mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-16 10:20:30 +00:00
Code Issues Releases Activity

Add new, from scratch implementation of hsearch() et al that actually works.

Browse Source 
Obtained from:	NetBSD
MFC after:	1 month
This commit is contained in:
Ruslan Ermilov 2001-05-15 07:08:20 +00:00
parent 9829d36a86
commit ec7d12549c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=76613
5 changed files with 395 additions and 113 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/libc/db/hash/Makefile.inc
View File

@ -4,4 +4,4 @@
.PATH: ${.CURDIR}/../libc/db/hash
SRCS+= hash.c hash_bigkey.c hash_buf.c hash_func.c hash_log2.c \
hash_page.c hsearch.c ndbm.c
hash_page.c ndbm.c

109
lib/libc/db/hash/hsearch.c
View File

@ -1,109 +0,0 @@
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Margo Seltzer.
*
* 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 by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)hsearch.c 8.4 (Berkeley) 7/21/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <db.h>
#include <search.h>
static DB *dbp = NULL;
static ENTRY retval;
extern int
hcreate(nel)
size_t nel;
{
HASHINFO info;
info.nelem = nel;
info.bsize = 256;
info.ffactor = 8;
info.cachesize = 0;
info.hash = NULL;
info.lorder = 0;
dbp = (DB *)__hash_open(NULL, O_CREAT | O_RDWR, 0600, &info, 0);
return (dbp != NULL);
}
extern ENTRY *
hsearch(item, action)
ENTRY item;
ACTION action;
{
DBT key, val;
int status;
if (!dbp)
return (NULL);
key.data = (u_char *)item.key;
key.size = strlen(item.key) + 1;
if (action == ENTER) {
val.data = (u_char *)item.data;
val.size = strlen(item.data) + 1;
status = (dbp->put)(dbp, &key, &val, R_NOOVERWRITE);
if (status)
return (NULL);
} else {
/* FIND */
status = (dbp->get)(dbp, &key, &val, 0);
if (status)
return (NULL);
else
item.data = (char *)val.data;
}
retval.key = item.key;
retval.data = item.data;
return (&retval);
}
extern void
hdestroy()
{
if (dbp) {
(void)(dbp->close)(dbp);
dbp = NULL;
}
}

7
lib/libc/stdlib/Makefile.inc
View File

@ -5,8 +5,8 @@
.PATH: ${.CURDIR}/../libc/${MACHINE_ARCH}/stdlib ${.CURDIR}/../libc/stdlib
MISRCS+=abort.c abs.c atexit.c atof.c atoi.c atol.c bsearch.c calloc.c div.c \
exit.c getenv.c getopt.c getsubopt.c heapsort.c labs.c ldiv.c \
malloc.c merge.c putenv.c qsort.c radixsort.c rand.c random.c \
exit.c getenv.c getopt.c getsubopt.c hcreate.c heapsort.c labs.c \
ldiv.c malloc.c merge.c putenv.c qsort.c radixsort.c rand.c random.c \
reallocf.c realpath.c setenv.c strhash.c strtol.c strtoll.c strtoq.c \
strtoul.c strtoull.c strtouq.c system.c tdelete.c tfind.c tsearch.c \
twalk.c
@ -25,11 +25,12 @@ SRCS+= strtod.c
.if ${LIB} == "c"
MAN+= abort.3 abs.3 alloca.3 atexit.3 atof.3 atoi.3 atol.3 bsearch.3 \
div.3 exit.3 getenv.3 getopt.3 getsubopt.3 labs.3 \
div.3 exit.3 getenv.3 getopt.3 getsubopt.3 hcreate.3 labs.3 \
ldiv.3 malloc.3 memory.3 qsort.3 radixsort.3 rand.3 random.3 \
realpath.3 strtod.3 strtol.3 strtoul.3 system.3 tsearch.3
MLINKS+=getenv.3 putenv.3 getenv.3 setenv.3 getenv.3 unsetenv.3
MLINKS+=hcreate.3 hdestroy.3 hcreate.3 hsearch.3
MLINKS+=qsort.3 heapsort.3 qsort.3 mergesort.3
MLINKS+=rand.3 rand_r.3 rand.3 srand.3 rand.3 sranddev.3
MLINKS+=random.3 initstate.3 random.3 setstate.3 random.3 srandom.3 \

206
lib/libc/stdlib/hcreate.3 Normal file
View File

@ -0,0 +1,206 @@
.\" $FreeBSD$
.\"
.Dd May 8, 2001
.Os
.Dt HCREATE 3
.Sh NAME
.Nm hcreate , hdestroy , hsearch
.Nd manage hash search table
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In search.h
.Ft int
.Fn hcreate "size_t nel"
.Ft void
.Fn hdestroy void
.Ft ENTRY *
.Fn hsearch "ENTRY item" "ACTION action"
.Sh DESCRIPTION
The
.Fn hcreate ,
.Fn hdestroy ,
and
.Fn hsearch
functions manage hash search tables.
.Pp
The
.Fn hcreate
function allocates sufficient space for the table, and the application should
ensure it is called before
.Fn hsearch
is used.
The
.Fa nel
argument is an estimate of the maximum
number of entries that the table should contain.
This number may be adjusted upward by the
algorithm in order to obtain certain mathematically favorable circumstances.
.Pp
The
.Fn hdestroy
function disposes of the search table, and may be followed by another call to
.Fn hcreate .
After the call to
.Fn hdestroy ,
the data can no longer be considered accessible.
.Pp
The
.Fn hsearch
function is a hash-table search routine.
It returns a pointer into a hash table
indicating the location at which an entry can be found.
The
.Fa item
argument is a structure of type
.Vt ENTRY
(defined in the
.Aq Pa search.h
header) containing two pointers:
.Fa item.key
points to the comparison key (a
.Vt "char *" ) ,
and
.Fa item.data
(a
.Vt "void *" )
points to any other data to be associated with
that key.
The comparison function used by
.Fn hsearch
is
.Xr strcmp 3 .
The
.Fa action
argument is a
member of an enumeration type
.Vt ACTION
indicating the disposition of the entry if it cannot be
found in the table.
.Dv ENTER
indicates that the
.Fa item
should be inserted in the table at an
appropriate point.
.Dv FIND
indicates that no entry should be made.
Unsuccessful resolution is
indicated by the return of a
.Dv NULL
pointer.
.Sh RETURN VALUES
The
.Fn hcreate
function returns 0 if it cannot allocate sufficient space for the table;
otherwise, it returns non-zero.
.Pp
The
.Fn hdestroy
function does not return a value.
.Pp
The
.Fn hsearch
function returns a
.Dv NULL
pointer if either the
.Fa action
is
.Dv FIND
and the
.Fa item
could not be found or the
.Fa action
is
.Dv ENTER
and the table is full.
.Sh ERRORS
The
.Fn hcreate
and
.Fn hsearch
functions may fail if:
.Bl -tag -width Er
.It Bq Er ENOMEM
Insufficient storage space is available.
.El
.Sh EXAMPLES
The following example reads in strings followed by two numbers
and stores them in a hash table, discarding duplicates.
It then reads in strings and finds the matching entry in the hash
table and prints it out.
.Bd -literal
#include <stdio.h>
#include <search.h>
#include <string.h>
struct info { /* This is the info stored in the table */
int age, room; /* other than the key. */
};
#define NUM_EMPL 5000 /* # of elements in search table. */
int
main(void)
{
char string_space[NUM_EMPL*20]; /* Space to store strings. */
struct info info_space[NUM_EMPL]; /* Space to store employee info. */
char *str_ptr = string_space; /* Next space in string_space. */
struct info *info_ptr = info_space; /* Next space in info_space. */
ENTRY item;
ENTRY *found_item; /* Name to look for in table. */
char name_to_find[30];
int i = 0;
/* Create table; no error checking is performed. */
(void) hcreate(NUM_EMPL);
while (scanf("%s%d%d", str_ptr, &info_ptr->age,
&info_ptr->room) != EOF && i++ < NUM_EMPL) {
/* Put information in structure, and structure in item. */
item.key = str_ptr;
item.data = info_ptr;
str_ptr += strlen(str_ptr) + 1;
info_ptr++;
/* Put item into table. */
(void) hsearch(item, ENTER);
}
/* Access table. */
item.key = name_to_find;
while (scanf("%s", item.key) != EOF) {
if ((found_item = hsearch(item, FIND)) != NULL) {
/* If item is in the table. */
(void)printf("found %s, age = %d, room = %d\n",
found_item->key,
((struct info *)found_item->data)->age,
((struct info *)found_item->data)->room);
} else
(void)printf("no such employee %s\n", name_to_find);
}
return 0;
}
.Ed
.Sh SEE ALSO
.Xr bsearch 3 ,
.Xr lsearch 3 ,
.Xr malloc 3 ,
.Xr strcmp 3 ,
.Xr tsearch 3
.Sh STANDARDS
The
.Fn hcreate ,
.Fn hdestroy ,
and
.Fn hsearch
functions conform to
.St -xpg4.2 .
.Sh HISTORY
The
.Fn hcreate ,
.Fn hdestroy ,
and
.Fn hsearch
functions first appeared in
.At V .
.Sh BUGS
The interface permits the use of only one hash table at a time.

184
lib/libc/stdlib/hcreate.c Normal file
View File

@ -0,0 +1,184 @@
/* $NetBSD: hcreate.c,v 1.2 2001/02/19 21:26:04 ross Exp $ */
/* $FreeBSD$ */
/*
* 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 1.2 2001/02/19 21:26:04 ross Exp $");
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/queue.h>
#include <errno.h>
#include <search.h>
#include <stdlib.h>
#include <string.h>
#include "namespace.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. */
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;
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;
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;
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;
}