appid_sessid

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<stdint.h>
/**----------------------creates linked list remembering position that require changes -------------*/


uint16_t dsess_id=1;
#define MAX 500

struct snode
{
    uint16_t index;
    struct snode *next;

}*start=NULL;


void insert(uint16_t ind)
{
    struct snode *p=start,*new,*prev=NULL;
    new=(struct snode *)malloc(sizeof(struct snode));


    if(start==NULL)
    {
        start=new;
        new->index=ind;
        new->next=NULL;
        return;
    }
    else
    {
        while(p!=NULL )
        {
            if((p->index)>ind)
            break;
            else
            {
                prev=p;
                p=p->next;
            }
        }
        new->next=p;
        if(prev!=NULL)
        prev->next=new;
        else
        start=new;
        new->index=ind;


    }
    return;

}

void remove_front()
{
    struct snode *ptr=NULL;

    if(start==NULL)
    {
        return ;
    }
    else
    {
        ptr=start;
        start=start->next;
        free(ptr);
        return;
    }
}

void remove_end()
{
    struct snode *ptr=start,*prev=NULL;

    if(start==NULL)
    {
        return;
    }
    else if(start->next==NULL)
    {
        ptr=start;
        start=start->next;
       free(ptr);
        return;

    }
    else
    {
        while(ptr->next!=NULL)
        {
            prev=ptr;
            ptr=ptr->next;
        }
        prev->next=NULL;
        free(ptr);
        return;
    }
}

void print()
{
    struct snode *ptr=start;
    if(start==NULL)
    return;
    while(ptr->next!=NULL)
    {
        printf("nnindex is %u ",ptr->index);
        ptr=ptr->next;
    }
    printf("nnindex is %u ",ptr->index);
}

uint16_t get_index()
{
    if(start==NULL)
    return (-1);
    return (start->index);

}

uint16_t get_last_index()
{
    struct snode *ptr=start;

    if(start==NULL)
    return -1;

    while(ptr->next!=NULL)
    ptr=ptr->next;
    return ptr->index;

}

uint16_t getSessionId()
{
    uint16_t i;
    if(start==NULL)
    {
        if(dsess_id>MAX)
        {
            dsess_id=0;
        }


        return dsess_id++;
    }
    else
    {
        i=get_index();
        remove_front();
        return i;

    }
}


int isNull()
{
    if(start==NULL)
        return 1;

    return 0;
}