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 5This program is free software; you can redistribute it and/or modify 6it under the terms of the GNU General Public License as published by 7the Free Software Foundation; either version 2 of the License, or 8(at your option) any later version. 9 10This program is distributed in the hope that it will be useful, 11but WITHOUT ANY WARRANTY; without even the implied warranty of 12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13GNU General Public License for more details. 14 15You should have received a copy of the GNU General Public License 16along with this program; if not, write to the Free Software 17Foundation, 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 36extern "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. */ 46typedef unsigned int hashval_t; 47 48/* Callback function pointer types. */ 49 50/* Calculate hash of a table entry. */ 51typedef hashval_t (*htab_hash) (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). */ 58typedef int (*htab_eq) (const void *, const void *); 59 60/* Cleanup function called whenever a live element is removed from 61 the hash table. */ 62typedef void (*htab_del) (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. */ 68typedef int (*htab_trav) (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. */ 74typedef void *(*htab_alloc) (size_t, size_t); 75 76/* We also need a free() routine. */ 77typedef void (*htab_free) (void *); 78 79/* Memory allocation and deallocation; variants which take an extra 80 argument. */ 81typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t); 82typedef void (*htab_free_with_arg) (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 99struct 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 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 144typedef struct htab *htab_t; 145 146/* An enum saying whether we insert into the hash table or not. */ 147enum insert_option {NO_INSERT, INSERT}; 148 149/* The prototypes of the package functions. */ 150 151extern htab_t htab_create_alloc (size_t, htab_hash, 152 htab_eq, htab_del, 153 htab_alloc, htab_free); 154 155extern 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. */ 161extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del); 162extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del); 163 164extern 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 169extern void htab_delete (htab_t); 170extern void htab_empty (htab_t); 171 172extern void * htab_find (htab_t, const void *); 173extern void ** htab_find_slot (htab_t, const void *, enum insert_option); 174extern void * htab_find_with_hash (htab_t, const void *, hashval_t); 175extern void ** htab_find_slot_with_hash (htab_t, const void *, 176 hashval_t, enum insert_option); 177extern void htab_clear_slot (htab_t, void **); 178extern void htab_remove_elt (htab_t, void *); 179extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t); 180 181extern void htab_traverse (htab_t, htab_trav, void *); 182extern void htab_traverse_noresize (htab_t, htab_trav, void *); 183 184extern size_t htab_size (htab_t); 185extern size_t htab_elements (htab_t); 186extern double htab_collisions (htab_t); 187 188/* A hash function for pointers. */ 189extern htab_hash htab_hash_pointer; 190 191/* An equality function for pointers. */ 192extern htab_eq htab_eq_pointer; 193 194/* A hash function for null-terminated strings. */ 195extern hashval_t htab_hash_string (const void *); 196 197/* An iterative hash function for arbitrary data. */ 198extern 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#ifdef __cplusplus 203} 204#endif /* __cplusplus */ 205 206#endif /* __HASHTAB_H */ 207