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/* Copyright (C) 2002, 2004 Christopher Clark <firstname.lastname@cl.cam.ac.uk> */
#include "hashtable_private.h"
#include "hashtable_itr.h"
#include <stdlib.h> /* defines NULL */
/*****************************************************************************/
/* hashtable_iterator - iterator constructor */
struct hashtable_itr *
hashtable_iterator(struct hashtable *h)
{
unsigned int i, tablelength;
struct hashtable_itr *itr = (struct hashtable_itr *)
malloc(sizeof(struct hashtable_itr));
if (NULL == itr) return NULL;
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 (NULL != h->table[i])
{
itr->e = h->table[i];
itr->index = i;
break;
}
}
return itr;
}
/*****************************************************************************/
/* key - return the key of the (key,value) pair at the current position */
/* value - return the value of the (key,value) pair at the current position */
#if 0 /* these are now inline functions! */
void *
hashtable_iterator_key(struct hashtable_itr *i)
{ return i->e->k; }
void *
hashtable_iterator_value(struct hashtable_itr *i)
{ return i->e->v; }
#endif
/*****************************************************************************/
/* advance - advance the iterator to the next element
* returns zero if advanced to end of table */
int
hashtable_iterator_advance(struct hashtable_itr *itr)
{
unsigned int j,tablelength;
struct entry **table;
struct entry *next;
if (NULL == itr->e) 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;
}
/*****************************************************************************/
/* remove - remove the entry at the current iterator position
* and advance the iterator, if there is a successive
* element.
* If you want the value, read it before you remove:
* beware memory leaks if you don't.
* Returns zero if end of iteration. */
int
hashtable_iterator_remove(struct hashtable_itr *itr)
{
struct entry *remember_e, *remember_parent;
int ret;
/* Do the removal */
if (NULL == (itr->parent))
{
/* 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--;
freekey(remember_e->k);
/* Advance the iterator, correcting the parent */
remember_parent = itr->parent;
ret = hashtable_iterator_advance(itr);
if (itr->parent == remember_e) { itr->parent = remember_parent; }
free(remember_e);
return ret;
}
/*****************************************************************************/
int /* returns zero if not found */
hashtable_iterator_search(struct hashtable_itr *itr,
struct hashtable *h, void *k)
{
struct entry *e, *parent;
unsigned int hashvalue, index;
hashvalue = hash(h,k);
index = indexFor(h->tablelength,hashvalue);
e = h->table[index];
parent = NULL;
while (NULL != e)
{
/* 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;
}
/*
* Copyright (c) 2002, 2004, 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.
*/
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