oslbag.ccp

早期freebsd实现

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

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 "<T>.OSLBag.h"


Pix <T>OSLBag::seek(<T&> item, Pix i)
{
  if (i == 0) i = p.first(); else next(i);
  for (; i != 0; p.next(i))
  {
    int cmp = <T>CMP(item, p(i));
    if (cmp == 0)
      return i;
    else if (cmp < 0)
      return 0;
  }
  return 0;
}

int <T>OSLBag::nof(<T&> item)
{
  int n = 0;
  for (Pix i = p.first(); i != 0; p.next(i))
  {
    int cmp = <T>CMP(item, p(i));
    if (cmp == 0)
      ++n;
    else if (cmp < 0)
      break;
  }
  return n;
}

Pix <T>OSLBag::add(<T&> item)
{
  Pix i = p.first();
  if (i == 0) 
  {
    ++count;
    return p.prepend(item);
  }
  int cmp = <T>CMP(item, p(i));
  if (cmp <= 0)
  {
    ++count;
    return p.prepend(item);
  }
  else
  {
    Pix trail = i;
    p.next(i);
    for (;;)
    {
      if (i == 0)
      {
        ++count;
        return p.append(item);
      }
      cmp = <T>CMP(item, p(i));
      if (cmp <= 0)
      {
        ++count;
        return p.ins_after(trail, item);
      }
      else
      {
        trail = i;
        p.next(i);
      }
    }
  }
}

void <T>OSLBag::del(<T&> item)
{
  Pix i = p.first();
  if (i == 0)
    return;
  int cmp = <T>CMP(item, p(i));
  if (cmp < 0)
    return;
  else if (cmp == 0)
  {
    --count;
    p.del_front();
  }
  else
  {
    Pix trail = i;
    p.next(i);
    while (i != 0)
    {
      cmp = <T>CMP(item, p(i));
      if (cmp < 0)
        return;
      else if (cmp == 0)
      {
        --count;
        p.del_after(trail);
        return;
      }
      else
      {
        trail = i;
        p.next(i);
      }
    }
  }
}

void <T>OSLBag::remove(<T&> item)
{
  Pix i = p.first();
  if (i == 0)
    return;
  int cmp = <T>CMP(item, p(i));
  if (cmp < 0)
    return;
  else if (cmp == 0)
  {
    do
    {
      --count;
      p.del_front();
      i = p.first();
    } while (i != 0 && <T>EQ(item, p(i)));
  }
  else
  {
    Pix trail = i;
    p.next(i);
    while (i != 0)
    {
      cmp = <T>CMP(item, p(i));
      if (cmp < 0)
        return;
      else if (cmp == 0)
      {
        do
        {
          --count;
          p.del_after(trail);
          i = trail;
          next(i);
        } while (i != 0 && <T>EQ(item, p(i)));
        return;
      }
      else
      {
        trail = i;
        p.next(i);
      }
    }
  }
}
        
int <T>OSLBag::OK()
{
  int v = p.OK();
  v &= count == p.length();
  Pix trail = p.first();
  if (trail == 0)
    v &= count == 0;
  else
  {
    Pix i = trail; next(i);
    while (i != 0)
    {
      v &= <T>CMP(p(trail), p(i)) <= 0;
      trail = i;
      next(i);
    }
  }
  if (!v) error("invariant failure");
  return v;
}