--- a/lib/hash.h
+++ b/lib/hash.h
@@ -1,193 +1,103 @@
-#ifndef HASH_H
-# define HASH_H 1
-
-# if HAVE_CONFIG_H
-#  include <config.h>
-# endif
-
-# include <stdio.h>
-# include <assert.h>
+/* hash - hashing table processing.
+   Copyright (C) 1998 Free Software Foundation, Inc.
+   Written by Jim Meyering <meyering@ascend.com>, 1998.
 
-# ifdef STDC_HEADERS
-#  include <stdlib.h>
-# endif
-
-# ifndef HAVE_DECL_FREE
-void free ();
-# endif
-
-# ifndef HAVE_DECL_MALLOC
-char *malloc ();
-# endif
+   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, or (at your option)
+   any later version.
 
-# ifndef PARAMS
-#  if defined PROTOTYPES || (defined __STDC__ && __STDC__)
-#   define PARAMS(Args) Args
-#  else
-#   define PARAMS(Args) ()
-#  endif
-# endif
+   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.
 
-# define USE_OBSTACK
-# ifdef USE_OBSTACK
-#  include "obstack.h"
-# endif
+   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.  */
 
-# define obstack_chunk_alloc malloc
-# define obstack_chunk_free free
-
-struct hash_ent
-  {
-    void *key;
-    struct hash_ent *next;
-  };
-typedef struct hash_ent HASH_ENT;
+/* A generic hash table package.  */
 
-/* This is particularly useful to cast uses in hash_initialize of the
-   system free function.  */
-typedef void (*Hash_key_freer_type) PARAMS((void *key));
-
-struct HT
-  {
-    /* User-supplied function for freeing keys.  It is specified in
-       hash_initialize.  If non-null, it is used by hash_free and
-       hash_clear.  You should specify `free' here only if you want
-       these functions to free all of your `key' data.  This is typically
-       the case when your key is simply an auxilliary struct that you
-       have malloc'd to aggregate several values.   */
-    Hash_key_freer_type hash_key_freer;
-
-    /* User-supplied hash function that hashes entry E to an integer
-       in the range 0..TABLE_SIZE-1.  */
-    unsigned int (*hash_hash) PARAMS((const void *e, unsigned int table_size));
-
-    /* User-supplied function that determines whether a new entry is
-       unique by comparing the new entry to entries that hashed to the
-       same bucket index.  It should return zero for a pair of entries
-       that compare equal, non-zero otherwise.  */
+/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use
+   obstacks instead of malloc, and recompile `hash.c' with same setting.  */
 
-    int (*hash_key_comparator) PARAMS((const void *, const void *));
-
-    HASH_ENT **hash_table;
-    unsigned int hash_table_size;
-    unsigned int hash_n_slots_used;
-    unsigned int hash_max_chain_length;
-
-    /* Gets set when an entry is deleted from a chain of length
-       hash_max_chain_length.  Indicates that hash_max_chain_length
-       may no longer be valid.  */
-    unsigned int hash_dirty_max_chain_length;
+#ifndef PARAMS
+# if PROTOTYPES || __STDC__
+#  define PARAMS(Args) Args
+# else
+#  define PARAMS(Args) ()
+# endif
+#endif
 
-    /* Sum of lengths of all chains (not counting any dummy
-       header entries).  */
-    unsigned int hash_n_keys;
+typedef unsigned int (*Hash_hasher) PARAMS ((const void *, unsigned int));
+typedef bool (*Hash_comparator) PARAMS ((const void *, const void *));
+typedef void (*Hash_data_freer) PARAMS ((void *));
+typedef bool (*Hash_processor) PARAMS ((void *, void *));
 
-    /* A linked list of freed HASH_ENT structs.
-       FIXME: Perhaps this is unnecessary and we should simply free
-       and reallocate such structs.  */
-    HASH_ENT *hash_free_entry_list;
-
-    /* FIXME: comment.  */
-# ifdef USE_OBSTACK
-    struct obstack ht_obstack;
-# endif
+struct hash_entry
+  {
+    void *data;
+    struct hash_entry *next;
   };
 
-typedef struct HT HT;
-
-unsigned int
-  hash_get_n_slots_used PARAMS((const HT *ht));
-
-unsigned int
-  hash_get_max_chain_length PARAMS((HT *ht));
-
-int
-  hash_rehash PARAMS((HT *ht, unsigned int new_table_size));
-
-unsigned int
-  hash_get_table_size PARAMS((const HT *ht));
-
-HT *
-  hash_initialize PARAMS((unsigned int table_size,
-			  void (*key_freer) PARAMS((void *key)),
-			  unsigned int (*hash) PARAMS((const void *,
-						       unsigned int)),
-			  int (*equality_tester) PARAMS((const void *,
-							 const void *))));
+struct hash_table
+  {
+    /* The array of buckets starts at BUCKET and extends to BUCKET_LIMIT-1,
+       for a possibility of N_BUCKETS.  Among those, N_BUCKETS_USED buckets
+       are not empty, there are N_ENTRIES active entries in the table.  */
+    struct hash_entry *bucket;
+    struct hash_entry *bucket_limit;
+    unsigned int n_buckets;
+    unsigned int n_buckets_used;
+    unsigned int n_entries;
 
-unsigned int
-  hash_get_n_keys PARAMS((const HT *ht));
-
-int
-  hash_query_in_table PARAMS((const HT *ht, const void *e));
-
-void *
-  hash_lookup PARAMS((const HT *ht, const void *e));
+    /* Three functions are given to `hash_initialize', see the documentation
+       block for this function.  In a word, HASHER randomizes a user entry
+       into a number up from 0 up to some maximum minus 1; COMPARATOR returns
+       true if two user entries compare equally; and DATA_FREER is the cleanup
+       function for a user entry.  */
+    Hash_hasher hasher;
+    Hash_comparator comparator;
+    Hash_data_freer data_freer;
 
-void *
-  hash_insert_if_absent PARAMS((HT *ht,
-				const void *e,
-				int *failed));
-
-void *
-  hash_delete_if_present PARAMS((HT *ht, const void *e));
+    /* A linked list of freed struct hash_entry structs.  */
+    struct hash_entry *free_entry_list;
 
-void
-  hash_print_statistics PARAMS((const HT *ht, FILE *stream));
-
-int
-  hash_get_statistics PARAMS((const HT *ht, unsigned int *n_slots_used,
-			      unsigned int *n_keys,
-			      unsigned int *max_chain_length));
+#if USE_OBSTACK
+    /* Whenever obstacks are used, it is possible to allocate all overflowed
+       entries into a single stack, so they all can be freed in a single
+       operation.  It is not clear if the speedup is worth the trouble.  */
+    struct obstack entry_stack;
+#endif
+  };
 
-int
-  hash_table_ok PARAMS((HT *ht));
-
-void
-  hash_do_for_each PARAMS((HT *ht,
-			   void (*f) PARAMS((void *e, void *aux)),
-			   void *aux));
+typedef struct hash_table Hash_table;
 
-int
-  hash_do_for_each_2 PARAMS((HT *ht,
-			     int (*f) PARAMS((void *e, void *aux)),
-			     void *aux));
-
-int
-  hash_do_for_each_in_selected_bucket PARAMS((HT *ht,
-					      const void *key,
-				      int (*f) PARAMS((const void *bucket_key,
-						       void *e,
-						       void *aux)),
-					      void *aux));
-
-void
-  hash_clear PARAMS((HT *ht));
+/* Information and lookup.  */
+unsigned int hash_get_n_buckets PARAMS ((const Hash_table *));
+unsigned int hash_get_n_buckets_used PARAMS ((const Hash_table *));
+unsigned int hash_get_n_entries PARAMS ((const Hash_table *));
+unsigned int hash_get_max_bucket_length PARAMS ((const Hash_table *));
+bool hash_table_ok PARAMS ((const Hash_table *));
+void hash_print_statistics PARAMS ((const Hash_table *, FILE *));
+void *hash_lookup PARAMS ((const Hash_table *, const void *));
 
-void
-  hash_free PARAMS((HT *ht));
-
-void
-  hash_get_key_list PARAMS((const HT *ht,
-			    unsigned int bufsize,
-			    void **buf));
-
-void *
-  hash_get_first PARAMS((const HT *ht));
-
-void *
-  hash_get_next PARAMS((const HT *ht, const void *e));
+/* Walking.  */
+void *hash_get_first PARAMS ((const Hash_table *));
+void *hash_get_next PARAMS ((const Hash_table *, const void *));
+unsigned int hash_get_entries PARAMS ((const Hash_table *, void **,
+				       unsigned int));
+unsigned int hash_do_for_each PARAMS ((const Hash_table *, Hash_processor,
+				       void *));
 
-/* This interface to hash_insert_if_absent is used frequently enough to
-   merit a macro here.  */
+/* Allocation and clean-up.  */
+unsigned int hash_string PARAMS ((const char *, unsigned int));
+Hash_table *hash_initialize PARAMS ((unsigned int, Hash_hasher,
+				     Hash_comparator, Hash_data_freer));
+void hash_clear PARAMS ((Hash_table *));
+void hash_free PARAMS ((Hash_table *));
 
-# define HASH_INSERT_NEW_ITEM(Ht, Item, Failp)				\
-  do									\
-    {									\
-      void *_already;							\
-      _already = hash_insert_if_absent ((Ht), (Item), Failp);		\
-      assert (_already == NULL);					\
-    }									\
-  while (0)
-
-#endif /* HASH_H */
+/* Insertion and deletion.  */
+bool hash_rehash PARAMS ((Hash_table *, unsigned int));
+void *hash_insert PARAMS ((Hash_table *, const void *, bool *));
+void *hash_delete PARAMS ((Hash_table *, const void *));