/*
 * memory.c
 *
 *  Created on: Jun 9, 2010
 *      Author: WangYun
 */
#include<stdio.h>

#define PAGE_NUM  20
#define BLOCK 3

void get_page(int page_seq[])
{
 int i=PAGE_NUM;
 printf("Please input %d numbers,which is  the sequence of page number "
   "such as(7 0 1 8 ...)\n",i);
 for(i=0;i<PAGE_NUM;i++)
  scanf("%d",&page_seq[i]);
}

int sum_found(int found[])
{
 int i;
 int sum=0;
 for(i=0;i<BLOCK;i++)
  sum+=found[i];
 return sum;
}

int opt(int page_seq[])
{
 int p;
 int i,j;
 int found[BLOCK]={0};
 int block[BLOCK];
 int lack=0;
 for(i=0;i<BLOCK;i++) /*Initiate the physical block*/
   block[i]=-1;
 for(i=0;i<PAGE_NUM;i++)
 {
  for(p=0;p<BLOCK;p++)
   found[p]=0;
  for(p=0;p<BLOCK;p++)
   if(block[p]==page_seq[i])
    break;
  if(p==BLOCK)  /*Not find the page in the physical block*/
  {
   lack++;
   for(p=0;p<BLOCK;p++)
    printf("%d\t",block[p]);
   printf("\nlack_page_number :%d\n",page_seq[i]);
   for(j=i+1;j<PAGE_NUM;j++)
   {
    for(p=0;p<BLOCK;p++)
     if(block[p]==page_seq[j])
     {
      found[p]=1;
      break;
     }
    if(sum_found(found)==3)
     break;
    else continue;
   }
   if(sum_found(found)==3)
    block[p]=page_seq[i];
   else
    for(p=0;p<BLOCK;p++)
     if(found[p]==0 || block[p]==-1)
     {block[p]=page_seq[i];break;}
  }
 }
 return lack;
}

int fifo(int page_seq[])
{
 int rear=-1;
 int i,p,k;
 int lack=0,replace=0;
 int block[BLOCK];
 for(i=0;i<BLOCK;i++) /*Initiate the physical block*/
   block[i]=-1;
 for(i=0;i<PAGE_NUM;i++)
 {
  for(p=0;p<BLOCK;p++)
   if(block[p]==page_seq[i])
   {
    replace=block[p];
    while(p<rear)
     {
     block[p]=block[p+1];
     p++;
     }
    block[rear]=replace;
    break;
   }
  if(p==BLOCK)
  {
   lack++;
   for(p=0;p<BLOCK;p++)
    printf("%d\t",block[p]);
   printf("\nlack_page_number :%d\n",page_seq[i]);
   for(p=0;p<BLOCK;p++)
    if(block[p]==-1)
    {
     block[p]=page_seq[i];
     rear=rear+1;
     break;
    }
   if(p==BLOCK)
   {
    for(p=0;p<BLOCK-1;p++)
     block[p]=block[p+1];
    block[BLOCK-1]=page_seq[i];
    for(k=0;k<BLOCK;k++)//////////
     printf("%d\t",block[k]);
    printf("\n");////////////
   }
  }
 }
 return lack;
}

int lru(int page_seq[])
{
 int p;
  int i,j;
  int found[BLOCK]={0};
  int block[BLOCK];
  int lack=0;
  for(i=0;i<BLOCK;i++) /*Initiate the physical block*/
    block[i]=-1;
  for(i=0;i<PAGE_NUM;i++)
  {
   for(p=0;p<BLOCK;p++)
    found[p]=0;
   for(p=0;p<BLOCK;p++)
    if(block[p]==page_seq[i])
     break;
   if(p==BLOCK)  /*Not find the page in the physical block*/
   {
    lack++;
    for(p=0;p<BLOCK;p++)
     printf("%d\t",block[p]);
    printf("\nlack_page_number :%d\n",page_seq[i]);
    for(j=i-1;j>=0;j--)
    {
     for(p=0;p<BLOCK;p++)
      if(block[p]==page_seq[j])
      {
       found[p]=1;
       break;
      }
     if(sum_found(found)==3)
      break;
     else continue;
    }
    if(sum_found(found)==3)
     block[p]=page_seq[i];
    else
     for(p=0;p<BLOCK;p++)
      if(found[p]==0 || block[p]==-1)
      {block[p]=page_seq[i];break;}
   }
  }
  return lack;
}

int main(void)
{
 int page_seq[PAGE_NUM];
 int lack=0;
 float lack_rate=0.0;
 get_page(page_seq);
// for(i=0;i<BLOCK;i++) /*Initiate the physical block*/
//  block[i]=-1;
 lack=opt(page_seq);
 lack_rate=(1.0*lack)/PAGE_NUM;
 printf("OPT:   lack_times=%d\tlack_rate=%f\n",lack,lack_rate);
 lack=fifo(page_seq);
  lack_rate=(1.0*lack)/PAGE_NUM;
 printf("FIFO:   lack_times=%d\tlack_rate=%f\n",lack,lack_rate);
 lack=lru(page_seq);
  lack_rate=(1.0*lack)/PAGE_NUM;
  printf("LRU:   lack_times=%d\tlack_rate=%f\n",lack,lack_rate);
 return 1;
}