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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* hash table library
*/
#include "hashlib.h"
/*
* hash table sequential scan
*
* Hash_position_t* pos;
* Hash_bucket_t* b;
* pos = hashscan(tab, flags);
* while (b = hashnext(&pos)) ...;
* hashdone(pos);
*/
/*
* return pos for scan on table
*/
Hash_position_t*
hashscan(register Hash_table_t* tab, register int flags)
{
register Hash_position_t* pos;
static Hash_bucket_t empty;
if (!(pos = newof(0, Hash_position_t, 1, 0))) return(0);
pos->tab = tab->root->last.table = tab;
pos->bucket = ∅
pos->slot = tab->table - 1;
pos->limit = tab->table + tab->size;
if (tab->scope && !(flags & HASH_NOSCOPE))
{
pos->flags = HASH_SCOPE;
do
{
register Hash_bucket_t* b;
if (tab->frozen)
{
register Hash_bucket_t** sp = tab->table;
register Hash_bucket_t** sx = tab->table + tab->size;
while (sp < sx)
for (b = *sp++; b; b = b->next)
b->hash &= ~HASH_HIDDEN;
}
} while (tab = tab->scope);
tab = pos->tab;
}
else pos->flags = 0;
tab->frozen++;
return(pos);
}
/*
* return next scan element
*/
Hash_bucket_t*
hashnext(register Hash_position_t* pos)
{
register Hash_bucket_t* b;
if (!pos) return(pos->tab->root->last.bucket = 0);
b = pos->bucket;
for (;;)
{
if (!(b = b->next))
{
do
{
if (++pos->slot >= pos->limit)
{
pos->tab->frozen--;
if (!pos->flags || !pos->tab->scope) return(0);
pos->tab = pos->tab->scope;
pos->tab->root->last.table = pos->tab;
pos->limit = (pos->slot = pos->tab->table) + pos->tab->size;
pos->tab->frozen++;
}
} while (!(b = *pos->slot));
}
if (!(b->hash & HASH_DELETED) && (!(pos->tab->flags & HASH_VALUE) || b->value) && (!pos->flags || !(b->hash & (HASH_HIDDEN|HASH_HIDES)))) break;
if (b->hash & HASH_HIDES)
{
register Hash_bucket_t* h = (Hash_bucket_t*)b->name;
if (!(h->hash & HASH_HIDDEN))
{
h->hash |= HASH_HIDDEN;
if (!(b->hash & HASH_DELETED)) break;
}
}
else b->hash &= ~HASH_HIDDEN;
}
return(pos->tab->root->last.bucket = pos->bucket = b);
}
/*
* terminate scan
*/
void
hashdone(register Hash_position_t* pos)
{
if (pos)
{
if (pos->tab->frozen)
pos->tab->frozen--;
free(pos);
}
}
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