/* This file is part of Mailfromd.
   Copyright (C) 2005-2020 Sergey Poznyakoff

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <mailutils/alloc.h>
#include "mailfromd.h"

struct mf_stack {
	char *base;
	size_t tos;
	size_t elsize;
	size_t elcount;
};

#define STACK_PTR(s, n) (void*)((s)->base + (n) * (s)->elsize)

mf_stack_t
mf_stack_create(size_t elsize, size_t count)
{
	mf_stack_t stk = mu_alloc(sizeof *stk);
	stk->elsize = elsize;
	stk->base = NULL;
	if (!count)
		count = 64;
	stk->elcount = count;
	stk->base = mu_2nrealloc(stk->base,
			       &stk->elcount,
			       stk->elsize);
	stk->tos = 0;
	return stk;
}

void
mf_stack_destroy(mf_stack_t *pstk)
{
	free((*pstk)->base);
	free(*pstk);
	*pstk = NULL;
}

void
mf_stack_push(mf_stack_t stk, void *item)
{
	if (stk->tos == stk->elcount)
		stk->base = mu_2nrealloc(stk->base,
				       &stk->elcount,
				       stk->elsize);
	memcpy(STACK_PTR(stk, stk->tos), item, stk->elsize);
	stk->tos++;
}

int
mf_stack_pop(mf_stack_t stk, void *ptr)
{
	if (stk->tos == 0)
		return 1;
	--stk->tos;
	if (ptr)
		memcpy(ptr, STACK_PTR(stk, stk->tos), stk->elsize);
	return 0;
}

int
mf_stack_peek(mf_stack_t stk, size_t n, void *ptr)
{
	if (stk->tos == 0 || n + 1 > stk->tos)
		return 1;
	if (ptr)
		memcpy(ptr, STACK_PTR(stk, stk->tos - 1 - n), stk->elsize);
	return 0;
}

size_t
mf_stack_count(mf_stack_t stk)
{
	return stk->tos;
}

int
mf_stack_enumerate_desc(mf_stack_t stk, mf_stack_enumerator fun, void *data)
{
	size_t i;
	for (i = stk->tos; i > 0; i--) {
		int rc = fun(STACK_PTR(stk, i - 1), data);
		if (rc)
			return rc;
	}
	return 0;
}

int
mf_stack_enumerate_asc(mf_stack_t stk, mf_stack_enumerator fun, void *data)
{
	size_t i;
	for (i = 0; i < stk->tos; i++) {
		int rc = fun(STACK_PTR(stk, i), data);
		if (rc)
			return rc;
	}
	return 0;
}