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/* An expandable hash tables datatype. |
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Copyright (C) 1999-2021 Free Software Foundation, Inc. |
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Contributed by Vladimir Makarov (vmakarov@cygnus.com). |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ |
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|
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/* This package implements basic hash table functionality. It is possible |
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to search for an entry, create an entry and destroy an entry. |
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|
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Elements in the table are generic pointers. |
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|
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The size of the table is not fixed; if the occupancy of the table |
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grows too high the hash table will be expanded. |
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|
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The abstract data implementation is based on generalized Algorithm D |
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from Knuth's book "The art of computer programming". Hash table is |
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expanded by creation of new hash table and transferring elements from |
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the old table to the new table. */ |
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|
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#ifndef __HASHTAB_H__ |
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#define __HASHTAB_H__ |
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|
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#ifdef __cplusplus |
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extern "C" { |
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#endif /* __cplusplus */ |
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|
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#include "ansidecl.h" |
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|
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/* The type for a hash code. */ |
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typedef unsigned int hashval_t; |
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|
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/* Callback function pointer types. */ |
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|
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/* Calculate hash of a table entry. */ |
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typedef hashval_t (*htab_hash) (const void *); |
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|
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/* Compare a table entry with a possible entry. The entry already in |
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the table always comes first, so the second element can be of a |
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different type (but in this case htab_find and htab_find_slot |
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cannot be used; instead the variants that accept a hash value |
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must be used). */ |
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typedef int (*htab_eq) (const void *, const void *); |
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|
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/* Cleanup function called whenever a live element is removed from |
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the hash table. */ |
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typedef void (*htab_del) (void *); |
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|
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/* Function called by htab_traverse for each live element. The first |
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arg is the slot of the element (which can be passed to htab_clear_slot |
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if desired), the second arg is the auxiliary pointer handed to |
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htab_traverse. Return 1 to continue scan, 0 to stop. */ |
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typedef int (*htab_trav) (void **, void *); |
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|
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/* Memory-allocation function, with the same functionality as calloc(). |
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Iff it returns NULL, the hash table implementation will pass an error |
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code back to the user, so if your code doesn't handle errors, |
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best if you use xcalloc instead. */ |
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typedef void *(*htab_alloc) (size_t, size_t); |
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|
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/* We also need a free() routine. */ |
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typedef void (*htab_free) (void *); |
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|
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/* Memory allocation and deallocation; variants which take an extra |
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argument. */ |
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typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t); |
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typedef void (*htab_free_with_arg) (void *, void *); |
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|
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/* This macro defines reserved value for empty table entry. */ |
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|
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#define HTAB_EMPTY_ENTRY ((PTR) 0) |
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|
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/* This macro defines reserved value for table entry which contained |
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a deleted element. */ |
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|
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#define HTAB_DELETED_ENTRY ((PTR) 1) |
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|
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/* Hash tables are of the following type. The structure |
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(implementation) of this type is not needed for using the hash |
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tables. All work with hash table should be executed only through |
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functions mentioned below. The size of this structure is subject to |
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change. */ |
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|
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struct htab { |
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/* Pointer to hash function. */ |
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htab_hash hash_f; |
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|
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/* Pointer to comparison function. */ |
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htab_eq eq_f; |
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|
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/* Pointer to cleanup function. */ |
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htab_del del_f; |
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|
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/* Table itself. */ |
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void **entries; |
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|
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/* Current size (in entries) of the hash table. */ |
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size_t size; |
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|
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/* Current number of elements including also deleted elements. */ |
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size_t n_elements; |
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|
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/* Current number of deleted elements in the table. */ |
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size_t n_deleted; |
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|
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/* The following member is used for debugging. Its value is number |
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of all calls of `htab_find_slot' for the hash table. */ |
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unsigned int searches; |
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|
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/* The following member is used for debugging. Its value is number |
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of collisions fixed for time of work with the hash table. */ |
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unsigned int collisions; |
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|
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/* Pointers to allocate/free functions. */ |
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htab_alloc alloc_f; |
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htab_free free_f; |
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|
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/* Alternate allocate/free functions, which take an extra argument. */ |
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void *alloc_arg; |
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htab_alloc_with_arg alloc_with_arg_f; |
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htab_free_with_arg free_with_arg_f; |
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|
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/* Current size (in entries) of the hash table, as an index into the |
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table of primes. */ |
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unsigned int size_prime_index; |
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}; |
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|
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typedef struct htab *htab_t; |
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|
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/* An enum saying whether we insert into the hash table or not. */ |
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enum insert_option {NO_INSERT, INSERT}; |
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|
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/* The prototypes of the package functions. */ |
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|
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extern htab_t htab_create_alloc (size_t, htab_hash, |
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htab_eq, htab_del, |
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htab_alloc, htab_free); |
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|
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extern htab_t htab_create_alloc_ex (size_t, htab_hash, |
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htab_eq, htab_del, |
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void *, htab_alloc_with_arg, |
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htab_free_with_arg); |
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|
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extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del, |
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htab_alloc, htab_alloc, htab_free); |
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|
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/* Backward-compatibility functions. */ |
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extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del); |
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extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del); |
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|
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extern void htab_set_functions_ex (htab_t, htab_hash, |
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htab_eq, htab_del, |
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void *, htab_alloc_with_arg, |
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htab_free_with_arg); |
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|
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extern void htab_delete (htab_t); |
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extern void htab_empty (htab_t); |
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|
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extern void * htab_find (htab_t, const void *); |
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extern void ** htab_find_slot (htab_t, const void *, enum insert_option); |
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extern void * htab_find_with_hash (htab_t, const void *, hashval_t); |
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extern void ** htab_find_slot_with_hash (htab_t, const void *, |
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hashval_t, enum insert_option); |
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extern void htab_clear_slot (htab_t, void **); |
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extern void htab_remove_elt (htab_t, const void *); |
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extern void htab_remove_elt_with_hash (htab_t, const void *, hashval_t); |
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|
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extern void htab_traverse (htab_t, htab_trav, void *); |
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extern void htab_traverse_noresize (htab_t, htab_trav, void *); |
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|
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extern size_t htab_size (htab_t); |
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extern size_t htab_elements (htab_t); |
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extern double htab_collisions (htab_t); |
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|
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/* A hash function for pointers. */ |
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extern htab_hash htab_hash_pointer; |
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|
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/* An equality function for pointers. */ |
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extern htab_eq htab_eq_pointer; |
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|
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/* A hash function for null-terminated strings. */ |
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extern hashval_t htab_hash_string (const void *); |
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|
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/* An equality function for null-terminated strings. */ |
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extern int htab_eq_string (const void *, const void *); |
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|
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/* An iterative hash function for arbitrary data. */ |
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extern hashval_t iterative_hash (const void *, size_t, hashval_t); |
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/* Shorthand for hashing something with an intrinsic size. */ |
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#define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT) |
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|
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#ifdef __cplusplus |
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} |
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#endif /* __cplusplus */ |
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|
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#endif /* __HASHTAB_H */ |
