forked from test34/can_wizard
428 lines
14 KiB
C
428 lines
14 KiB
C
/*
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* SPDX-FileCopyrightText: 2013-2019 Tom G. Huang
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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/*******************************************************************************
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* arg_hashtable: Implements the hash table utilities
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*
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* This file is part of the argtable3 library.
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*
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* Copyright (C) 2013-2019 Tom G. Huang
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* <tomghuang@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of STEWART HEITMANN nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL STEWART HEITMANN BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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******************************************************************************/
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#ifndef ARG_AMALGAMATION
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#include "argtable3_private.h"
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#endif
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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* This hash table module is adapted from the C hash table implementation by
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* Christopher Clark. Here is the copyright notice from the library:
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*
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* Copyright (c) 2002, Christopher Clark
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* * Neither the name of the original author; nor the names of any contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Credit for primes table: Aaron Krowne
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* http://br.endernet.org/~akrowne/
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* http://planetmath.org/encyclopedia/GoodHashTablePrimes.html
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*/
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static const unsigned int primes[] = {53, 97, 193, 389, 769, 1543, 3079, 6151, 12289,
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24593, 49157, 98317, 196613, 393241, 786433, 1572869, 3145739, 6291469,
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12582917, 25165843, 50331653, 100663319, 201326611, 402653189, 805306457, 1610612741};
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const unsigned int prime_table_length = sizeof(primes) / sizeof(primes[0]);
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const float max_load_factor = (float)0.65;
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static unsigned int enhanced_hash(arg_hashtable_t* h, const void* k) {
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/*
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* Aim to protect against poor hash functions by adding logic here.
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* The logic is taken from Java 1.4 hash table source.
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*/
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unsigned int i = h->hashfn(k);
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i += ~(i << 9);
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i ^= ((i >> 14) | (i << 18)); /* >>> */
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i += (i << 4);
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i ^= ((i >> 10) | (i << 22)); /* >>> */
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return i;
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}
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static unsigned int index_for(unsigned int tablelength, unsigned int hashvalue) {
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return (hashvalue % tablelength);
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}
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arg_hashtable_t* arg_hashtable_create(unsigned int minsize, unsigned int (*hashfn)(const void*), int (*eqfn)(const void*, const void*)) {
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arg_hashtable_t* h;
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unsigned int pindex;
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unsigned int size = primes[0];
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/* Check requested hash table isn't too large */
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if (minsize > (1u << 30))
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return NULL;
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/*
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* Enforce size as prime. The reason is to avoid clustering of values
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* into a small number of buckets (yes, distribution). A more even
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* distributed hash table will perform more consistently.
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*/
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for (pindex = 0; pindex < prime_table_length; pindex++) {
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if (primes[pindex] > minsize) {
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size = primes[pindex];
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break;
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}
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}
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h = (arg_hashtable_t*)xmalloc(sizeof(arg_hashtable_t));
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h->table = (struct arg_hashtable_entry**)xmalloc(sizeof(struct arg_hashtable_entry*) * size);
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memset(h->table, 0, size * sizeof(struct arg_hashtable_entry*));
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h->tablelength = size;
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h->primeindex = pindex;
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h->entrycount = 0;
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h->hashfn = hashfn;
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h->eqfn = eqfn;
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h->loadlimit = (unsigned int)ceil(size * (double)max_load_factor);
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return h;
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}
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static int arg_hashtable_expand(arg_hashtable_t* h) {
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/* Double the size of the table to accommodate more entries */
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struct arg_hashtable_entry** newtable;
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struct arg_hashtable_entry* e;
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unsigned int newsize;
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unsigned int i;
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unsigned int index;
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/* Check we're not hitting max capacity */
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if (h->primeindex == (prime_table_length - 1))
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return 0;
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newsize = primes[++(h->primeindex)];
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newtable = (struct arg_hashtable_entry**)xmalloc(sizeof(struct arg_hashtable_entry*) * newsize);
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memset(newtable, 0, newsize * sizeof(struct arg_hashtable_entry*));
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/*
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* This algorithm is not 'stable': it reverses the list
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* when it transfers entries between the tables
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*/
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for (i = 0; i < h->tablelength; i++) {
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while (NULL != (e = h->table[i])) {
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h->table[i] = e->next;
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index = index_for(newsize, e->h);
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e->next = newtable[index];
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newtable[index] = e;
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}
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}
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xfree(h->table);
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h->table = newtable;
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h->tablelength = newsize;
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h->loadlimit = (unsigned int)ceil(newsize * (double)max_load_factor);
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return -1;
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}
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unsigned int arg_hashtable_count(arg_hashtable_t* h) {
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return h->entrycount;
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}
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void arg_hashtable_insert(arg_hashtable_t* h, void* k, void* v) {
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/* This method allows duplicate keys - but they shouldn't be used */
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unsigned int index;
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struct arg_hashtable_entry* e;
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if ((h->entrycount + 1) > h->loadlimit) {
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/*
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* Ignore the return value. If expand fails, we should
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* still try cramming just this value into the existing table
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* -- we may not have memory for a larger table, but one more
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* element may be ok. Next time we insert, we'll try expanding again.
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*/
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arg_hashtable_expand(h);
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}
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e = (struct arg_hashtable_entry*)xmalloc(sizeof(struct arg_hashtable_entry));
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e->h = enhanced_hash(h, k);
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index = index_for(h->tablelength, e->h);
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e->k = k;
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e->v = v;
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e->next = h->table[index];
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h->table[index] = e;
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h->entrycount++;
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}
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void* arg_hashtable_search(arg_hashtable_t* h, const void* k) {
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struct arg_hashtable_entry* e;
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unsigned int hashvalue;
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unsigned int index;
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hashvalue = enhanced_hash(h, k);
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index = index_for(h->tablelength, hashvalue);
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e = h->table[index];
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while (e != NULL) {
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/* Check hash value to short circuit heavier comparison */
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if ((hashvalue == e->h) && (h->eqfn(k, e->k)))
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return e->v;
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e = e->next;
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}
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return NULL;
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}
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void arg_hashtable_remove(arg_hashtable_t* h, const void* k) {
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/*
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* TODO: consider compacting the table when the load factor drops enough,
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* or provide a 'compact' method.
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*/
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struct arg_hashtable_entry* e;
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struct arg_hashtable_entry** pE;
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unsigned int hashvalue;
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unsigned int index;
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hashvalue = enhanced_hash(h, k);
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index = index_for(h->tablelength, hashvalue);
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pE = &(h->table[index]);
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e = *pE;
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while (NULL != e) {
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/* Check hash value to short circuit heavier comparison */
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if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {
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*pE = e->next;
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h->entrycount--;
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xfree(e->k);
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xfree(e->v);
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xfree(e);
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return;
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}
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pE = &(e->next);
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e = e->next;
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}
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}
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void arg_hashtable_destroy(arg_hashtable_t* h, int free_values) {
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unsigned int i;
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struct arg_hashtable_entry *e, *f;
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struct arg_hashtable_entry** table = h->table;
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if (free_values) {
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for (i = 0; i < h->tablelength; i++) {
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e = table[i];
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while (NULL != e) {
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f = e;
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e = e->next;
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xfree(f->k);
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xfree(f->v);
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xfree(f);
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}
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}
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} else {
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for (i = 0; i < h->tablelength; i++) {
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e = table[i];
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while (NULL != e) {
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f = e;
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e = e->next;
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xfree(f->k);
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xfree(f);
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}
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}
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}
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xfree(h->table);
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xfree(h);
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}
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arg_hashtable_itr_t* arg_hashtable_itr_create(arg_hashtable_t* h) {
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unsigned int i;
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unsigned int tablelength;
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arg_hashtable_itr_t* itr = (arg_hashtable_itr_t*)xmalloc(sizeof(arg_hashtable_itr_t));
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itr->h = h;
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itr->e = NULL;
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itr->parent = NULL;
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tablelength = h->tablelength;
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itr->index = tablelength;
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if (0 == h->entrycount)
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return itr;
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for (i = 0; i < tablelength; i++) {
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if (h->table[i] != NULL) {
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itr->e = h->table[i];
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itr->index = i;
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break;
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}
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}
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return itr;
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}
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void arg_hashtable_itr_destroy(arg_hashtable_itr_t* itr) {
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xfree(itr);
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}
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void* arg_hashtable_itr_key(arg_hashtable_itr_t* i) {
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return i->e->k;
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}
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void* arg_hashtable_itr_value(arg_hashtable_itr_t* i) {
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return i->e->v;
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}
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int arg_hashtable_itr_advance(arg_hashtable_itr_t* itr) {
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unsigned int j;
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unsigned int tablelength;
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struct arg_hashtable_entry** table;
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struct arg_hashtable_entry* next;
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if (itr->e == NULL)
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return 0; /* stupidity check */
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next = itr->e->next;
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if (NULL != next) {
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itr->parent = itr->e;
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itr->e = next;
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return -1;
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}
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tablelength = itr->h->tablelength;
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itr->parent = NULL;
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if (tablelength <= (j = ++(itr->index))) {
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itr->e = NULL;
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return 0;
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}
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table = itr->h->table;
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while (NULL == (next = table[j])) {
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if (++j >= tablelength) {
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itr->index = tablelength;
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itr->e = NULL;
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return 0;
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}
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}
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itr->index = j;
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itr->e = next;
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return -1;
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}
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int arg_hashtable_itr_remove(arg_hashtable_itr_t* itr) {
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struct arg_hashtable_entry* remember_e;
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struct arg_hashtable_entry* remember_parent;
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int ret;
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/* Do the removal */
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if ((itr->parent) == NULL) {
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/* element is head of a chain */
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itr->h->table[itr->index] = itr->e->next;
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} else {
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/* element is mid-chain */
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itr->parent->next = itr->e->next;
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}
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/* itr->e is now outside the hashtable */
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remember_e = itr->e;
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itr->h->entrycount--;
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xfree(remember_e->k);
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xfree(remember_e->v);
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/* Advance the iterator, correcting the parent */
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remember_parent = itr->parent;
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ret = arg_hashtable_itr_advance(itr);
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if (itr->parent == remember_e) {
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itr->parent = remember_parent;
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}
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xfree(remember_e);
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return ret;
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}
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int arg_hashtable_itr_search(arg_hashtable_itr_t* itr, arg_hashtable_t* h, void* k) {
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struct arg_hashtable_entry* e;
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struct arg_hashtable_entry* parent;
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unsigned int hashvalue;
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unsigned int index;
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hashvalue = enhanced_hash(h, k);
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index = index_for(h->tablelength, hashvalue);
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e = h->table[index];
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parent = NULL;
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while (e != NULL) {
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/* Check hash value to short circuit heavier comparison */
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if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {
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itr->index = index;
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itr->e = e;
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itr->parent = parent;
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itr->h = h;
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return -1;
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}
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parent = e;
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e = e->next;
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}
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return 0;
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}
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int arg_hashtable_change(arg_hashtable_t* h, void* k, void* v) {
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struct arg_hashtable_entry* e;
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unsigned int hashvalue;
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unsigned int index;
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hashvalue = enhanced_hash(h, k);
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index = index_for(h->tablelength, hashvalue);
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e = h->table[index];
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while (e != NULL) {
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/* Check hash value to short circuit heavier comparison */
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if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {
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xfree(e->v);
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e->v = v;
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return -1;
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}
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e = e->next;
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}
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return 0;
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}
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