1/* hashlib.h -- the data structures used in hashing in Bash. */
2
3/* Copyright (C) 1993 Free Software Foundation, Inc.
4
5   This file is part of GNU Bash, the Bourne Again SHell.
6
7   Bash is free software; you can redistribute it and/or modify it under
8   the terms of the GNU General Public License as published by the Free
9   Software Foundation; either version 2, or (at your option) any later
10   version.
11
12   Bash is distributed in the hope that it will be useful, but WITHOUT ANY
13   WARRANTY; without even the implied warranty of MERCHANTABILITY or
14   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15   for more details.
16
17   You should have received a copy of the GNU General Public License along
18   with Bash; see the file COPYING.  If not, write to the Free Software
19   Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
20
21#if !defined (_HASHLIB_H_)
22#define _HASHLIB_H_
23
24#include "stdc.h"
25
26#ifndef PTR_T
27#  ifdef __STDC__
28#    define PTR_T void *
29#  else
30#    define PTR_T char *
31#  endif
32#endif
33
34typedef struct bucket_contents {
35  struct bucket_contents *next;	/* Link to next hashed key in this bucket. */
36  char *key;			/* What we look up. */
37  PTR_T data;			/* What we really want. */
38  unsigned int khash;		/* What key hashes to */
39  int times_found;		/* Number of times this item has been found. */
40} BUCKET_CONTENTS;
41
42typedef struct hash_table {
43  BUCKET_CONTENTS **bucket_array;	/* Where the data is kept. */
44  int nbuckets;			/* How many buckets does this table have. */
45  int nentries;			/* How many entries does this table have. */
46} HASH_TABLE;
47
48typedef int hash_wfunc __P((BUCKET_CONTENTS *));
49
50/* Operations on tables as a whole */
51extern HASH_TABLE *hash_create __P((int));
52extern HASH_TABLE *hash_copy __P((HASH_TABLE *, sh_string_func_t *));
53extern void hash_flush __P((HASH_TABLE *, sh_free_func_t *));
54extern void hash_dispose __P((HASH_TABLE *));
55extern void hash_walk __P((HASH_TABLE *, hash_wfunc *));
56
57/* Operations to extract information from or pieces of tables */
58extern int hash_bucket __P((const char *, HASH_TABLE *));
59extern int hash_size __P((HASH_TABLE *));
60
61/* Operations on hash table entries */
62extern BUCKET_CONTENTS *hash_search __P((const char *, HASH_TABLE *, int));
63extern BUCKET_CONTENTS *hash_insert __P((char *, HASH_TABLE *, int));
64extern BUCKET_CONTENTS *hash_remove __P((const char *, HASH_TABLE *, int));
65
66/* Miscellaneous */
67extern unsigned int hash_string __P((const char *));
68
69/* Redefine the function as a macro for speed. */
70#define hash_items(bucket, table) \
71	((table && (bucket < table->nbuckets)) ?  \
72		table->bucket_array[bucket] : \
73		(BUCKET_CONTENTS *)NULL)
74
75/* Default number of buckets in the hash table. */
76#define DEFAULT_HASH_BUCKETS 64	/* was 107, then 53, must be power of two now */
77
78#define HASH_ENTRIES(ht)	((ht) ? (ht)->nentries : 0)
79
80/* flags for hash_search and hash_insert */
81#define HASH_NOSRCH	0x01
82#define HASH_CREATE	0x02
83
84#if !defined (NULL)
85#  if defined (__STDC__)
86#    define NULL ((void *) 0)
87#  else
88#    define NULL 0x0
89#  endif /* !__STDC__ */
90#endif /* !NULL */
91
92#endif /* _HASHLIB_H */
93