/* do not edit automatically generated by mc from IO.  */
/* IO.mod provides Read, Write, Errors procedures mapping onto 0, 1 and 2.

Copyright (C) 2001-2024 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Modula-2 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
General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include <stdbool.h>
#   if !defined (PROC_D)
#      define PROC_D
       typedef void (*PROC_t) (void);
       typedef struct { PROC_t proc; } PROC;
#   endif

#   if !defined (TRUE)
#      define TRUE (1==1)
#   endif

#   if !defined (FALSE)
#      define FALSE (1==0)
#   endif

#define _IO_H
#define _IO_C

#   include "GStrLib.h"
#   include "GSYSTEM.h"
#   include "Glibc.h"
#   include "GFIO.h"
#   include "Gerrno.h"
#   include "GASCII.h"
#   include "Gtermios.h"

#   define MaxDefaultFd 2
typedef struct IO_BasicFds_r IO_BasicFds;

typedef struct IO__T1_a IO__T1;

struct IO_BasicFds_r {
                       bool IsEof;
                       bool IsRaw;
                     };

struct IO__T1_a { IO_BasicFds array[MaxDefaultFd+1]; };
static IO__T1 fdState;

/*
   IsDefaultFd - returns TRUE if, fd, is 0, 1 or 2.
*/

extern "C" void IO_Read (char *ch);

/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

extern "C" void IO_Write (char ch);

/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

extern "C" void IO_Error (char ch);
extern "C" void IO_UnBufferedMode (int fd, bool input);
extern "C" void IO_BufferedMode (int fd, bool input);

/*
   EchoOn - turns on echoing for file descriptor, fd.  This
            only really makes sence for a file descriptor opened
            for terminal input or maybe some specific file descriptor
            which is attached to a particular piece of hardware.
*/

extern "C" void IO_EchoOn (int fd, bool input);

/*
   EchoOff - turns off echoing for file descriptor, fd.  This
             only really makes sence for a file descriptor opened
             for terminal input or maybe some specific file descriptor
             which is attached to a particular piece of hardware.
*/

extern "C" void IO_EchoOff (int fd, bool input);

/*
   IsDefaultFd - returns TRUE if, fd, is 0, 1 or 2.
*/

static bool IsDefaultFd (int fd);

/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

static void doWrite (int fd, FIO_File f, char ch);

/*
   setFlag - sets or unsets the appropriate flag in, t.
*/

static void setFlag (termios_TERMIOS t, termios_Flag f, bool b);

/*
   doraw - sets all the flags associated with making this
           file descriptor into raw input/output.
*/

static void doraw (termios_TERMIOS term);

/*
   dononraw - sets all the flags associated with making this
              file descriptor into non raw input/output.
*/

static void dononraw (termios_TERMIOS term);

/*
   Init -
*/

static void Init (void);


/*
   IsDefaultFd - returns TRUE if, fd, is 0, 1 or 2.
*/

static bool IsDefaultFd (int fd)
{
  return (fd <= MaxDefaultFd) && (fd >= 0);
  /* static analysis guarentees a RETURN statement will be used before here.  */
  __builtin_unreachable ();
}


/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

static void doWrite (int fd, FIO_File f, char ch)
{
  int r;

  if (fdState.array[fd].IsRaw)
    {
      /* avoid dangling else.  */
      if (! fdState.array[fd].IsEof)
        {
          for (;;)
          {
            r = static_cast<int> (libc_write (FIO_GetUnixFileDescriptor (f), &ch, static_cast<size_t> (1)));
            if (r == 1)
              {
                return ;
              }
            else if (r == -1)
              {
                /* avoid dangling else.  */
                r = errno_geterrno ();
                if ((r != errno_EAGAIN) && (r != errno_EINTR))
                  {
                    fdState.array[fd].IsEof = true;
                    return ;
                  }
              }
          }
        }
    }
  else
    {
      FIO_WriteChar (f, ch);
    }
}


/*
   setFlag - sets or unsets the appropriate flag in, t.
*/

static void setFlag (termios_TERMIOS t, termios_Flag f, bool b)
{
  if (termios_SetFlag (t, f, b))
    {}  /* empty.  */
}


/*
   doraw - sets all the flags associated with making this
           file descriptor into raw input/output.
*/

static void doraw (termios_TERMIOS term)
{
  /* 
    * from man 3 termios
    *           termios_p->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
    *                                   | INLCR | IGNCR | ICRNL | IXON);
    *           termios_p->c_oflag &= ~OPOST;
    *           termios_p->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
    *           termios_p->c_cflag &= ~(CSIZE | PARENB);
    *           termios_p->c_cflag |= CS8;
  */
  setFlag (term, termios_ignbrk, false);
  setFlag (term, termios_ibrkint, false);
  setFlag (term, termios_iparmrk, false);
  setFlag (term, termios_istrip, false);
  setFlag (term, termios_inlcr, false);
  setFlag (term, termios_igncr, false);
  setFlag (term, termios_icrnl, false);
  setFlag (term, termios_ixon, false);
  setFlag (term, termios_opost, false);
  setFlag (term, termios_lecho, false);
  setFlag (term, termios_lechonl, false);
  setFlag (term, termios_licanon, false);
  setFlag (term, termios_lisig, false);
  setFlag (term, termios_liexten, false);
  setFlag (term, termios_parenb, false);
  setFlag (term, termios_cs8, true);
}


/*
   dononraw - sets all the flags associated with making this
              file descriptor into non raw input/output.
*/

static void dononraw (termios_TERMIOS term)
{
  /* 
    * we undo these settings, (although we leave the character size alone)
    *
    * from man 3 termios
    *           termios_p->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
    *                                   | INLCR | IGNCR | ICRNL | IXON);
    *           termios_p->c_oflag &= ~OPOST;
    *           termios_p->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
    *           termios_p->c_cflag &= ~(CSIZE | PARENB);
    *           termios_p->c_cflag |= CS8;
  */
  setFlag (term, termios_ignbrk, true);
  setFlag (term, termios_ibrkint, true);
  setFlag (term, termios_iparmrk, true);
  setFlag (term, termios_istrip, true);
  setFlag (term, termios_inlcr, true);
  setFlag (term, termios_igncr, true);
  setFlag (term, termios_icrnl, true);
  setFlag (term, termios_ixon, true);
  setFlag (term, termios_opost, true);
  setFlag (term, termios_lecho, true);
  setFlag (term, termios_lechonl, true);
  setFlag (term, termios_licanon, true);
  setFlag (term, termios_lisig, true);
  setFlag (term, termios_liexten, true);
}


/*
   Init -
*/

static void Init (void)
{
  unsigned int fdi;

  for (fdi=0; fdi<=MaxDefaultFd; fdi++)
    {
      fdState.array[fdi].IsEof = false;
      fdState.array[fdi].IsRaw = false;
    }
}


/*
   IsDefaultFd - returns TRUE if, fd, is 0, 1 or 2.
*/

extern "C" void IO_Read (char *ch)
{
  int r;

  FIO_FlushBuffer (FIO_StdOut);
  FIO_FlushBuffer (FIO_StdErr);
  if (fdState.array[0].IsRaw)
    {
      if (fdState.array[0].IsEof)
        {
          (*ch) = ASCII_eof;
        }
      else
        {
          for (;;)
          {
            r = static_cast<int> (libc_read (FIO_GetUnixFileDescriptor (FIO_StdIn), ch, static_cast<size_t> (1)));
            if (r == 1)
              {
                return ;
              }
            else if (r == -1)
              {
                /* avoid dangling else.  */
                r = errno_geterrno ();
                if (r != errno_EAGAIN)
                  {
                    fdState.array[0].IsEof = true;
                    (*ch) = ASCII_eof;
                    return ;
                  }
              }
          }
        }
    }
  else
    {
      (*ch) = FIO_ReadChar (FIO_StdIn);
    }
}


/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

extern "C" void IO_Write (char ch)
{
  doWrite (1, FIO_StdOut, ch);
}


/*
   doWrite - performs the write of a single character, ch,
             onto fd or f.
*/

extern "C" void IO_Error (char ch)
{
  doWrite (2, FIO_StdErr, ch);
}

extern "C" void IO_UnBufferedMode (int fd, bool input)
{
  termios_TERMIOS term;
  int result;

  if (IsDefaultFd (fd))
    {
      fdState.array[fd].IsRaw = true;
    }
  term = termios_InitTermios ();
  if ((termios_tcgetattr (fd, term)) == 0)
    {
      doraw (term);
      if (input)
        {
          result = termios_tcsetattr (fd, termios_tcsflush (), term);
        }
      else
        {
          result = termios_tcsetattr (fd, termios_tcsdrain (), term);
        }
    }
  term = termios_KillTermios (term);
}

extern "C" void IO_BufferedMode (int fd, bool input)
{
  termios_TERMIOS term;
  int r;

  if (IsDefaultFd (fd))
    {
      fdState.array[fd].IsRaw = false;
    }
  term = termios_InitTermios ();
  if ((termios_tcgetattr (fd, term)) == 0)
    {
      dononraw (term);
      if (input)
        {
          r = termios_tcsetattr (fd, termios_tcsflush (), term);
        }
      else
        {
          r = termios_tcsetattr (fd, termios_tcsdrain (), term);
        }
    }
  term = termios_KillTermios (term);
}


/*
   EchoOn - turns on echoing for file descriptor, fd.  This
            only really makes sence for a file descriptor opened
            for terminal input or maybe some specific file descriptor
            which is attached to a particular piece of hardware.
*/

extern "C" void IO_EchoOn (int fd, bool input)
{
  termios_TERMIOS term;
  int result;

  term = termios_InitTermios ();
  if ((termios_tcgetattr (fd, term)) == 0)
    {
      setFlag (term, termios_lecho, true);
      if (input)
        {
          result = termios_tcsetattr (fd, termios_tcsflush (), term);
        }
      else
        {
          result = termios_tcsetattr (fd, termios_tcsdrain (), term);
        }
    }
  term = termios_KillTermios (term);
}


/*
   EchoOff - turns off echoing for file descriptor, fd.  This
             only really makes sence for a file descriptor opened
             for terminal input or maybe some specific file descriptor
             which is attached to a particular piece of hardware.
*/

extern "C" void IO_EchoOff (int fd, bool input)
{
  termios_TERMIOS term;
  int result;

  term = termios_InitTermios ();
  if ((termios_tcgetattr (fd, term)) == 0)
    {
      setFlag (term, termios_lecho, false);
      if (input)
        {
          result = termios_tcsetattr (fd, termios_tcsflush (), term);
        }
      else
        {
          result = termios_tcsetattr (fd, termios_tcsdrain (), term);
        }
    }
  term = termios_KillTermios (term);
}

extern "C" void _M2_IO_init (__attribute__((unused)) int argc,__attribute__((unused)) char *argv[],__attribute__((unused)) char *envp[])
{
  Init ();
}

extern "C" void _M2_IO_fini (__attribute__((unused)) int argc,__attribute__((unused)) char *argv[],__attribute__((unused)) char *envp[])
{
}