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[glibc.git] / misc / search.h
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1 /* Declarations for System V style searching functions.
2 Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
20 #ifndef _SEARCH_H
21 #define _SEARCH_H 1
23 #include <features.h>
25 #define __need_size_t
26 #include <stddef.h>
28 __BEGIN_DECLS
30 #if defined __USE_SVID || defined __USE_XOPEN_EXTENDED
31 /* Prototype structure for a linked-list data structure.
32 This is the type used by the `insque' and `remque' functions. */
34 # ifdef __USE_GNU
35 struct qelem
37 struct qelem *q_forw;
38 struct qelem *q_back;
39 char q_data[1];
41 # endif
44 /* Insert ELEM into a doubly-linked list, after PREV. */
45 extern void insque (void *__elem, void *__prev) __THROW;
47 /* Unlink ELEM from the doubly-linked list that it is in. */
48 extern void remque (void *__elem) __THROW;
49 #endif
52 /* For use with hsearch(3). */
53 #ifndef __COMPAR_FN_T
54 # define __COMPAR_FN_T
55 typedef int (*__compar_fn_t) (__const void *, __const void *);
57 # ifdef __USE_GNU
58 typedef __compar_fn_t comparison_fn_t;
59 # endif
60 #endif
62 /* Action which shall be performed in the call the hsearch. */
63 typedef enum
65 FIND,
66 ENTER
68 ACTION;
70 typedef struct entry
72 char *key;
73 char *data;
75 ENTRY;
77 /* Opaque type for internal use. */
78 struct _ENTRY;
80 /* Family of hash table handling functions. The functions also
81 have reentrant counterparts ending with _r. The non-reentrant
82 functions all work on a signle internal hashing table. */
84 /* Search for entry matching ITEM.key in internal hash table. If
85 ACTION is `FIND' return found entry or signal error by returning
86 NULL. If ACTION is `ENTER' replace existing data (if any) with
87 ITEM.data. */
88 extern ENTRY *hsearch (ENTRY __item, ACTION __action) __THROW;
90 /* Create a new hashing table which will at most contain NEL elements. */
91 extern int hcreate (size_t __nel) __THROW;
93 /* Destroy current internal hashing table. */
94 extern void hdestroy (void) __THROW;
96 #ifdef __USE_GNU
97 /* Data type for reentrant functions. */
98 struct hsearch_data
100 struct _ENTRY *table;
101 unsigned int size;
102 unsigned int filled;
105 /* Reentrant versions which can handle multiple hashing tables at the
106 same time. */
107 extern int hsearch_r (ENTRY __item, ACTION __action, ENTRY **__retval,
108 struct hsearch_data *__htab) __THROW;
109 extern int hcreate_r (size_t __nel, struct hsearch_data *__htab) __THROW;
110 extern void hdestroy_r (struct hsearch_data *__htab) __THROW;
111 #endif
114 /* The tsearch routines are very interesting. They make many
115 assumptions about the compiler. It assumes that the first field
116 in node must be the "key" field, which points to the datum.
117 Everything depends on that. */
118 /* For tsearch */
119 typedef enum
121 preorder,
122 postorder,
123 endorder,
124 leaf
126 VISIT;
128 /* Search for an entry matching the given KEY in the tree pointed to
129 by *ROOTP and insert a new element if not found. */
130 extern void *tsearch (__const void *__key, void **__rootp,
131 __compar_fn_t __compar);
133 /* Search for an entry matching the given KEY in the tree pointed to
134 by *ROOTP. If no matching entry is available return NULL. */
135 extern void *tfind (__const void *__key, void *__const *__rootp,
136 __compar_fn_t __compar);
138 /* Remove the element matching KEY from the tree pointed to by *ROOTP. */
139 extern void *tdelete (__const void *__key, void **__rootp,
140 __compar_fn_t __compar);
142 #ifndef __ACTION_FN_T
143 # define __ACTION_FN_T
144 typedef void (*__action_fn_t) (__const void *__nodep, VISIT __value,
145 int __level);
146 #endif
148 /* Walk through the whole tree and call the ACTION callback for every node
149 or leaf. */
150 extern void twalk (__const void *__root, __action_fn_t __action);
152 #ifdef __USE_GNU
153 /* Callback type for function to free a tree node. If the keys are atomic
154 data this function should do nothing. */
155 typedef void (*__free_fn_t) (void *__nodep);
157 /* Destroy the whole tree, call FREEFCT for each node or leaf. */
158 extern void tdestroy (void *__root, __free_fn_t __freefct);
159 #endif
162 /* Perform linear search for KEY by comparing by COMPAR in an array
163 [BASE,BASE+NMEMB*SIZE). */
164 extern void *lfind (__const void *__key, __const void *__base,
165 size_t *__nmemb, size_t __size, __compar_fn_t __compar);
167 /* Perform linear search for KEY by comparing by COMPAR function in
168 array [BASE,BASE+NMEMB*SIZE) and insert entry if not found. */
169 extern void *lsearch (__const void *__key, void *__base,
170 size_t *__nmemb, size_t __size, __compar_fn_t __compar);
172 __END_DECLS
174 #endif /* search.h */