// SPDX-License-Identifier: ISC

#include <libbasis/misc.h>

#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>

uint64_t iec_unit_post(uint64_t val, char **unit)
{
	static const char unit_table[] = "kKmMgGtTpPeEzZyY";
	char *match;
	size_t pos;

	match = strchr(unit_table, **unit);
	if (!match)
		return val;

	(*unit)++;
	pos = (match - unit_table) / 2 + 1;

	for (; pos; --pos)
		val *= 1024;

	return val;
}

int fd_set_block(int fd, bool block)
{
	int fl;

	fl = fcntl(fd, F_GETFL, 0);
	if (fl == -1)
		return -1;

	if (block)
		fl = fl & ~O_NONBLOCK;
	else
		fl = fl | O_NONBLOCK;

	if (fcntl(fd, F_SETFL, fl) == -1)
		return -1;

	return 0;
}

ssize_t read_blocking(int fd, void *buf, size_t len)
{
	struct pollfd pfd = { .fd = fd, .events = POLLIN };
	ssize_t rv;

	for (;;) {
		rv = read(fd, buf, len);
		if (rv >= 0 || (rv < 0 && errno != EAGAIN))
			return rv;

		if (poll(&pfd, 1, -1) < 0)
			return -1;
	}
}

ssize_t write_blocking(int fd, const void *buf, size_t len)
{
	struct pollfd pfd = { .fd = fd, .events = POLLOUT };
	ssize_t rv;

	for (;;) {
		rv = write(fd, buf, len);
		if (rv >= 0 || (rv < 0 && errno != EAGAIN))
			return rv;

		if (poll(&pfd, 1, -1) < 0)
			return -1;
	};
}

ssize_t read_all(int fd, void *buf, size_t len)
{
	ssize_t r;
	size_t rem = len;

	while (rem) {
		r = read_blocking(fd, buf, rem);
		if (r < 0)
			return -1;
		else if (!r)
			return len - rem;
		buf += r;
		rem -= r;
	}

	return len;
}


ssize_t write_all(int fd, const void *buf, size_t len)
{
	ssize_t r;
	size_t rem = len;

	while (rem) {
		r = write_blocking(fd, buf, rem);
		if (r < 0)
			return -1;
		buf += r;
		rem -= r;
	}

	return len;
}

int read_exact(int fd, void *buf, size_t len)
{
	ssize_t r;

	r = read_all(fd, buf, len);
	if (r < 0) {
		return -1;
	} else if ((size_t)r != len) {
		errno = EPIPE;
		return -1;
	}

	return 0;
}

int openat_read_all_close(int dirfd, const char *name, void *buf, size_t len)
{
	int fd, ret, errsv;

	fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC);
	if (fd < 0)
		return -1;

	ret = read_all(fd, buf, len);
	if (ret < 0)
		errsv = errno;
	close(fd);
	if (ret < 0)
		errno = errsv;

	return ret;
}

int openat_write_all_close(int dirfd, const char *name, const void *buf, size_t len, bool append)
{
	int fd, flags, ret, errsv;

	flags = O_WRONLY | O_CLOEXEC;
	if (append)
		flags |= O_APPEND;
	else
		flags |= O_TRUNC;

	fd = openat(dirfd, name, flags);
	if (fd < 0)
		return -1;

	ret = write_all(fd, buf, len);
	if (ret < 0)
		errsv = errno;
	close(fd);
	if (ret < 0)
		errno = errsv;

	return ret;
}

int openat_read_exact_close(int dirfd, const char *name, void *buf, size_t len)
{
	int fd, ret, errsv;

	fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC);
	if (fd < 0)
		return -1;

	ret = read_exact(fd, buf, len);
	if (ret < 0)
		errsv = errno;
	close(fd);
	if (ret < 0)
		errno = errsv;

	return ret;
}