modules/up/src/rpsl/gnu/SymID.VHSet.cc
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FUNCTIONS
This source file includes following functions.
- SymIDVHSet
- SymIDVHSet
- doublehashinc
- seek
- add
- del
- clear
- resize
- first
- next
- OK
// This may look like C code, but it is really -*- C++ -*-
/*
Copyright (C) 1988 Free Software Foundation
written by Doug Lea (dl@rocky.oswego.edu)
This file is part of the GNU C++ Library. This library is free
software; you can redistribute it and/or modify it under the terms of
the GNU Library General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version. This library is distributed in the hope
that it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef __GNUG__
#pragma implementation
#endif
#include "config.h"
#include "SymID.VHSet.h"
/* codes for status fields */
#define EMPTYCELL 0
#define VALIDCELL 1
#define DELETEDCELL 2
SymIDVHSet::SymIDVHSet(unsigned int sz)
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{
tab = new SymID[size = sz];
status = new char[size];
for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL;
count = 0;
}
SymIDVHSet::SymIDVHSet(const SymIDVHSet& a)
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{
tab = new SymID[size = a.size];
status = new char[size];
for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL;
count = 0;
for (Pix p = a.first(); p; a.next(p)) add(a(p));
}
/*
* hashing method: double hash based on high bits of hash fct,
* followed by linear probe. Can't do too much better if table
* sizes not constrained to be prime.
*/
static inline unsigned int doublehashinc(unsigned int h, unsigned int s)
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{
unsigned int dh = ((h / s) % s);
return (dh > 1)? dh : 1;
}
Pix SymIDVHSet::seek(SymID key) const
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{
unsigned int hashval = SymIDHASH(key);
unsigned int h = hashval % size;
for (unsigned int i = 0; i <= size; ++i)
{
if (status[h] == EMPTYCELL)
return 0;
else if (status[h] == VALIDCELL && SymIDEQ(key, tab[h]))
return Pix(&tab[h]);
if (i == 0)
h = (h + doublehashinc(hashval, size)) % size;
else if (++h >= size)
h -= size;
}
return 0;
}
Pix SymIDVHSet::add(SymID item)
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{
if (HASHTABLE_TOO_CROWDED(count, size))
resize();
unsigned int bestspot = size;
unsigned int hashval = SymIDHASH(item);
unsigned int h = hashval % size;
for (unsigned int i = 0; i <= size; ++i)
{
if (status[h] == EMPTYCELL)
{
if (bestspot >= size) bestspot = h;
tab[bestspot] = item;
status[bestspot] = VALIDCELL;
++count;
return Pix(&tab[bestspot]);
}
else if (status[h] == DELETEDCELL)
{
if (bestspot >= size) bestspot = h;
}
else if (SymIDEQ(tab[h],item))
return Pix(&tab[h]);
if (i == 0)
h = (h + doublehashinc(hashval, size)) % size;
else if (++h >= size)
h -= size;
}
tab[bestspot] = item;
status[bestspot] = VALIDCELL;
++count;
return Pix(&tab[bestspot]);
}
void SymIDVHSet::del(SymID key)
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{
unsigned int hashval = SymIDHASH(key);
unsigned int h = hashval % size;
for (unsigned int i = 0; i <= size; ++i)
{
if (status[h] == EMPTYCELL)
return;
else if (status[h] == VALIDCELL && SymIDEQ(key, tab[h]))
{
status[h] = DELETEDCELL;
--count;
return;
}
if (i == 0)
h = (h + doublehashinc(hashval, size)) % size;
else if (++h >= size)
h -= size;
}
}
void SymIDVHSet::clear()
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{
for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL;
count = 0;
}
void SymIDVHSet::resize(unsigned int newsize)
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{
if (newsize <= count)
{
newsize = DEFAULT_INITIAL_CAPACITY;
while (HASHTABLE_TOO_CROWDED(count, newsize)) newsize <<= 1;
}
SymID* oldtab = tab;
char* oldstatus = status;
unsigned int oldsize = size;
tab = new SymID[size = newsize];
status = new char[size];
for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL;
count = 0;
for (unsigned int i = 0; i < oldsize; ++i) if (oldstatus[i] == VALIDCELL) add(oldtab[i]);
delete [] oldtab;
delete oldstatus;
}
Pix SymIDVHSet::first() const
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{
for (unsigned int pos = 0; pos < size; ++pos)
if (status[pos] == VALIDCELL) return Pix(&tab[pos]);
return 0;
}
void SymIDVHSet::next(Pix& i) const
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{
if (i == 0) return;
unsigned int pos = ((unsigned)i - (unsigned)tab) / sizeof(SymID) + 1;
for (; pos < size; ++pos)
if (status[pos] == VALIDCELL)
{
i = Pix(&tab[pos]);
return;
}
i = 0;
}
int SymIDVHSet:: operator == (const SymIDVHSet& b) const
{
if (count != b.count)
return 0;
else
{
for (unsigned int i = 0; i < size; ++i)
if (status[i] == VALIDCELL && b.seek(tab[i]) == 0)
return 0;
for (unsigned int i = 0; i < b.size; ++i)
if (b.status[i] == VALIDCELL && seek(b.tab[i]) == 0)
return 0;
return 1;
}
}
int SymIDVHSet::operator <= (const SymIDVHSet& b) const
{
if (count > b.count)
return 0;
else
{
for (unsigned int i = 0; i < size; ++i)
if (status[i] == VALIDCELL && b.seek(tab[i]) == 0)
return 0;
return 1;
}
}
void SymIDVHSet::operator |= (SymIDVHSet& b)
{
if (&b == this || b.count == 0)
return;
for (unsigned int i = 0; i < b.size; ++i)
if (b.status[i] == VALIDCELL) add(b.tab[i]);
}
void SymIDVHSet::operator &= (SymIDVHSet& b)
{
if (&b == this || count == 0)
return;
for (unsigned int i = 0; i < size; ++i)
{
if (status[i] == VALIDCELL && b.seek(tab[i]) == 0)
{
status[i] = DELETEDCELL;
--count;
}
}
}
void SymIDVHSet::operator -= (SymIDVHSet& b)
{
for (unsigned int i = 0; i < size; ++i)
{
if (status[i] == VALIDCELL && b.seek(tab[i]) != 0)
{
status[i] = DELETEDCELL;
--count;
}
}
}
int SymIDVHSet::OK()
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{
int v = tab != 0;
v &= status != 0;
int n = 0;
for (unsigned int i = 0; i < size; ++i)
{
if (status[i] == VALIDCELL) ++n;
else if (status[i] != DELETEDCELL && status[i] != EMPTYCELL)
v = 0;
}
v &= n == count;
if (!v) error("invariant failure");
return v;
}