
* +--------+----------+----------+
|
||||
*
|
||||
* calculating the offsets for free area: if the number
|
||||
* of entries (ino[0]) is zero, the offset to the END of
|
||||
* the free area is the block size. Otherwise, it is the
|
||||
* nth (ino[ino[0]]) entry's offset.
|
||||
*/
|
||||
|
||||
static int
|
||||
fitpair(pag, need)
|
||||
char *pag;
|
||||
int need;
|
||||
{
|
||||
register int n;
|
||||
register int off;
|
||||
register int free;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
off = ((n = GET_SHORT(ino,0)) > 0) ? GET_SHORT(ino,n) : PBLKSIZ;
|
||||
free = off - (n + 1) * sizeof(short);
|
||||
need += 2 * sizeof(short);
|
||||
|
||||
debug(("free %d need %d\n", free, need));
|
||||
|
||||
return need <= free;
|
||||
}
|
||||
|
||||
static void
|
||||
putpair(pag, key, val)
|
||||
char *pag;
|
||||
datum key;
|
||||
datum val;
|
||||
{
|
||||
register int n;
|
||||
register int off;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
off = ((n = GET_SHORT(ino,0)) > 0) ? GET_SHORT(ino,n) : PBLKSIZ;
|
||||
/*
|
||||
* enter the key first
|
||||
*/
|
||||
off -= key.dsize;
|
||||
if (key.dsize)
|
||||
(void) memcpy(pag + off, key.dptr, key.dsize);
|
||||
PUT_SHORT(ino,n + 1,off);
|
||||
/*
|
||||
* now the data
|
||||
*/
|
||||
off -= val.dsize;
|
||||
if (val.dsize)
|
||||
(void) memcpy(pag + off, val.dptr, val.dsize);
|
||||
PUT_SHORT(ino,n + 2,off);
|
||||
/*
|
||||
* adjust item count
|
||||
*/
|
||||
PUT_SHORT(ino,0,GET_SHORT(ino,0) + 2);
|
||||
}
|
||||
|
||||
static datum
|
||||
getpair(pag, key)
|
||||
char *pag;
|
||||
datum key;
|
||||
{
|
||||
register int i;
|
||||
register int n;
|
||||
datum val;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
if ((n = GET_SHORT(ino,0)) == 0)
|
||||
return nullitem;
|
||||
|
||||
if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
|
||||
return nullitem;
|
||||
|
||||
val.dptr = pag + GET_SHORT(ino,i + 1);
|
||||
val.dsize = GET_SHORT(ino,i) - GET_SHORT(ino,i + 1);
|
||||
return val;
|
||||
}
|
||||
|
||||
#ifdef SEEDUPS
|
||||
static int
|
||||
duppair(pag, key)
|
||||
char *pag;
|
||||
datum key;
|
||||
{
|
||||
register short *ino = (short *) pag;
|
||||
return GET_SHORT(ino,0) > 0 &&
|
||||
seepair(pag, GET_SHORT(ino,0), key.dptr, key.dsize) > 0;
|
||||
}
|
||||
#endif
|
||||
|
||||
static datum
|
||||
getnkey(pag, num)
|
||||
char *pag;
|
||||
int num;
|
||||
{
|
||||
datum key;
|
||||
register int off;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
num = num * 2 - 1;
|
||||
if (GET_SHORT(ino,0) == 0 || num > GET_SHORT(ino,0))
|
||||
return nullitem;
|
||||
|
||||
off = (num > 1) ? GET_SHORT(ino,num - 1) : PBLKSIZ;
|
||||
|
||||
key.dptr = pag + GET_SHORT(ino,num);
|
||||
key.dsize = off - GET_SHORT(ino,num);
|
||||
|
||||
return key;
|
||||
}
|
||||
|
||||
static int
|
||||
delpair(pag, key)
|
||||
char *pag;
|
||||
datum key;
|
||||
{
|
||||
register int n;
|
||||
register int i;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
if ((n = GET_SHORT(ino,0)) == 0)
|
||||
return 0;
|
||||
|
||||
if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
|
||||
return 0;
|
||||
/*
|
||||
* found the key. if it is the last entry
|
||||
* [i.e. i == n - 1] we just adjust the entry count.
|
||||
* hard case: move all data down onto the deleted pair,
|
||||
* shift offsets onto deleted offsets, and adjust them.
|
||||
* [note: 0 < i < n]
|
||||
*/
|
||||
if (i < n - 1) {
|
||||
register int m;
|
||||
register char *dst = pag + (i == 1 ? PBLKSIZ : GET_SHORT(ino,i - 1));
|
||||
register char *src = pag + GET_SHORT(ino,i + 1);
|
||||
register int zoo = dst - src;
|
||||
|
||||
debug(("free-up %d ", zoo));
|
||||
/*
|
||||
* shift data/keys down
|
||||
*/
|
||||
m = GET_SHORT(ino,i + 1) - GET_SHORT(ino,n);
|
||||
#ifdef DUFF
|
||||
#define MOVB *--dst = *--src
|
||||
|
||||
if (m > 0) {
|
||||
register int loop = (m + 8 - 1) >> 3;
|
||||
|
||||
switch (m & (8 - 1)) {
|
||||
case 0: do {
|
||||
MOVB; case 7: MOVB;
|
||||
case 6: MOVB; case 5: MOVB;
|
||||
case 4: MOVB; case 3: MOVB;
|
||||
case 2: MOVB; case 1: MOVB;
|
||||
} while (--loop);
|
||||
}
|
||||
}
|
||||
#else
|
||||
#ifdef MEMMOVE
|
||||
memmove(dst, src, m);
|
||||
#else
|
||||
while (m--)
|
||||
*--dst = *--src;
|
||||
#endif
|
||||
#endif
|
||||
/*
|
||||
* adjust offset index up
|
||||
*/
|
||||
while (i < n - 1) {
|
||||
PUT_SHORT(ino,i, GET_SHORT(ino,i + 2) + zoo);
|
||||
i++;
|
||||
}
|
||||
}
|
||||
PUT_SHORT(ino, 0, GET_SHORT(ino, 0) - 2);
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* search for the key in the page.
|
||||
* return offset index in the range 0 < i < n.
|
||||
* return 0 if not found.
|
||||
*/
|
||||
static int
|
||||
seepair(pag, n, key, siz)
|
||||
char *pag;
|
||||
register int n;
|
||||
register char *key;
|
||||
register int siz;
|
||||
{
|
||||
register int i;
|
||||
register int off = PBLKSIZ;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
for (i = 1; i < n; i += 2) {
|
||||
if (siz == off - GET_SHORT(ino,i) &&
|
||||
memcmp(key, pag + GET_SHORT(ino,i), siz) == 0)
|
||||
return i;
|
||||
off = GET_SHORT(ino,i + 1);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void
|
||||
splpage(pag, new, sbit)
|
||||
char *pag;
|
||||
char *new;
|
||||
long sbit;
|
||||
{
|
||||
datum key;
|
||||
datum val;
|
||||
|
||||
register int n;
|
||||
register int off = PBLKSIZ;
|
||||
char cur[PBLKSIZ];
|
||||
register short *ino = (short *) cur;
|
||||
|
||||
(void) memcpy(cur, pag, PBLKSIZ);
|
||||
(void) memset(pag, 0, PBLKSIZ);
|
||||
(void) memset(new, 0, PBLKSIZ);
|
||||
|
||||
n = GET_SHORT(ino,0);
|
||||
for (ino++; n > 0; ino += 2) {
|
||||
key.dptr = cur + GET_SHORT(ino,0);
|
||||
key.dsize = off - GET_SHORT(ino,0);
|
||||
val.dptr = cur + GET_SHORT(ino,1);
|
||||
val.dsize = GET_SHORT(ino,0) - GET_SHORT(ino,1);
|
||||
/*
|
||||
* select the page pointer (by looking at sbit) and insert
|
||||
*/
|
||||
(void) putpair((exhash(key) & sbit) ? new : pag, key, val);
|
||||
|
||||
off = GET_SHORT(ino,1);
|
||||
n -= 2;
|
||||
}
|
||||
|
||||
debug(("%d split %d/%d\n", ((short *) cur)[0] / 2,
|
||||
((short *) new)[0] / 2,
|
||||
((short *) pag)[0] / 2));
|
||||
}
|
||||
|
||||
/*
|
||||
* check page sanity:
|
||||
* number of entries should be something
|
||||
* reasonable, and all offsets in the index should be in order.
|
||||
* this could be made more rigorous.
|
||||
*/
|
||||
static int
|
||||
chkpage(pag)
|
||||
char *pag;
|
||||
{
|
||||
register int n;
|
||||
register int off;
|
||||
register short *ino = (short *) pag;
|
||||
|
||||
if ((n = GET_SHORT(ino,0)) < 0 || n > PBLKSIZ / sizeof(short))
|
||||
return 0;
|
||||
|
||||
if (n > 0) {
|
||||
off = PBLKSIZ;
|
||||
for (ino++; n > 0; ino += 2) {
|
||||
if (GET_SHORT(ino,0) > off || GET_SHORT(ino,1) > off ||
|
||||
GET_SHORT(ino,1) > GET_SHORT(ino,0))
|
||||
return 0;
|
||||
off = GET_SHORT(ino,1);
|
||||
n -= 2;
|
||||
}
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* hash.c */
|
||||
/*
|
||||
* sdbm - ndbm work-alike hashed database library
|
||||
* based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
|
||||
* author: oz@nexus.yorku.ca
|
||||
* status: public domain. keep it that way.
|
||||
*
|
||||
* hashing routine
|
||||
*/
|
||||
|
||||
/*
|
||||
* polynomial conversion ignoring overflows
|
||||
* [this seems to work remarkably well, in fact better
|
||||
* then the ndbm hash function. Replace at your own risk]
|
||||
* use: 65599 nice.
|
||||
* 65587 even better.
|
||||
*/
|
||||
long
|
||||
dbm_hash(str, len)
|
||||
register char *str;
|
||||
register int len;
|
||||
{
|
||||
register unsigned long n = 0;
|
||||
|
||||
#ifdef DUFF
|
||||
|
||||
#define HASHC n = *str++ + 65599 * n
|
||||
|
||||
if (len > 0) {
|
||||
register int loop = (len + 8 - 1) >> 3;
|
||||
|
||||
switch(len & (8 - 1)) {
|
||||
case 0: do {
|
||||
HASHC; case 7: HASHC;
|
||||
case 6: HASHC; case 5: HASHC;
|
||||
case 4: HASHC; case 3: HASHC;
|
||||
case 2: HASHC; case 1: HASHC;
|
||||
} while (--loop);
|
||||
}
|
||||
|
||||
}
|
||||
#else
|
||||
while (len--)
|
||||
n = ((*str++) & 255) + 65587L * n;
|
||||
#endif
|
||||
return n;
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue