1 /* An expandable hash tables datatype. 2 Copyright (C) 1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc. 3 Contributed by Vladimir Makarov (vmakarov@cygnus.com). 4 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. 9 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. 14 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ 18 19 /* This package implements basic hash table functionality. It is possible 20 to search for an entry, create an entry and destroy an entry. 21 22 Elements in the table are generic pointers. 23 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. 26 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. */ 31 32 #ifndef __HASHTAB_H__ 33 #define __HASHTAB_H__ 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif /* __cplusplus */ 38 39 #include "ansidecl.h" 40 41 #ifndef GTY 42 #define GTY(X) 43 #endif 44 45 /* The type for a hash code. */ 46 typedef unsigned int hashval_t; 47 48 /* Callback function pointer types. */ 49 50 /* Calculate hash of a table entry. */ 51 typedef hashval_t (*htab_hash) PARAMS ((const void *)); 52 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 *)); 59 60 /* Cleanup function called whenever a live element is removed from 61 the hash table. */ 62 typedef void (*htab_del) PARAMS ((void *)); 63 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 *)); 69 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)); 75 76 /* We also need a free() routine. */ 77 typedef void (*htab_free) PARAMS ((PTR)); 78 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 *)); 83 84 /* This macro defines reserved value for empty table entry. */ 85 86 #define HTAB_EMPTY_ENTRY ((PTR) 0) 87 88 /* This macro defines reserved value for table entry which contained 89 a deleted element. */ 90 91 #define HTAB_DELETED_ENTRY ((PTR) 1) 92 93 /* Hash tables are of the following type. The structure 94 (implementation) of this type is not needed for using the hash 95 tables. All work with hash table should be executed only through 96 functions mentioned below. The size of this structure is subject to 97 change. */ 98 99 struct htab GTY(()) 100 { 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 PTR * 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 PTR 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 /* Backward-compatibility functions. */ 161 extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del); 162 extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del); 163 164 extern void htab_set_functions_ex (htab_t, htab_hash, 165 htab_eq, htab_del, 166 void *, htab_alloc_with_arg, 167 htab_free_with_arg); 168 169 extern void htab_delete (htab_t); 170 extern void htab_empty (htab_t); 171 172 extern void * htab_find (htab_t, const void *); 173 extern void ** htab_find_slot (htab_t, const void *, enum insert_option); 174 extern void * htab_find_with_hash (htab_t, const void *, hashval_t); 175 extern void ** htab_find_slot_with_hash (htab_t, const void *, 176 hashval_t, enum insert_option); 177 extern void htab_clear_slot (htab_t, void **); 178 extern void htab_remove_elt (htab_t, void *); 179 extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t); 180 181 extern void htab_traverse (htab_t, htab_trav, void *); 182 extern void htab_traverse_noresize (htab_t, htab_trav, void *); 183 184 extern size_t htab_size (htab_t); 185 extern size_t htab_elements (htab_t); 186 extern double htab_collisions (htab_t); 187 188 /* A hash function for pointers. */ 189 extern htab_hash htab_hash_pointer; 190 191 /* An equality function for pointers. */ 192 extern htab_eq htab_eq_pointer; 193 194 /* A hash function for null-terminated strings. */ 195 extern hashval_t htab_hash_string (const void *); 196 197 /* An iterative hash function for arbitrary data. */ 198 extern hashval_t iterative_hash (const void *, size_t, hashval_t); 199 /* Shorthand for hashing something with an intrinsic size. */ 200 #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT) 201 202 /* XXX Old hash table functions, kept for compatibility */ 203 204 /* The hash table element is represented by the following type. */ 205 206 typedef const void *hash_table_entry_t; 207 208 /* Hash tables are of the following type. The structure 209 (implementation) of this type is not needed for using the hash 210 tables. All work with hash table should be executed only through 211 functions mentioned below. */ 212 213 typedef struct 214 { 215 /* Current size (in entries) of the hash table */ 216 size_t size; 217 /* Current number of elements including also deleted elements */ 218 size_t number_of_elements; 219 /* Current number of deleted elements in the table */ 220 size_t number_of_deleted_elements; 221 /* The following member is used for debugging. Its value is number 222 of all calls of `find_hash_table_entry' for the hash table. */ 223 int searches; 224 /* The following member is used for debugging. Its value is number 225 of collisions fixed for time of work with the hash table. */ 226 int collisions; 227 /* Pointer to function for evaluation of hash value (any unsigned value). 228 This function has one parameter of type hash_table_entry_t. */ 229 unsigned (*hash_function) (hash_table_entry_t); 230 /* Pointer to function for test on equality of hash table elements (two 231 parameter of type hash_table_entry_t. */ 232 int (*eq_function) (hash_table_entry_t, hash_table_entry_t); 233 /* Table itself */ 234 hash_table_entry_t *entries; 235 } *hash_table_t; 236 237 238 /* The prototypes of the package functions. */ 239 240 extern hash_table_t create_hash_table 241 (size_t, unsigned (*) (hash_table_entry_t), 242 int (*) (hash_table_entry_t, hash_table_entry_t)); 243 244 extern void delete_hash_table (hash_table_t); 245 246 extern void empty_hash_table (hash_table_t); 247 248 extern hash_table_entry_t *find_hash_table_entry 249 (hash_table_t, hash_table_entry_t, int); 250 251 extern void remove_element_from_hash_table_entry (hash_table_t, 252 hash_table_entry_t); 253 254 extern size_t hash_table_size (hash_table_t); 255 256 extern size_t hash_table_elements_number (hash_table_t); 257 258 extern int hash_table_collisions (hash_table_t); 259 260 extern int all_hash_table_collisions (void); 261 262 #ifdef __cplusplus 263 } 264 #endif /* __cplusplus */ 265 266 #endif /* __HASHTAB_H */ 267