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[binutils.git] / include / hashtab.h
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1 /* An expandable hash tables datatype.
2 Copyright (C) 1999, 2000, 2002, 2003 Free Software Foundation, Inc.
3 Contributed by Vladimir Makarov (vmakarov@cygnus.com).
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program 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
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
19 /* This package implements basic hash table functionality. It is possible
20 to search for an entry, create an entry and destroy an entry.
22 Elements in the table are generic pointers.
24 The size of the table is not fixed; if the occupancy of the table
25 grows too high the hash table will be expanded.
27 The abstract data implementation is based on generalized Algorithm D
28 from Knuth's book "The art of computer programming". Hash table is
29 expanded by creation of new hash table and transferring elements from
30 the old table to the new table. */
32 #ifndef __HASHTAB_H__
33 #define __HASHTAB_H__
35 #ifdef __cplusplus
36 extern "C" {
37 #endif /* __cplusplus */
39 #include "ansidecl.h"
41 #ifndef GTY
42 #define GTY(X)
43 #endif
45 /* The type for a hash code. */
46 typedef unsigned int hashval_t;
48 /* Callback function pointer types. */
50 /* Calculate hash of a table entry. */
51 typedef hashval_t (*htab_hash) PARAMS ((const void *));
53 /* Compare a table entry with a possible entry. The entry already in
54 the table always comes first, so the second element can be of a
55 different type (but in this case htab_find and htab_find_slot
56 cannot be used; instead the variants that accept a hash value
57 must be used). */
58 typedef int (*htab_eq) PARAMS ((const void *, const void *));
60 /* Cleanup function called whenever a live element is removed from
61 the hash table. */
62 typedef void (*htab_del) PARAMS ((void *));
64 /* Function called by htab_traverse for each live element. The first
65 arg is the slot of the element (which can be passed to htab_clear_slot
66 if desired), the second arg is the auxiliary pointer handed to
67 htab_traverse. Return 1 to continue scan, 0 to stop. */
68 typedef int (*htab_trav) PARAMS ((void **, void *));
70 /* Memory-allocation function, with the same functionality as calloc().
71 Iff it returns NULL, the hash table implementation will pass an error
72 code back to the user, so if your code doesn't handle errors,
73 best if you use xcalloc instead. */
74 typedef PTR (*htab_alloc) PARAMS ((size_t, size_t));
76 /* We also need a free() routine. */
77 typedef void (*htab_free) PARAMS ((PTR));
79 /* Memory allocation and deallocation; variants which take an extra
80 argument. */
81 typedef PTR (*htab_alloc_with_arg) PARAMS ((void *, size_t, size_t));
82 typedef void (*htab_free_with_arg) PARAMS ((void *, void *));
84 /* Hash tables are of the following type. The structure
85 (implementation) of this type is not needed for using the hash
86 tables. All work with hash table should be executed only through
87 functions mentioned below. The size of this structure is subject to
88 change. */
90 struct htab GTY(())
92 /* Pointer to hash function. */
93 htab_hash hash_f;
95 /* Pointer to comparison function. */
96 htab_eq eq_f;
98 /* Pointer to cleanup function. */
99 htab_del del_f;
101 /* Table itself. */
102 PTR * GTY ((use_param (""), length ("%h.size"))) entries;
104 /* Current size (in entries) of the hash table */
105 size_t size;
107 /* Current number of elements including also deleted elements */
108 size_t n_elements;
110 /* Current number of deleted elements in the table */
111 size_t n_deleted;
113 /* The following member is used for debugging. Its value is number
114 of all calls of `htab_find_slot' for the hash table. */
115 unsigned int searches;
117 /* The following member is used for debugging. Its value is number
118 of collisions fixed for time of work with the hash table. */
119 unsigned int collisions;
121 /* Pointers to allocate/free functions. */
122 htab_alloc alloc_f;
123 htab_free free_f;
125 /* Alternate allocate/free functions, which take an extra argument. */
126 PTR GTY((skip (""))) alloc_arg;
127 htab_alloc_with_arg alloc_with_arg_f;
128 htab_free_with_arg free_with_arg_f;
131 typedef struct htab *htab_t;
133 /* An enum saying whether we insert into the hash table or not. */
134 enum insert_option {NO_INSERT, INSERT};
136 /* The prototypes of the package functions. */
138 extern htab_t htab_create_alloc PARAMS ((size_t, htab_hash,
139 htab_eq, htab_del,
140 htab_alloc, htab_free));
142 extern htab_t htab_create_alloc_ex PARAMS ((size_t, htab_hash,
143 htab_eq, htab_del,
144 PTR, htab_alloc_with_arg,
145 htab_free_with_arg));
147 /* Backward-compatibility functions. */
148 extern htab_t htab_create PARAMS ((size_t, htab_hash, htab_eq, htab_del));
149 extern htab_t htab_try_create PARAMS ((size_t, htab_hash, htab_eq, htab_del));
151 extern void htab_set_functions_ex PARAMS ((htab_t, htab_hash,
152 htab_eq, htab_del,
153 PTR, htab_alloc_with_arg,
154 htab_free_with_arg));
156 extern void htab_delete PARAMS ((htab_t));
157 extern void htab_empty PARAMS ((htab_t));
159 extern PTR htab_find PARAMS ((htab_t, const void *));
160 extern PTR *htab_find_slot PARAMS ((htab_t, const void *,
161 enum insert_option));
162 extern PTR htab_find_with_hash PARAMS ((htab_t, const void *,
163 hashval_t));
164 extern PTR *htab_find_slot_with_hash PARAMS ((htab_t, const void *,
165 hashval_t,
166 enum insert_option));
167 extern void htab_clear_slot PARAMS ((htab_t, void **));
168 extern void htab_remove_elt PARAMS ((htab_t, void *));
170 extern void htab_traverse PARAMS ((htab_t, htab_trav, void *));
171 extern void htab_traverse_noresize PARAMS ((htab_t, htab_trav, void *));
173 extern size_t htab_size PARAMS ((htab_t));
174 extern size_t htab_elements PARAMS ((htab_t));
175 extern double htab_collisions PARAMS ((htab_t));
177 /* A hash function for pointers. */
178 extern htab_hash htab_hash_pointer;
180 /* An equality function for pointers. */
181 extern htab_eq htab_eq_pointer;
183 /* A hash function for null-terminated strings. */
184 extern hashval_t htab_hash_string PARAMS ((const PTR));
186 /* An iterative hash function for arbitrary data. */
187 extern hashval_t iterative_hash PARAMS ((const PTR, size_t, hashval_t));
188 /* Shorthand for hashing something with an intrinsic size. */
189 #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)
191 #ifdef __cplusplus
193 #endif /* __cplusplus */
195 #endif /* __HASHTAB_H */