mirror of
https://git.code.sf.net/p/quake/quakeforge
synced 2024-11-06 05:01:26 +00:00
494 lines
10 KiB
C
494 lines
10 KiB
C
/*
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hash.c
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hash tables
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Copyright (C) 2000 Bill Currie <bill@taniwha.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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static __attribute__ ((used)) const char rcsid[] =
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"$Id$";
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif
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#include <math.h>
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#include <stdlib.h> // should be sys/types.h, but bc is stupid
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#include "QF/hash.h"
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#include "QF/sys.h"
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#include "compat.h"
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typedef struct hashlink_s {
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struct hashlink_s *next;
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struct hashlink_s **prev;
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void *data;
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} hashlink_t;
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struct hashtab_s {
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size_t tab_size;
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unsigned int size_bits;
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size_t num_ele;
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void *user_data;
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int (*compare)(void*,void*,void*);
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unsigned long (*get_hash)(void*,void*);
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const char *(*get_key)(void*,void*);
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void (*free_ele)(void*,void*);
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hashlink_t *tab[1]; // variable size
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};
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static hashlink_t *free_hashlinks;
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static hashlink_t *
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new_hashlink (void)
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{
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hashlink_t *link;
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if (!free_hashlinks) {
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int i;
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if (!(free_hashlinks = calloc (1024, sizeof (hashlink_t))))
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return 0;
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for (i = 0, link = free_hashlinks; i < 1023; i++, link++)
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link->next = link + 1;
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link->next = 0;
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}
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link = free_hashlinks;
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free_hashlinks = link->next;
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link->next = 0;
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return link;
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}
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static void
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free_hashlink (hashlink_t *link)
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{
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link->next = free_hashlinks;
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free_hashlinks = link;
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}
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unsigned long
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Hash_String (const char *str)
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{
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#if 0
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unsigned long h = 0;
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while (*str) {
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h = (h << 4) + (unsigned char)*str++;
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if (h&0xf0000000)
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h = (h ^ (h >> 24)) & 0xfffffff;
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}
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return h;
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#else
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// dx_hack_hash
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// shamelessly stolen from Daniel Phillips <phillips@innominate.de>
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// from his post to lkml
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unsigned long hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
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while (*str) {
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unsigned long hash = hash1 + (hash0 ^ ((unsigned char)*str++ * 71523));
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if (hash < 0) hash -= 0x7fffffff;
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hash1 = hash0;
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hash0 = hash;
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}
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return hash0;
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#endif
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}
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unsigned long
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Hash_Buffer (const void *_buf, int len)
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{
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const unsigned char *buf = _buf;
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#if 0
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unsigned long h = 0;
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while (len-- > 0) {
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h = (h << 4) + (unsigned char)*buf++;
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if (h&0xf0000000)
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h = (h ^ (h >> 24)) & 0xfffffff;
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}
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return h;
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#else
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// dx_hack_hash
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// shamelessly stolen from Daniel Phillips <phillips@innominate.de>
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// from his post to lkml
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unsigned long hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
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while (len-- > 0) {
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unsigned long hash = hash1 + (hash0 ^ ((unsigned char)*buf++ * 71523));
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if (hash < 0) hash -= 0x7fffffff;
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hash1 = hash0;
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hash0 = hash;
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}
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return hash0;
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#endif
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}
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static unsigned long
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get_hash (void *ele, void *data)
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{
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return (unsigned long)ele;
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}
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static int
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compare (void *a, void *b, void *data)
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{
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return a == b;
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}
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static inline int
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get_index (unsigned long hash, size_t size, size_t bits)
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{
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#if 0
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unsigned long mask = ~0UL << bits;
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unsigned long extract;
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size -= 1;
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for (extract = (hash & mask) >> bits;
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extract;
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extract = (hash & mask) >> bits) {
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hash &= ~mask;
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hash ^= extract;
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} while (extract);
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if (hash > size) {
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extract = hash - size;
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hash = size - (extract >> 1);
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}
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return hash;
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#else
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return hash % size;
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#endif
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}
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hashtab_t *
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Hash_NewTable (int tsize, const char *(*gk)(void*,void*),
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void (*f)(void*,void*), void *ud)
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{
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hashtab_t *tab = calloc (1, field_offset (hashtab_t, tab[tsize]));
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if (!tab)
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return 0;
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tab->tab_size = tsize;
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tab->user_data = ud;
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tab->get_key = gk;
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tab->free_ele = f;
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while (tsize) {
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tab->size_bits++;
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tsize = ((unsigned int) tsize) >> 1;
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}
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tab->get_hash = get_hash;
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tab->compare = compare;
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return tab;
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}
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void
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Hash_SetHashCompare (hashtab_t *tab, unsigned long (*gh)(void*,void*),
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int (*cmp)(void*,void*,void*))
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{
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tab->get_hash = gh;
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tab->compare = cmp;
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}
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void
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Hash_DelTable (hashtab_t *tab)
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{
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Hash_FlushTable (tab);
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free (tab);
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}
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void
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Hash_FlushTable (hashtab_t *tab)
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{
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size_t i;
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for (i = 0; i < tab->tab_size; i++) {
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while (tab->tab[i]) {
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hashlink_t *t = tab->tab[i]->next;
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void *data = tab->tab[i]->data;
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free_hashlink (tab->tab[i]);
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tab->tab[i] = t;
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if (tab->free_ele)
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tab->free_ele (data, tab->user_data);
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}
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}
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tab->num_ele = 0;
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}
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int
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Hash_Add (hashtab_t *tab, void *ele)
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{
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unsigned long h = Hash_String (tab->get_key(ele, tab->user_data));
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = new_hashlink ();
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if (!lnk)
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return -1;
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if (tab->tab[ind])
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tab->tab[ind]->prev = &lnk->next;
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lnk->next = tab->tab[ind];
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lnk->prev = &tab->tab[ind];
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lnk->data = ele;
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tab->tab[ind] = lnk;
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tab->num_ele++;
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return 0;
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}
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int
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Hash_AddElement (hashtab_t *tab, void *ele)
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{
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unsigned long h = tab->get_hash (ele, tab->user_data);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = new_hashlink ();
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if (!lnk)
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return -1;
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if (tab->tab[ind])
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tab->tab[ind]->prev = &lnk->next;
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lnk->next = tab->tab[ind];
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lnk->prev = &tab->tab[ind];
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lnk->data = ele;
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tab->tab[ind] = lnk;
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tab->num_ele++;
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return 0;
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}
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void *
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Hash_Find (hashtab_t *tab, const char *key)
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{
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unsigned long h = Hash_String (key);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind];
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while (lnk) {
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if (strequal (key, tab->get_key (lnk->data, tab->user_data)))
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return lnk->data;
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lnk = lnk->next;
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}
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return 0;
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}
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void *
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Hash_FindElement (hashtab_t *tab, void *ele)
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{
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unsigned long h = tab->get_hash (ele, tab->user_data);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind];
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while (lnk) {
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if (tab->compare (lnk->data, ele, tab->user_data))
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return lnk->data;
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lnk = lnk->next;
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}
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return 0;
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}
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void **
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Hash_FindList (hashtab_t *tab, const char *key)
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{
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unsigned long h = Hash_String (key);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind], *start = 0;
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int count = 0;
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void **list;
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while (lnk) {
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if (strequal (key, tab->get_key (lnk->data, tab->user_data))) {
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count++;
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if (!start)
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start = lnk;
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}
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lnk = lnk->next;
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}
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if (!count)
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return 0;
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list = malloc ((count + 1) * sizeof (void *));
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for (count = 0, lnk = start; lnk; lnk = lnk->next) {
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if (strequal (key, tab->get_key (lnk->data, tab->user_data)))
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list[count++] = lnk->data;
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}
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list[count] = 0;
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return list;
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}
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void **
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Hash_FindElementList (hashtab_t *tab, void *ele)
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{
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unsigned long h = tab->get_hash (ele, tab->user_data);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind], *start = 0;
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int count = 0;
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void **list;
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while (lnk) {
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if (tab->compare (lnk->data, ele, tab->user_data)) {
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count++;
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if (!start)
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start = lnk;
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}
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lnk = lnk->next;
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}
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if (!count)
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return 0;
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list = malloc ((count + 1) * sizeof (void *));
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for (count = 0, lnk = start; lnk; lnk = lnk->next) {
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if (tab->compare (lnk->data, ele, tab->user_data))
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list[count++] = lnk->data;
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}
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list[count] = 0;
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return list;
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}
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void *
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Hash_Del (hashtab_t *tab, const char *key)
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{
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unsigned long h = Hash_String (key);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind];
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void *data;
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while (lnk) {
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if (strequal (key, tab->get_key (lnk->data, tab->user_data))) {
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data = lnk->data;
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if (lnk->next)
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lnk->next->prev = lnk->prev;
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*lnk->prev = lnk->next;
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free_hashlink (lnk);
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tab->num_ele--;
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return data;
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}
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lnk = lnk->next;
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}
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return 0;
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}
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void *
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Hash_DelElement (hashtab_t *tab, void *ele)
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{
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unsigned long h = tab->get_hash (ele, tab->user_data);
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size_t ind = get_index (h, tab->tab_size, tab->size_bits);
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hashlink_t *lnk = tab->tab[ind];
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void *data;
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while (lnk) {
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if (tab->compare (lnk->data, ele, tab->user_data)) {
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data = lnk->data;
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if (lnk->next)
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lnk->next->prev = lnk->prev;
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*lnk->prev = lnk->next;
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free_hashlink (lnk);
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tab->num_ele--;
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return data;
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}
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lnk = lnk->next;
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}
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return 0;
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}
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void
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Hash_Free (hashtab_t *tab, void *ele)
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{
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if (ele && tab->free_ele)
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tab->free_ele (ele, tab->user_data);
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}
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size_t
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Hash_NumElements (hashtab_t *tab)
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{
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return tab->num_ele;
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}
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void **
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Hash_GetList (hashtab_t *tab)
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{
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void **list;
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void **l;
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size_t ind;
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l = list = malloc ((tab->num_ele + 1) * sizeof (void *));
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if (!list)
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return 0;
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for (ind = 0; ind < tab->tab_size; ind++) {
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hashlink_t *lnk;
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for (lnk = tab->tab[ind]; lnk; lnk = lnk->next) {
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*l++ = lnk->data;
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}
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}
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*l++ = 0;
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return list;
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}
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static inline double
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sqr (double x)
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{
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return x * x;
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}
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void
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Hash_Stats (hashtab_t *tab)
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{
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int *lengths = calloc (tab->tab_size, sizeof (int));
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int chains = 0;
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size_t i;
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int min_length = tab->num_ele;
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int max_length = 0;
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if (!lengths) {
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Sys_Printf ("Hash_Stats: memory alloc error\n");
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return;
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}
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for (i = 0; i < tab->tab_size; i++) {
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hashlink_t *lnk = tab->tab[i];
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while (lnk) {
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lengths[i]++;
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lnk = lnk->next;
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}
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if (lengths[i]) {
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min_length = min (min_length, lengths[i]);
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max_length = max (max_length, lengths[i]);
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chains++;
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}
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}
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Sys_Printf ("%d elements\n", (int)tab->num_ele);
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Sys_Printf ("%d / %d chains\n", chains, (int)tab->tab_size);
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if (chains) {
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double average = (double) tab->num_ele / chains;
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double variance = 0;
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Sys_Printf ("%d minium chain length\n", min_length);
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Sys_Printf ("%d maximum chain length\n", max_length);
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Sys_Printf ("%.3g average chain length\n", average);
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for (i = 0; i < tab->tab_size; i++) {
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if (lengths[i])
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variance += sqr (lengths[i] - average);
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}
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variance /= chains;
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Sys_Printf ("%.3g variance, %.3g standard deviation\n",
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variance, sqrt (variance));
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}
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}
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