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/* gdbmseq.c - Routines to visit all keys. Not in sorted order. */
/* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc.
GDBM 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, or (at your option)
any later version.
GDBM 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 GDBM; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
You may contact the author by:
e-mail: phil@cs.wwu.edu
us-mail: Philip A. Nelson
Computer Science Department
Western Washington University
Bellingham, WA 98226
*************************************************************************/
/* include system configuration before all else. */
#include "autoconf.h"
#include "gdbmdefs.h"
#include "gdbmerrno.h"
/* Special extern for this file. */
extern char *_gdbm_read_entry __P((gdbm_file_info *, int));
/* Find and read the next entry in the hash structure for DBF starting
at ELEM_LOC of the current bucket and using RETURN_VAL as the place to
put the data that is found. */
static void
get_next_key (dbf, elem_loc, return_val)
gdbm_file_info *dbf;
int elem_loc;
datum *return_val;
{
int found; /* Have we found the next key. */
char *find_data; /* Data pointer returned by find_key. */
/* Find the next key. */
found = FALSE;
while (!found)
{
/* Advance to the next location in the bucket. */
elem_loc++;
if (elem_loc == dbf->header->bucket_elems)
{
/* We have finished the current bucket, get the next bucket. */
elem_loc = 0;
/* Find the next bucket. It is possible several entries in
the bucket directory point to the same bucket. */
while (dbf->bucket_dir < dbf->header->dir_size / sizeof (off_t)
&& dbf->cache_entry->ca_adr == dbf->dir[dbf->bucket_dir])
dbf->bucket_dir++;
/* Check to see if there was a next bucket. */
if (dbf->bucket_dir < dbf->header->dir_size / sizeof (off_t))
_gdbm_get_bucket (dbf, dbf->bucket_dir);
else
/* No next key, just return. */
return ;
}
found = dbf->bucket->h_table[elem_loc].hash_value != -1;
}
/* Found the next key, read it into return_val. */
find_data = _gdbm_read_entry (dbf, elem_loc);
return_val->dsize = dbf->bucket->h_table[elem_loc].key_size;
if (return_val->dsize == 0)
return_val->dptr = (char *) malloc (1);
else
return_val->dptr = (char *) malloc (return_val->dsize);
if (return_val->dptr == NULL) _gdbm_fatal (dbf, "malloc error");
bcopy (find_data, return_val->dptr, return_val->dsize);
}
/* Start the visit of all keys in the database. This produces something in
hash order, not in any sorted order. */
datum
gdbm_firstkey (dbf)
gdbm_file_info *dbf;
{
datum return_val; /* To return the first key. */
/* Set the default return value for not finding a first entry. */
return_val.dptr = NULL;
/* Initialize the gdbm_errno variable. */
gdbm_errno = GDBM_NO_ERROR;
/* Get the first bucket. */
_gdbm_get_bucket (dbf, 0);
/* Look for first entry. */
get_next_key (dbf, -1, &return_val);
return return_val;
}
/* Continue visiting all keys. The next key following KEY is returned. */
datum
gdbm_nextkey (dbf, key)
gdbm_file_info *dbf;
datum key;
{
datum return_val; /* The return value. */
int elem_loc; /* The location in the bucket. */
char *find_data; /* Data pointer returned by _gdbm_findkey. */
int hash_val; /* Returned by _gdbm_findkey. */
/* Initialize the gdbm_errno variable. */
gdbm_errno = GDBM_NO_ERROR;
/* Set the default return value for no next entry. */
return_val.dptr = NULL;
/* Do we have a valid key? */
if (key.dptr == NULL) return return_val;
/* Find the key. */
elem_loc = _gdbm_findkey (dbf, key, &find_data, &hash_val);
if (elem_loc == -1) return return_val;
/* Find the next key. */
get_next_key (dbf, elem_loc, &return_val);
return return_val;
}
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