yap-6.3/os/iopreds.c

/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		iopreds.c *
* Last rev:	5/2/88							 *
* mods: *
* comments:	Input/Output C implemented predicates			 *
*									 *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif

/**
 * @file   iopreds.c
 * @author VITOR SANTOS COSTA <vsc@VITORs-MBP.lan>
 * @date   Wed Jan 20 00:45:56 2016
 *
 * @brief  main open and close predicates over generic streams.
 *
 */
/*
 * This file includes the definition of a miscellania of standard predicates *
 *for yap refering to: Files and GLOBAL_Streams, Simple Input/Output,
 *
 */

#include "Yap.h"
#include "YapHeap.h"
#include "YapText.h"
#include "Yatom.h"
#include "YapEval.h"
#include "yapio.h"
#include <stdlib.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDARG_H
#include <stdarg.h>
#endif
#if HAVE_CTYPE_H
#include <ctype.h>
#endif
#if HAVE_WCTYPE_H
#include <wctype.h>
#endif
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_SELECT_H && !_MSC_VER && !defined(__MINGW32__)
#include <sys/select.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_SIGNAL_H
#include <signal.h>
#endif
#if HAVE_FCNTL_H
/* for O_BINARY and O_TEXT in WIN32 */
#include <fcntl.h>
#endif
#ifdef _WIN32
#if HAVE_IO_H
/* Windows */
#include <io.h>
#endif
#endif
#if !HAVE_STRNCAT
#define strncat(X, Y, Z) strcat(X, Y)
#endif
#if !HAVE_STRNCPY
#define strncpy(X, Y, Z) strcpy(X, Y)
#endif
#if _MSC_VER || defined(__MINGW32__)
#if HAVE_SOCKET
#include <winsock2.h>
#endif
#include <windows.h>
#ifndef S_ISDIR
#define S_ISDIR(x) (((x)&_S_IFDIR) == _S_IFDIR)
#endif
#endif

#include "iopreds.h"

#include "getw.h"

static int get_wchar_from_file(int);

FILE *Yap_stdin;
FILE *Yap_stdout;
FILE *Yap_stderr;

static Term gethdir(Term t) {
  CACHE_REGS
  Atom aref = AtomOfTerm(t);
  char *s = RepAtom(aref)->StrOfAE;
  size_t nsz;

  s = strncpy(LOCAL_FileNameBuf, RepAtom(aref)->StrOfAE, MAXPATHLEN - 1);
  if (!s) {
    return false;
  }
  if (TermDot == t) {
    return TermEmptyAtom;
  }
  nsz = strlen(s);
  if (!Yap_dir_separator(s[nsz - 1])) {
#if _WIN32
    s[nsz] = '\\';
#else
    s[nsz] = '/';
#endif
    s[nsz + 1] = '\0';
  }
  return MkAtomTerm(Yap_LookupAtom(s));
}

static Term issolutions(Term t) {
  if (t == TermFirst || t == TermAll)
    return t;

  if (IsVarTerm(t)) {
    Yap_Error(INSTANTIATION_ERROR, t, "solutions in {first, all}.");
    return TermZERO;
  }
  if (IsAtomTerm(t)) {
    Yap_Error(DOMAIN_ERROR_SOLUTIONS, t, "solutions in {first, all}");
    return TermZERO;
  }
  Yap_Error(TYPE_ERROR_ATOM, t, "solutions in {first, all}}");
  return TermZERO;
}

static Term is_file_type(Term t) {
  if (t == TermTxt || t == TermProlog || t == TermSource ||
      t == TermExecutable || t == TermQly || t == TermDirectory)
    return t;

  if (IsVarTerm(t)) {
    Yap_Error(INSTANTIATION_ERROR, t,
              "file_type in {txt,prolog,exe,directory...}");
    return TermZERO;
  }
  if (IsAtomTerm(t)) {
    Yap_Error(DOMAIN_ERROR_FILE_TYPE, t,
              "file_type in {txt,prolog,exe,directory...}");
    return TermZERO;
  }
  Yap_Error(TYPE_ERROR_ATOM, t, "file_type in {txt,prolog,exe,directory...}");
  return TermZERO;
}

static Term is_file_errors(Term t) {
  if (t == TermFail || t == TermError)
    return t;

  if (IsVarTerm(t)) {
    Yap_Error(INSTANTIATION_ERROR, t, "file_error in {fail,error}.");
    return TermZERO;
  }
  if (IsAtomTerm(t)) {
    Yap_Error(DOMAIN_ERROR_FILE_ERRORS, t, "file_error in {fail,error}.");
    return TermZERO;
  }
  Yap_Error(TYPE_ERROR_ATOM, t, "file_error in {fail,error}.");
  return TermZERO;
}

static void unix_upd_stream_info(StreamDesc *s) {
  if (s->status & InMemory_Stream_f) {
    s->status |= Seekable_Stream_f;
    return;
  }
  Yap_socketStream(s);
#if _MSC_VER || defined(__MINGW32__)
  {
    if (_isatty(_fileno(s->file))) {
      s->status |= Tty_Stream_f | Reset_Eof_Stream_f | Promptable_Stream_f;
      /* make all console descriptors unbuffered */
      setvbuf(s->file, NULL, _IONBF, 0);
      return;
    }
#if _MSC_VER
    /* standard error stream should never be buffered */
    else if (StdErrStream == s - GLOBAL_Stream) {
      setvbuf(s->file, NULL, _IONBF, 0);
    }
#endif
    s->status |= Seekable_Stream_f;
    return;
  }
#else
#if HAVE_ISATTY
#if __simplescalar__
  /* isatty does not seem to work with simplescar. I'll assume the first
   three streams will probably be ttys (pipes are not thatg different) */
  if (s - Stream < 3) {
    s->name = AtomTty;
    s->status |= Tty_Stream_f | Reset_Eof_Stream_f | Promptable_Stream_f;
  }
#else
  {
    int filedes; /* visualc */
    if (!s->file) {
      s->name = AtomNil;
      return;
    }
    filedes = fileno(s->file);
    if (isatty(filedes)) {
#if HAVE_TTYNAME
      int rc = ttyname_r(filedes, LOCAL_FileNameBuf, YAP_FILENAME_MAX - 1);
      if (rc == 0)
        s->name = Yap_LookupAtom(LOCAL_FileNameBuf);
      else
        s->name = AtomTtys;
#else
      s->name = AtomTty;
#endif
      s->status |= Tty_Stream_f | Reset_Eof_Stream_f | Promptable_Stream_f;
      return;
    }
  }
#endif
#endif /* HAVE_ISATTY */
#endif /* _MSC_VER */
  s->status |= Seekable_Stream_f;
}

void Yap_DefaultStreamOps(StreamDesc *st) {
  CACHE_REGS
  st->stream_wputc = put_wchar;
  st->stream_wgetc = get_wchar_UTF8;
  st->stream_putc = FilePutc;
  st->stream_getc = PlGetc;
  if (st->status & (Promptable_Stream_f)) {
    Yap_ConsoleOps(st);
  }
#ifndef _WIN32
  else if (st->file != NULL && 0 && !(st->status & InMemory_Stream_f)) {
    st->stream_wgetc = get_wchar_from_file;
  }
#endif
  if (GLOBAL_CharConversionTable != NULL)
    st->stream_wgetc_for_read = ISOWGetc;
  else
    st->stream_wgetc_for_read = st->stream_wgetc;
  if (st->status & Pipe_Stream_f) {
    Yap_PipeOps(st);
  } else if (st->status & InMemory_Stream_f) {
    Yap_MemOps(st);
  } else if (st->status & Tty_Stream_f) {
    Yap_ConsoleOps(st);
  } else {
    unix_upd_stream_info(st);
  }
}

static void InitFileIO(StreamDesc *s) {
  CACHE_REGS
  Yap_DefaultStreamOps(s);
}

static void InitStdStream(int sno, SMALLUNSGN flags, FILE *file) {
  StreamDesc *s = &GLOBAL_Stream[sno];
  s->file = file;
  s->status = flags;
  s->linepos = 0;
  s->linecount = 1;
  s->charcount = 0.;
  s->encoding = ENC_ISO_UTF8;
  INIT_LOCK(s->streamlock);
  unix_upd_stream_info(s);
  /* Getting streams to prompt is a mess because we need for cooperation
   between readers and writers to the stream :-(
   */
  InitFileIO(s);
  switch (sno) {
  case 0:
    s->name = AtomUserIn;
    break;
  case 1:
    s->name = AtomUserOut;
    break;
  default:
    s->name = AtomUserErr;
    break;
  }
  s->user_name = MkAtomTerm(s->name);
#if LIGHT
  s->status |= Tty_Stream_f | Promptable_Stream_f;
#endif
  Yap_DefaultStreamOps(s);
#if HAVE_SETBUF
  if (s->status & Tty_Stream_f && sno == 0) {
    /* make sure input is unbuffered if it comes from stdin, this
     makes life simpler for interrupt handling */
    setbuf(stdin, NULL);
    //    fprintf(stderr,"here I am\n");
  }
#endif /* HAVE_SETBUF */
}

Term Yap_StreamUserName(int sno) {
  Term atname;
  StreamDesc *s = &GLOBAL_Stream[sno];
  if (s->user_name != 0L) {
    return (s->user_name);
  }
  if ((atname = StreamName(sno)))
    return atname;
  return TermNil;
}

static void InitStdStreams(void) {
  CACHE_REGS
  if (LOCAL_sockets_io) {
    InitStdStream(StdInStream, Input_Stream_f, NULL);
    InitStdStream(StdOutStream, Output_Stream_f, NULL);
    InitStdStream(StdErrStream, Output_Stream_f, NULL);
  } else {
    InitStdStream(StdInStream, Input_Stream_f, stdin);
    InitStdStream(StdOutStream, Output_Stream_f, stdout);
    InitStdStream(StdErrStream, Output_Stream_f, stderr);
  }
  GLOBAL_Stream[StdInStream].name = Yap_LookupAtom("user_input");
  GLOBAL_Stream[StdOutStream].name = Yap_LookupAtom("user_output");
  GLOBAL_Stream[StdErrStream].name = Yap_LookupAtom("user_error");
#if USE_READLINE
  if (GLOBAL_Stream[StdInStream].status & Tty_Stream_f &&
      GLOBAL_Stream[StdOutStream].status & Tty_Stream_f &&
      GLOBAL_Stream[StdErrStream].status & Tty_Stream_f &&
      ! Yap_embedded) {
    Yap_InitReadline(TermTrue);
  }
#endif
  LOCAL_c_input_stream = StdInStream;
  LOCAL_c_output_stream = StdOutStream;
  LOCAL_c_error_stream = StdErrStream;
}

void Yap_InitStdStreams(void) { InitStdStreams(); }

Int PlIOError__(const char *file, const char *function, int lineno,
                yap_error_number type, Term culprit, ...) {
  if (trueLocalPrologFlag(FILEERRORS_FLAG) ||
      type == RESOURCE_ERROR_MAX_STREAMS /* do not catch resource errors */) {
    va_list args;
    const char *format;
    char who[1024];

    va_start(args, culprit);
    format = va_arg(args, char *);
    if (format) {
      vsnprintf(who, 1023, format, args);
    } else {
      who[0] = '\0';
    }
    va_end(args);
    Yap_Error__(file, function, lineno, type, culprit, who);
    /* and fail */
    return false;
  } else {
    return false;
  }
}

static int eolflg = 1;

static char my_line[200] = {0};
static char *lp = my_line;

FILE *curfile, *Yap_logfile;

bool Yap_Option[256];

#ifdef MACC

static void InTTYLine(char *line) {
  char *p = line;
  char ch;
  while ((ch = InKey()) != '\n' && ch != '\r')
    if (ch == 8) {
      if (line < p)
        BackupTTY(*--p);
    } else
      TTYChar(*p++ = ch);
  TTYChar('\n');
  *p = 0;
}
#endif

void Yap_DebugSetIFile(char *fname) {
  if (curfile)
    fclose(curfile);
  curfile = fopen(fname, "r");
  if (curfile == NULL) {
    curfile = stdin;
    Yap_Warning("%% YAP  open %s for input\n", fname);
  }
}

void Yap_DebugEndline() { *lp = 0; }

int Yap_DebugGetc() {
  int ch;
  if (eolflg) {
    if (curfile != NULL) {
      if (fgets(my_line, 200, curfile) == 0)
        curfile = NULL;
    }
    if (curfile == NULL)
      if (fgets(my_line, 200, stdin) == NULL) {
        return EOF;
      }
    eolflg = 0;
    lp = my_line;
  }
  if ((ch = *lp++) == 0)
    ch = '\n', eolflg = 1;
  if (Yap_Option['l' - 96])
    putc(ch, Yap_logfile);
  return (ch);
}

int Yap_DebugPutc(FILE *s, wchar_t ch) {
  if (Yap_Option['l' - 96])
    (void)putc(ch, Yap_logfile);
  return (putc(ch, s));
}

int Yap_DebugPuts(FILE *s, const char *sch) {
  if (Yap_Option['l' - 96])
    (void)fputs(sch, Yap_logfile);
  return fputs(sch, s);
}

void Yap_DebugErrorPuts(const char *s) { Yap_DebugPuts(stderr, s); }

void Yap_DebugPlWrite(Term t) {
  if (t == 0)
    fprintf(stderr, "NULL");
  Yap_plwrite(t, GLOBAL_Stream + 2, 0, 0, GLOBAL_MaxPriority);
}

void Yap_DebugPlWriteln(Term t) {
  CACHE_REGS
  if (t == 0)
    fprintf(stderr, "NULL");
  Yap_plwrite(t, NULL, 15, 0, GLOBAL_MaxPriority);
  Yap_DebugPutc(GLOBAL_Stream[LOCAL_c_error_stream].file, '.');
  Yap_DebugPutc(GLOBAL_Stream[LOCAL_c_error_stream].file, 10);
}

void Yap_DebugErrorPutc(int c) {
  CACHE_REGS
  Yap_DebugPutc(GLOBAL_Stream[LOCAL_c_error_stream].file, c);
}

void Yap_DebugWriteIndicator(PredEntry *ap) {
  CACHE_REGS
  Term tmod = ap->ModuleOfPred;
  if (!tmod)
    tmod = TermProlog;
#if THREADS
  Yap_DebugPlWrite(MkIntegerTerm(worker_id));
  Yap_DebugPutc(stderr, ' ');
#endif
  Yap_DebugPutc(stderr, '>');
  Yap_DebugPutc(stderr, '\t');
  Yap_DebugPlWrite(tmod);
  Yap_DebugPutc(stderr, ':');
  if (ap->ModuleOfPred == IDB_MODULE) {
    Term t = Deref(ARG1);
    if (IsAtomTerm(t)) {
      Yap_DebugPlWrite(t);
    } else if (IsIntegerTerm(t)) {
      Yap_DebugPlWrite(t);
    } else {
      Functor f = FunctorOfTerm(t);
      Atom At = NameOfFunctor(f);
      Yap_DebugPlWrite(MkAtomTerm(At));
      Yap_DebugPutc(stderr, '/');
      Yap_DebugPlWrite(MkIntegerTerm(ArityOfFunctor(f)));
    }
  } else {
    if (ap->ArityOfPE == 0) {
      Atom At = (Atom)ap->FunctorOfPred;
      Yap_DebugPlWrite(MkAtomTerm(At));
    } else {
      Functor f = ap->FunctorOfPred;
      Atom At = NameOfFunctor(f);
      Yap_DebugPlWrite(MkAtomTerm(At));
      Yap_DebugPutc(stderr, '/');
      Yap_DebugPlWrite(MkIntegerTerm(ArityOfFunctor(f)));
    }
  }

  Yap_DebugPutc(stderr, '\n');
}

/* static */
int FilePutc(int sno, int ch) {
  StreamDesc *s = &GLOBAL_Stream[sno];
#if MAC || _MSC_VER
  if (ch == 10) {
    ch = '\n';
  }
#endif
  putc(ch, s->file);
#if MAC || _MSC_VER
  if (ch == 10) {
    fflush(s->file);
  }
#endif
  count_output_char(ch, s);
  return ((int)ch);
}

static int NullPutc(int sno, int ch) {
  StreamDesc *s = &GLOBAL_Stream[sno];
#if MAC || _MSC_VER
  if (ch == 10) {
    ch = '\n';
  }
#endif
  count_output_char(ch, s);
  return ((int)ch);
}

int ResetEOF(StreamDesc *s) {
  if (s->status & Eof_Error_Stream_f) {
    Atom name = s->name;
    // Yap_CloseStream(s - GLOBAL_Stream);
    Yap_Error(PERMISSION_ERROR_INPUT_PAST_END_OF_STREAM, MkAtomTerm(name),
              "GetC");
    return FALSE;
  } else if (s->status & Reset_Eof_Stream_f) {
    s->status &= ~Push_Eof_Stream_f;
    /* reset the eof indicator on file */
    if (feof(s->file))
      clearerr(s->file);
    /* reset our function for reading input */
    Yap_DefaultStreamOps(s);
    /* next, reset our own error indicator */
    s->status &= ~Eof_Stream_f;
    /* try reading again */
    return TRUE;
  } else {
    s->status |= Past_Eof_Stream_f;
    return FALSE;
  }
}

/* handle reading from a stream after having found an EOF */
static int EOFWGetc(int sno) {
  register StreamDesc *s = &GLOBAL_Stream[sno];

  if (s->status & Push_Eof_Stream_f) {
    /* ok, we have pushed an EOF, send it away */
    s->status &= ~Push_Eof_Stream_f;
    return EOF;
  }
  if (ResetEOF(s)) {
    Yap_DefaultStreamOps(s);
    return (s->stream_wgetc(sno));
  }
  return EOF;
}

static int EOFGetc(int sno) {
  register StreamDesc *s = &GLOBAL_Stream[sno];

  if (s->status & Push_Eof_Stream_f) {
    /* ok, we have pushed an EOF, send it away */
    s->status &= ~Push_Eof_Stream_f;
    ResetEOF(s);
    return EOF;
  }
  if (ResetEOF(s)) {
    Yap_DefaultStreamOps(s);
    return s->stream_getc(sno);
  }
  return EOF;
}

/* check if we read a LOCAL_newline or an EOF */
int console_post_process_eof(StreamDesc *s) {
  CACHE_REGS
  if (!ResetEOF(s)) {
    s->status |= Eof_Stream_f;
    s->stream_getc = EOFGetc;
    s->stream_wgetc = EOFWGetc;
    s->stream_wgetc_for_read = EOFWGetc;
    LOCAL_newline = true;
  }
  return EOFCHAR;
}

/* check if we read a newline or an EOF */
int post_process_read_wchar(int ch, size_t n, StreamDesc *s) {
  if (ch == EOF) {
    return post_process_weof(s);
  }
#if DEBUG
  if (GLOBAL_Option[1]) {
    static int v;
    fprintf(stderr, "%d %C\n", v, ch);
    v++;
  }
#endif
  s->charcount += n;
  s->linepos += n;
  if (ch == '\n') {
    ++s->linecount;
    s->linepos = 0;
    /* don't convert if the stream is binary */
    if (!(s->status & Binary_Stream_f))
      ch = 10;
  }
  return ch;
}

int post_process_weof(StreamDesc *s) {
  if (!ResetEOF(s)) {
    s->status |= Eof_Stream_f;
    s->stream_wgetc = EOFWGetc;
    s->stream_getc = EOFGetc;
    s->stream_wgetc_for_read = EOFWGetc;
  }
  return EOFCHAR;
}

/**
 * caled after EOF found a peek, it just calls console_post_process to
 *conclude
 *the job.
 *
 * @param sno
 *
 * @return EOF
 */
int EOFPeek(int sno) { return EOFCHAR; }

int EOFWPeek(int sno) { return EOFCHAR; }

/* standard routine, it should read from anything pointed by a FILE *.
 It could be made more efficient by doing our own buffering and avoiding
 post_process_read_char, something to think about */
int PlGetc(int sno) {
  StreamDesc *s = &GLOBAL_Stream[sno];
  return fgetc(s->file);
}

// layered version
static inline int get_wchar_from_file(int sno) {
  return post_process_read_wchar(fgetwc(GLOBAL_Stream[sno].file), 1,
                                 GLOBAL_Stream + sno);
}

#ifndef MB_LEN_MAX
#define MB_LEN_MAX 6
#endif

static int handle_write_encoding_error(int sno, wchar_t ch) {
  if (GLOBAL_Stream[sno].status & RepError_Xml_f) {
    /* use HTML/XML encoding in ASCII */
    int i = ch, digits = 1;
    GLOBAL_Stream[sno].stream_putc(sno, '&');
    GLOBAL_Stream[sno].stream_putc(sno, '#');
    while (digits < i)
      digits *= 10;
    if (digits > i)
      digits /= 10;
    while (i) {
      GLOBAL_Stream[sno].stream_putc(sno, i / digits);
      i %= 10;
      digits /= 10;
    }
    GLOBAL_Stream[sno].stream_putc(sno, ';');
    return ch;
  } else if (GLOBAL_Stream[sno].status & RepError_Prolog_f) {
    /* write quoted */
    GLOBAL_Stream[sno].stream_putc(sno, '\\');
    GLOBAL_Stream[sno].stream_putc(sno, 'u');
    GLOBAL_Stream[sno].stream_putc(sno, ch >> 24);
    GLOBAL_Stream[sno].stream_putc(sno, 256 & (ch >> 16));
    GLOBAL_Stream[sno].stream_putc(sno, 256 & (ch >> 8));
    GLOBAL_Stream[sno].stream_putc(sno, 256 & ch);
    return ch;
  } else {
    CACHE_REGS
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, MkIntegerTerm(ch),
              "charater %ld cannot be encoded in stream %d",
              (unsigned long int)ch, sno);
    return -1;
  }
}

int put_wchar(int sno, wchar_t ch) {
  /* pass the bucck if we can */
  switch (GLOBAL_Stream[sno].encoding) {
  case ENC_OCTET:
    return GLOBAL_Stream[sno].stream_putc(sno, ch);
  case ENC_ISO_LATIN1:
    if (ch >= 0xff) {
      return handle_write_encoding_error(sno, ch);
    }
    return GLOBAL_Stream[sno].stream_putc(sno, ch);
  case ENC_ISO_ASCII:
    if (ch >= 0x80) {
      return handle_write_encoding_error(sno, ch);
    }
    return GLOBAL_Stream[sno].stream_putc(sno, ch);
  case ENC_ISO_ANSI: {
    char buf[MB_LEN_MAX];
    mbstate_t mbstate;
    int n;

    memset((void *)&mbstate, 0, sizeof(mbstate_t));
    if ((n = wcrtomb(buf, ch, &mbstate)) < 0) {
      /* error */
      GLOBAL_Stream[sno].stream_putc(sno, ch);
      return -1;
    } else {
      int i;

      for (i = 0; i < n; i++) {
        GLOBAL_Stream[sno].stream_putc(sno, buf[i]);
      }
      return ch;
    }
  case ENC_ISO_UTF8:
    if (ch < 0x80) {
      GLOBAL_Stream[sno].stream_putc(sno, ch);
    } else if (ch < 0x800) {
      GLOBAL_Stream[sno].stream_putc(sno, 0xC0 | ch >> 6);
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch & 0x3F));
    } else if (ch < 0x10000) {
      GLOBAL_Stream[sno].stream_putc(sno, 0xE0 | ch >> 12);
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch >> 6 & 0x3F));
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch & 0x3F));
    } else if (ch < 0x200000) {
      GLOBAL_Stream[sno].stream_putc(sno, 0xF0 | ch >> 18);
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch >> 12 & 0x3F));
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch >> 6 & 0x3F));
      GLOBAL_Stream[sno].stream_putc(sno, 0x80 | (ch & 0x3F));
    } else {
      /* should never happen */
      return -1;
    }
    return ch;
    break;
  case ENC_UTF16_LE: {
    if (ch < 0x10000) {
      GLOBAL_Stream[sno].stream_putc(sno, (ch & 0xff));
      GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8));
    } else {
      // computations
      uint16_t ich = ch;
      uint16_t lead = LEAD_OFFSET + (ich >> 10);
      uint16_t trail = 0xDC00 + (ich & 0x3FF);

      GLOBAL_Stream[sno].stream_putc(sno, (trail & 0xff));
      GLOBAL_Stream[sno].stream_putc(sno, (trail >> 8));
      GLOBAL_Stream[sno].stream_putc(sno, (lead & 0xff));
      GLOBAL_Stream[sno].stream_putc(sno, (lead >> 8));
    }
    return ch;
  }
  case ENC_UTF16_BE: {
    // computations
    if (ch < 0x10000) {
      GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8));
      GLOBAL_Stream[sno].stream_putc(sno, (ch & 0xff));
    } else {
      uint16_t lead = (uint16_t)LEAD_OFFSET + ((uint16_t)ch >> 10);
      uint16_t trail = 0xDC00 + ((uint16_t)ch & 0x3FF);

      GLOBAL_Stream[sno].stream_putc(sno, (lead >> 8));
      GLOBAL_Stream[sno].stream_putc(sno, (lead & 0xff));
      GLOBAL_Stream[sno].stream_putc(sno, (trail >> 8));
      GLOBAL_Stream[sno].stream_putc(sno, (trail & 0xff));
    }
    return ch;
  }
  case ENC_UCS2_LE: {
    if (ch >= 0x10000) {
      return 0;
    }
    GLOBAL_Stream[sno].stream_putc(sno, (ch & 0xff));
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8));
    return ch;
  }
  case ENC_UCS2_BE: {
    // computations
    if (ch < 0x10000) {
      GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8));
      GLOBAL_Stream[sno].stream_putc(sno, (ch & 0xff));
      return ch;
    } else {
      return 0;
    }
  }

  case ENC_ISO_UTF32_BE:
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 24) & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 16) & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8) & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, ch & 0xff);
    return ch;
  case ENC_ISO_UTF32_LE:
    GLOBAL_Stream[sno].stream_putc(sno, ch & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 8) & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 16) & 0xff);
    GLOBAL_Stream[sno].stream_putc(sno, (ch >> 24) & 0xff);
    return ch;
  }
  }
  return -1;
}

/* used by user-code to read characters from the current input stream */
int Yap_PlGetchar(void) {
  CACHE_REGS
  return (
      GLOBAL_Stream[LOCAL_c_input_stream].stream_getc(LOCAL_c_input_stream));
}

int Yap_PlGetWchar(void) {
  CACHE_REGS
  return get_wchar(LOCAL_c_input_stream);
}

/* avoid using a variable to call a function */
int Yap_PlFGetchar(void) {
  CACHE_REGS
  return (PlGetc(LOCAL_c_input_stream));
}

Term Yap_MkStream(int n) {
  Term t[1];
  t[0] = MkIntTerm(n);
  return (Yap_MkApplTerm(FunctorStream, 1, t));
}

/* given a stream index, get the corresponding fd */
Int GetStreamFd(int sno) {
#if HAVE_SOCKET
  if (GLOBAL_Stream[sno].status & Socket_Stream_f) {
    return (GLOBAL_Stream[sno].u.socket.fd);
  } else
#endif
      if (GLOBAL_Stream[sno].status & Pipe_Stream_f) {
    return (GLOBAL_Stream[sno].u.pipe.fd);
  } else if (GLOBAL_Stream[sno].status & InMemory_Stream_f) {
    return (-1);
  }
  return (fileno(GLOBAL_Stream[sno].file));
}

Int Yap_GetStreamFd(int sno) { return GetStreamFd(sno); }

static int binary_file(const char *file_name) {
#if HAVE_STAT
#if _MSC_VER || defined(__MINGW32__)
  struct _stat ss;
  if (_stat(file_name, &ss) != 0)
#else
  struct stat ss;
  if (stat(file_name, &ss) != 0)
#endif
  {
    /* ignore errors while checking a file */
    return (FALSE);
  }
  return (S_ISDIR(ss.st_mode));
#else
  return (FALSE);
#endif
}

static int write_bom(int sno, StreamDesc *st) {
  /* dump encoding */
  switch (st->encoding) {
  case ENC_ISO_UTF8:
    if (st->stream_putc(sno, 0xEF) < 0)
      return false;
    if (st->stream_putc(sno, 0xBB) < 0)
      return false;
    if (st->stream_putc(sno, 0xBF) < 0)
      return false;
    st->status |= HAS_BOM_f;
    return true;
  case ENC_UTF16_BE:
  case ENC_UCS2_BE:
    if (st->stream_putc(sno, 0xFE) < 0)
      return false;
    if (st->stream_putc(sno, 0xFF) < 0)
      return false;
    st->status |= HAS_BOM_f;
    return true;
  case ENC_UTF16_LE:
  case ENC_UCS2_LE:
    if (st->stream_putc(sno, 0xFF) < 0)
      return false;
    if (st->stream_putc(sno, 0xFE) < 0)
      return false;
    st->status |= HAS_BOM_f;
    return true;
  case ENC_ISO_UTF32_BE:
    if (st->stream_putc(sno, 0x00) < 0)
      return false;
    if (st->stream_putc(sno, 0x00) < 0)
      return false;
    if (st->stream_putc(sno, 0xFE) < 0)
      return false;
    if (st->stream_putc(sno, 0xFF) < 0)
      return false;
    st->status |= HAS_BOM_f;
    return true;
  case ENC_ISO_UTF32_LE:
    if (st->stream_putc(sno, 0xFF) < 0)
      return false;
    if (st->stream_putc(sno, 0xFE) < 0)
      return false;
    if (st->stream_putc(sno, 0x00) < 0)
      return false;
    if (st->stream_putc(sno, 0x00) < 0)
      return false;
    st->status |= HAS_BOM_f;
    return true;
  default:
    return true;
  }
}

static void check_bom(int sno, StreamDesc *st) {
  int ch1, ch2, ch3, ch4;

  ch1 = fgetc(st->file);
  switch (ch1) {
  case 0x00: {
    ch2 = fgetc(st->file);
    if (ch2 != 0x00) {
      ungetc(ch1, st->file);
      ungetc(ch2, st->file);
      return;
    } else {
      ch3 = fgetc(st->file);
      if (ch3 == EOFCHAR || ch3 != 0xFE) {
        ungetc(ch1, st->file);
        ungetc(ch2, st->file);
        ungetc(ch3, st->file);
        return;
      } else {
        ch4 = fgetc(st->file);
        if (ch4 == EOFCHAR || ch3 != 0xFF) {
          ungetc(ch1, st->file);
          ungetc(ch2, st->file);
          ungetc(ch3, st->file);
          ungetc(ch4, st->file);
          return;
        } else {
          st->status |= HAS_BOM_f;
          st->encoding = ENC_ISO_UTF32_BE;
          return;
        }
      }
    }
  }
  case 0xFE: {
    ch2 = fgetc(st->file);
    if (ch2 != 0xFF) {
      ungetc(ch1, st->file);
      ungetc(ch2, st->file);
      return;
    } else {
      st->status |= HAS_BOM_f;
      st->encoding = ENC_UTF16_BE;
      return;
    }
  }
  case 0xFF: {
    ch2 = fgetc(st->file);
    if (ch2 != 0xFE) {
      ungetc(ch1, st->file);
      ungetc(ch2, st->file);
      return;
    } else {
      ch3 = fgetc(st->file);
      if (ch3 != 0x00) {
        ungetc(ch3, st->file);
      } else {
        ch4 = fgetc(st->file);
        if (ch4 == 0x00) {
          st->status |= HAS_BOM_f;
          st->encoding = ENC_ISO_UTF32_LE;
          return;
        } else {
          ungetc(ch4, st->file);
          ungetc(0x00, st->file);
        }
      }
    }
    st->status |= HAS_BOM_f;
    st->encoding = ENC_UTF16_LE;
    return;
  }
  case 0xEF:
    ch2 = fgetc(st->file);
    if (ch2 != 0xBB) {
      ungetc(ch1, st->file);
      ungetc(ch2, st->file);
      return;
    } else {
      ch3 = fgetc(st->file);
      if (ch3 != 0xBF) {
        ungetc(ch1, st->file);
        ungetc(ch2, st->file);
        ungetc(ch3, st->file);
        return;
      } else {
        st->status |= HAS_BOM_f;
        st->encoding = ENC_ISO_UTF8;
        return;
      }
    }
  default:
    ungetc(ch1, st->file);
  }
}

bool Yap_initStream(int sno, FILE *fd, const char *name, Term file_name,
                    encoding_t encoding, stream_flags_t flags, Atom open_mode) {
  StreamDesc *st = &GLOBAL_Stream[sno];
  st->status = flags;

  st->charcount = 0;
  st->linecount = 1;
  if (flags & Binary_Stream_f) {
    st->encoding = ENC_OCTET;
  } else {
    st->encoding = encoding;
  }

  if (name == NULL) {
    char buf[YAP_FILENAME_MAX + 1];
    name = Yap_guessFileName(fd, sno, buf, YAP_FILENAME_MAX);
    if (name)
      st->name = Yap_LookupAtom(name);
  }
  st->user_name = file_name;
  st->file = fd;
  st->linepos = 0;
  Yap_DefaultStreamOps(st);
  return true;
}

static bool open_header(int sno, Atom open_mode) {
  if (open_mode == AtomWrite) {
    const char *ptr;
    const char s[] = "#!";
    int ch;

    ptr = s;
    while ((ch = *ptr++))
      GLOBAL_Stream[sno].stream_wputc(sno, ch);
    const char *b = Yap_FindExecutable();
    ptr = b;
    while ((ch = *ptr++))
      GLOBAL_Stream[sno].stream_wputc(sno, ch);
    const char *l = " -L --\n\n YAP script\n#\n# .\n";
    ptr = l;
    while ((ch = *ptr++))
      GLOBAL_Stream[sno].stream_wputc(sno, ch);

  } else if (open_mode == AtomRead) {
    // skip header
    int ch;
    while ((ch = Yap_peek(sno)) == '#') {
      while ((ch = GLOBAL_Stream[sno].stream_wgetc(sno)) != 10 && ch != -1)
        ;
    }
  }
  return true;
}

#define OPEN_DEFS()                                                            \
  PAR("alias", isatom, OPEN_ALIAS)                                             \
  , PAR("bom", booleanFlag, OPEN_BOM), PAR("buffer", isatom, OPEN_BUFFER),     \
      PAR("close_on_abort", booleanFlag, OPEN_CLOSE_ON_ABORT),                 \
      PAR("create", isatom, OPEN_CREATE),                                      \
      PAR("encoding", isatom, OPEN_ENCODING),                                  \
      PAR("eof_action", isatom, OPEN_EOF_ACTION),                              \
      PAR("expand_filename", booleanFlag, OPEN_EXPAND_FILENAME),               \
      PAR("file_name", isatom, OPEN_FILE_NAME), PAR("input", ok, OPEN_INPUT),  \
      PAR("locale", isatom, OPEN_LOCALE), PAR("lock", isatom, OPEN_LOCK),      \
      PAR("mode", isatom, OPEN_MODE), PAR("output", ok, OPEN_OUTPUT),          \
      PAR("representation_errors", booleanFlag, OPEN_REPRESENTATION_ERRORS),   \
      PAR("reposition", booleanFlag, OPEN_REPOSITION),                         \
      PAR("script", booleanFlag, OPEN_SCRIPT), PAR("type", isatom, OPEN_TYPE), \
      PAR("wait", booleanFlag, OPEN_WAIT), PAR(NULL, ok, OPEN_END)

#define PAR(x, y, z) z
typedef enum open_enum_choices { OPEN_DEFS() } open_choices_t;

#undef PAR

#define PAR(x, y, z)                                                           \
  { x, y, z }

static const param_t open_defs[] = {OPEN_DEFS()};
#undef PAR

static Int
do_open(Term file_name, Term t2,
        Term tlist USES_REGS) { /* '$open'(+File,+Mode,?Stream,-ReturnCode) */
  Atom open_mode;
  int sno;
  SMALLUNSGN s;
  char io_mode[8];
  StreamDesc *st;
  bool avoid_bom = false, needs_bom = false;
  const char *fname;
  char fbuf[FILENAME_MAX];
  stream_flags_t flags;
  FILE *fd;
  const char *s_encoding;
  encoding_t encoding;
  Term tenc;
  // original file name
  if (IsVarTerm(file_name)) {
    Yap_Error(INSTANTIATION_ERROR, file_name, "open/3");
    return FALSE;
  }
  if (!IsAtomTerm(file_name)) {
    if (IsStringTerm(file_name)) {
      fname = (char *)StringOfTerm(file_name);
    } else {
      Yap_Error(DOMAIN_ERROR_SOURCE_SINK, file_name, "open/3");
      return FALSE;
    }
  } else {
    fname = RepAtom(AtomOfTerm(file_name))->StrOfAE;
  }
  // open mode
  if (IsVarTerm(t2)) {
    Yap_Error(INSTANTIATION_ERROR, t2, "open/3");
    return FALSE;
  }
  if (!IsAtomTerm(t2)) {
    if (IsStringTerm(t2)) {
      open_mode = Yap_LookupAtom(StringOfTerm(t2));
    } else {
      Yap_Error(TYPE_ERROR_ATOM, t2, "open/3");
      return (FALSE);
    }
  } else {
    open_mode = AtomOfTerm(t2);
  }
  // read, write, append
  if (open_mode == AtomRead) {
    strncpy(io_mode, "rb", 8);
    s = Input_Stream_f;
  } else if (open_mode == AtomWrite) {
    strncpy(io_mode, "w", 8);
    s = Output_Stream_f;
  } else if (open_mode == AtomAppend) {
    strncpy(io_mode, "a", 8);
    s = Append_Stream_f | Output_Stream_f;
  } else {
    Yap_Error(DOMAIN_ERROR_IO_MODE, t2, "open/3");
    return (FALSE);
  }
  /* get options */
  xarg *args = Yap_ArgListToVector(tlist, open_defs, OPEN_END);
  if (args == NULL) {
    if (LOCAL_Error_TYPE != YAP_NO_ERROR) {
      if (LOCAL_Error_TYPE == DOMAIN_ERROR_PROLOG_FLAG)
        LOCAL_Error_TYPE = DOMAIN_ERROR_OPEN_OPTION;
      Yap_Error(LOCAL_Error_TYPE, tlist, "option handling in open/3");
    }
    return false;
  }
  /* done */
  sno = GetFreeStreamD();
  if (sno < 0) {
    free(args);
    return PlIOError(RESOURCE_ERROR_MAX_STREAMS, TermNil, "open/3");
  }
  st = &GLOBAL_Stream[sno];
  st->user_name = file_name;
  flags = s;
  // user requested encoding?
  if (args[OPEN_ALIAS].used) {
    Atom al = AtomOfTerm(args[OPEN_ALIAS].tvalue);
    if (!Yap_AddAlias(al, sno)) {
      free(args);
      return false;
    }
  }
  if (args[OPEN_ENCODING].used) {
    tenc = args[OPEN_ENCODING].tvalue;
    s_encoding = RepAtom(AtomOfTerm(tenc))->StrOfAE;
  } else {
    s_encoding = "default";
  }
  // default encoding, no bom yet
  encoding = enc_id(s_encoding, ENC_OCTET);
  // only set encoding after getting BOM
  bool ok = (args[OPEN_EXPAND_FILENAME].used
                 ? args[OPEN_EXPAND_FILENAME].tvalue == TermTrue
                 : false) ||
            trueGlobalPrologFlag(OPEN_EXPANDS_FILENAME_FLAG);
  // expand file name?
  fname = Yap_AbsoluteFile(fname, fbuf, ok);
  if (fname) {
    st->name = Yap_LookupAtom(fname);
  } else {
    PlIOError(EXISTENCE_ERROR_SOURCE_SINK, ARG1, NULL);
  }

  // Skip scripts that start with !#/.. or similar
  bool script =
      (args[OPEN_SCRIPT].used ? args[OPEN_SCRIPT].tvalue == TermTrue : false);
  // binary type
  if (args[OPEN_TYPE].used) {
    Term t = args[OPEN_TYPE].tvalue;
    bool bin = (t == TermBinary);
    if (bin) {
#ifdef _WIN32
      strncat(io_mode, "b", 8);
#endif
      flags |= Binary_Stream_f;
      encoding = ENC_OCTET;
      avoid_bom = true;
      needs_bom = false;
    } else if (t == TermText) {
#ifdef _WIN32
      strncat(io_mode, "t", 8);
#endif
      /* note that this matters for UNICODE style  conversions */
    } else {
      Yap_Error(DOMAIN_ERROR_STREAM, tlist,
                "type is ~a, must be one of binary or text", t);
    }
  }
  // BOM mess
  if (encoding == ENC_UTF16_BE || encoding == ENC_UTF16_LE ||
      encoding == ENC_UCS2_BE || encoding == ENC_UCS2_LE ||
      encoding == ENC_ISO_UTF32_BE || encoding == ENC_ISO_UTF32_LE) {
    needs_bom = true;
  }
  if (args[OPEN_BOM].used) {
    if (args[OPEN_BOM].tvalue == TermTrue) {
      avoid_bom = false;
      needs_bom = true;
    } else if (args[OPEN_BOM].tvalue == TermFalse) {
      avoid_bom = true;
      needs_bom = false;
    }
  }
  if (st - GLOBAL_Stream < 3) {
    flags |= RepError_Prolog_f;
  }
  if ((fd = fopen(fname, io_mode)) == NULL ||
      (!(flags & Binary_Stream_f) && binary_file(fname))) {
    strncpy(LOCAL_FileNameBuf, fname, MAXPATHLEN);
    if (fname != fbuf)
      freeBuffer((void *)fname);
    fname = LOCAL_FileNameBuf;
    UNLOCK(st->streamlock);
    if (errno == ENOENT) {
      free(args);
      return (PlIOError(EXISTENCE_ERROR_SOURCE_SINK, file_name, "%s: %s", fname,
                        strerror(errno)));
    } else {
      return (PlIOError(PERMISSION_ERROR_OPEN_SOURCE_SINK, file_name, "%s: %s",
                        fname, strerror(errno)));
    }
  }
#if MAC
  if (open_mode == AtomWrite) {
    Yap_SetTextFile(RepAtom(AtomOfTerm(file_name))->StrOfAE);
  }
#endif
  //  __android_log_print(ANDROID_LOG_INFO, "YAPDroid", "open %s", fname);
  flags &= ~(Free_Stream_f);
  if (!Yap_initStream(sno, fd, fname, file_name, encoding, flags, open_mode))
    return false;
  if (open_mode == AtomWrite) {
    if (needs_bom && !write_bom(sno, st))
      return false;
  } else if (open_mode == AtomRead && !avoid_bom) {
    check_bom(sno, st); // can change encoding
  }
  // follow declaration unless there is v
  if (st->status & HAS_BOM_f)
    st->encoding = enc_id(s_encoding, st->encoding);
  else
    st->encoding = encoding;
  Yap_DefaultStreamOps(st);
  if (script)
    open_header(sno, open_mode);
  if (fname != fbuf)
    freeBuffer(fname);

  free(args);
  UNLOCK(st->streamlock);
  {
    Term t = Yap_MkStream(sno);
    return (Yap_unify(ARG3, t));
  }
}

/** @pred  open(+ _F_,+ _M_,- _S_) is iso


Opens the file with name  _F_ in mode  _M_ (`read`, `write` or
`append`), returning  _S_ unified with the stream name.

Yap allows 64 streams opened at the same time. If you need more,
 redefine the MaxStreams constant.  Each stream is either an input or
 an output stream but not both. There are always 3 open streams:
 user_input for reading, user_output for writing and user_error for
 writing. If there is no ambiguity, the atoms user_input and
 user_output may be referred to as `user`.

The `file_errors` flag controls whether errors are reported when in
mode `read` or `append` the file  _F_ does not exist or is not
readable, and whether in mode `write` or `append` the file is not
writable.

*/

static Int open3(USES_REGS1) { /* '$open'(+File,+Mode,?Stream,-ReturnCode) */
  return do_open(Deref(ARG1), Deref(ARG2), TermNil PASS_REGS);
}

/** @pred open(+ _F_,+ _M_,- _S_,+ _Opts_) is iso

Opens the file with name  _F_ in mode  _M_ (`read`,  `write` or
`append`), returning  _S_ unified with the stream name, and following
these options:



+ `type(+ _T_)` is iso

  Specify whether the stream is a `text` stream (default), or a
`binary` stream.

+ `reposition(+ _Bool_)` is iso
  Specify whether it is possible to reposition the stream (`true`), or
not (`false`). By default, YAP enables repositioning for all
files, except terminal files and sockets.

+ `eof(+ _Action_)` is iso

  Specify the action to take if attempting to input characters from a
stream where we have previously found an `end_of_file`. The possible
actions are `error`, that raises an error, `reset`, that tries to
reset the stream and is used for `tty` type files, and `eof_code`,
which generates a new `end_of_file` (default for non-tty files).

+ `alias(+ _Name_)` is iso

  Specify an alias to the stream. The alias <tt>Name</tt> must be an atom.
The
alias can be used instead of the stream descriptor for every operation
concerning the stream.

    The operation will fail and give an error if the alias name is already
in use. YAP allows several aliases for the same file, but only
one is returned by stream_property/2

+ `bom(+ _Bool_)`

  If present and `true`, a BOM (<em>Byte Order Mark</em>) was
detected while opening the file for reading or a BOM was written while
opening the stream. See BOM for details.

+ `encoding(+ _Encoding_)`

Set the encoding used for text.  See Encoding for an overview of
wide character and encoding issues.

+ `representation_errors(+ _Mode_)`

  Change the behaviour when writing characters to the stream that cannot
be represented by the encoding.  The behaviour is one of `error`
(throw and Input/Output error exception), `prolog` (write `\u...\`
escape code or `xml` (write `\&#...;` XML character entity).
The initial mode is `prolog` for the user streams and
`error` for all other streams. See also Encoding.

+ `expand_filename(+ _Mode_)`

  If  _Mode_ is `true` then do filename expansion, then ask Prolog
to do file name expansion before actually trying to opening the file:
this includes processing `~` characters and processing `$`
environment variables at the beginning of the file. Otherwise, just try
to open the file using the given name.

  The default behavior is given by the Prolog flag
open_expands_filename.

+ `script( + _Boolean_ )` YAP extension.

  The file may be a Prolog script. In `read` mode just check for
  initial lines if they start with the hash symbol, and skip them. In
  `write` mode output an header that can be used to launch the file by
  calling `yap -l file -- $*`. Note that YAP will not set file
  permissions as executable. In `append` mode ignore the flag.


*/
static Int open4(USES_REGS1) { /* '$open'(+File,+Mode,?Stream,-ReturnCode) */
  return do_open(Deref(ARG1), Deref(ARG2), Deref(ARG4) PASS_REGS);
}

static Int p_file_expansion(USES_REGS1) { /* '$file_expansion'(+File,-Name) */
  Term file_name = Deref(ARG1);

  /* we know file_name is bound */
  if (IsVarTerm(file_name)) {
    PlIOError(INSTANTIATION_ERROR, file_name, "absolute_file_name/3");
    return (FALSE);
  }
  if (!Yap_findFile(RepAtom(AtomOfTerm(file_name))->StrOfAE, NULL, NULL,
                    LOCAL_FileNameBuf, true, YAP_ANY_FILE, true, false))
    return (PlIOError(EXISTENCE_ERROR_SOURCE_SINK, file_name,
                      "absolute_file_name/3"));
  return (Yap_unify(ARG2, MkAtomTerm(Yap_LookupAtom(LOCAL_FileNameBuf))));
}

static Int p_open_null_stream(USES_REGS1) {
  Term t;
  StreamDesc *st;
  int sno = GetFreeStreamD();
  if (sno < 0)
    return (PlIOError(SYSTEM_ERROR_INTERNAL, TermNil,
                      "new stream not available for open_null_stream/1"));
  st = &GLOBAL_Stream[sno];
  st->status = Append_Stream_f | Output_Stream_f | Null_Stream_f;
#if _WIN32
  st->file = fopen("NUL", "w");
#else
  st->file = fopen("/dev/null", "w");
#endif
  if (st->file == NULL) {
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil,
              "Could not open NULL stream (/dev/null,NUL)");
    return false;
  }
  st->linepos = 0;
  st->charcount = 0;
  st->linecount = 1;
  st->stream_putc = NullPutc;
  st->stream_wputc = put_wchar;
  st->stream_getc = PlGetc;
  st->stream_wgetc = get_wchar;
  st->stream_wgetc_for_read = get_wchar;
  st->user_name = MkAtomTerm(st->name = AtomDevNull);
  UNLOCK(st->streamlock);
  t = Yap_MkStream(sno);
  return (Yap_unify(ARG1, t));
}

int Yap_OpenStream(FILE *fd, char *name, Term file_name, int flags) {
  CACHE_REGS
  int sno;
  Atom at;

  sno = GetFreeStreamD();
  if (sno < 0)
    return (PlIOError(RESOURCE_ERROR_MAX_STREAMS, file_name,
                      "new stream not available for opening"));
  if (flags & Output_Stream_f) {
    if (flags & Append_Stream_f)
      at = AtomAppend;
    else
      at = AtomWrite;
  } else
    at = AtomRead;
  Yap_initStream(sno, fd, name, file_name, LOCAL_encoding, flags, at);
  return sno;
}

#define CheckStream(arg, kind, msg)                                            \
  CheckStream__(__FILE__, __FUNCTION__, __LINE__, arg, kind, msg)

static int CheckStream__(const char *file, const char *f, int line, Term arg,
                         int kind, const char *msg) {
  int sno = -1;
  arg = Deref(arg);
  if (IsVarTerm(arg)) {
    Yap_Error(INSTANTIATION_ERROR, arg, msg);
    return -1;
  } else if (IsAtomTerm(arg)) {
    Atom sname = AtomOfTerm(arg);

    if (sname == AtomUser) {
      if (kind & Input_Stream_f) {
        if (kind & (Output_Stream_f | Append_Stream_f)) {
          PlIOError__(file, f, line, PERMISSION_ERROR_OUTPUT_STREAM, arg,
                      "ambiguous use of 'user' as a stream");
          return (-1);
        }
        sname = AtomUserIn;
      } else {
        sname = AtomUserOut;
      }
    }
    if ((sno = Yap_CheckAlias(sname)) < 0) {
      UNLOCK(GLOBAL_Stream[sno].streamlock);
      PlIOError__(file, f, line, EXISTENCE_ERROR_STREAM, arg, msg);
      return -1;
    } else {
      LOCK(GLOBAL_Stream[sno].streamlock);
    }
  } else if (IsApplTerm(arg) && FunctorOfTerm(arg) == FunctorStream) {
    arg = ArgOfTerm(1, arg);
    if (!IsVarTerm(arg) && IsIntegerTerm(arg)) {
      sno = IntegerOfTerm(arg);
    }
  }
  if (sno < 0) {
    Yap_Error(DOMAIN_ERROR_STREAM_OR_ALIAS, arg, msg);
    return -1;
  }
  if (GLOBAL_Stream[sno].status & Free_Stream_f) {
    PlIOError__(file, f, line, EXISTENCE_ERROR_STREAM, arg, msg);
    return -1;
  }
  LOCK(GLOBAL_Stream[sno].streamlock);
  if ((GLOBAL_Stream[sno].status & Input_Stream_f) &&
      !(kind & Input_Stream_f)) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    PlIOError__(file, f, line, PERMISSION_ERROR_OUTPUT_STREAM, arg, msg);
    return -1;
  }
  if ((GLOBAL_Stream[sno].status & (Append_Stream_f | Output_Stream_f)) &&
      !(kind & Output_Stream_f)) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    PlIOError__(file, f, line, PERMISSION_ERROR_INPUT_STREAM, arg, msg);
    return -1;
  }
  return sno;
}

int Yap_CheckStream__(const char *file, const char *f, int line, Term arg,
                      int kind, const char *msg) {
  return CheckStream__(file, f, line, arg, kind, msg);
}

int Yap_CheckTextStream__(const char *file, const char *f, int line, Term arg,
                          int kind, const char *msg) {
  int sno;
  if ((sno = CheckStream__(file, f, line, arg, kind, msg)) < 0)
    return -1;
  if ((GLOBAL_Stream[sno].status & Binary_Stream_f)) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    if (kind == Input_Stream_f)
      PlIOError__(file, f, line, PERMISSION_ERROR_INPUT_BINARY_STREAM, arg,
                  msg);
    else
      PlIOError__(file, f, line, PERMISSION_ERROR_OUTPUT_BINARY_STREAM, arg,
                  msg);
    return -1;
  }
  return sno;
}

int Yap_CheckBinaryStream__(const char *file, const char *f, int line, Term arg,
                            int kind, const char *msg) {
  int sno;
  if ((sno = CheckStream__(file, f, line, arg, kind, msg)) < 0)
    return -1;
  if (!(GLOBAL_Stream[sno].status & Binary_Stream_f)) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    if (kind == Input_Stream_f)
      PlIOError__(file, f, line, PERMISSION_ERROR_INPUT_TEXT_STREAM, arg, msg);
    else
      PlIOError__(file, f, line, PERMISSION_ERROR_OUTPUT_TEXT_STREAM, arg, msg);
    return -1;
  }
  return sno;
}

/* used from C-interface */
int Yap_GetFreeStreamDForReading(void) {
  int sno = GetFreeStreamD();
  StreamDesc *s;

  if (sno < 0)
    return sno;
  s = GLOBAL_Stream + sno;
  s->status |= User_Stream_f | Input_Stream_f;
  s->charcount = 0;
  s->linecount = 1;
  s->linepos = 0;
  Yap_DefaultStreamOps(s);
  UNLOCK(s->streamlock);
  return sno;
}

/**
 * @pred always_prompt_user
 *
 * Ensure that the stream always prompts before asking the standard input
 stream for data.

 */
static Int always_prompt_user(USES_REGS1) {
  StreamDesc *s = GLOBAL_Stream + StdInStream;

  s->status |= Promptable_Stream_f;
  Yap_DefaultStreamOps(s);
  return (TRUE);
}

static Int close1 /** @pred  close(+ _S_) is iso


 Closes the stream  _S_. If  _S_ does not stand for a stream
 currently opened an error is reported. The streams user_input,
 user_output, and user_error can never be closed.


 */

    (USES_REGS1) { /* '$close'(+GLOBAL_Stream) */
  Int sno = CheckStream(
      ARG1, (Input_Stream_f | Output_Stream_f | Socket_Stream_f), "close/2");
  if (sno < 0)
    return (FALSE);
  if (sno <= StdErrStream) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    return TRUE;
  }
  Yap_CloseStream(sno);
  UNLOCK(GLOBAL_Stream[sno].streamlock);
  return (TRUE);
}

#define CLOSE_DEFS()                                                           \
  PAR("force", booleanFlag, CLOSE_FORCE), PAR(NULL, ok, CLOSE_END)

#define PAR(x, y, z) z

typedef enum close_enum_choices { CLOSE_DEFS() } close_choices_t;

#undef PAR

#define PAR(x, y, z)                                                           \
  { x, y, z }

static const param_t close_defs[] = {CLOSE_DEFS()};
#undef PAR

/** @pred  close(+ _S_,+ _O_) is iso

Closes the stream  _S_, following options  _O_.

The only valid options are `force(true)` and `force(false)`.
YAP currently ignores these options.


*/
static Int close2(USES_REGS1) { /* '$close'(+GLOBAL_Stream) */
  Int sno = CheckStream(
      ARG1, (Input_Stream_f | Output_Stream_f | Socket_Stream_f), "close/2");
  Term tlist;
  if (sno < 0)
    return (FALSE);
  if (sno <= StdErrStream) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    return TRUE;
  }
  xarg *args =
      Yap_ArgListToVector((tlist = Deref(ARG2)), close_defs, CLOSE_END);
  if (args == NULL) {
    if (LOCAL_Error_TYPE != YAP_NO_ERROR) {
      if (LOCAL_Error_TYPE == DOMAIN_ERROR_PROLOG_FLAG)
        LOCAL_Error_TYPE = DOMAIN_ERROR_CLOSE_OPTION;
      Yap_Error(LOCAL_Error_TYPE, tlist, NULL);
    }
    return false;
    return FALSE;
  }
  // if (args[CLOSE_FORCE].used) {
  // }
  Yap_CloseStream(sno);
  UNLOCK(GLOBAL_Stream[sno].streamlock);
  return (TRUE);
}

Term read_line(int sno) {
  CACHE_REGS
  Term tail;
  Int ch;

  if ((ch = GLOBAL_Stream[sno].stream_wgetc(sno)) == 10) {
    return (TermNil);
  }
  tail = read_line(sno);
  return (MkPairTerm(MkIntTerm(ch), tail));
}

#define ABSOLUTE_FILE_NAME_DEFS()                                              \
  PAR("access", isatom, ABSOLUTE_FILE_NAME_ACCESS)                             \
  , PAR("expand", booleanFlag, ABSOLUTE_FILE_NAME_EXPAND),                     \
      PAR("extensions", ok, ABSOLUTE_FILE_NAME_EXTENSIONS),                    \
      PAR("file_errors", is_file_errors, ABSOLUTE_FILE_NAME_FILE_ERRORS),      \
      PAR("file_type", is_file_type, ABSOLUTE_FILE_NAME_FILE_TYPE),            \
      PAR("glob", ok, ABSOLUTE_FILE_NAME_GLOB),                                \
      PAR("relative_to", isatom, ABSOLUTE_FILE_NAME_RELATIVE_TO),              \
      PAR("solutions", issolutions, ABSOLUTE_FILE_NAME_SOLUTIONS),             \
      PAR("verbose_file_search", booleanFlag,                                  \
          ABSOLUTE_FILE_NAME_VERBOSE_FILE_SEARCH),                             \
      PAR(NULL, ok, ABSOLUTE_FILE_NAME_END)

#define PAR(x, y, z) z

typedef enum ABSOLUTE_FILE_NAME_enum_ {
  ABSOLUTE_FILE_NAME_DEFS()
} absolute_file_name_choices_t;

#undef PAR

#define PAR(x, y, z)                                                           \
  { x, y, z }

static const param_t absolute_file_name_search_defs[] = {
    ABSOLUTE_FILE_NAME_DEFS()};
#undef PAR

static Int abs_file_parameters(USES_REGS1) {
  Term t[ABSOLUTE_FILE_NAME_END];
  Term tlist = Deref(ARG1), tf;
  /* get options */
  xarg *args = Yap_ArgListToVector(tlist, absolute_file_name_search_defs,
                                   ABSOLUTE_FILE_NAME_END);
  if (args == NULL) {
    if (LOCAL_Error_TYPE != YAP_NO_ERROR) {
      if (LOCAL_Error_TYPE == DOMAIN_ERROR_PROLOG_FLAG)
        LOCAL_Error_TYPE = DOMAIN_ERROR_ABSOLUTE_FILE_NAME_OPTION;
      Yap_Error(LOCAL_Error_TYPE, tlist, NULL);
    }
    return false;
  }
  /* done */
  if (args[ABSOLUTE_FILE_NAME_EXTENSIONS].used) {
    t[ABSOLUTE_FILE_NAME_EXTENSIONS] =
        args[ABSOLUTE_FILE_NAME_EXTENSIONS].tvalue;
  } else {
    t[ABSOLUTE_FILE_NAME_EXTENSIONS] = TermNil;
  }
  if (args[ABSOLUTE_FILE_NAME_RELATIVE_TO].used) {
    t[ABSOLUTE_FILE_NAME_RELATIVE_TO] =
        gethdir(args[ABSOLUTE_FILE_NAME_RELATIVE_TO].tvalue);
  } else {
    t[ABSOLUTE_FILE_NAME_RELATIVE_TO] = gethdir(TermDot);
  }
  if (args[ABSOLUTE_FILE_NAME_FILE_TYPE].used)
    t[ABSOLUTE_FILE_NAME_FILE_TYPE] = args[ABSOLUTE_FILE_NAME_FILE_TYPE].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_FILE_TYPE] = TermTxt;
  if (args[ABSOLUTE_FILE_NAME_ACCESS].used)
    t[ABSOLUTE_FILE_NAME_ACCESS] = args[ABSOLUTE_FILE_NAME_ACCESS].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_ACCESS] = TermNone;
  if (args[ABSOLUTE_FILE_NAME_FILE_ERRORS].used)
    t[ABSOLUTE_FILE_NAME_FILE_ERRORS] =
        args[ABSOLUTE_FILE_NAME_FILE_ERRORS].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_FILE_ERRORS] = TermError;
  if (args[ABSOLUTE_FILE_NAME_SOLUTIONS].used)
    t[ABSOLUTE_FILE_NAME_SOLUTIONS] = args[ABSOLUTE_FILE_NAME_SOLUTIONS].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_SOLUTIONS] = TermFirst;
  if (args[ABSOLUTE_FILE_NAME_EXPAND].used)
    t[ABSOLUTE_FILE_NAME_EXPAND] = args[ABSOLUTE_FILE_NAME_EXPAND].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_EXPAND] = TermFalse;
  if (args[ABSOLUTE_FILE_NAME_GLOB].used) {
    t[ABSOLUTE_FILE_NAME_GLOB] = args[ABSOLUTE_FILE_NAME_GLOB].tvalue;
    t[ABSOLUTE_FILE_NAME_EXPAND] = TermTrue;
  } else
    t[ABSOLUTE_FILE_NAME_GLOB] = TermEmptyAtom;
  if (args[ABSOLUTE_FILE_NAME_VERBOSE_FILE_SEARCH].used)
    t[ABSOLUTE_FILE_NAME_VERBOSE_FILE_SEARCH] =
        args[ABSOLUTE_FILE_NAME_VERBOSE_FILE_SEARCH].tvalue;
  else
    t[ABSOLUTE_FILE_NAME_VERBOSE_FILE_SEARCH] =
        (trueGlobalPrologFlag(VERBOSE_FILE_SEARCH_FLAG) ? TermTrue : TermFalse);
  tf = Yap_MkApplTerm(Yap_MkFunctor(AtomOpt, ABSOLUTE_FILE_NAME_END),
                      ABSOLUTE_FILE_NAME_END, t);
  return (Yap_unify(ARG2, tf));
}

static Int get_abs_file_parameter(USES_REGS1) {
  Term t = Deref(ARG1), topts = ARG2;
  /* get options */
  /* done */
  int i = Yap_ArgKey(AtomOfTerm(t), absolute_file_name_search_defs,
                     ABSOLUTE_FILE_NAME_END);
  if (i >= 0)
    return Yap_unify(ARG3, ArgOfTerm(i + 1, topts));
  Yap_Error(DOMAIN_ERROR_ABSOLUTE_FILE_NAME_OPTION, ARG1, NULL);
  return false;
}
void Yap_InitPlIO(void) {
  Int i;

  Yap_stdin = stdin;
  Yap_stdout = stdout;
  Yap_stderr = stderr;
  GLOBAL_Stream =
      (StreamDesc *)Yap_AllocCodeSpace(sizeof(StreamDesc) * MaxStreams);
  for (i = 0; i < MaxStreams; ++i) {
    INIT_LOCK(GLOBAL_Stream[i].streamlock);
    GLOBAL_Stream[i].status = Free_Stream_f;
  }
  InitStdStreams();
}

void Yap_InitIOPreds(void) {
  /* here the Input/Output predicates */
  Yap_InitCPred("always_prompt_user", 0, always_prompt_user,
                SafePredFlag | SyncPredFlag);
  Yap_InitCPred("close", 1, close1, SafePredFlag | SyncPredFlag);
  Yap_InitCPred("close", 2, close2, SafePredFlag | SyncPredFlag);
  Yap_InitCPred("open", 4, open4, SyncPredFlag);
  Yap_InitCPred("open", 3, open3, SyncPredFlag);
  Yap_InitCPred("abs_file_parameters", 2, abs_file_parameters,
                SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("get_abs_file_parameter", 3, get_abs_file_parameter,
                SafePredFlag | SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$file_expansion", 2, p_file_expansion,
                SafePredFlag | SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$open_null_stream", 1, p_open_null_stream,
                SafePredFlag | SyncPredFlag | HiddenPredFlag);
  Yap_InitIOStreams();
  Yap_InitCharsio();
  Yap_InitChtypes();
  Yap_InitConsole();
  Yap_InitReadUtil();
  Yap_InitMems();
  Yap_InitPipes();
  Yap_InitFiles();
  Yap_InitWriteTPreds();
  Yap_InitReadTPreds();
  Yap_InitFormat();
  Yap_InitRandomPreds();
#if USE_READLINE
  Yap_InitReadlinePreds();
#endif
  Yap_InitSockets();
  Yap_InitSignalPreds();
  Yap_InitSysPreds();
  Yap_InitTimePreds();
}