stack.h

compiler

/*@A (C) 1992 Allen I. Holub                                                */

/* Stack.h	Stack-maintenance macros. Creates downward-growing stacks
 *		(which should work in all six memory models).
 */
#ifndef __STACK_H
#define __STACK_H

#define stack_cls    /* empty */

#define stack_dcl(stack,type,size)  typedef type t_##stack;		    \
				    stack_cls t_##stack stack[size];	    \
				    stack_cls t_##stack (*p_##stack) 	    \
							    = stack + (size)
#define stack_clear(stack) (  (p_##stack)  = (stack + \
						sizeof(stack)/sizeof(*stack)) )

#define stack_full(stack)  (  (p_##stack) <= stack )
#define stack_empty(stack) (  (p_##stack) >= (stack + \
						sizeof(stack)/sizeof(*stack)) )

#define stack_ele(stack)   ((sizeof(stack)/sizeof(*stack)) - (p_##stack-stack))

#define stack_item(stack,offset) ( *(p_##stack + (offset)) )
#define stack_p(stack)	   	 p_##stack

#define push_(stack,x)	 ( *--p_##stack = (x)	)
#define pop_(stack)	 ( *p_##stack++		)

#define push(stack,x)    ( stack_full(stack) 				\
				? ((t_##stack)(long)(stack_err(1)))   	\
			        : push_(stack,x) 			)

#define pop(stack)       ( stack_empty(stack)				\
				? ((t_##stack)(long)(stack_err(0)))	\
			        : pop_(stack)				)

#define popn_(stack,amt) ( (p_##stack += amt)[-amt]  )
#define popn( stack,amt) ( (stack_ele(stack) < amt)			\
				? ((t_##stack)(long)(stack_err(0)))	\
			        : popn_(stack,amt)			)

#define stack_err(o)	 ((o) ? ferr("Stack overflow\n" ) \
			      : ferr("Stack underflow\n") )
#endif /* __STACK_H */