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/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2005-2022, University of Amsterdam
VU University Amsterdam
SWI-Prolog Solutions b.v.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#include <SWI-Stream.h>
#include <SWI-Prolog.h>
#include "utf8.h"
#define BUFSIZE 1024
#define UCFLAGS (REP_UTF8|PL_CODE_LIST)
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
This library is dynamically picked up by library(readline), which falls
back to a pure Prolog implementation if this library cannot be found.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
static atom_t ATOM_end_of_file;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
read_line_to_codes(+Stream, -Codes, ?Tail)
Read a line, upto the next '\n' from Stream. Normally the line is
returned as a difference list Codes-Tail. If EOF is encountered, the
Codes list is closed and Tail is unified with [].
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
static foreign_t
read_line_to_codes3(term_t stream, term_t codes, term_t tail)
{ char buf[BUFSIZE];
char *o = buf, *e = &buf[BUFSIZE];
IOSTREAM *s;
term_t diff = PL_new_term_refs(2);
term_t cl = diff;
int rc = FALSE;
if ( !PL_unify(codes, cl) )
return FALSE;
if ( !PL_get_stream(stream, &s, SIO_INPUT) )
return FALSE;
for(;;)
{ int c = Sgetcode(s);
if ( c == EOF )
{ if ( Sferror(s) || PL_exception(0) )
goto out; /* error */
if ( tail == 0 && o == buf )
{ rc = PL_unify_atom(codes, ATOM_end_of_file);
goto out;
}
if ( PL_unify_chars(cl, UCFLAGS, o-buf, buf) &&
(tail == 0 || PL_unify_nil(tail)) )
rc = TRUE;
goto out;
}
if ( o+8 >= e && o[-1] != '\r' ) /* UTF-8 <= 6 bytes, may discard \r */
{ if ( !PL_unify_chars(diff, PL_DIFF_LIST|UCFLAGS, o-buf, buf) ||
!PL_put_term(cl, diff+1) )
goto out;
o = buf;
}
o = utf8_put_char(o, c);
if ( c == '\n' )
{ if ( tail )
{ rc = ( PL_unify_chars(diff, PL_DIFF_LIST|UCFLAGS, o-buf, buf) &&
PL_unify(diff+1, tail) );
} else
{ o--;
if ( o>buf && o[-1] == '\r' )
o--;
rc = PL_unify_chars(cl, REP_UTF8|PL_CODE_LIST, o-buf, buf);
}
goto out;
}
}
out:
PL_release_stream(s);
return rc;
}
static foreign_t
read_line_to_codes2(term_t stream, term_t codes)
{ return read_line_to_codes3(stream, codes, 0);
}
static foreign_t
read_stream_to_codes3(term_t stream, term_t codes, term_t tail)
{ char buf[BUFSIZE];
char *o = buf, *e = &buf[BUFSIZE];
IOSTREAM *s;
term_t diff = PL_new_term_refs(2);
term_t cl = diff;
if ( !PL_unify(codes, cl) )
return FALSE;
if ( !PL_get_stream(stream, &s, SIO_INPUT) )
return FALSE;
for(;;)
{ int c = Sgetcode(s);
if ( c == EOF )
{ if ( !PL_release_stream(s) )
return FALSE; /* error */
if ( PL_exception(0) )
return FALSE;
if ( tail )
{ return ( PL_unify_chars(diff, PL_DIFF_LIST|UCFLAGS, o-buf, buf) &&
PL_unify(diff+1, tail) );
} else
{ return PL_unify_chars(cl, REP_UTF8|PL_CODE_LIST, o-buf, buf);
}
}
if ( o+7 >= e )
{ if ( !PL_unify_chars(diff, PL_DIFF_LIST|UCFLAGS, o-buf, buf) ||
!PL_put_term(cl, diff+1) )
{ PL_release_stream(s);
return FALSE;
}
o = buf;
}
o = utf8_put_char(o, c);
}
}
static foreign_t
read_stream_to_codes2(term_t stream, term_t codes)
{ return read_stream_to_codes3(stream, codes, 0);
}
install_t
install_readutil()
{ ATOM_end_of_file = PL_new_atom("end_of_file");
PL_register_foreign("read_line_to_codes", 3, read_line_to_codes3, 0);
PL_register_foreign("read_line_to_codes", 2, read_line_to_codes2, 0);
PL_register_foreign("read_stream_to_codes", 3, read_stream_to_codes3, 0);
PL_register_foreign("read_stream_to_codes", 2, read_stream_to_codes2, 0);
}
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