// SPDX-License-Identifier: ISC

#include <libbasis/dynalloc.h>

#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#define DYNALLOC_MIN 64

bool dynalloc_reserve_add(struct dynalloc *s, size_t len)
{
	size_t new_res;
	void *new_buf;

	if (len > SIZE_MAX - s->len)
		return errno = ERANGE, false;

	new_res = s->res;
	while (new_res < s->len + len) {
		if (new_res < DYNALLOC_MIN)
			new_res = DYNALLOC_MIN;
		else if (new_res <= SIZE_MAX / 2)
			new_res *= 2;
		else
			return errno = ERANGE, false;
	}

	new_buf = realloc(s->buf, new_res);
	if (!new_buf)
		return false;

	s->buf = new_buf;
	s->res = new_res;

	return true;
}

bool dynalloc_catb(struct dynalloc *s, const char *buf, size_t len)
{
	if (!dynalloc_reserve_add(s, len))
		return false;

	memcpy(s->buf + s->len, buf, len);
	s->len += len;

	return true;
}

bool dynalloc_cats(struct dynalloc *s, const char *buf)
{
	return dynalloc_catb(s, buf, strlen(buf));
}

bool dynalloc_cat0(struct dynalloc *s)
{
	return dynalloc_catb(s, "", 1);
}

void dynalloc_free(struct dynalloc *s)
{
	free(s->buf);

	s->len = 0;
	s->res = 0;
}