//
//  Symtab.cpp
//  assembly
//
//  Created by Ethan Laur on 3/11/14.
//  Copyright (c) 2014 Ethan Laur. All rights reserved.
//

#include "Symtab.h"
#include <string.h>
#include <stdio.h>

int Symtab::findNodeByName_private(char *sym_name)
{
    Symtab_struct *list = head;
    int i;
    for (i = 0; list != NULL; list = list->next, i++)
        if (strcmp(sym_name, list->sym_name) == 0)
            break;
    return list == NULL ? -1 : i;
}

Symtab_struct *Symtab::findNodeByNumber(int sym_id)
{
    Symtab_struct *list = head;
    int i;
    if (sym_id < 0) return NULL;
    for (i = 0; i < sym_id && list != NULL; list = list->next, i++);
    return list;
}

void Symtab::insertNode(char *sym_name, int sym_location)
{
    Symtab_struct *node = (Symtab_struct *)malloc(sizeof(Symtab_struct));
    strcpy(node->sym_name, sym_name);
    node->sym_location = sym_location;
    if (findNodeByName_private(sym_name) >= 0)
    {
        printf("[WARN in Symtab::insertNode] Redefinition of symbol %s is ignored\n", sym_name);
        return; //don't add it twice
    }
    if (head == NULL) //empty list
    {
        head = tail = node;
    }
    else
    {
        tail->next = node;
        tail = node;
    }
    tail->next = NULL;
}

void Symtab::deleteNode(char *sym_name)
{
    Symtab_struct *parent, *child, *node;
    int nodenum = findNodeByName_private(sym_name);
    parent = findNodeByNumber(nodenum - 1);
    node = findNodeByNumber(nodenum);
    child = findNodeByNumber(nodenum + 1);
    if (nodenum == 0) //deleting the head
    {
        free(node);
        head = child;
    }
    else if (node == tail) //delete the tail
    {
        free(node);
        tail = parent;
    }
    else if (node == NULL) //node does not exist
    {
        printf("[WARN in Symtab::deleteNode] Attempting to delete a symbol %s that does not exist\n",
              sym_name);
    }
    else //somewhere in mid list
    {
        parent->next = child;
        free(node);
    }
}

Symtab_struct *Symtab::findNodeByName(char *sym_name)
{
    return findNodeByNumber(findNodeByName_private(sym_name));
}