1 /* An expandable hash tables datatype. 2 Copyright (C) 1999, 2000, 2002 Free Software Foundation, Inc. 3 Contributed by Vladimir Makarov ([email protected]). 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 /* Hash tables are of the following type. The structure 80 (implementation) of this type is not needed for using the hash 81 tables. All work with hash table should be executed only through 82 functions mentioned below. */ 83 84 struct htab GTY(()) 85 { 86 /* Pointer to hash function. */ 87 htab_hash hash_f; 88 89 /* Pointer to comparison function. */ 90 htab_eq eq_f; 91 92 /* Pointer to cleanup function. */ 93 htab_del del_f; 94 95 /* Table itself. */ 96 PTR * GTY ((use_param (""), length ("%h.size"))) entries; 97 98 /* Current size (in entries) of the hash table */ 99 size_t size; 100 101 /* Current number of elements including also deleted elements */ 102 size_t n_elements; 103 104 /* Current number of deleted elements in the table */ 105 size_t n_deleted; 106 107 /* The following member is used for debugging. Its value is number 108 of all calls of `htab_find_slot' for the hash table. */ 109 unsigned int searches; 110 111 /* The following member is used for debugging. Its value is number 112 of collisions fixed for time of work with the hash table. */ 113 unsigned int collisions; 114 115 /* Pointers to allocate/free functions. */ 116 htab_alloc alloc_f; 117 htab_free free_f; 118 }; 119 120 typedef struct htab *htab_t; 121 122 /* An enum saying whether we insert into the hash table or not. */ 123 enum insert_option {NO_INSERT, INSERT}; 124 125 /* The prototypes of the package functions. */ 126 127 extern htab_t htab_create_alloc PARAMS ((size_t, htab_hash, 128 htab_eq, htab_del, 129 htab_alloc, htab_free)); 130 131 /* Backward-compatibility functions. */ 132 extern htab_t htab_create PARAMS ((size_t, htab_hash, htab_eq, htab_del)); 133 extern htab_t htab_try_create PARAMS ((size_t, htab_hash, htab_eq, htab_del)); 134 135 extern void htab_delete PARAMS ((htab_t)); 136 extern void htab_empty PARAMS ((htab_t)); 137 138 extern PTR htab_find PARAMS ((htab_t, const void *)); 139 extern PTR *htab_find_slot PARAMS ((htab_t, const void *, 140 enum insert_option)); 141 extern PTR htab_find_with_hash PARAMS ((htab_t, const void *, 142 hashval_t)); 143 extern PTR *htab_find_slot_with_hash PARAMS ((htab_t, const void *, 144 hashval_t, 145 enum insert_option)); 146 extern void htab_clear_slot PARAMS ((htab_t, void **)); 147 extern void htab_remove_elt PARAMS ((htab_t, void *)); 148 149 extern void htab_traverse PARAMS ((htab_t, htab_trav, void *)); 150 151 extern size_t htab_size PARAMS ((htab_t)); 152 extern size_t htab_elements PARAMS ((htab_t)); 153 extern double htab_collisions PARAMS ((htab_t)); 154 155 /* A hash function for pointers. */ 156 extern htab_hash htab_hash_pointer; 157 158 /* An equality function for pointers. */ 159 extern htab_eq htab_eq_pointer; 160 161 /* A hash function for null-terminated strings. */ 162 extern hashval_t htab_hash_string PARAMS ((const PTR)); 163 164 #ifdef __cplusplus 165 } 166 #endif /* __cplusplus */ 167 168 #endif /* __HASHTAB_H */ 169