* hashtab.h: New file.

From-SVN: r30013

1 files changed, 103 insertions, 0 deletions

diff --git a/include/hashtab.h b/include/hashtab.h
new file mode 100644
index 0000000..67c37a2
--- /dev/null
+++ b/include/hashtab.h
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+/* An expandable hash tables datatype.  
+   Copyright (C) 1999 Free Software Foundation, Inc.
+   Contributed by Vladimir Makarov (vmakarov@cygnus.com).
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* This package implements basic hash table functionality.  It is possible
+   to search for an entry, create an entry and destroy an entry.
+
+   Elements in the table are generic pointers.
+
+   The size of the table is not fixed; if the occupancy of the table
+   grows too high the hash table will be expanded.
+
+   The abstract data implementation is based on generalized Algorithm D
+   from Knuth's book "The art of computer programming".  Hash table is
+   expanded by creation of new hash table and transferring elements from
+   the old table to the new table.  */
+
+#ifndef __HASHTAB_H__
+#define __HASHTAB_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#include <ansidecl.h>
+
+/* The hash table element is represented by the following type. */
+
+typedef const void *hash_table_entry_t;
+
+/* 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
+{
+  /* Current size (in entries) of the hash table */
+  size_t size;
+  /* Current number of elements including also deleted elements */
+  size_t number_of_elements;
+  /* Current number of deleted elements in the table */
+  size_t number_of_deleted_elements;
+  /* 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;
+  /* 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)));
+
+extern void delete_hash_table PARAMS ((hash_table_t));
+
+extern void empty_hash_table PARAMS ((hash_table_t));
+
+extern hash_table_entry_t *find_hash_table_entry
+  PARAMS ((hash_table_t, hash_table_entry_t, int));
+
+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));
+
+extern int all_hash_table_collisions ();
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __HASHTAB_H */