#ifndef STACK_H_
#define STACK_H_

#include "config.h"
#include "xmalloc.h"

#include <stddef.h>

#define stack(T) struct T##STACK
#define stack_func(T, f) T##STACK##f

#define stack_declare(T, X) \
 \
stack(T) { \
	T *arr; \
	size_t size, length; \
}; \
 \
X void stack_func(T, init)(stack(T) *); \
X void stack_func(T, end)(stack(T) *); \
X void stack_func(T, clear)(stack(T) *, size_t); \
 \
X void stack_func(T, push)(stack(T) *, const T *); \
X void stack_func(T, pushnull)(stack(T) *); \
X int stack_func(T, pop)(stack(T) *, T *); \
/* X int stack_func(T, peek)(const stack(T) *, T *); */ \
ATTR_PURE \
X T *stack_func(T, at)(const stack(T) *, size_t); \
ATTR_PURE \
X size_t stack_func(T, size)(const stack(T) *); \
/* end of declaration */

#define stack_define(T, X, prepare, clean, copy) \
X void stack_func(T, init)(stack(T) *s) { \
	s->arr = xmalloc(s->size = 7, sizeof *s->arr); \
	s->length = 0; \
} \
 \
X void stack_func(T, end)(stack(T) *s) { \
	while (s->length) { \
		--s->length; \
		(clean)(&s->arr[s->length]); \
	} \
	xfree(s->arr); \
	s->arr = 0; \
} \
 \
X void stack_func(T, clear)(stack(T) *s, size_t n) { \
	while (n && s->length) { \
		--n; \
		--s->length; \
		(clean)(&s->arr[s->length]); \
	} \
} \
 \
X void stack_func(T, push)(stack(T) *s, const T *x) { \
	if (s->length >= s->size) { \
		s->arr = xrealloc(s->arr, s->size *= 2); \
	} \
	(prepare)(&s->arr[s->length]); \
	(copy)(&s->arr[s->length], x); \
	++s->length; \
} \
 \
X void stack_func(T, pushnull)(stack(T) *s) { \
	if (s->length >= s->size) { \
		s->arr = xrealloc(s->arr, s->size *= 2); \
	} \
	(prepare)(&s->arr[s->length]); \
	++s->length; \
} \
 \
X int stack_func(T, pop)(stack(T) *s, T *x) { \
	if (s->length) { \
		--s->length; \
		(copy)(x, &s->arr[s->length]); \
		(clean)(&s->arr[s->length]); \
		return 0; \
	} \
	return 1; \
} \
 \
/* X int stack_func(T, peek)(const stack(T) *s, T *x) { \
	if (s->length) { \
		(copy)(x, &s->arr[s->length - 1]); \
		return 0; \
	} \
	return 1; \
} */ \
 \
X size_t stack_func(T, size)(const stack(T) *s) { \
	return s->length; \
} \
 \
X T *stack_func(T, at)(const stack(T) *s, size_t n) { \
	if (n < s->length) { \
		return &s->arr[s->length - n - 1u]; \
	} \
	return NULL; \
} \
/* end of definition */

#endif /* STACK_H_ */