#include <stdint.h>
#include <stddef.h>
#include <sys/stat.h>
#include <sys/mman.h>

#include "common.h"
#include "scaffold.h"
#include "types.h"
#include "mbuf.h"

// https://nullprogram.com/blog/2023/09/27/
// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1428r0.pdf
// mmap()
int
mkmbuf(int fd, struct mbuf *ch)
{
	struct stat sb = { 0 };
	u8 *addr;

	if (fstat(fd, &sb) == -1)
		return -1;

	addr = mmap(NULL, (usize)sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	if (addr == MAP_FAILED)
		return -1;

	ch->buf = addr;
	ch->len = sb.st_size;
	return 0;
}

void
freembuf(struct mbuf *b)
{
	/* FIXME check return code of munmap() */
	munmap(b->buf, (usize)b->len);
}