mirror of
https://git.savannah.gnu.org/git/guile.git
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254 lines
7.1 KiB
C
254 lines
7.1 KiB
C
/* Copyright (C) 1995,1996,1998,1999,2000,2001, 2002 Free Software Foundation, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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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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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA
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*
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* As a special exception, the Free Software Foundation gives permission
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* for additional uses of the text contained in its release of GUILE.
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*
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* The exception is that, if you link the GUILE library with other files
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* to produce an executable, this does not by itself cause the
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* resulting executable to be covered by the GNU General Public License.
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* Your use of that executable is in no way restricted on account of
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* linking the GUILE library code into it.
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*
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*
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* This exception applies only to the code released by the
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* Free Software Foundation under the name GUILE. If you copy
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* code from other Free Software Foundation releases into a copy of
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* GUILE, as the General Public License permits, the exception does
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* not apply to the code that you add in this way. To avoid misleading
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* anyone as to the status of such modified files, you must delete
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* this exception notice from them.
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*
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* If you write modifications of your own for GUILE, it is your choice
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* whether to permit this exception to apply to your modifications.
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* If you do not wish that, delete this exception notice. */
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#include <stdio.h>
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#include <errno.h>
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#include "libguile/_scm.h"
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#include "libguile/eval.h"
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#include "libguile/chars.h"
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#include "libguile/fports.h"
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#include "libguile/root.h"
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#include "libguile/strings.h"
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#include "libguile/vectors.h"
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#include "libguile/validate.h"
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#include "libguile/vports.h"
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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/* {Ports - soft ports}
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*
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*/
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static scm_t_bits scm_tc16_sfport;
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static void
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sf_flush (SCM port)
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{
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scm_t_port *pt = SCM_PTAB_ENTRY (port);
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SCM stream = SCM_PACK (pt->stream);
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if (pt->write_pos > pt->write_buf)
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{
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/* write the byte. */
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scm_call_1 (SCM_VELTS (stream)[0], SCM_MAKE_CHAR (*pt->write_buf));
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pt->write_pos = pt->write_buf;
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/* flush the output. */
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{
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SCM f = SCM_VELTS (stream)[2];
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if (!SCM_FALSEP (f))
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scm_call_0 (f);
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}
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}
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}
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static void
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sf_write (SCM port, const void *data, size_t size)
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{
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SCM p = SCM_PACK (SCM_STREAM (port));
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scm_call_1 (SCM_VELTS (p)[1], scm_mem2string ((char *) data, size));
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}
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/* calling the flush proc (element 2) is in case old code needs it,
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but perhaps softports could the use port buffer in the same way as
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fports. */
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/* places a single char in the input buffer. */
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static int
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sf_fill_input (SCM port)
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{
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SCM p = SCM_PACK (SCM_STREAM (port));
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SCM ans;
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ans = scm_call_0 (SCM_VELTS (p)[3]); /* get char. */
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if (SCM_FALSEP (ans) || SCM_EOF_OBJECT_P (ans))
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return EOF;
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SCM_ASSERT (SCM_CHARP (ans), ans, SCM_ARG1, "sf_fill_input");
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{
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scm_t_port *pt = SCM_PTAB_ENTRY (port);
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*pt->read_buf = SCM_CHAR (ans);
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pt->read_pos = pt->read_buf;
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pt->read_end = pt->read_buf + 1;
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return *pt->read_buf;
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}
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}
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static int
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sf_close (SCM port)
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{
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SCM p = SCM_PACK (SCM_STREAM (port));
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SCM f = SCM_VELTS (p)[4];
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if (SCM_FALSEP (f))
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return 0;
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f = scm_call_0 (f);
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errno = 0;
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return SCM_FALSEP (f) ? EOF : 0;
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}
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static int
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sf_input_waiting (SCM port)
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{
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SCM p = SCM_PACK (SCM_STREAM (port));
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if (SCM_VECTOR_LENGTH (p) >= 6)
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{
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SCM f = SCM_VELTS (p)[5];
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if (SCM_NFALSEP (f))
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return scm_num2int (scm_call_0 (f), SCM_ARGn, NULL);
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}
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/* Default is such that char-ready? for soft ports returns #t, as it
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did before this extension was implemented. */
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return 1;
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}
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SCM_DEFINE (scm_make_soft_port, "make-soft-port", 2, 0, 0,
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(SCM pv, SCM modes),
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"Return a port capable of receiving or delivering characters as\n"
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"specified by the @var{modes} string (@pxref{File Ports,\n"
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"open-file}). @var{pv} must be a vector of length 5 or 6. Its\n"
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"components are as follows:\n"
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"\n"
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"@enumerate 0\n"
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"@item\n"
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"procedure accepting one character for output\n"
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"@item\n"
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"procedure accepting a string for output\n"
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"@item\n"
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"thunk for flushing output\n"
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"@item\n"
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"thunk for getting one character\n"
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"@item\n"
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"thunk for closing port (not by garbage collection)\n"
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"@item\n"
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"(if present and not @code{#f}) thunk for computing the number of\n"
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"characters that can be read from the port without blocking.\n"
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"@end enumerate\n"
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"\n"
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"For an output-only port only elements 0, 1, 2, and 4 need be\n"
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"procedures. For an input-only port only elements 3 and 4 need\n"
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"be procedures. Thunks 2 and 4 can instead be @code{#f} if\n"
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"there is no useful operation for them to perform.\n"
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"\n"
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"If thunk 3 returns @code{#f} or an @code{eof-object}\n"
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"(@pxref{Input, eof-object?, ,r5rs, The Revised^5 Report on\n"
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"Scheme}) it indicates that the port has reached end-of-file.\n"
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"For example:\n"
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"\n"
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"@lisp\n"
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"(define stdout (current-output-port))\n"
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"(define p (make-soft-port\n"
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" (vector\n"
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" (lambda (c) (write c stdout))\n"
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" (lambda (s) (display s stdout))\n"
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" (lambda () (display \".\" stdout))\n"
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" (lambda () (char-upcase (read-char)))\n"
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" (lambda () (display \"@@\" stdout)))\n"
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" \"rw\"))\n"
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"\n"
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"(write p p) @result{} #<input-output: soft 8081e20>\n"
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"@end lisp")
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#define FUNC_NAME s_scm_make_soft_port
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{
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int vlen;
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scm_t_port *pt;
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SCM z;
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SCM_VALIDATE_VECTOR (1, pv);
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vlen = SCM_VECTOR_LENGTH (pv);
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SCM_ASSERT ((vlen == 5) || (vlen == 6), pv, 1, FUNC_NAME);
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SCM_VALIDATE_STRING (2, modes);
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SCM_DEFER_INTS;
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z = scm_new_port_table_entry (scm_tc16_sfport);
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pt = SCM_PTAB_ENTRY (z);
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scm_port_non_buffer (pt);
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SCM_SET_CELL_TYPE (z, scm_tc16_sfport | scm_mode_bits (SCM_STRING_CHARS (modes)));
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SCM_SETSTREAM (z, SCM_UNPACK (pv));
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SCM_ALLOW_INTS;
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return z;
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}
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#undef FUNC_NAME
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static scm_t_bits
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scm_make_sfptob ()
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{
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scm_t_bits tc = scm_make_port_type ("soft", sf_fill_input, sf_write);
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scm_set_port_mark (tc, scm_markstream);
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scm_set_port_flush (tc, sf_flush);
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scm_set_port_close (tc, sf_close);
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scm_set_port_input_waiting (tc, sf_input_waiting);
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return tc;
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}
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void
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scm_init_vports ()
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{
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scm_tc16_sfport = scm_make_sfptob ();
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#include "libguile/vports.x"
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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