statstak.cpp

基于单片机的 snmp协议解析的一些原代码 给有用的 同行

//  Copyright (c) 1996  Federal Highway Administration
//
//  This software has been developed for the Federal Highway Administration
//  by Viggen Corporation under contract with Oak Ridge National Lab.
//
//  Permission to use, copy, and distribute this software for any purpose
//  without fee is hereby granted, provided that the above copyright notice
//  appears in all copies and that both the copyright and this permission notice
//  appear in the supporting documentation.
//
//  Permission to modify this software is granted provided that the above
//  copyright and this permission notice appears in the modified software.
//
//  This software is provided "as is" with no warranty expressed or implied.
//
//  For additional information, please go to the Web site www.ntcip.org.
//
/*******************************************************************************
 *
 * Copyright (c) 1997 Viggen Corporation
 *
 * Permission to use, copy, and distribute this software for any purpose
 * without fee is hereby granted, provided that this copyright notice
 * appears in all copies and this permission notice appears in the
 * supporting documentation.
 *
 * Permission to modify this software is granted provided that the above
 * copyright and this permission notice appears in the modified software.
 *
 ******************************************************************************/


 /*********************************************
 *
 * statstak.cpp
 *
 * 9/29/97		Glenn Pruitt
 *********************************************/

//Statement Stack source file
#include <string>
using namespace std;

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <conio.h>
#include "api.h"
#include "symboltab.h"
#include "stattab.h"
#include "executor.h"
#include "lexical.h"
#include "statstak.h"

void push(struct STSTK **the_stack, int index, int eval)
{
	STSTK *curr;

   curr = (STSTK *)safe_alloc(1,sizeof(STSTK));
   curr->index = index;
   curr->evaluated = eval;
   curr->next = *the_stack;
   *the_stack = curr;
   //printf("pushed %d\n",index);
	//dump_stat_stak(*the_stack);
   return;
}

void pop(struct STSTK **the_stack)
{
	STSTK *curr;

   curr = *the_stack;
   *the_stack = curr->next;
   safe_free(curr);
   //printf("popped\n");
	//dump_stat_stak(*the_stack);
}

int get_top_index(struct STSTK *the_stack)
{
	return(the_stack->index);
}

int get_top_evaluated(struct STSTK *the_stack)
{
	return(the_stack->evaluated);
}

int stack_empty(struct STSTK *the_stack)
{
	if( the_stack == NULL)
   	return(1);
   else
   	return(0);
}

void set_top_evaluated(struct STSTK *the_stack, int eval)
{
	the_stack->evaluated = eval;
   return;
}

void extract(struct STSTK **the_stack, int index)
{
	struct STSTK *curr;
   struct STSTK *prev;

   curr = *the_stack;
   prev = NULL;

   //printf("Extracting %d\n",index);
   if(*the_stack == NULL)
   {
   	//stack is empty
      return;
   }
   while(curr && curr->index != index)
   {
   	prev = curr;
   	curr = curr->next;
   }
	if(curr == *the_stack)
   {
   	//target is the head
      *the_stack = curr->next;
      safe_free(curr);
      //printf("Extracted head\n");
      //dump_stat_stak(*the_stack);
      return;
   }
   if(!curr)
   {
   	//target does not exist
      return;
   }
	prev->next = curr->next;
   safe_free(curr);
   //printf("Extracted non-head node\n");
	//dump_stat_stak(*the_stack);
   return;
}

void dump_stat_stak(struct STSTK *the_stack)
{
	struct STSTK *curr;

   curr = the_stack;
   while(curr)
   {
   	printf("Statement %3d eval? %1d\n",curr->index,curr->evaluated);
      curr = curr->next;
   }
   getch();
   return;
}