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). 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 /* 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. */ 89 90 struct htab GTY(()) 91 { 92 /* Pointer to hash function. */ 93 htab_hash hash_f; 94 95 /* Pointer to comparison function. */ 96 htab_eq eq_f; 97 98 /* Pointer to cleanup function. */ 99 htab_del del_f; 100 101 /* Table itself. */ 102 PTR * GTY ((use_param (""), length ("%h.size"))) entries; 103 104 /* Current size (in entries) of the hash table */ 105 size_t size; 106 107 /* Current number of elements including also deleted elements */ 108 size_t n_elements; 109 110 /* Current number of deleted elements in the table */ 111 size_t n_deleted; 112 113 /* 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; 116 117 /* 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; 120 121 /* Pointers to allocate/free functions. */ 122 htab_alloc alloc_f; 123 htab_free free_f; 124 125 /* 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; 129 }; 130 131 typedef struct htab *htab_t; 132 133 /* An enum saying whether we insert into the hash table or not. */ 134 enum insert_option {NO_INSERT, INSERT}; 135 136 /* The prototypes of the package functions. */ 137 138 extern htab_t htab_create_alloc PARAMS ((size_t, htab_hash, 139 htab_eq, htab_del, 140 htab_alloc, htab_free)); 141 142 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)); 146 147 /* 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)); 150 151 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)); 155 156 extern void htab_delete PARAMS ((htab_t)); 157 extern void htab_empty PARAMS ((htab_t)); 158 159 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 *)); 169 170 extern void htab_traverse PARAMS ((htab_t, htab_trav, void *)); 171 extern void htab_traverse_noresize PARAMS ((htab_t, htab_trav, void *)); 172 173 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)); 176 177 /* A hash function for pointers. */ 178 extern htab_hash htab_hash_pointer; 179 180 /* An equality function for pointers. */ 181 extern htab_eq htab_eq_pointer; 182 183 /* A hash function for null-terminated strings. */ 184 extern hashval_t htab_hash_string PARAMS ((const PTR)); 185 186 /* 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) 190 191 #ifdef __cplusplus 192 } 193 #endif /* __cplusplus */ 194 195 #endif /* __HASHTAB_H */ 196