C Program of iget & iput algorithm

#include<iostream.h>

#include<conio.h>

#include<stdio.h>

#include<dos.h>

#include<sys/stat.h>

#include<alloc.h>

#include<stdlib.h>

typedef struct used

{

    int inode;

    struct stat temp;

    struct used *next;

    struct time create;

    struct time modi;

    int lock;

    int ref;

};

 used *getnode()

 {    used *t=(used *)malloc(sizeof(used));

    t->next=NULL;

    t->ref=1;

    struct  time temptime;

    gettime(&temptime);

    t->create=temptime;

    return t;

 }

used *fre,*start;

void init(int number)

{

    used *t1,*t2,*t3;

    // capacity of the inode list is 10

    int i,j,k,l;

    fre=getnode();

    start=NULL;

    t2=fre;

    for(i=0;i<number;i++)

    {     t1=getnode();

        t2->next=t1;

        t2=t1;

    }

}

// max inode number will be 1000

used *cache;

void usenode();

void copy_in(used *);

void input(used *);

void display();

char loop();

void close();

int search(used *);

void incref(used *);

void main()

{

    clrscr();

    init(19);

    char c;

    int j=0;

    while(1)

    {       c=loop();

        j=0;

        if(c==13)

        {    input(cache);

            if(search(cache))

                incref(cache);

            else

                usenode();

        }

        if(c==27)

            close();

    }

    display();

    getch();

}

char loop()

{

    while(!kbhit())

    {     display();

        delay(1000);

        clrscr();

    }

    char c=getch();

    return c;

}

void usenode()

{

    used *t,*temp;

    t=fre;

    if(t->next==NULL)

    {

        printf("No fre node avail.\n");

        return ;

    }

    while(t->next!=NULL)

    {       temp=t;

        t=t->next;

    }

    temp->next=NULL;

    // one node is deleted

    t=start;

    if(start==NULL)

    {

        start=getnode();

        copy_in(start);

        return ;

    }

    while(t->next!=NULL)

    {

        t=t->next;

    }

    temp=getnode();

    copy_in(temp);

    t->next=temp;

    return ;

}

void copy_in(used *temp)

{

    temp->inode=cache->inode;

}

void display()

{

    used *t;

    t=start;

    int i=0;

    // displaying used incore inodes

    while(t!=NULL)

    {       gotoxy(10,4+i);

        cout<<t->inode<<":"<<t->ref;

        printf(" Created on : %2d:%02d:%02d",t->create.ti_hour,t->create.ti_min,t->create.ti_sec);

        t=t->next;

        i++;

    }

    cout<<"\nUsed incore copies : "<<i<<"\n\n\n";

    i=0;

    // displaying fre inode list

    t=fre;

    while(t!=NULL)

    {       t=t->next;

        i++;

    }

    cout<<"Free incore copies : "<<i<<"\n\n\n";

}

void input(used *ch)

{   //    clrscr();

    int i,j,k;

    cout<<"inode number : ";

    cin>>ch->inode;

    cout<<"\nEnter permission :  ";

    cin>>i;

    ch->lock=i;

}

void close()

{

    cout<<"Enter inode for closing file :  ";

    int i;

    cin>>i;

    used *t,*pred,*succ;

    t=start;

    pred=t;

    int flag=0;

    if(t->inode==i)

    {

        flag=1;

    }

    while(t!=NULL && t->inode!=i)

    {      pred=t;

           t=t->next;

           if(t->inode==i)

           {      flag=1;

            break;

           }

    }

    if(flag==0)

    {    printf("No such found..\n");

        return ;

    }

    if(t->ref>=1)

    {        t->ref--;

    }

    if(t->ref!=0)

        return ;

    if(pred==t)

    {       if(start->next!=NULL)

            start=start->next;

        else

            start=NULL;

    }

    else

    {

        pred->next=t->next;

        t->next=NULL;

    }

    // increments free inode list

    t=fre;

    while(t->next!=NULL)

    {       t=t->next;

    }

    succ=getnode();

    t->next=succ;

}

int search(used *ch)

{

    used *t;

    t=start;

    if(t==NULL)

        return 0;

    int flag=0;

    while(t!=NULL)

    {          if(t->inode == ch->inode)

        {    flag=1;

            return flag;

        }

        t=t->next;

    }

    return flag;

}

void incref(used *ch)

{

    used *t;

    t=start;

    int flag=0;

    while(t!=NULL)

    {          if(t->inode == ch->inode)

        {       t->ref++;

            break;

        }

        t=t->next;

    }

}