esp-idf/components/console/argtable3/arg_hashtable.c

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