--- /dev/null
+/* Hash tables.
+ Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of XEmacs.
+
+XEmacs 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.
+
+XEmacs 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 XEmacs; see the file COPYING. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+/* Synched up with: Not in FSF. */
+
+#include <config.h>
+#include "lisp.h"
+#include "hash.h"
+
+#define NULL_ENTRY ((void *) 0xdeadbeef)
+
+#define COMFORTABLE_SIZE(size) (21 * (size) / 16)
+
+#define KEYS_DIFFER_P(old, new, testfun) \
+ (((old) != (new)) && (!(testfun) || !(testfun) ((old),(new))))
+
+static void rehash (hentry *harray, struct hash_table *ht, hash_size_t size);
+
+unsigned long
+memory_hash (const void *xv, size_t size)
+{
+ unsigned int h = 0;
+ unsigned const char *x = (unsigned const char *) xv;
+
+ if (!x) return 0;
+
+ while (size--)
+ {
+ unsigned int g;
+ h = (h << 4) + *x++;
+ if ((g = h & 0xf0000000) != 0)
+ h = (h ^ (g >> 24)) ^ g;
+ }
+
+ return h;
+}
+
+unsigned long
+string_hash (const char *xv)
+{
+ unsigned int h = 0;
+ unsigned const char *x = (unsigned const char *) xv;
+
+ if (!x) return 0;
+
+ while (*x)
+ {
+ unsigned int g;
+ h = (h << 4) + *x++;
+ if ((g = h & 0xf0000000) != 0)
+ h = (h ^ (g >> 24)) ^ g;
+ }
+
+ return h;
+}
+
+/* Return a suitable size for a hash table, with at least SIZE slots. */
+static size_t
+hash_table_size (size_t requested_size)
+{
+ /* Return some prime near, but greater than or equal to, SIZE.
+ Decades from the time of writing, someone will have a system large
+ enough that the list below will be too short... */
+ static const size_t primes [] =
+ {
+ 19, 29, 41, 59, 79, 107, 149, 197, 263, 347, 457, 599, 787, 1031,
+ 1361, 1777, 2333, 3037, 3967, 5167, 6719, 8737, 11369, 14783,
+ 19219, 24989, 32491, 42257, 54941, 71429, 92861, 120721, 156941,
+ 204047, 265271, 344857, 448321, 582821, 757693, 985003, 1280519,
+ 1664681, 2164111, 2813353, 3657361, 4754591, 6180989, 8035301,
+ 10445899, 13579681, 17653589, 22949669, 29834603, 38784989,
+ 50420551, 65546729, 85210757, 110774011, 144006217, 187208107,
+ 243370577, 316381771, 411296309, 534685237, 695090819, 903618083,
+ 1174703521, 1527114613, 1985248999, 2580823717UL, 3355070839UL
+ };
+ /* We've heard of binary search. */
+ int low, high;
+ for (low = 0, high = countof (primes) - 1; high - low > 1;)
+ {
+ /* Loop Invariant: size < primes [high] */
+ int mid = (low + high) / 2;
+ if (primes [mid] < requested_size)
+ low = mid;
+ else
+ high = mid;
+ }
+ return primes [high];
+}
+
+const void *
+gethash (const void *key, struct hash_table *hash_table, const void **ret_value)
+{
+ if (!key)
+ {
+ *ret_value = hash_table->zero_entry;
+ return (void *) hash_table->zero_set;
+ }
+ else
+ {
+ hentry *harray = hash_table->harray;
+ hash_table_test_function test_function = hash_table->test_function;
+ hash_size_t size = hash_table->size;
+ unsigned int hcode_initial =
+ hash_table->hash_function ?
+ hash_table->hash_function (key) :
+ (unsigned long) key;
+ unsigned int hcode = hcode_initial % size;
+ hentry *e = &harray [hcode];
+ const void *e_key = e->key;
+
+ if (e_key ?
+ KEYS_DIFFER_P (e_key, key, test_function) :
+ e->contents == NULL_ENTRY)
+ {
+ size_t h2 = size - 2;
+ unsigned int incr = 1 + (hcode_initial % h2);
+ do
+ {
+ hcode += incr; if (hcode >= size) hcode -= size;
+ e = &harray [hcode];
+ e_key = e->key;
+ }
+ while (e_key ?
+ KEYS_DIFFER_P (e_key, key, test_function) :
+ e->contents == NULL_ENTRY);
+ }
+
+ *ret_value = e->contents;
+ return e->key;
+ }
+}
+
+void
+clrhash (struct hash_table *hash_table)
+{
+ memset (hash_table->harray, 0, sizeof (hentry) * hash_table->size);
+ hash_table->zero_entry = 0;
+ hash_table->zero_set = 0;
+ hash_table->fullness = 0;
+}
+
+void
+free_hash_table (struct hash_table *hash_table)
+{
+ xfree (hash_table->harray);
+ xfree (hash_table);
+}
+
+struct hash_table*
+make_hash_table (hash_size_t size)
+{
+ struct hash_table *hash_table = xnew_and_zero (struct hash_table);
+ hash_table->size = hash_table_size (COMFORTABLE_SIZE (size));
+ hash_table->harray = xnew_array (hentry, hash_table->size);
+ clrhash (hash_table);
+ return hash_table;
+}
+
+struct hash_table *
+make_general_hash_table (hash_size_t size,
+ hash_table_hash_function hash_function,
+ hash_table_test_function test_function)
+{
+ struct hash_table* hash_table = make_hash_table (size);
+ hash_table->hash_function = hash_function;
+ hash_table->test_function = test_function;
+ return hash_table;
+}
+
+static void
+grow_hash_table (struct hash_table *hash_table, hash_size_t new_size)
+{
+ hash_size_t old_size = hash_table->size;
+ hentry *old_harray = hash_table->harray;
+
+ hash_table->size = hash_table_size (new_size);
+ hash_table->harray = xnew_array (hentry, hash_table->size);
+
+ /* do the rehash on the "grown" table */
+ {
+ long old_zero_set = hash_table->zero_set;
+ void *old_zero_entry = hash_table->zero_entry;
+ clrhash (hash_table);
+ hash_table->zero_set = old_zero_set;
+ hash_table->zero_entry = old_zero_entry;
+ rehash (old_harray, hash_table, old_size);
+ }
+
+ xfree (old_harray);
+}
+
+void
+puthash (const void *key, void *contents, struct hash_table *hash_table)
+{
+ if (!key)
+ {
+ hash_table->zero_entry = contents;
+ hash_table->zero_set = 1;
+ }
+ else
+ {
+ hash_table_test_function test_function = hash_table->test_function;
+ hash_size_t size = hash_table->size;
+ hentry *harray = hash_table->harray;
+ unsigned int hcode_initial =
+ hash_table->hash_function ?
+ hash_table->hash_function (key) :
+ (unsigned long) key;
+ unsigned int hcode = hcode_initial % size;
+ size_t h2 = size - 2;
+ unsigned int incr = 1 + (hcode_initial % h2);
+ const void *e_key = harray [hcode].key;
+ const void *oldcontents;
+
+ if (e_key && KEYS_DIFFER_P (e_key, key, test_function))
+ {
+ do
+ {
+ hcode += incr; if (hcode >= size) hcode -= size;
+ e_key = harray [hcode].key;
+ }
+ while (e_key && KEYS_DIFFER_P (e_key, key, test_function));
+ }
+ oldcontents = harray [hcode].contents;
+ harray [hcode].key = key;
+ harray [hcode].contents = contents;
+ /* If the entry that we used was a deleted entry,
+ check for a non deleted entry of the same key,
+ then delete it. */
+ if (!e_key && oldcontents == NULL_ENTRY)
+ {
+ hentry *e;
+
+ do
+ {
+ hcode += incr; if (hcode >= size) hcode -= size;
+ e = &harray [hcode];
+ e_key = e->key;
+ }
+ while (e_key ?
+ KEYS_DIFFER_P (e_key, key, test_function):
+ e->contents == NULL_ENTRY);
+
+ if (e_key)
+ {
+ e->key = 0;
+ e->contents = NULL_ENTRY;
+ }
+ }
+
+ /* only increment the fullness when we used up a new hentry */
+ if (!e_key || KEYS_DIFFER_P (e_key, key, test_function))
+ {
+ hash_size_t comfortable_size = COMFORTABLE_SIZE (++(hash_table->fullness));
+ if (hash_table->size < comfortable_size)
+ grow_hash_table (hash_table, comfortable_size + 1);
+ }
+ }
+}
+
+static void
+rehash (hentry *harray, struct hash_table *hash_table, hash_size_t size)
+{
+ hentry *limit = harray + size;
+ hentry *e;
+ for (e = harray; e < limit; e++)
+ {
+ if (e->key)
+ puthash (e->key, e->contents, hash_table);
+ }
+}
+
+void
+remhash (const void *key, struct hash_table *hash_table)
+{
+ if (!key)
+ {
+ hash_table->zero_entry = 0;
+ hash_table->zero_set = 0;
+ }
+ else
+ {
+ hentry *harray = hash_table->harray;
+ hash_table_test_function test_function = hash_table->test_function;
+ hash_size_t size = hash_table->size;
+ unsigned int hcode_initial =
+ (hash_table->hash_function) ?
+ (hash_table->hash_function (key)) :
+ ((unsigned long) key);
+ unsigned int hcode = hcode_initial % size;
+ hentry *e = &harray [hcode];
+ const void *e_key = e->key;
+
+ if (e_key ?
+ KEYS_DIFFER_P (e_key, key, test_function) :
+ e->contents == NULL_ENTRY)
+ {
+ size_t h2 = size - 2;
+ unsigned int incr = 1 + (hcode_initial % h2);
+ do
+ {
+ hcode += incr; if (hcode >= size) hcode -= size;
+ e = &harray [hcode];
+ e_key = e->key;
+ }
+ while (e_key?
+ KEYS_DIFFER_P (e_key, key, test_function):
+ e->contents == NULL_ENTRY);
+ }
+ if (e_key)
+ {
+ e->key = 0;
+ e->contents = NULL_ENTRY;
+ /* Note: you can't do fullness-- here, it breaks the world. */
+ }
+ }
+}
+
+void
+maphash (maphash_function mf, struct hash_table *hash_table, void *arg)
+{
+ hentry *e;
+ hentry *limit;
+
+ if (hash_table->zero_set)
+ {
+ if (mf (0, hash_table->zero_entry, arg))
+ return;
+ }
+
+ for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
+ {
+ if (e->key && mf (e->key, e->contents, arg))
+ return;
+ }
+}
+
+void
+map_remhash (remhash_predicate predicate, struct hash_table *hash_table, void *arg)
+{
+ hentry *e;
+ hentry *limit;
+
+ if (hash_table->zero_set && predicate (0, hash_table->zero_entry, arg))
+ {
+ hash_table->zero_set = 0;
+ hash_table->zero_entry = 0;
+ }
+
+ for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
+ if (predicate (e->key, e->contents, arg))
+ {
+ e->key = 0;
+ e->contents = NULL_ENTRY;
+ }
+}
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