[src/netbsd-1-5]: src/lib/libc/stdlib Pull up revisions 1.1-1.3 (new, request...

[he <he%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2af97fd5d65b
branches:  netbsd-1-5
changeset: 490864:2af97fd5d65b
user:      he <he%NetBSD.org@localhost>
date:      Tue Mar 13 21:19:36 2001 +0000

description:
Pull up revisions 1.1-1.3 (new, requested by cgd):
  Replace hcreate() / hsearch() / hdestroy() implementation with
  one that actually works as it's supposed to.

diffstat:

 lib/libc/stdlib/hcreate.c |  196 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 196 insertions(+), 0 deletions(-)

diffs (200 lines):

diff -r 0ae262bf5d6e -r 2af97fd5d65b lib/libc/stdlib/hcreate.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/stdlib/hcreate.c Tue Mar 13 21:19:36 2001 +0000
@@ -0,0 +1,196 @@
+/* $NetBSD: hcreate.c,v 1.3.4.2 2001/03/13 21:19:36 he Exp $ */
+
+/*
+ * Copyright (c) 2001 Christopher G. Demetriou
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *          This product includes software developed for the
+ *          NetBSD Project.  See http://www.netbsd.org/ for
+ *          information about NetBSD.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
+ */
+
+/*
+ * hcreate() / hsearch() / hdestroy()
+ *
+ * SysV/XPG4 hash table functions.
+ *
+ * Implementation done based on NetBSD manual page and Solaris manual page,
+ * plus my own personal experience about how they're supposed to work.
+ *
+ * I tried to look at Knuth (as cited by the Solaris manual page), but
+ * nobody had a copy in the office, so...
+ */
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: hcreate.c,v 1.3.4.2 2001/03/13 21:19:36 he Exp $");
+#endif /* LIBC_SCCS and not lint */
+
+#if !defined(lint)
+__COPYRIGHT(
+"@(#) Copyright (c) 2001 Christopher G. Demetriou.  All rights reserved.\n");
+#endif /* not lint */
+
+#include "namespace.h"
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <search.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/queue.h>
+
+/*
+ * DO NOT MAKE THIS STRUCTURE LARGER THAN 32 BYTES (4 ptrs on 64-bit
+ * ptr machine) without adjusting MAX_BUCKETS_LG2 below.
+ */
+struct internal_entry {
+       SLIST_ENTRY(internal_entry) link;
+       ENTRY ent;
+};
+SLIST_HEAD(internal_head, internal_entry);
+
+#define        MIN_BUCKETS_LG2 4
+#define        MIN_BUCKETS     (1 << MIN_BUCKETS_LG2)
+
+/*
+ * max * sizeof internal_entry must fit into size_t.
+ * assumes internal_entry is <= 32 (2^5) bytes.
+ */
+#define        MAX_BUCKETS_LG2 (sizeof (size_t) * 8 - 1 - 5)
+#define        MAX_BUCKETS     ((size_t)1 << MAX_BUCKETS_LG2)
+
+/* Default hash function, from db/hash/hash_func.c */
+extern u_int32_t (*__default_hash)(const void *, size_t);
+
+static struct internal_head *htable;
+static size_t htablesize;
+
+int
+hcreate(size_t nel)
+{
+       size_t idx;
+       unsigned int p2;
+
+       /* Make sure this this isn't called when a table already exists. */
+       _DIAGASSERT(htable == NULL);
+       if (htable != NULL) {
+               errno = EINVAL;
+               return 0;
+       }
+
+       /* If nel is too small, make it min sized. */
+       if (nel < MIN_BUCKETS)
+               nel = MIN_BUCKETS;
+
+       /* If it's too large, cap it. */
+       if (nel > MAX_BUCKETS)
+               nel = MAX_BUCKETS;
+
+       /* If it's is not a power of two in size, round up. */
+       if ((nel & (nel - 1)) != 0) {
+               for (p2 = 0; nel != 0; p2++)
+                       nel >>= 1;
+               _DIAGASSERT(p2 <= MAX_BUCKETS_LG2);
+               nel = 1 << p2;
+       }
+       
+       /* Allocate the table. */
+       htablesize = nel;
+       htable = malloc(htablesize * sizeof htable[0]);
+       if (htable == NULL) {
+               errno = ENOMEM;
+               return 0;
+       }
+
+       /* Initialize it. */
+       for (idx = 0; idx < htablesize; idx++)
+               SLIST_INIT(&htable[idx]);
+
+       return 1;
+}
+
+void
+hdestroy(void)
+{
+       struct internal_entry *ie;
+       size_t idx;
+
+       _DIAGASSERT(htable != NULL);
+       if (htable == NULL)
+               return;
+
+       for (idx = 0; idx < htablesize; idx++) {
+               while (!SLIST_EMPTY(&htable[idx])) {
+                       ie = SLIST_FIRST(&htable[idx]);
+                       SLIST_REMOVE_HEAD(&htable[idx], link);
+                       free(ie->ent.key);
+                       free(ie);
+               }
+       }
+       free(htable);
+       htable = NULL;
+}
+
+ENTRY *
+hsearch(ENTRY item, ACTION action)
+{
+       struct internal_head *head;
+       struct internal_entry *ie;
+       uint32_t hashval;
+       size_t len;
+
+       _DIAGASSERT(htable != NULL);
+       _DIAGASSERT(item.key != NULL);
+       _DIAGASSERT(action == ENTER || action == FIND);
+
+       len = strlen(item.key);
+       hashval = (*__default_hash)(item.key, len);
+
+       head = &htable[hashval & (htablesize - 1)];
+       ie = SLIST_FIRST(head);
+       while (ie != NULL) {
+               if (strcmp(ie->ent.key, item.key) == 0)
+                       break;
+               ie = SLIST_NEXT(ie, link);
+       }
+
+       if (ie != NULL)
+               return &ie->ent;
+       else if (action == FIND)
+               return NULL;
+
+       ie = malloc(sizeof *ie);
+       if (ie == NULL)
+               return NULL;
+       ie->ent.key = item.key;
+       ie->ent.data = item.data;
+
+       SLIST_INSERT_HEAD(head, ie, link);
+       return &ie->ent;
+}