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/*******************************************************************/
/*** FILE : Po_syn_stack.c ***/
/*** AUTHOR: Sekhar Muddana ***/
/*** PUBLIC ROUTINES: ***/
/*** void Push_token() ***/
/*** int Get_top_token() ***/
/*** int Get_next_to_top_token() ***/
/*** int Pop_token() ***/
/*** void Print_stack() ***/
/*** PRIVARE ROUTINES: None. ***/
/*** MODULE DESCRIPTION: ***/
/*** This module contains routines which manipulate Syntax ***/
/*** stack These routines are called by the module ***/
/*** Po_parse_poly.c while doing the parsing. ***/
/*******************************************************************/
#include <stdio.h>
#include "Po_syn_stack.h"
/*******************************************************************/
/* MODIFIES: */
/* Stack -- Syntax stack. */
/* Sp_ptr -- Syntax stack pointer. */
/* REQUIRES: */
/* token -- to be pushed onto the stack. */
/* RETURNS: None. */
/*******************************************************************/
void Push_token(Stack,Sp_ptr,Token)
int Stack[];
int *Sp_ptr;
int Token;
{
if (*Sp_ptr < STACK_SIZE - 1)
Stack[++(*Sp_ptr)] = Token;
else
printf(" Stack full\n");
}
/*******************************************************************/
/* MODIFIES: None. */
/* REQUIRES: */
/* Stack -- Syntax stack. */
/* Sp -- Syntax stack pointer. */
/* RETURNS: */
/* Token at the top of the stack. */
/*******************************************************************/
int Get_top_token(Stack,Sp)
int Stack[];
int Sp;
{
return(Stack[Sp]);
}
/*******************************************************************/
/* MODIFIES: None. */
/* REQUIRES: */
/* Stack -- Syntax stack. */
/* Sp -- Syntax stack pointer. */
/* RETURNS: */
/* Token at second from the top of the Stack. */
/*******************************************************************/
int Get_next_to_top_token(Stack,Sp)
int Stack[];
int Sp;
{
return(Stack[Sp-1]);
}
/*******************************************************************/
/* MODIFIES: */
/* Stack -- Syntax stack. */
/* Sp_ptr -- Syntax stack pointer. */
/* REQUIRES: None. */
/* RETURNS: */
/* Token popped from the top of the Stack. */
/*******************************************************************/
int Pop_token(Stack,Sp_ptr)
int Stack[];
int *Sp_ptr;
{
if ((*Sp_ptr >= 0) && (*Sp_ptr < STACK_SIZE))
return(Stack[(*Sp_ptr)--]);
else
printf(" Stack index out of bounds\n");
}
/*******************************************************************/
/* MODIFIES: None. */
/* REQUIRES: */
/* Stack -- Syntax stack. */
/* Sp -- Syntax stack pointer. */
/* RETURNS: None. */
/* FUNCTION: */
/* Print the tokens stored in the stack. */
/*******************************************************************/
void Print_syn_stack(Stack,Sp)
int Stack[];
int Sp;
{
int i;
for (i=0;i<=Sp;i++)
printf("Stack[%d] = %d\n",i,Stack[i]);
}
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