/* SPDX-License-Identifier: LGPL-2.1 OR MIT */

#include "../nolibc.h"

#ifndef _NOLIBC_SYS_SELECT_H
#define _NOLIBC_SYS_SELECT_H

#include <linux/time.h>
#include <linux/unistd.h>

/* commonly an fd_set represents 256 FDs */
#ifndef FD_SETSIZE
#define FD_SETSIZE     256
#endif

#define FD_SETIDXMASK (8 * sizeof(unsigned long))
#define FD_SETBITMASK (8 * sizeof(unsigned long)-1)

/* for select() */
typedef struct {
        unsigned long fds[(FD_SETSIZE + FD_SETBITMASK) / FD_SETIDXMASK];
} fd_set;

#define FD_CLR(fd, set) do {                                            \
                fd_set *__set = (set);                                  \
                int __fd = (fd);                                        \
                if (__fd >= 0)                                          \
                        __set->fds[__fd / FD_SETIDXMASK] &=             \
                                ~(1U << (__fd & FD_SETBITMASK));        \
        } while (0)

#define FD_SET(fd, set) do {                                            \
                fd_set *__set = (set);                                  \
                int __fd = (fd);                                        \
                if (__fd >= 0)                                          \
                        __set->fds[__fd / FD_SETIDXMASK] |=             \
                                1 << (__fd & FD_SETBITMASK);            \
        } while (0)

#define FD_ISSET(fd, set) ({                                            \
                        fd_set *__set = (set);                          \
                        int __fd = (fd);                                \
                int __r = 0;                                            \
                if (__fd >= 0)                                          \
                        __r = !!(__set->fds[__fd / FD_SETIDXMASK] &     \
1U << (__fd & FD_SETBITMASK));                                          \
                __r;                                                    \
        })

#define FD_ZERO(set) do {                                               \
                fd_set *__set = (set);                                  \
                int __idx;                                              \
                int __size = (FD_SETSIZE+FD_SETBITMASK) / FD_SETIDXMASK;\
                for (__idx = 0; __idx < __size; __idx++)                \
                        __set->fds[__idx] = 0;                          \
        } while (0)

/*
 * int select(int nfds, fd_set *read_fds, fd_set *write_fds,
 *            fd_set *except_fds, struct timeval *timeout);
 */

static __attribute__((unused))
int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
{
#if defined(__NR_pselect6_time64)
        struct __kernel_timespec t;

        if (timeout) {
                t.tv_sec  = timeout->tv_sec;
                t.tv_nsec = (uint32_t)timeout->tv_usec * 1000;
        }
        return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
#else
        struct __kernel_old_timespec t;

        if (timeout) {
                t.tv_sec  = timeout->tv_sec;
                t.tv_nsec = (uint32_t)timeout->tv_usec * 1000;
        }
        return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
#endif
}

static __attribute__((unused))
int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
{
        return __sysret(sys_select(nfds, rfds, wfds, efds, timeout));
}


#endif /* _NOLIBC_SYS_SELECT_H */