/*
	Copyright 1982
	Alcyon Corporation
	8716 Production Ave.
	San Diego, Ca.  92121
*/

/* node allocation, node stack manipulation routines */

#include "parser.h"

int opdontop;
int strassign;

/* talloc - expression area tree node allocation
 *		Allocates area and checks for overflow.*/
char *talloc(size)					/* returns pointer to node*/
int size;							/* size of node to alloc*/
{
	register char *p;

	p = opap;
	if( p + size >= &exprarea[EXPSIZE] )
		ferror("expression too complex");
	opap = p + size;
	return(p);
}

/*
 * enalloc - external name alloc
 *		Allocates an expression tree node for an external name and
 *		copies symbol table info and symbol into tree node.
 */
char *enalloc(sp)					/* returns - none*/
struct symbol *sp;					/* pointer to symbol table entry*/
{
	register struct extnode *ep;

	ep = talloc(sizeof(*ep));
	ep->t_op = SYMBOL;
	ep->t_sc = sp->s_sc;
	ep->t_type = sp->s_type;
	ep->t_dp = sp->s_dp;
	ep->t_ssp = sp->s_ssp;
	ep->t_offset = sp->s_offset;
	symcopy(sp->s_symbol,ep->t_symbol);
	return(ep);
}

/* cnalloc - constant node allocation
 *		Allocates a constant tree node and fills the info fields.*/
char *cnalloc(type,value)		/* returns pointer to node*/
int type;							/* data type*/
int value;							/* constant value*/
{
	register struct conode *cp;

	cp = talloc(sizeof(*cp));
	cp->t_op = CINT;
	cp->t_type = type;
	cp->t_dp = 0;
	cp->t_ssp = 0;
	cp->t_value = value;
	return(cp);
}

/* lcnalloc - long constant node allocation*/
/*		Allocates a constant tree node and fills the info fields.*/
char *lcnalloc(type,value)		/* returns pointer to node*/
int type;						/* data type*/
long value;						/* constant value*/
{
	register struct lconode *cp;

	cp = talloc(sizeof(*cp));
	cp->t_op = CLONG;
	cp->t_type = type;
	cp->t_dp = 0;
	cp->t_ssp = 0;
	cp->t_lvalue = value;
	return(cp);
}

/* fpcnalloc - floating point constant node allocation*/
/*		Allocates a constant tree node and fills the info fields.*/
char *fpcnalloc(type,value)		/*[vlh] 3.4 returns pointer to node*/
int type;						/* data type*/
long value;						/* constant value*/
{
	register struct lconode *cp;

	cp = talloc(sizeof(*cp));
	cp->t_op = CFLOAT;
	cp->t_type = type;
	cp->t_dp = 0;
	cp->t_ssp = 0;
	cp->t_lvalue = value;
	return(cp);
}

/* tnalloc - tree node allocation*/
/*		Allocates an operator tree node and fills the info fields*/
char *tnalloc(op,type,dp,ssp,left,right)	/* returns pointer to node*/
int op;								/* operator*/
int type;							/* operator type*/
int dp;								/* dimension pointer or other info*/
int ssp;							/* structure length pointer*/
char *left;							/* left subtree*/
char *right;						/* right subtree*/
{
	register struct tnode *tp;

	tp = talloc(sizeof(*tp));
	tp->t_op = op;
	tp->t_type = type;
	tp->t_dp = dp;
	tp->t_ssp = ssp;
	tp->t_left = left;
	tp->t_right = right;
	return(tp);
}

/* snalloc - symbol node allocation*/
/*		Allocates a tree symbol node and sets the info in it*/
char *snalloc(type,sc,off,dp,ssp)	/* returns pointer to node alloc'ed*/
int type;							/* symbol type*/
int sc;								/* storage class*/
int off;							/* offset*/
int dp;								/* dimension pointer or other info*/
int ssp;							/* structure size pointer*/
{
	register struct symnode *snp;

	snp = talloc(sizeof(*snp));
	snp->t_op = SYMBOL;
	snp->t_sc = sc;
	snp->t_type = type;
	snp->t_dp = dp;
	snp->t_ssp = ssp;
	snp->t_offset = off;
	return(snp);
}

/* pushopd - put operand node onto operand stack*/
/*		Checks for operand stack overflow.*/
pushopd(tp)							/* returns - none*/
struct tnode *tp;					/* pointer to tree node to push*/
{
	if( opdp >= &opdstack[OPDSIZE] )
		ferror("expression too complex");
	*opdp++ = tp;
}

/* popopd - pop operand stack*/
/*		Checks for stack underflow*/
char *popopd()						/* returns ptr to top operand*/
{
	register struct tnode *tp;

	if( opdp <= &opdstack[0] )
		return(0);
	tp = *--opdp;
	return(tp);
}