clib package
This commit is contained in:
Vítor Santos Costa
170
packages/clib/readutil.c
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170
packages/clib/readutil.c
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/* $Id$
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Part of SWI-Prolog
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Author: Jan Wielemaker
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E-mail: jan@science.uva.nl
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WWW: http://www.swi-prolog.org
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Copyright (C): 1985-2005, University of Amsterdam
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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As a special exception, if you link this library with other files,
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compiled with a Free Software compiler, to produce an executable, this
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library does not by itself cause the resulting executable to be covered
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by the GNU General Public License. This exception does not however
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invalidate any other reasons why the executable file might be covered by
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the GNU General Public License.
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*/
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#include <SWI-Stream.h>
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#include <SWI-Prolog.h>
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#define BUFSIZE 256
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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This library is dynamically picked up by library(readline), which falls
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back to a pure Prolog implementation if this library cannot be found.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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static atom_t ATOM_end_of_file;
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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read_line_to_codes(+Stream, -Codes, ?Tail)
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Read a line, upto the next '\n' from Stream. Normally the line is
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returned as a difference list Codes-Tail. If EOF is encountered, the
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Codes list is closed and Tail is unified with [].
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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static foreign_t
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read_line_to_codes3(term_t stream, term_t codes, term_t tail)
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{ wchar_t buf[BUFSIZE];
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wchar_t *o = buf, *e = &buf[BUFSIZE];
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IOSTREAM *s;
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term_t cl = PL_copy_term_ref(codes);
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int rc = FALSE;
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if ( !PL_get_stream_handle(stream, &s) )
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return FALSE;
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for(;;)
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{ int c = Sgetcode(s);
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if ( c == EOF )
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{ if ( (s->flags & SIO_FERR) )
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goto out; /* error */
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if ( tail == 0 && o == buf )
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{ rc = PL_unify_atom(codes, ATOM_end_of_file);
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goto out;
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}
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if ( PL_unify_wchars(cl, PL_CODE_LIST, o-buf, buf) &&
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(tail == 0 || PL_unify_nil(tail)) )
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rc = TRUE;
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goto out;
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}
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if ( o == e )
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{ if ( !PL_unify_wchars_diff(cl, cl, PL_CODE_LIST, o-buf, buf) )
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goto out;
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o = buf;
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}
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*o++ = c;
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if ( c == '\n' )
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{ if ( tail )
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{ if ( PL_unify_wchars_diff(cl, cl, PL_CODE_LIST, o-buf, buf) &&
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PL_unify(cl, tail) )
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rc = TRUE;
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} else
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{ o--;
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if ( o>buf && o[-1] == '\r' )
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o--;
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rc = PL_unify_wchars(cl, PL_CODE_LIST, o-buf, buf);
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}
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goto out;
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}
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}
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out:
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PL_release_stream(s);
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return rc;
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}
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static foreign_t
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read_line_to_codes2(term_t stream, term_t codes)
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{ return read_line_to_codes3(stream, codes, 0);
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}
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static foreign_t
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read_stream_to_codes3(term_t stream, term_t codes, term_t tail)
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{ wchar_t buf[BUFSIZE];
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wchar_t *o = buf, *e = &buf[BUFSIZE];
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IOSTREAM *s;
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term_t cl = PL_copy_term_ref(codes);
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if ( !PL_get_stream_handle(stream, &s) )
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return FALSE;
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for(;;)
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{ int c = Sgetcode(s);
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if ( c == EOF )
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{ if ( !PL_release_stream(s) )
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return FALSE; /* error */
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if ( tail )
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{ if ( PL_unify_wchars_diff(cl, cl, PL_CODE_LIST, o-buf, buf) &&
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PL_unify(cl, tail) )
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return TRUE;
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return FALSE;
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} else
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{ return PL_unify_wchars(cl, PL_CODE_LIST, o-buf, buf);
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}
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}
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if ( o == e )
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{ if ( !PL_unify_wchars_diff(cl, cl, PL_CODE_LIST, o-buf, buf) )
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{ PL_release_stream(s);
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return FALSE;
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}
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o = buf;
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}
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*o++ = c;
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}
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}
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static foreign_t
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read_stream_to_codes2(term_t stream, term_t codes)
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{ return read_stream_to_codes3(stream, codes, 0);
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}
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install_t
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install_readutil()
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{ ATOM_end_of_file = PL_new_atom("end_of_file");
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PL_register_foreign("read_line_to_codes", 3, read_line_to_codes3, 0);
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PL_register_foreign("read_line_to_codes", 2, read_line_to_codes2, 0);
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PL_register_foreign("read_stream_to_codes", 3, read_stream_to_codes3, 0);
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PL_register_foreign("read_stream_to_codes", 2, read_stream_to_codes2, 0);
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}
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