/* termios functions internal implementation header for Linux

   Copyright (C) 1991-2025 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef TERMIOS_INTERNALS_H
#define TERMIOS_INTERNALS_H 1

#include <stddef.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sysdep.h>
#include <shlib-compat.h>

#include <k_termios.h>

/* ---- Application interface definitions ---- */

/*
 * Should old speed_t and struct termios (if applicable) compatibility
 * functions be included?
 */
#define _TERMIOS_OLD_COMPAT SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_42)

/*
 * Old struct termios (without c_ispeed and c_ospeed fields) if
 * applicable. The new struct termios *must* be binary identical up to
 * the sizeof the old structure.
 *
 * This only applies to SPARC and MIPS; for other architectures the
 * new and old speed_t interfaces both use the same struct termios.
 */
#if _HAVE_STRUCT_OLD_TERMIOS
typedef struct old_termios old_termios_t;
#else
# define OLD_NCCS NCCS
typedef struct termios old_termios_t;
#endif

/* ---- Internal function definitions ---- */

/*
 * Copy a set of c_cc fields of possibly different width. If the target
 * field is longer, then fill with _POSIX_VDISABLE == -1.
 */
static inline void
copy_c_cc (cc_t *to, size_t nto, const cc_t *from, size_t nfrom)
{
  if (nto < nfrom)
    nfrom = nto;

  to = __mempcpy (to, from, nfrom * sizeof(cc_t));
  if (nto > nfrom)
    memset (to, _POSIX_VDISABLE, (nto - nfrom) * sizeof(cc_t));
}

/* Extract the output and input legacy speed fields from c_cflag. */
static inline tcflag_t
cbaud (tcflag_t c_cflag)
{
  return c_cflag & CBAUD;
}

static inline tcflag_t
cibaud (tcflag_t c_cflag)
{
  return cbaud (c_cflag >> IBSHIFT);
}

extern speed_t
___cbaud_to_speed (tcflag_t c_cflag, speed_t other)
    __attribute_const__ attribute_hidden;

extern tcflag_t
___speed_to_cbaud (speed_t speed)
    __attribute_const__ attribute_hidden;

extern void
___termios2_canonicalize_speeds (struct termios2 *k_termios_p)
    attribute_hidden;

#endif /* TERMIOS_INTERNALS_H */