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Diffstat (limited to 'src/gdbmseq.c')
| -rw-r--r-- | src/gdbmseq.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/src/gdbmseq.c b/src/gdbmseq.c new file mode 100644 index 0000000..4167697 --- /dev/null +++ b/src/gdbmseq.c @@ -0,0 +1,129 @@ +/* gdbmseq.c - Routines to visit all keys. Not in sorted order. */ + +/* This file is part of GDBM, the GNU data base manager. + Copyright (C) 1990, 1991, 1993, 2007, 2011, 2013 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 3, 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. If not, see <http://www.gnu.org/licenses/>. */ + +/* Include system configuration before all else. */ +#include "autoconf.h" + +#include "gdbmdefs.h" + +/* Special extern for this file. */ +extern char *_gdbm_read_entry (GDBM_FILE , 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 (GDBM_FILE 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 < GDBM_DIR_COUNT (dbf) + && 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 < GDBM_DIR_COUNT (dbf)) + _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")); + memcpy (return_val->dptr, find_data, 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 (GDBM_FILE 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 (GDBM_FILE 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; +} |