// History.cpp: implementation of the History class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "History.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

History::History()
{
  head = tail = NULL;
}

History::~History()
{
  clear();
}

long 
History::find(Generation* pg)
{
  Record *p = head;
  while(p)
  {
    if(*pg == *p->pg)
      return p->step;
    p = p->next;
  }
  return -1;
}

void
History::append(Generation* pg, long step)
{
  Record *p = new Record();

  p->pg = pg;
  p->step = step;
  p->next = NULL;

  if(head)
  {
    tail->next = p;
    tail = p;
  } 
  else head = tail = p;
}

void
History::clear()
{
  Record *p = head, *temp;
  while(p)
  {
    temp = p->next;
    delete p->pg;
    delete p;
    p = temp;
  }
  head = tail = NULL;
}