322 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			322 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C
		
	
	
	
/* x-hash.c - basic hash tables
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 *
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 * Copyright (c) 2002-2012 Apple Inc. All rights reserved.
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 *
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 * Permission is hereby granted, free of charge, to any person
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 * obtaining a copy of this software and associated documentation files
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 * (the "Software"), to deal in the Software without restriction,
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 * including without limitation the rights to use, copy, modify, merge,
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 * publish, distribute, sublicense, and/or sell copies of the Software,
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 * and to permit persons to whom the Software is furnished to do so,
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 * subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be
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 * included in all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * NONINFRINGEMENT.  IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT
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 * HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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 * DEALINGS IN THE SOFTWARE.
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 *
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 * Except as contained in this notice, the name(s) of the above
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 * copyright holders shall not be used in advertising or otherwise to
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 * promote the sale, use or other dealings in this Software without
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 * prior written authorization.
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 */
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#ifdef HAVE_DIX_CONFIG_H
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#include <dix-config.h>
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#endif
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#include "x-hash.h"
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#include "x-list.h"
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#include <stdlib.h>
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#include <assert.h>
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#define ARRAY_SIZE(a)  (sizeof((a)) / sizeof((a)[0]))
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struct x_hash_table_struct {
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    unsigned int bucket_index;
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    unsigned int total_keys;
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    x_list **buckets;
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    x_hash_fun *hash_key;
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    x_compare_fun *compare_keys;
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    x_destroy_fun *destroy_key;
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    x_destroy_fun *destroy_value;
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};
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#define ITEM_NEW(k, v) X_PFX(list_prepend) ((x_list *)(k), v)
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#define ITEM_FREE(i)   X_PFX(list_free_1) (i)
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#define ITEM_KEY(i)    ((void *)(i)->next)
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#define ITEM_VALUE(i)  ((i)->data)
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#define SPLIT_THRESHOLD_FACTOR 2
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/* http://planetmath.org/?op=getobj&from=objects&name=GoodHashTablePrimes */
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static const unsigned int bucket_sizes[] = {
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    29,       53,        97,        193,        389,        769,       1543,
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    3079,     6151, 12289, 24593, 49157,
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    98317,    196613,   393241,    786433,    1572869,   3145739,   6291469,
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    12582917,
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    25165843, 50331653, 100663319, 201326611, 402653189, 805306457,
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    1610612741
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};
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static inline unsigned int
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hash_table_total_buckets(x_hash_table *h)
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{
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    return bucket_sizes[h->bucket_index];
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}
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static inline void
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hash_table_destroy_item(x_hash_table *h, void *k, void *v)
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{
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    if (h->destroy_key != 0)
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        (*h->destroy_key)(k);
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    if (h->destroy_value != 0)
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        (*h->destroy_value)(v);
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}
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static inline size_t
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hash_table_hash_key(x_hash_table *h, void *k)
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{
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    if (h->hash_key != 0)
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        return (*h->hash_key)(k);
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    else
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        return (size_t)k;
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}
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static inline int
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hash_table_compare_keys(x_hash_table *h, void *k1, void *k2)
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{
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    if (h->compare_keys == 0)
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        return k1 == k2;
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    else
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        return (*h->compare_keys)(k1, k2) == 0;
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}
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static void
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hash_table_split(x_hash_table *h)
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{
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    x_list **new, **old;
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    x_list *node, *item, *next;
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    int new_size, old_size;
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    size_t b;
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    int i;
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    if (h->bucket_index == ARRAY_SIZE(bucket_sizes) - 1)
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        return;
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    old_size = hash_table_total_buckets(h);
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    old = h->buckets;
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    h->bucket_index++;
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    new_size = hash_table_total_buckets(h);
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    new = calloc(new_size, sizeof(x_list *));
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    if (new == 0) {
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        h->bucket_index--;
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        return;
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    }
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    for (i = 0; i < old_size; i++) {
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        for (node = old[i]; node != 0; node = next) {
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            next = node->next;
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            item = node->data;
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            b = hash_table_hash_key(h, ITEM_KEY(item)) % new_size;
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            node->next = new[b];
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            new[b] = node;
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        }
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    }
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    h->buckets = new;
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    free(old);
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}
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X_EXTERN x_hash_table *
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X_PFX(hash_table_new) (x_hash_fun * hash,
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                       x_compare_fun * compare,
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                       x_destroy_fun * key_destroy,
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                       x_destroy_fun * value_destroy) {
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    x_hash_table *h;
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    h = calloc(1, sizeof(x_hash_table));
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    if (h == 0)
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        return 0;
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    h->bucket_index = 0;
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    h->buckets = calloc(hash_table_total_buckets(h), sizeof(x_list *));
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    if (h->buckets == 0) {
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        free(h);
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        return 0;
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    }
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    h->hash_key = hash;
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    h->compare_keys = compare;
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    h->destroy_key = key_destroy;
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    h->destroy_value = value_destroy;
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    return h;
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}
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X_EXTERN void
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X_PFX(hash_table_free) (x_hash_table * h) {
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    int n, i;
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    x_list *node, *item;
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    assert(h != NULL);
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    n = hash_table_total_buckets(h);
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    for (i = 0; i < n; i++) {
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        for (node = h->buckets[i]; node != 0; node = node->next) {
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            item = node->data;
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            hash_table_destroy_item(h, ITEM_KEY(item), ITEM_VALUE(item));
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            ITEM_FREE(item);
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        }
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        X_PFX(list_free) (h->buckets[i]);
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    }
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    free(h->buckets);
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    free(h);
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}
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X_EXTERN unsigned int
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X_PFX(hash_table_size) (x_hash_table * h) {
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    assert(h != NULL);
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    return h->total_keys;
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}
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static void
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hash_table_modify(x_hash_table *h, void *k, void *v, int replace)
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{
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    size_t hash_value;
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    x_list *node, *item;
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    assert(h != NULL);
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    hash_value = hash_table_hash_key(h, k);
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    for (node = h->buckets[hash_value % hash_table_total_buckets(h)];
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         node != 0; node = node->next) {
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        item = node->data;
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        if (hash_table_compare_keys(h, ITEM_KEY(item), k)) {
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            if (replace) {
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                hash_table_destroy_item(h, ITEM_KEY(item),
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                                        ITEM_VALUE(item));
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                item->next = k;
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                ITEM_VALUE(item) = v;
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            }
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            else {
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                hash_table_destroy_item(h, k, ITEM_VALUE(item));
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                ITEM_VALUE(item) = v;
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            }
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            return;
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        }
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    }
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    /* Key isn't already in the table. Insert it. */
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    if (h->total_keys + 1
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        > hash_table_total_buckets(h) * SPLIT_THRESHOLD_FACTOR) {
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        hash_table_split(h);
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    }
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    hash_value = hash_value % hash_table_total_buckets(h);
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    h->buckets[hash_value] = X_PFX(list_prepend) (h->buckets[hash_value],
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                                                  ITEM_NEW(k, v));
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    h->total_keys++;
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}
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X_EXTERN void
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X_PFX(hash_table_insert) (x_hash_table * h, void *k, void *v) {
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    hash_table_modify(h, k, v, 0);
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}
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X_EXTERN void
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X_PFX(hash_table_replace) (x_hash_table * h, void *k, void *v) {
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    hash_table_modify(h, k, v, 1);
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}
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X_EXTERN void
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X_PFX(hash_table_remove) (x_hash_table * h, void *k) {
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    size_t hash_value;
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    x_list **ptr, *item;
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    assert(h != NULL);
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    hash_value = hash_table_hash_key(h, k);
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    for (ptr = &h->buckets[hash_value % hash_table_total_buckets(h)];
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         *ptr != 0; ptr = &((*ptr)->next)) {
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        item = (*ptr)->data;
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        if (hash_table_compare_keys(h, ITEM_KEY(item), k)) {
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            hash_table_destroy_item(h, ITEM_KEY(item), ITEM_VALUE(item));
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            ITEM_FREE(item);
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            item = *ptr;
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            *ptr = item->next;
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            X_PFX(list_free_1) (item);
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            h->total_keys--;
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            return;
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        }
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    }
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}
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X_EXTERN void *
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X_PFX(hash_table_lookup) (x_hash_table * h, void *k, void **k_ret) {
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    size_t hash_value;
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    x_list *node, *item;
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    assert(h != NULL);
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    hash_value = hash_table_hash_key(h, k);
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    for (node = h->buckets[hash_value % hash_table_total_buckets(h)];
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         node != 0; node = node->next) {
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        item = node->data;
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        if (hash_table_compare_keys(h, ITEM_KEY(item), k)) {
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            if (k_ret != 0)
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                *k_ret = ITEM_KEY(item);
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            return ITEM_VALUE(item);
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        }
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    }
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    if (k_ret != 0)
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        *k_ret = 0;
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    return 0;
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}
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X_EXTERN void
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X_PFX(hash_table_foreach) (x_hash_table * h,
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                           x_hash_foreach_fun * fun, void *data) {
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    int i, n;
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    x_list *node, *item;
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    assert(h != NULL);
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    n = hash_table_total_buckets(h);
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    for (i = 0; i < n; i++) {
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        for (node = h->buckets[i]; node != 0; node = node->next) {
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            item = node->data;
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            (*fun)(ITEM_KEY(item), ITEM_VALUE(item), data);
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        }
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    }
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}
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