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 (at) cygnus.com). 5 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. 10 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. 15 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. */ 19 20 /* This package implements basic hash table functionality. It is possible 21 to search for an entry, create an entry and destroy an entry. 22 23 Elements in the table are generic pointers. 24 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. 27 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. */ 32 33 #ifndef __HASHTAB_H__ 34 #define __HASHTAB_H__ 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif /* __cplusplus */ 39 40 #include "ansidecl.h" 41 42 #ifndef GTY 43 #define GTY(X) 44 #endif 45 46 /* The type for a hash code. */ 47 typedef unsigned int hashval_t; 48 49 /* Callback function pointer types. */ 50 51 /* Calculate hash of a table entry. */ 52 typedef hashval_t (*htab_hash) (const void *); 53 54 /* Compare a table entry with a possible entry. The entry already in 55 the table always comes first, so the second element can be of a 56 different type (but in this case htab_find and htab_find_slot 57 cannot be used; instead the variants that accept a hash value 58 must be used). */ 59 typedef int (*htab_eq) (const void *, const void *); 60 61 /* Cleanup function called whenever a live element is removed from 62 the hash table. */ 63 typedef void (*htab_del) (void *); 64 65 /* Function called by htab_traverse for each live element. The first 66 arg is the slot of the element (which can be passed to htab_clear_slot 67 if desired), the second arg is the auxiliary pointer handed to 68 htab_traverse. Return 1 to continue scan, 0 to stop. */ 69 typedef int (*htab_trav) (void **, void *); 70 71 /* Memory-allocation function, with the same functionality as calloc(). 72 Iff it returns NULL, the hash table implementation will pass an error 73 code back to the user, so if your code doesn't handle errors, 74 best if you use xcalloc instead. */ 75 typedef void *(*htab_alloc) (size_t, size_t); 76 77 /* We also need a free() routine. */ 78 typedef void (*htab_free) (void *); 79 80 /* Memory allocation and deallocation; variants which take an extra 81 argument. */ 82 typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t); 83 typedef void (*htab_free_with_arg) (void *, void *); 84 85 /* This macro defines reserved value for empty table entry. */ 86 87 #define HTAB_EMPTY_ENTRY ((PTR) 0) 88 89 /* This macro defines reserved value for table entry which contained 90 a deleted element. */ 91 92 #define HTAB_DELETED_ENTRY ((PTR) 1) 93 94 /* Hash tables are of the following type. The structure 95 (implementation) of this type is not needed for using the hash 96 tables. All work with hash table should be executed only through 97 functions mentioned below. The size of this structure is subject to 98 change. */ 99 100 struct GTY(()) htab { 101 /* Pointer to hash function. */ 102 htab_hash hash_f; 103 104 /* Pointer to comparison function. */ 105 htab_eq eq_f; 106 107 /* Pointer to cleanup function. */ 108 htab_del del_f; 109 110 /* Table itself. */ 111 void ** GTY ((use_param, length ("%h.size"))) entries; 112 113 /* Current size (in entries) of the hash table. */ 114 size_t size; 115 116 /* Current number of elements including also deleted elements. */ 117 size_t n_elements; 118 119 /* Current number of deleted elements in the table. */ 120 size_t n_deleted; 121 122 /* The following member is used for debugging. Its value is number 123 of all calls of `htab_find_slot' for the hash table. */ 124 unsigned int searches; 125 126 /* The following member is used for debugging. Its value is number 127 of collisions fixed for time of work with the hash table. */ 128 unsigned int collisions; 129 130 /* Pointers to allocate/free functions. */ 131 htab_alloc alloc_f; 132 htab_free free_f; 133 134 /* Alternate allocate/free functions, which take an extra argument. */ 135 void * GTY((skip)) alloc_arg; 136 htab_alloc_with_arg alloc_with_arg_f; 137 htab_free_with_arg free_with_arg_f; 138 139 /* Current size (in entries) of the hash table, as an index into the 140 table of primes. */ 141 unsigned int size_prime_index; 142 }; 143 144 typedef struct htab *htab_t; 145 146 /* An enum saying whether we insert into the hash table or not. */ 147 enum insert_option {NO_INSERT, INSERT}; 148 149 /* The prototypes of the package functions. */ 150 151 extern htab_t htab_create_alloc (size_t, htab_hash, 152 htab_eq, htab_del, 153 htab_alloc, htab_free); 154 155 extern htab_t htab_create_alloc_ex (size_t, htab_hash, 156 htab_eq, htab_del, 157 void *, htab_alloc_with_arg, 158 htab_free_with_arg); 159 160 extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del, 161 htab_alloc, htab_alloc, htab_free); 162 163 /* Backward-compatibility functions. */ 164 extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del); 165 extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del); 166 167 extern void htab_set_functions_ex (htab_t, htab_hash, 168 htab_eq, htab_del, 169 void *, htab_alloc_with_arg, 170 htab_free_with_arg); 171 172 extern void htab_delete (htab_t); 173 extern void htab_empty (htab_t); 174 175 extern void * htab_find (htab_t, const void *); 176 extern void ** htab_find_slot (htab_t, const void *, enum insert_option); 177 extern void * htab_find_with_hash (htab_t, const void *, hashval_t); 178 extern void ** htab_find_slot_with_hash (htab_t, const void *, 179 hashval_t, enum insert_option); 180 extern void htab_clear_slot (htab_t, void **); 181 extern void htab_remove_elt (htab_t, void *); 182 extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t); 183 184 extern void htab_traverse (htab_t, htab_trav, void *); 185 extern void htab_traverse_noresize (htab_t, htab_trav, void *); 186 187 extern size_t htab_size (htab_t); 188 extern size_t htab_elements (htab_t); 189 extern double htab_collisions (htab_t); 190 191 /* A hash function for pointers. */ 192 extern htab_hash htab_hash_pointer; 193 194 /* An equality function for pointers. */ 195 extern htab_eq htab_eq_pointer; 196 197 /* A hash function for null-terminated strings. */ 198 extern hashval_t htab_hash_string (const void *); 199 200 /* An iterative hash function for arbitrary data. */ 201 extern hashval_t iterative_hash (const void *, size_t, hashval_t); 202 /* Shorthand for hashing something with an intrinsic size. */ 203 #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT) 204 205 #ifdef __cplusplus 206 } 207 #endif /* __cplusplus */ 208 209 #endif /* __HASHTAB_H */ 210
