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authorRoland McGrath <roland@gnu.org>1995-05-18 09:00:09 +0000
committerRoland McGrath <roland@gnu.org>1995-05-18 09:00:09 +0000
commit2b83a2a4d978012cdf78b648337c31091e20526d (patch)
tree6a5130b031f6815b6edbbb6e2b084c79ece15b1d /locale/hash.c
parent4f6dc78a9237bb327a1d694635be9b0f50cc395e (diff)
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Wed May 17 16:50:21 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
Merged 1003.2 locale and localedef programs by Ulrich Drepper. * locale/charmap.c: New file. * locale/collate.c: New file. * locale/config.h: New file. * locale/ctype.c: New file. * locale/ctypedump.c: New file. * locale/hash.c: New file. * locale/hash.h: New file. * locale/iso-4217.def: New file. * locale/keyword.gperf: New file. * locale/keyword.h: New file. * locale/libintl.h: New file. * locale/locale.c: New file. * locale/localedef.c: New file. * locale/localedef.h: New file. * locale/locfile-lex.c: New file. * locale/locfile-parse.c: New file. * locale/messages.c: New file. * locale/monetary.c: New file. * locale/numeric.c: New file. * locale/token.h: New file. * posix/regex.c, posix/regex.h: New files, incorporated from GNU regex. * posix/Makefile (headers): Add regex.h. (routines): Add regex. (gpl2lgpl): Add regex.c and regex.h. Tue May 16 17:35:07 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu> * locale/loadlocale.c: Expect macro LOCALE_PATH to be defined, instead of hard-coding "/share/locale".
Diffstat (limited to 'locale/hash.c')
-rw-r--r--locale/hash.c254
1 files changed, 254 insertions, 0 deletions
diff --git a/locale/hash.c b/locale/hash.c
new file mode 100644
index 0000000000..75cb77f882
--- /dev/null
+++ b/locale/hash.c
@@ -0,0 +1,254 @@
+/* Copyright (C) 1995 Free Software Foundation, Inc.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <obstack.h>
+#include <stdlib.h>
+#include <string.h>
+#include <values.h>
+
+#include "hash.h"
+
+#define obstack_chunk_alloc xmalloc
+#define obstack_chunk_free free
+
+void *xmalloc (size_t n);
+
+typedef struct hash_entry
+ {
+ int used;
+ char *key;
+ void *data;
+ struct hash_entry *next;
+ }
+hash_entry;
+
+/* Prototypes for local functions. */
+static size_t lookup (hash_table *htab, const char *key, size_t keylen,
+ unsigned long hval);
+static unsigned long compute_hashval(const char *key, size_t keylen);
+static unsigned long next_prime(unsigned long seed);
+static int is_prime(unsigned long candidate);
+
+
+int
+init_hash(hash_table *htab, unsigned long init_size)
+{
+ /* We need the size to be a prime. */
+ init_size = next_prime (init_size);
+
+ /* Initialize the data structure. */
+ htab->size = init_size;
+ htab->filled = 0;
+ htab->first = NULL;
+ htab->table = calloc (init_size + 1, sizeof (hash_entry));
+ obstack_init (&htab->mem_pool);
+
+ return htab->table == NULL;
+}
+
+
+int
+delete_hash(hash_table *htab)
+{
+ free (htab->table);
+ obstack_free (&htab->mem_pool, NULL);
+ return 0;
+}
+
+
+int
+insert_entry (hash_table *htab, const char *key, size_t keylen, void *data)
+{
+ unsigned long hval = compute_hashval (key, keylen);
+ hash_entry *table = (hash_entry *) htab->table;
+ size_t idx = lookup (htab, key, keylen, hval);
+
+ if (table[idx].used)
+ /* We don't want to overwrite the old value. */
+ return 1;
+ else
+ {
+ hash_entry **p;
+
+ /* An empty bucket has been found. */
+ table[idx].used = hval;
+ table[idx].key = obstack_copy0 (&htab->mem_pool, key, keylen);
+ table[idx].data = data;
+
+ /* List the new value in the ordered list. */
+ for (p = (hash_entry **) &htab->first; *p != NULL && (*p)->data < data;
+ p = &(*p)->next);
+ if (*p == NULL || (*p)->data > data)
+ /* Insert new value in the list. */
+ {
+ table[idx].next = *p;
+ *p = &table[idx];
+ }
+
+ ++htab->filled;
+ if (100 * htab->filled > 90 * htab->size)
+ {
+ /* Resize the table. */
+ unsigned long old_size = htab->size;
+
+ htab->size = next_prime (htab->size * 2);
+ htab->filled = 0;
+ htab->first = NULL;
+ htab->table = calloc (htab->size, sizeof (hash_entry));
+
+ for (idx = 1; idx <= old_size; ++idx)
+ if (table[idx].used)
+ insert_entry (htab, table[idx].key, strlen(table[idx].key),
+ table[idx].data);
+
+ free (table);
+ }
+ return 0;
+ }
+ /* NOTREACHED */
+}
+
+
+int
+find_entry (hash_table *htab, const char *key, size_t keylen, void **result)
+{
+ hash_entry *table = (hash_entry *) htab->table;
+ size_t idx = lookup (htab, key, keylen, compute_hashval (key, keylen));
+ int retval;
+
+ retval = table[idx].used;
+ *result = retval ? table[idx].data : NULL;
+
+ return retval;
+}
+
+
+int
+iterate_table (hash_table *htab, void **ptr, void **result)
+{
+ if (*ptr == NULL)
+ *ptr = (void *) htab->first;
+ else
+ {
+ *ptr = (void *) (((hash_entry *) *ptr)->next);
+ if (*ptr == NULL)
+ return 0;
+ }
+
+ *result = ((hash_entry *) *ptr)->data;
+ return 1;
+}
+
+
+static size_t
+lookup (hash_table *htab, const char *key, size_t keylen, unsigned long hval)
+{
+ unsigned long hash;
+ size_t idx;
+ hash_entry *table = (hash_entry *) htab->table;
+
+ /* First hash function: simply take the modul but prevent zero. */
+ hash = 1 + hval % htab->size;
+
+ idx = hash;
+
+ if (table[idx].used)
+ {
+ if (table[idx].used == hval && table[idx].key[keylen] == '\0'
+ && strncmp (key, table[idx].key, keylen) == 0)
+ return idx;
+
+ /* Second hash function as suggested in [Knuth]. */
+ hash = 1 + hash % (htab->size - 2);
+
+ do
+ {
+ if (idx <= hash)
+ idx = htab->size + idx - hash;
+ else
+ idx -= hash;
+
+ /* If entry is found use it. */
+ if (table[idx].used == hval && table[idx].key[keylen] == '\0'
+ && strncmp (key, table[idx].key, keylen) == 0)
+ return idx;
+ }
+ while (table[idx].used);
+ }
+ return idx;
+}
+
+
+static unsigned long
+compute_hashval(const char *key, size_t keylen)
+{
+ size_t cnt;
+ unsigned long hval, g;
+ /* Compute the hash value for the given string. */
+ cnt = 0;
+ hval = keylen;
+ while (cnt < keylen)
+ {
+ hval <<= 4;
+ hval += key[cnt++];
+ g = hval & (0xf << (LONGBITS - 4));
+ if (g != 0)
+ {
+ hval ^= g >> (LONGBITS - 8);
+ hval ^= g;
+ }
+ }
+ return hval;
+}
+
+
+static unsigned long
+next_prime(unsigned long seed)
+{
+ /* Make it definitely odd. */
+ seed |= 1;
+
+ while (!is_prime (seed))
+ seed += 2;
+
+ return seed;
+}
+
+
+static int
+is_prime(unsigned long candidate)
+{
+ /* No even number and none less than 10 will be passwd here. */
+ unsigned long div = 3;
+ unsigned long sq = div * div;
+
+ while (sq < candidate && candidate % div != 0)
+ {
+ ++div;
+ sq += 4 * div;
+ ++div;
+ }
+
+ return candidate % div != 0;
+}
+
+/*
+ * Local Variables:
+ * mode:c
+ * c-basic-offset:2
+ * End:
+ */