PR ipa/63566
[official-gcc.git] / include / hashtab.h
blob188b8494db2d9d35dc7f7f659376c8466a78042d
1 /* An expandable hash tables datatype.
2 Copyright (C) 1999, 2000, 2002, 2003, 2004, 2005, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Vladimir Makarov (vmakarov@cygnus.com).
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
20 /* This package implements basic hash table functionality. It is possible
21 to search for an entry, create an entry and destroy an entry.
23 Elements in the table are generic pointers.
25 The size of the table is not fixed; if the occupancy of the table
26 grows too high the hash table will be expanded.
28 The abstract data implementation is based on generalized Algorithm D
29 from Knuth's book "The art of computer programming". Hash table is
30 expanded by creation of new hash table and transferring elements from
31 the old table to the new table. */
33 #ifndef __HASHTAB_H__
34 #define __HASHTAB_H__
36 #ifdef __cplusplus
37 extern "C" {
38 #endif /* __cplusplus */
40 #include "ansidecl.h"
42 /* The type for a hash code. */
43 typedef unsigned int hashval_t;
45 /* Callback function pointer types. */
47 /* Calculate hash of a table entry. */
48 typedef hashval_t (*htab_hash) (const void *);
50 /* Compare a table entry with a possible entry. The entry already in
51 the table always comes first, so the second element can be of a
52 different type (but in this case htab_find and htab_find_slot
53 cannot be used; instead the variants that accept a hash value
54 must be used). */
55 typedef int (*htab_eq) (const void *, const void *);
57 /* Cleanup function called whenever a live element is removed from
58 the hash table. */
59 typedef void (*htab_del) (void *);
61 /* Function called by htab_traverse for each live element. The first
62 arg is the slot of the element (which can be passed to htab_clear_slot
63 if desired), the second arg is the auxiliary pointer handed to
64 htab_traverse. Return 1 to continue scan, 0 to stop. */
65 typedef int (*htab_trav) (void **, void *);
67 /* Memory-allocation function, with the same functionality as calloc().
68 Iff it returns NULL, the hash table implementation will pass an error
69 code back to the user, so if your code doesn't handle errors,
70 best if you use xcalloc instead. */
71 typedef void *(*htab_alloc) (size_t, size_t);
73 /* We also need a free() routine. */
74 typedef void (*htab_free) (void *);
76 /* Memory allocation and deallocation; variants which take an extra
77 argument. */
78 typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t);
79 typedef void (*htab_free_with_arg) (void *, void *);
81 /* This macro defines reserved value for empty table entry. */
83 #define HTAB_EMPTY_ENTRY ((PTR) 0)
85 /* This macro defines reserved value for table entry which contained
86 a deleted element. */
88 #define HTAB_DELETED_ENTRY ((PTR) 1)
90 /* Hash tables are of the following type. The structure
91 (implementation) of this type is not needed for using the hash
92 tables. All work with hash table should be executed only through
93 functions mentioned below. The size of this structure is subject to
94 change. */
96 struct htab {
97 /* Pointer to hash function. */
98 htab_hash hash_f;
100 /* Pointer to comparison function. */
101 htab_eq eq_f;
103 /* Pointer to cleanup function. */
104 htab_del del_f;
106 /* Table itself. */
107 void **entries;
109 /* Current size (in entries) of the hash table. */
110 size_t size;
112 /* Current number of elements including also deleted elements. */
113 size_t n_elements;
115 /* Current number of deleted elements in the table. */
116 size_t n_deleted;
118 /* The following member is used for debugging. Its value is number
119 of all calls of `htab_find_slot' for the hash table. */
120 unsigned int searches;
122 /* The following member is used for debugging. Its value is number
123 of collisions fixed for time of work with the hash table. */
124 unsigned int collisions;
126 /* Pointers to allocate/free functions. */
127 htab_alloc alloc_f;
128 htab_free free_f;
130 /* Alternate allocate/free functions, which take an extra argument. */
131 void *alloc_arg;
132 htab_alloc_with_arg alloc_with_arg_f;
133 htab_free_with_arg free_with_arg_f;
135 /* Current size (in entries) of the hash table, as an index into the
136 table of primes. */
137 unsigned int size_prime_index;
140 typedef struct htab *htab_t;
142 /* An enum saying whether we insert into the hash table or not. */
143 enum insert_option {NO_INSERT, INSERT};
145 /* The prototypes of the package functions. */
147 extern htab_t htab_create_alloc (size_t, htab_hash,
148 htab_eq, htab_del,
149 htab_alloc, htab_free);
151 extern htab_t htab_create_alloc_ex (size_t, htab_hash,
152 htab_eq, htab_del,
153 void *, htab_alloc_with_arg,
154 htab_free_with_arg);
156 extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del,
157 htab_alloc, htab_alloc, htab_free);
159 /* Backward-compatibility functions. */
160 extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del);
161 extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del);
163 extern void htab_set_functions_ex (htab_t, htab_hash,
164 htab_eq, htab_del,
165 void *, htab_alloc_with_arg,
166 htab_free_with_arg);
168 extern void htab_delete (htab_t);
169 extern void htab_empty (htab_t);
171 extern void * htab_find (htab_t, const void *);
172 extern void ** htab_find_slot (htab_t, const void *, enum insert_option);
173 extern void * htab_find_with_hash (htab_t, const void *, hashval_t);
174 extern void ** htab_find_slot_with_hash (htab_t, const void *,
175 hashval_t, enum insert_option);
176 extern void htab_clear_slot (htab_t, void **);
177 extern void htab_remove_elt (htab_t, void *);
178 extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t);
180 extern void htab_traverse (htab_t, htab_trav, void *);
181 extern void htab_traverse_noresize (htab_t, htab_trav, void *);
183 extern size_t htab_size (htab_t);
184 extern size_t htab_elements (htab_t);
185 extern double htab_collisions (htab_t);
187 /* A hash function for pointers. */
188 extern htab_hash htab_hash_pointer;
190 /* An equality function for pointers. */
191 extern htab_eq htab_eq_pointer;
193 /* A hash function for null-terminated strings. */
194 extern hashval_t htab_hash_string (const void *);
196 /* An iterative hash function for arbitrary data. */
197 extern hashval_t iterative_hash (const void *, size_t, hashval_t);
198 /* Shorthand for hashing something with an intrinsic size. */
199 #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)
201 #ifdef __cplusplus
203 #endif /* __cplusplus */
205 #endif /* __HASHTAB_H */