/* Hash tables.
Copyright (C) 2000, 2001 Free Software Foundation, Inc.
-This file is part of Wget.
+This file is part of GNU Wget.
-This program is free software; you can redistribute it and/or modify
+GNU Wget 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,
+GNU Wget 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
+along with Wget; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifdef HAVE_CONFIG_H
The basics are all covered. hash_table_new creates a hash table,
and hash_table_destroy deletes it. hash_table_put establishes a
mapping between a key and a value. hash_table_get retrieves the
- value that corresponds to a key. hash_table_exists queries whether
- a key is stored in a table at all. hash_table_remove removes a
- mapping that corresponds to a key. hash_table_map allows you to
- map through all the entries in a hash table. hash_table_clear
- clears all the entries from the hash table.
+ value that corresponds to a key. hash_table_contains queries
+ whether a key is stored in a table at all. hash_table_remove
+ removes a mapping that corresponds to a key. hash_table_map allows
+ you to map through all the entries in a hash table.
+ hash_table_clear clears all the entries from the hash table.
The number of mappings in a table is not limited, except by the
amount of memory. As you add new elements to a table, it regrows
#define LOOP_NON_EMPTY(mp, mappings, size) \
for (; !EMPTY_MAPPING_P (mp); mp = NEXT_MAPPING (mp, mappings, size))
+/* #### We might want to multiply with the "golden ratio" here to get
+ better randomness for keys that do not result from a good hash
+ function. This is currently not a problem in Wget because we only
+ use the string hash tables. */
+
#define HASH_POSITION(ht, key) (ht->hash_function (key) % ht->size)
/* Find a prime near, but greather than or equal to SIZE. */
/* Get the value that corresponds to the key KEY in the hash table HT.
If no value is found, return NULL. Note that NULL is a legal value
for value; if you are storing NULLs in your hash table, you can use
- hash_table_exists to be sure that a (possibly NULL) value exists in
- the table. Or, you can use hash_table_get_pair instead of this
+ hash_table_contains to be sure that a (possibly NULL) value exists
+ in the table. Or, you can use hash_table_get_pair instead of this
function. */
void *
return 0;
}
-/* Return 1 if KEY exists in HT, 0 otherwise. */
+/* Return 1 if HT contains KEY, 0 otherwise. */
int
-hash_table_exists (struct hash_table *ht, const void *key)
+hash_table_contains (struct hash_table *ht, const void *key)
{
return find_mapping (ht, key) != NULL;
}
return ht->count;
}
\f
-/* Support for hash tables whose keys are strings. */
+/* Functions from this point onward are meant for convenience and
+ don't strictly belong to this file. However, this is as good a
+ place for them as any. */
+
+/* ========
+ Support for hash tables whose keys are strings.
+ ======== */
/* 31 bit hash function. Taken from Gnome's glib, modified to use
standard C types.
return h;
}
+/* Frontend for strcmp usable for hash tables. */
+
+int
+string_cmp (const void *s1, const void *s2)
+{
+ return !strcmp ((const char *)s1, (const char *)s2);
+}
+
+/* Return a hash table of initial size INITIAL_SIZE suitable to use
+ strings as keys. */
+
+struct hash_table *
+make_string_hash_table (int initial_size)
+{
+ return hash_table_new (initial_size, string_hash, string_cmp);
+}
+
+/* ========
+ Support for hash tables whose keys are strings, but which are
+ compared case-insensitively.
+ ======== */
+
+/* Like string_hash, but produce the same hash regardless of the case. */
+
+static unsigned long
+string_hash_nocase (const void *key)
+{
+ const char *p = key;
+ unsigned int h = TOLOWER (*p);
+
+ if (h)
+ for (p += 1; *p != '\0'; p++)
+ h = (h << 5) - h + TOLOWER (*p);
+
+ return h;
+}
+
+/* Like string_cmp, but doing case-insensitive compareison. */
+
+static int
+string_cmp_nocase (const void *s1, const void *s2)
+{
+ return !strcasecmp ((const char *)s1, (const char *)s2);
+}
+
+/* Like make_string_hash_table, but uses string_hash_nocase and
+ string_cmp_nocase. */
+
+struct hash_table *
+make_nocase_string_hash_table (int initial_size)
+{
+ return hash_table_new (initial_size, string_hash_nocase, string_cmp_nocase);
+}
+
#if 0
/* If I ever need it: hashing of integers. */
return key;
}
#endif
-
-int
-string_cmp (const void *s1, const void *s2)
-{
- return !strcmp ((const char *)s1, (const char *)s2);
-}
-
-/* Return a hash table of initial size INITIAL_SIZE suitable to use
- strings as keys. */
-
-struct hash_table *
-make_string_hash_table (int initial_size)
-{
- return hash_table_new (initial_size, string_hash, string_cmp);
-}
-
\f
#ifdef STANDALONE
if (len <= 1)
continue;
line[--len] = '\0';
- if (!hash_table_exists (ht, line))
+ if (!hash_table_contains (ht, line))
hash_table_put (ht, strdup (line), "here I am!");
#if 1
if (len % 5 == 0)
projects / wget / blobdiff