/* An expandable hash tables datatype.
- Copyright (C) 1999 Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000 Free Software Foundation, Inc.
Contributed by Vladimir Makarov (vmakarov@cygnus.com).
This program is free software; you can redistribute it and/or modify
#include <ansidecl.h>
-/* The hash table element is represented by the following type. */
+/* The type for a hash code. */
+typedef unsigned int hashval_t;
-typedef const void *hash_table_entry_t;
+/* Callback function pointer types. */
+
+/* Calculate hash of a table entry. */
+typedef hashval_t (*htab_hash) PARAMS ((const void *));
+
+/* Compare a table entry with a possible entry. The entry already in
+ the table always comes first, so the second element can be of a
+ different type (but in this case htab_find and htab_find_slot
+ cannot be used; instead the variants that accept a hash value
+ must be used). */
+typedef int (*htab_eq) PARAMS ((const void *, const void *));
+
+/* Cleanup function called whenever a live element is removed from
+ the hash table. */
+typedef void (*htab_del) PARAMS ((void *));
+
+/* Function called by htab_traverse for each live element. The first
+ arg is the slot of the element (which can be passed to htab_clear_slot
+ if desired), the second arg is the auxiliary pointer handed to
+ htab_traverse. Return 1 to continue scan, 0 to stop. */
+typedef int (*htab_trav) PARAMS ((void **, void *));
/* Hash tables are of the following type. The structure
(implementation) of this type is not needed for using the hash
tables. All work with hash table should be executed only through
functions mentioned below. */
-typedef struct
+struct htab
{
+ /* Pointer to hash function. */
+ htab_hash hash_f;
+
+ /* Pointer to comparison function. */
+ htab_eq eq_f;
+
+ /* Pointer to cleanup function. */
+ htab_del del_f;
+
+ /* Table itself. */
+ PTR *entries;
+
/* Current size (in entries) of the hash table */
size_t size;
+
/* Current number of elements including also deleted elements */
- size_t number_of_elements;
+ size_t n_elements;
+
/* Current number of deleted elements in the table */
- size_t number_of_deleted_elements;
+ size_t n_deleted;
+
/* The following member is used for debugging. Its value is number
- of all calls of `find_hash_table_entry' for the hash table. */
- int searches;
+ of all calls of `htab_find_slot' for the hash table. */
+ unsigned int searches;
+
/* The following member is used for debugging. Its value is number
of collisions fixed for time of work with the hash table. */
- int collisions;
- /* Pointer to function for evaluation of hash value (any unsigned value).
- This function has one parameter of type hash_table_entry_t. */
- unsigned (*hash_function) PARAMS ((hash_table_entry_t));
- /* Pointer to function for test on equality of hash table elements (two
- parameter of type hash_table_entry_t. */
- int (*eq_function) PARAMS ((hash_table_entry_t, hash_table_entry_t));
- /* Table itself */
- hash_table_entry_t *entries;
-} *hash_table_t;
-
-
-/* The prototypes of the package functions. */
-
-extern hash_table_t create_hash_table
- PARAMS ((size_t, unsigned (*) (hash_table_entry_t),
- int (*) (hash_table_entry_t, hash_table_entry_t)));
+ unsigned int collisions;
-extern void delete_hash_table PARAMS ((hash_table_t));
+ /* This is non-zero if we are allowed to return NULL for function calls
+ that allocate memory. */
+ int return_allocation_failure;
+};
-extern void empty_hash_table PARAMS ((hash_table_t));
+typedef struct htab *htab_t;
-extern hash_table_entry_t *find_hash_table_entry
- PARAMS ((hash_table_t, hash_table_entry_t, int));
+/* An enum saying whether we insert into the hash table or not. */
+enum insert_option {NO_INSERT, INSERT};
-extern void remove_element_from_hash_table_entry PARAMS ((hash_table_t,
- hash_table_entry_t));
-
-extern size_t hash_table_size PARAMS ((hash_table_t));
-
-extern size_t hash_table_elements_number PARAMS ((hash_table_t));
-
-extern int hash_table_collisions PARAMS ((hash_table_t));
+/* The prototypes of the package functions. */
-extern int all_hash_table_collisions ();
+extern htab_t htab_create PARAMS ((size_t, htab_hash,
+ htab_eq, htab_del));
+
+/* This function is like htab_create, but may return NULL if memory
+ allocation fails, and also signals that htab_find_slot_with_hash and
+ htab_find_slot are allowed to return NULL when inserting. */
+extern htab_t htab_try_create PARAMS ((size_t, htab_hash,
+ htab_eq, htab_del));
+extern void htab_delete PARAMS ((htab_t));
+extern void htab_empty PARAMS ((htab_t));
+
+extern PTR htab_find PARAMS ((htab_t, const void *));
+extern PTR *htab_find_slot PARAMS ((htab_t, const void *,
+ enum insert_option));
+extern PTR htab_find_with_hash PARAMS ((htab_t, const void *,
+ hashval_t));
+extern PTR *htab_find_slot_with_hash PARAMS ((htab_t, const void *,
+ hashval_t,
+ enum insert_option));
+extern void htab_clear_slot PARAMS ((htab_t, void **));
+extern void htab_remove_elt PARAMS ((htab_t, void *));
+
+extern void htab_traverse PARAMS ((htab_t, htab_trav, void *));
+
+extern size_t htab_size PARAMS ((htab_t));
+extern size_t htab_elements PARAMS ((htab_t));
+extern double htab_collisions PARAMS ((htab_t));
+
+/* A hash function for pointers. */
+extern htab_hash htab_hash_pointer;
+
+/* An equality function for pointers. */
+extern htab_eq htab_eq_pointer;
+
+/* A hash function for null-terminated strings. */
+extern hashval_t htab_hash_string PARAMS ((const PTR));
#ifdef __cplusplus
}
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