// 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)
    based on code by Marc Shapiro (shapiro@sor.inria.fr)

This file is part of GNU CC.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY.  No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing.  Refer to the GNU CC General Public
License for full details.

Everyone is granted permission to copy, modify and redistribute
GNU CC, but only under the conditions described in the
GNU CC General Public License.   A copy of this license is
supposed to have been given to you along with GNU CC so you
can know your rights and responsibilities.  It should be in a
file named COPYING.  Among other things, the copyright notice
and this notice must be preserved on all copies.  
*/

#ifdef __GNUG__
#pragma implementation
#endif
#include <stream.h>
#include "<T>.Plex.h"

// IChunk support

volatile void <T>IChunk::error(const char* msg) const
{
  (*lib_error_handler)("<T>IChunk", msg);
}

volatile void <T>IChunk::index_error() const
{
  error("attempt to use invalid index");
}

volatile void <T>IChunk::empty_error() const
{
  error("invalid use of empty chunk");
}

volatile void <T>IChunk::full_error() const
{
  error("attempt to extend chunk beyond bounds");
}

<T>IChunk:: ~<T>IChunk() {}

<T>IChunk::<T>IChunk(<T>*     d,    
                     int      baseidx,
                     int      lowidx,
                     int      fenceidx,
                     int      topidx)
{
  if (d == 0 || baseidx > lowidx || lowidx > fenceidx || fenceidx > topidx)
    error("inconsistent specification");
  data = d;
  base = baseidx;
  low = lowidx;
  fence = fenceidx;
  top = topidx;
  nxt = prv = this;
}

void <T>IChunk:: re_index(int lo)
{
  int delta = lo - low;
  base += delta;
  low += delta;
  fence += delta;
  top += delta;
}


void <T>IChunk::clear(int lo)
{
  int s = top - base;
  low = base = fence = lo;
  top = base + s;
}

void <T>IChunk::cleardown(int hi)
{
  int s = top - base;
  low = top = fence = hi;
  base = top - s;
}

int <T>IChunk:: OK() const
{
  int v = data != 0;             // have some data
  v &= base <= low;              // ok, index-wise
  v &= low <= fence;
  v &= fence <= top;

  v &=  nxt->prv == this;      // and links are OK
  v &=  prv->nxt == this;
  if (!v) error("invariant failure");
  return(v);
}


// error handling


volatile void <T>Plex::error(const char* msg) const
{
  (*lib_error_handler)("Plex", msg);
}

volatile void <T>Plex::index_error() const
{
  error("attempt to access invalid index");
}

volatile void <T>Plex::empty_error() const
{
  error("attempted operation on empty plex");
}

volatile void <T>Plex::full_error() const
{
  error("attempt to increase size of plex past limit");
}

// generic plex ops

<T>Plex:: ~<T>Plex()
{
  invalidate();
}  


void <T>Plex::append (const <T>Plex& a)
{
  for (int i = a.low(); i < a.fence(); a.next(i)) add_high(a[i]);
}

void <T>Plex::prepend (const <T>Plex& a)
{
  for (int i = a.high(); i > a.ecnef(); a.prev(i)) add_low(a[i]);
}

void <T>Plex::reverse()
{
  <T> tmp;
  int l = low();
  int h = high();
  while (l < h)
  {
    tmp = (*this)[l];
    (*this)[l] = (*this)[h];
    (*this)[h] = tmp;
    next(l);
    prev(h);
  }
}


void <T>Plex::fill(const <T&> x)
{
  for (int i = lo; i < fnc; ++i) (*this)[i] = x;
}

void <T>Plex::fill(const <T&> x, int lo, int hi)
{
  for (int i = lo; i <= hi; ++i) (*this)[i] = x;
}


void <T>Plex::del_chunk(<T>IChunk* x)
{
  if (x != 0)
  {
    x->unlink();
    int sz = x->size();
    <T>* data = (<T>*)(x->invalidate());
    delete [sz] data;
    delete x;
  }
}


void <T>Plex::invalidate()
{
  <T>IChunk* t = hd;
  if (t != 0)
  {
    <T>IChunk* tail = tl();
    while (t != tail)
    {
      <T>IChunk* nxt = t->next();
      del_chunk(t);
      t = nxt;
    } 
    del_chunk(t);
    hd = 0;
  }
}

int <T>Plex::reset_low(int l)
{
  int old = lo;
  int diff = l - lo;
  if (diff != 0)
  {
    lo += diff;
    fnc += diff;
    <T>IChunk* t = hd;
    do
    {
      t->re_index(t->low_index() + diff);
      t = t->next();
    } while (t != hd);
  }
  return old;
}