From 479cbd55ee5739d3cd2566379575451dbecf4c54 Mon Sep 17 00:00:00 2001
From: Stef Walter <stefw@collabora.co.uk>
Date: Thu, 31 Mar 2011 12:41:43 +0200
Subject: Documentation and API cleanup.
* Rename source directory
* More consistent with return values from URI functions.
* Allow formatting URI to take a uri type.
---
module/hash.c | 453 ----------------------------------------------------------
1 file changed, 453 deletions(-)
delete mode 100644 module/hash.c
(limited to 'module/hash.c')
diff --git a/module/hash.c b/module/hash.c
deleted file mode 100644
index 30efced..0000000
--- a/module/hash.c
+++ /dev/null
@@ -1,453 +0,0 @@
-/*
- * Copyright (c) 2004, Stefan Walter
- * Copyright (c) 2011, Collabora Ltd.
- *
- * 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.
- * * The names of contributors to this software may not 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.
- */
-
-/*
- * Originally from apache 2.0
- * Modifications for general use by <stef@memberwebs.com>
- */
-
-/* Copyright 2000-2004 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <sys/types.h>
-
-#include <assert.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "hash.h"
-
-/*
- * The internal form of a hash table.
- *
- * The table is an array indexed by the hash of the key; collisions
- * are resolved by hanging a linked list of hash entries off each
- * element of the array. Although this is a really simple design it
- * isn't too bad given that pools have a low allocation overhead.
- */
-
-typedef struct hash_entry hash_entry_t;
-
-struct hash_entry
-{
- hash_entry_t* next;
- unsigned int hash;
- void* key;
- void* val;
-};
-
-/*
- * The size of the array is always a power of two. We use the maximum
- * index rather than the size so that we can use bitwise-AND for
- * modular arithmetic.
- * The count of hash entries may be greater depending on the chosen
- * collision rate.
- */
-struct hash {
- hash_entry_t** array;
- unsigned int count;
- unsigned int max;
- hash_hash_func hash_func;
- hash_equal_func equal_func;
- hash_destroy_func key_destroy_func;
- hash_destroy_func value_destroy_func;
-};
-
-#define INITIAL_MAX 15 /* tunable == 2^n - 1 */
-#define int_malloc malloc
-#define int_calloc calloc
-#define int_free free
-
-/*
- * Hash creation functions.
- */
-
-static hash_entry_t**
-alloc_array(hash_t* ht, unsigned int max)
-{
- return (hash_entry_t**)int_calloc (sizeof (*(ht->array)), (max + 1));
-}
-
-hash_t*
-hash_create (hash_hash_func hash_func,
- hash_equal_func equal_func,
- hash_destroy_func key_destroy_func,
- hash_destroy_func value_destroy_func)
-{
- hash_t* ht;
-
- assert (hash_func);
- assert (equal_func);
-
- ht = int_malloc (sizeof (hash_t));
- if (ht) {
- ht->count = 0;
- ht->max = INITIAL_MAX;
- ht->hash_func = hash_func;
- ht->equal_func = equal_func;
- ht->key_destroy_func = key_destroy_func;
- ht->value_destroy_func = value_destroy_func;
- ht->array = alloc_array (ht, ht->max);
- if (!ht->array) {
- int_free (ht);
- return NULL;
- }
- }
- return ht;
-}
-
-void
-hash_free (hash_t* ht)
-{
- hash_iter_t hi;
-
- if (!ht)
- return;
-
- hash_iterate (ht, &hi);
- while (hash_next (&hi, NULL, NULL)) {
- if (ht->key_destroy_func)
- ht->key_destroy_func (hi.ths->key);
- if (ht->value_destroy_func)
- ht->value_destroy_func (hi.ths->val);
- }
-
- if (ht->array)
- int_free (ht->array);
-
- int_free (ht);
-}
-
-/*
- * Hash iteration functions.
- */
-int
-hash_next (hash_iter_t* hi, void **key, void **value)
-{
- hi->ths = hi->next;
- while (!hi->ths) {
- if (hi->index > hi->ht->max)
- return 0;
- hi->ths = hi->ht->array[hi->index++];
- }
- hi->next = hi->ths->next;
- if (key)
- *key = hi->ths->key;
- if (value)
- *value = hi->ths->val;
- return 1;
-}
-
-void
-hash_iterate (hash_t* ht, hash_iter_t *hi)
-{
- hi->ht = ht;
- hi->index = 0;
- hi->ths = NULL;
- hi->next = NULL;
-}
-
-/*
- * Expanding a hash table
- */
-
-static int
-expand_array (hash_t* ht)
-{
- hash_iter_t hi;
- hash_entry_t** new_array;
- unsigned int new_max;
-
- new_max = ht->max * 2 + 1;
- new_array = alloc_array (ht, new_max);
-
- if(!new_array)
- return 0;
-
- hash_iterate (ht, &hi);
- while (hash_next (&hi, NULL, NULL)) {
- unsigned int i = hi.ths->hash & new_max;
- hi.ths->next = new_array[i];
- new_array[i] = hi.ths;
- }
-
- if(ht->array)
- int_free (ht->array);
-
- ht->array = new_array;
- ht->max = new_max;
- return 1;
-}
-
-/*
- * This is where we keep the details of the hash function and control
- * the maximum collision rate.
- *
- * If val is non-NULL it creates and initializes a new hash entry if
- * there isn't already one there; it returns an updatable pointer so
- * that hash entries can be removed.
- */
-
-static hash_entry_t**
-find_entry (hash_t* ht, const void* key, void* val)
-{
- hash_entry_t** hep;
- hash_entry_t* he;
- unsigned int hash;
-
- /* Perform the hashing */
- hash = ht->hash_func (key);
-
- /* scan linked list */
- for (hep = &ht->array[hash & ht->max], he = *hep;
- he; hep = &he->next, he = *hep) {
- if(he->hash == hash && ht->equal_func (he->key, key))
- break;
- }
-
- if(he || !val)
- return hep;
-
- /* add a new entry for non-NULL val */
- he = int_malloc (sizeof (*he));
-
- if(he) {
- he->key = (void*)key;
- he->next = NULL;
- he->hash = hash;
- he->val = val;
-
- *hep = he;
- ht->count++;
- }
-
- return hep;
-}
-
-void*
-hash_get (hash_t* ht, const void *key)
-{
- hash_entry_t** he = find_entry (ht, key, NULL);
- if (he && *he)
- return (void*)((*he)->val);
- else
- return NULL;
-}
-
-int
-hash_set (hash_t* ht, void* key, void* val)
-{
- hash_entry_t** hep = find_entry (ht, key, val);
- if(hep && *hep) {
- /* replace entry */
- (*hep)->val = val;
-
- /* check that the collision rate isn't too high */
- if (ht->count > ht->max) {
- if (!expand_array (ht))
- return 0;
- }
-
- return 1;
- }
-
- return 0;
-}
-
-int
-hash_remove (hash_t* ht, const void* key)
-{
- hash_entry_t** hep = find_entry (ht, key, NULL);
-
- if (hep && *hep) {
- hash_entry_t* old = *hep;
- *hep = (*hep)->next;
- --ht->count;
- if (ht->key_destroy_func)
- ht->key_destroy_func (old->key);
- if (ht->value_destroy_func)
- ht->value_destroy_func (old->val);
- free (old);
- return 1;
- }
-
- return 0;
-}
-
-void
-hash_clear (hash_t* ht)
-{
- hash_entry_t *he, *next;
- int i;
-
- /* Free all entries in the array */
- for (i = 0; i < ht->max; ++i) {
- he = ht->array[i];
- while (he) {
- next = he->next;
- if (ht->key_destroy_func)
- ht->key_destroy_func (he->key);
- if (ht->value_destroy_func)
- ht->value_destroy_func (he->val);
- free (he);
- he = next;
- }
- }
-
- memset (ht->array, 0, ht->max * sizeof (hash_entry_t*));
- ht->count = 0;
-}
-
-unsigned int
-hash_count (hash_t* ht)
-{
- return ht->count;
-}
-
-unsigned int
-hash_string_hash (const void *string)
-{
- unsigned int hash;
- const unsigned char *p;
-
- assert (string);
-
- /*
- * This is the popular `times 33' hash algorithm which is used by
- * perl and also appears in Berkeley DB. This is one of the best
- * known hash functions for strings because it is both computed
- * very fast and distributes very well.
- *
- * The originator may be Dan Bernstein but the code in Berkeley DB
- * cites Chris Torek as the source. The best citation I have found
- * is "Chris Torek, Hash function for text in C, Usenet message
- * <27038@mimsy.umd.edu> in comp.lang.c , October, 1990." in Rich
- * Salz's USENIX 1992 paper about INN which can be found at
- * <http://citeseer.nj.nec.com/salz92internetnews.html>.
- *
- * The magic of number 33, i.e. why it works better than many other
- * constants, prime or not, has never been adequately explained by
- * anyone. So I try an explanation: if one experimentally tests all
- * multipliers between 1 and 256 (as I did while writing a low-level
- * data structure library some time ago) one detects that even
- * numbers are not useable at all. The remaining 128 odd numbers
- * (except for the number 1) work more or less all equally well.
- * They all distribute in an acceptable way and this way fill a hash
- * table with an average percent of approx. 86%.
- *
- * If one compares the chi^2 values of the variants (see
- * Bob Jenkins ``Hashing Frequently Asked Questions'' at
- * http://burtleburtle.net/bob/hash/hashfaq.html for a description
- * of chi^2), the number 33 not even has the best value. But the
- * number 33 and a few other equally good numbers like 17, 31, 63,
- * 127 and 129 have nevertheless a great advantage to the remaining
- * numbers in the large set of possible multipliers: their multiply
- * operation can be replaced by a faster operation based on just one
- * shift plus either a single addition or subtraction operation. And
- * because a hash function has to both distribute good _and_ has to
- * be very fast to compute, those few numbers should be preferred.
- *
- * -- Ralf S. Engelschall <rse@engelschall.com>
- */
-
- hash = 0;
-
- for(p = string; *p; p++)
- hash = hash * 33 + *p;
-
- return hash;
-}
-
-int
-hash_string_equal (const void *string_one, const void *string_two)
-{
- assert (string_one);
- assert (string_two);
-
- return strcmp (string_one, string_two) == 0;
-}
-
-unsigned int
-hash_ulongptr_hash (const void *to_ulong)
-{
- assert (to_ulong);
- return (unsigned int)*((unsigned long*)to_ulong);
-}
-
-int
-hash_ulongptr_equal (const void *ulong_one, const void *ulong_two)
-{
- assert (ulong_one);
- assert (ulong_two);
- return *((unsigned long*)ulong_one) == *((unsigned long*)ulong_two);
-}
-
-unsigned int
-hash_intptr_hash (const void *to_int)
-{
- assert (to_int);
- return (unsigned int)*((unsigned long*)to_int);
-}
-
-int
-hash_intptr_equal (const void *int_one, const void *int_two)
-{
- assert (int_one);
- assert (int_two);
- return *((unsigned long*)int_one) == *((unsigned long*)int_two);
-}
-
-unsigned int
-hash_direct_hash (const void *ptr)
-{
- return (unsigned int)ptr;
-}
-
-int
-hash_direct_equal (const void *ptr_one, const void *ptr_two)
-{
- return ptr_one == ptr_two;
-}
-
--
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