Category : OS/2 Files
Archive   : GPPDEV8F.ZIP
Filename : DLLIST.CCP

// This may look like C code, but it is really -*- C++ -*-
/*
Copyright (C) 1988 Free Software Foundation
written by Doug Lea ([email protected])

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, 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifdef __GNUG__
#pragma implementation
#endif
#include
#include
#include
#include ".DLList.h"

// error handling



void DLList::error(const char* msg)
{
(*lib_error_handler)("DLList", msg);
}

int DLList::length()
{
int l = 0;
DLListNode* t = h;
if (t != 0) do { ++l; t = t->fd; } while (t != h);
return l;
}

DLList::DLList(const DLList& a)
{
if (a.h == 0)
h = 0;
else
{
DLListNode* p = a.h;
DLListNode* t = new DLListNode(p->hd);
h = t;
p = p->fd;
while (p != a.h)
{
DLListNode* n = new DLListNode(p->hd);
t->fd = n;
n->bk = t;
t = n;
p = p->fd;
}
t->fd = h;
h->bk = t;
return;
}
}

DLList& DLList::operator = (const DLList& a)
{
if (h != a.h)
{
clear();
if (a.h != 0)
{
DLListNode* p = a.h;
DLListNode* t = new DLListNode(p->hd);
h = t;
p = p->fd;
while (p != a.h)
{
DLListNode* n = new DLListNode(p->hd);
t->fd = n;
n->bk = t;
t = n;
p = p->fd;
}
t->fd = h;
h->bk = t;
}
}
return *this;
}

void DLList::clear()
{
if (h == 0)
return;

DLListNode* p = h->fd;
h->fd = 0;
h = 0;

while (p != 0)
{
DLListNode* nxt = p->fd;
delete(p);
p = nxt;
}
}


Pix DLList::prepend( item)
{
DLListNode* t = new DLListNode(item);
if (h == 0)
t->fd = t->bk = h = t;
else
{
t->fd = h;
t->bk = h->bk;
h->bk->fd = t;
h->bk = t;
h = t;
}
return Pix(t);
}

Pix DLList::append( item)
{
DLListNode* t = new DLListNode(item);
if (h == 0)
t->fd = t->bk = h = t;
else
{
t->bk = h->bk;
t->bk->fd = t;
t->fd = h;
h->bk = t;
}
return Pix(t);
}

Pix DLList::ins_after(Pix p, item)
{
if (p == 0) return prepend(item);
DLListNode* u = (DLListNode*) p;
DLListNode* t = new DLListNode(item, u, u->fd);
u->fd->bk = t;
u->fd = t;
return Pix(t);
}

Pix DLList::ins_before(Pix p, item)
{
if (p == 0) error("null Pix");
DLListNode* u = (DLListNode*) p;
DLListNode* t = new DLListNode(item, u->bk, u);
u->bk->fd = t;
u->bk = t;
if (u == h) h = t;
return Pix(t);
}

void DLList::join(DLList& b)
{
DLListNode* t = b.h;
b.h = 0;
if (h == 0)
h = t;
else if (t != 0)
{
DLListNode* l = t->bk;
h->bk->fd = t;
t->bk = h->bk;
h->bk = l;
l->fd = h;
}
}

int DLList::owns(Pix p)
{
DLListNode* t = h;
if (t != 0 && p != 0)
{
do
{
if (Pix(t) == p) return 1;
t = t->fd;
} while (t != h);
}
return 0;
}

void DLList::del(Pix& p, int dir)
{
if (p == 0) error("null Pix");
DLListNode* t = (DLListNode*) p;
if (t->fd == t)
{
h = 0;
p = 0;
}
else
{
if (dir < 0)
{
if (t == h)
p = 0;
else
p = Pix(t->bk);
}
else
{
if (t == h->bk)
p = 0;
else
p = Pix(t->fd);
}
t->bk->fd = t->fd;
t->fd->bk = t->bk;
if (t == h) h = t->fd;
}
delete t;
}

void DLList::del_after(Pix& p)
{
if (p == 0)
{
del_front();
return;
}

DLListNode* b = (DLListNode*) p;
DLListNode* t = b->fd;

if (b == t)
{
h = 0;
p = 0;
}
else
{
t->bk->fd = t->fd;
t->fd->bk = t->bk;
if (t == h) h = t->fd;
}
delete t;
}

DLList::remove_front()
{
if (h == 0)
error("remove_front of empty list");
DLListNode* t = h;
res = t->hd;
if (h->fd == h)
h = 0;
else
{
h->fd->bk = h->bk;
h->bk->fd = h->fd;
h = h->fd;
}
delete t;
return res;
}


void DLList::del_front()
{
if (h == 0)
error("del_front of empty list");
DLListNode* t = h;
if (h->fd == h)
h = 0;
else
{
h->fd->bk = h->bk;
h->bk->fd = h->fd;
h = h->fd;
}
delete t;
}

DLList::remove_rear()
{
if (h == 0)
error("remove_rear of empty list");
DLListNode* t = h->bk;
res = t->hd;
if (h->fd == h)
h = 0;
else
{
t->fd->bk = t->bk;
t->bk->fd = t->fd;
}
delete t;
return res;
}


void DLList::del_rear()
{
if (h == 0)
error("del_rear of empty list");
DLListNode* t = h->bk;
if (h->fd == h)
h = 0;
else
{
t->fd->bk = t->bk;
t->bk->fd = t->fd;
}
delete t;
}


int DLList::OK()
{
int v = 1;
if (h != 0)
{
DLListNode* t = h;
long count = MAXLONG; // Lots of chances to find h!
do
{
count--;
v &= t->bk->fd == t;
v &= t->fd->bk == t;
t = t->fd;
} while (v && count > 0 && t != h);
v &= count > 0;
}
if (!v) error("invariant failure");
return v;
}