/* hash - hashing table processing.
- Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+
+ Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Free Software
+ Foundation, Inc.
+
Written by Jim Meyering, 1992.
This program is free software; you can redistribute it and/or modify
#if HAVE_CONFIG_H
# include <config.h>
#endif
-#if HAVE_STDLIB_H
-# include <stdlib.h>
-#endif
-#if HAVE_STDBOOL_H
-# include <stdbool.h>
-#else
-typedef enum {false = 0, true = 1} bool;
-#endif
-#include <stdio.h>
-#include <assert.h>
-
-#ifndef HAVE_DECL_FREE
-"this configure-time declaration test was not run"
-#endif
-#if !HAVE_DECL_FREE
-void free ();
-#endif
-#ifndef HAVE_DECL_MALLOC
-"this configure-time declaration test was not run"
-#endif
-#if !HAVE_DECL_MALLOC
-char *malloc ();
-#endif
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
#if USE_OBSTACK
# include "obstack.h"
#include "hash.h"
+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 n_buckets;
+ unsigned n_buckets_used;
+ unsigned n_entries;
+
+ /* Tuning arguments, kept in a physicaly separate structure. */
+ const Hash_tuning *tuning;
+
+ /* 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;
+
+ /* A linked list of freed struct hash_entry structs. */
+ struct hash_entry *free_entry_list;
+
+#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
+ };
+
/* A hash table contains many internal entries, each holding a pointer to
some user provided data (also called a user entry). An entry indistinctly
refers to both the internal entry and its associated user entry. A user
DEFAULT_SHRINK_FACTOR,
DEFAULT_GROWTH_THRESHOLD,
DEFAULT_GROWTH_FACTOR,
- 0
+ false
};
/* Information and lookup. */
= table->bucket + table->hasher (entry, table->n_buckets);
struct hash_entry *cursor;
- assert (bucket < table->bucket_limit);
+ if (! (bucket < table->bucket_limit))
+ abort ();
if (bucket->data == NULL)
return NULL;
if (table->n_entries == 0)
return NULL;
- for (bucket = table->bucket; bucket < table->bucket_limit; bucket++)
- if (bucket->data)
+ for (bucket = table->bucket; ; bucket++)
+ if (! (bucket < table->bucket_limit))
+ abort ();
+ else if (bucket->data)
return bucket->data;
-
- assert (0);
- return NULL;
}
/* Return the user data for the entry following ENTRY, where ENTRY has been
= table->bucket + table->hasher (entry, table->n_buckets);
struct hash_entry *cursor;
- assert (bucket < table->bucket_limit);
+ if (! (bucket < table->bucket_limit))
+ abort ();
/* Find next entry in the same bucket. */
for (cursor = bucket; cursor; cursor = cursor->next)
unsigned
hash_string (const char *string, unsigned n_buckets)
{
-# ifndef CHAR_BIT
-# define CHAR_BIT 8
-# endif
# define ROTATE_LEFT(Value, Shift) \
((Value) << (Shift) | (Value) >> ((sizeof (unsigned) * CHAR_BIT) - (Shift)))
# define HASH_ONE_CHAR(Value, Byte) \
hash_clear (Hash_table *table)
{
struct hash_entry *bucket;
- struct hash_entry *cursor;
for (bucket = table->bucket; bucket < table->bucket_limit; bucket++)
{
if (bucket->data)
{
+ struct hash_entry *cursor;
+ struct hash_entry *next;
+
/* Free the bucket overflow. */
- for (cursor = bucket->next; cursor; cursor = cursor->next)
+ for (cursor = bucket->next; cursor; cursor = next)
{
if (table->data_freer)
(*table->data_freer) (cursor->data);
cursor->data = NULL;
+ next = cursor->next;
/* Relinking is done one entry at a time, as it is to be expected
that overflows are either rare or short. */
cursor->next = table->free_entry_list;
= table->bucket + table->hasher (entry, table->n_buckets);
struct hash_entry *cursor;
- assert (bucket < table->bucket_limit);
+ if (! (bucket < table->bucket_limit))
+ abort ();
+
*bucket_head = bucket;
/* Test for empty bucket. */
= (new_table->bucket
+ new_table->hasher (data, new_table->n_buckets));
- assert (new_bucket < new_table->bucket_limit);
+ if (! (new_bucket < new_table->bucket_limit))
+ abort ();
+
next = cursor->next;
if (new_bucket->data)
void *data;
struct hash_entry *bucket;
- assert (entry); /* cannot insert a NULL entry */
+ /* The caller cannot insert a NULL entry. */
+ if (! entry)
+ abort ();
/* If there's a matching entry already in the table, return that. */
if ((data = hash_find_entry (table, entry, &bucket, false)) != NULL)
struct hash_entry *cursor;
if (bucket)
- printf ("%d:\n", slot);
+ printf ("%d:\n", bucket - table->bucket);
for (cursor = bucket; cursor; cursor = cursor->next)
{
char *s = (char *) cursor->data;
/* FIXME */
- printf (" %s\n", s);
+ if (s)
+ printf (" %s\n", s);
}
}
}
projects / gnulib.git / blobdiff