glibc/locale/programs/simple-hash.c
Ulrich Drepper 77e1d15a1a Update.
2000-03-28  Ulrich Drepper  <drepper@redhat.com>

	* iconvdata/TESTS: Use UCS-2BE instead of UCS2.

	* iconv/loop.c: Define get16, get32, put16, and put32 macros to
	allow as well reading from/writing to unaligned addresses on machines
	which don't support this in hardware.  Use FCTNAME macro to define
	function name.  Include the file a second time for platforms which
	need special unaligned handling.
	* iconv/skeleton.c: Define get16u, get32u, put16u, and put32u macros
	to access potentially unaligned addresses.  These macros are intended
	to be used only outside the loops.
	(unaligned): New definition.  In case the machine can handle unaligned
	access define as zero.  Otherwise as a variable which is initialized
	as nonzero in case the buffer passed in at runtime is unaligned with
	respect to the character set encoding involved.
	Call aligned or unaligned looop functions according to unaligned
	variable.
	* iconvdata/8bit-gap.c: Use get16, get32, put16, and put32 instead
	of direct casting pointer to potentially handle unaligned memory
	accesses.
	* iconvdata/8bit-generic.c: Likewise.
	* iconvdata/ansi_x3.110.c: Likewise.
	* iconvdata/big5.c: Likewise.
	* iconvdata/euc-cn.c: Likewise.
	* iconvdata/euc-jp.c: Likewise.
	* iconvdata/euc-kr.c: Likewise.
	* iconvdata/euc-tw.c: Likewise.
	* iconvdata/gbk.c: Likewise.
	* iconvdata/iso-2022-cn.c: Likewise.
	* iconvdata/iso-2022-jp.c: Likewise.
	* iconvdata/iso-2022-kr.c: Likewise.
	* iconvdata/iso646.c: Likewise.
	* iconvdata/iso_6937-2.c: Likewise.
	* iconvdata/iso_6937.c: Likewise.
	* iconvdata/johab.c: Likewise.
	* iconvdata/sjis.c: Likewise.
	* iconvdata/t.61.c: Likewise.
	* iconvdata/uhc.c: Likewise.
	* iconvdata/unicode.c: Likewise.
	* iconvdata/utf-16.c: Likewise.

	* locale/programs/simple-hash.c: Little optimizations.  Remove K&R
	prototypes.

	* malloc/Versions [libc] (GLIBC_2.2): Add mcheck_check_all.
	* malloc/mcheck.c (mcheck_check_all): Renamed from check_all and made
	public.
	* malloc/mcheck.h (mcheck_check_all): Declare.

	* stdio-common/Makefile (tests): Add tst-obprintf.
2000-03-28 17:33:37 +00:00

400 lines
8.9 KiB
C

/* Implement simple hashing table with string based keys.
Copyright (C) 1994, 1995, 1996, 1997, 2000 Free Software Foundation, Inc.
Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, October 1994.
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., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#if HAVE_OBSTACK
# include <obstack.h>
#else
# include "obstack.h"
#endif
#ifdef HAVE_VALUES_H
# include <values.h>
#endif
#include "simple-hash.h"
#define obstack_chunk_alloc malloc
#define obstack_chunk_free free
#ifndef BITSPERBYTE
# define BITSPERBYTE 8
#endif
#ifndef LONGBITS
# define LONGBITS (sizeof (long) * BITSPERBYTE)
#endif
#ifndef bcopy
# define bcopy(s, d, n) memcpy ((d), (s), (n))
#endif
extern void *xmalloc (size_t __n);
extern void *xcalloc (size_t __n, size_t __m);
typedef struct hash_entry
{
unsigned long used;
const void *key;
size_t keylen;
void *data;
struct hash_entry *next;
}
hash_entry;
/* Prototypes for local functions. */
static void insert_entry_2 (hash_table *htab, const void *key, size_t keylen,
unsigned long hval, size_t idx, void *data);
static size_t lookup (hash_table *htab, const void *key, size_t keylen,
unsigned long int hval);
static size_t lookup_2 (hash_table *htab, const void *key, size_t keylen,
unsigned long int hval);
static unsigned long compute_hashval (const void *key, size_t keylen);
static int is_prime (unsigned long int candidate);
int
init_hash (htab, init_size)
hash_table *htab;
unsigned long int 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 = (void *) xcalloc (init_size + 1, sizeof (hash_entry));
if (htab->table == NULL)
return -1;
obstack_init (&htab->mem_pool);
return 0;
}
int
delete_hash (htab)
hash_table *htab;
{
free (htab->table);
obstack_free (&htab->mem_pool, NULL);
return 0;
}
int
insert_entry (htab, key, keylen, data)
hash_table *htab;
const void *key;
size_t keylen;
void *data;
{
unsigned long int 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
{
/* An empty bucket has been found. */
insert_entry_2 (htab, obstack_copy (&htab->mem_pool, key, keylen),
keylen, hval, idx, data);
return 0;
}
}
static void
insert_entry_2 (htab, key, keylen, hval, idx, data)
hash_table *htab;
const void *key;
size_t keylen;
unsigned long int hval;
size_t idx;
void *data;
{
hash_entry *table = (hash_entry *) htab->table;
table[idx].used = hval;
table[idx].key = key;
table[idx].keylen = keylen;
table[idx].data = data;
/* List the new value in the list. */
if ((hash_entry *) htab->first == NULL)
{
table[idx].next = &table[idx];
*(hash_entry **) &htab->first = &table[idx];
}
else
{
table[idx].next = ((hash_entry *) htab->first)->next;
((hash_entry *) htab->first)->next = &table[idx];
*(hash_entry **) &htab->first = &table[idx];
}
++htab->filled;
if (100 * htab->filled > 90 * htab->size)
{
/* Table is filled more than 90%. Resize the table. */
unsigned long int old_size = htab->size;
htab->size = next_prime (htab->size * 2);
htab->filled = 0;
htab->first = NULL;
htab->table = (void *) xcalloc (1 + htab->size, sizeof (hash_entry));
for (idx = 1; idx <= old_size; ++idx)
if (table[idx].used)
insert_entry_2 (htab, table[idx].key, table[idx].keylen,
table[idx].used,
lookup_2 (htab, table[idx].key, table[idx].keylen,
table[idx].used),
table[idx].data);
free (table);
}
}
int
find_entry (htab, key, keylen, result)
hash_table *htab;
const void *key;
size_t keylen;
void **result;
{
hash_entry *table = (hash_entry *) htab->table;
size_t idx = lookup (htab, key, keylen, compute_hashval (key, keylen));
if (table[idx].used == 0)
return -1;
*result = table[idx].data;
return 0;
}
int
set_entry (htab, key, keylen, newval)
hash_table *htab;
const void *key;
size_t keylen;
void *newval;
{
hash_entry *table = (hash_entry *) htab->table;
size_t idx = lookup (htab, key, keylen, compute_hashval (key, keylen));
if (table[idx].used == 0)
return -1;
table[idx].data = newval;
return 0;
}
int
iterate_table (htab, ptr, key, keylen, data)
hash_table *htab;
void **ptr;
const void **key;
size_t *keylen;
void **data;
{
if (*ptr == NULL)
{
if (htab->first == NULL)
return -1;
*ptr = (void *) ((hash_entry *) htab->first)->next;
}
else
{
if (*ptr == htab->first)
return -1;
*ptr = (void *) (((hash_entry *) *ptr)->next);
}
*key = ((hash_entry *) *ptr)->key;
*keylen = ((hash_entry *) *ptr)->keylen;
*data = ((hash_entry *) *ptr)->data;
return 0;
}
static size_t
lookup (htab, key, keylen, hval)
hash_table *htab;
const void *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].keylen == keylen
&& memcmp (key, table[idx].key, keylen) == 0)
return idx;
/* Second hash function as suggested in [Knuth]. */
hash = 1 + hval % (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].keylen == keylen
&& memcmp (key, table[idx].key, keylen) == 0)
return idx;
}
while (table[idx].used);
}
return idx;
}
/* References:
[Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
[Knuth] The Art of Computer Programming, part3 (6.4) */
static size_t
lookup_2 (htab, key, keylen, hval)
hash_table *htab;
const void *key;
size_t keylen;
unsigned long int hval;
{
unsigned long int 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].keylen == keylen
&& memcmp (table[idx].key, key, keylen) == 0)
return idx;
/* Second hash function as suggested in [Knuth]. */
hash = 1 + hval % (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].keylen == keylen
&& memcmp (table[idx].key, key, keylen) == 0)
return idx;
}
while (table[idx].used);
}
return idx;
}
static unsigned long
compute_hashval (key, keylen)
const void *key;
size_t keylen;
{
size_t cnt;
unsigned long int hval, g;
/* Compute the hash value for the given string. The algorithm
is taken from [Aho,Sethi,Ullman]. */
cnt = 0;
hval = keylen;
while (cnt < keylen)
{
hval <<= 4;
hval += (unsigned long int) *(((char *) key) + cnt++);
g = hval & ((unsigned long) 0xf << (LONGBITS - 4));
if (g != 0)
{
hval ^= g >> (LONGBITS - 8);
hval ^= g;
}
}
return hval != 0 ? hval : ~((unsigned long) 0);
}
unsigned long
next_prime (seed)
unsigned long int seed;
{
/* Make it definitely odd. */
seed |= 1;
while (!is_prime (seed))
seed += 2;
return seed;
}
static int
is_prime (candidate)
unsigned long int candidate;
{
/* No even number and none less than 10 will be passed here. */
unsigned long int divn = 3;
unsigned long int sq = divn * divn;
while (sq < candidate && candidate % divn != 0)
{
++divn;
sq += 4 * divn;
++divn;
}
return candidate % divn != 0;
}