libguile/vports.c

   1 /*      Copyright (C) 1995,1996,1998,1999 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include <stdio.h>
  48 #include "_scm.h"
  49 #include "eval.h"
  50 #include "chars.h"
  51 #include "fports.h"
  52 #include "root.h"
  53 #include "strings.h"
  54 #include "vectors.h"
  55
  56 #include "validate.h"
  57 #include "vports.h"
  58
  59 #ifdef HAVE_STRING_H
  60 #include <string.h>
  61 #endif
  62
  63 \f
  64
  65 /* {Ports - soft ports}
  66  *
  67  */
  68
  69
  70 static void
  71 sf_flush (SCM port)
  72 {
  73   scm_port *pt = SCM_PTAB_ENTRY (port);
  74   SCM stream = SCM_PACK (pt->stream);
  75
  76   if (pt->write_pos > pt->write_buf)
  77     {
  78       /* write the byte. */
  79       scm_apply (SCM_VELTS (stream)[0], SCM_MAKE_CHAR (*pt->write_buf),
  80                  scm_listofnull);
  81       pt->write_pos = pt->write_buf;
  82
  83       /* flush the output.  */
  84       {
  85         SCM f = SCM_VELTS (stream)[2];
  86
  87         if (!SCM_FALSEP (f))
  88           scm_apply (f, SCM_EOL, SCM_EOL);
  89       }
  90     }
  91 }
  92
  93 static void
  94 sf_write (SCM port, const void *data, size_t size)
  95 {
  96   SCM p = SCM_PACK (SCM_STREAM (port));
  97
  98   scm_apply (SCM_VELTS (p)[1],
  99              scm_cons (scm_makfromstr ((char *) data, size, 0), SCM_EOL),
 100              SCM_EOL);
 101 }
 102
 103 /* calling the flush proc (element 2) is in case old code needs it,
 104    but perhaps softports could the use port buffer in the same way as
 105    fports.  */
 106
 107 /* places a single char in the input buffer.  */
 108 static int
 109 sf_fill_input (SCM port)
 110 {
 111   SCM p = SCM_PACK (SCM_STREAM (port));
 112   SCM ans;
 113
 114   ans = scm_apply (SCM_VELTS (p)[3], SCM_EOL, SCM_EOL); /* get char.  */
 115   if (SCM_FALSEP (ans) || SCM_EOF_OBJECT_P (ans))
 116     return EOF;
 117   SCM_ASSERT (SCM_CHARP (ans), ans, SCM_ARG1, "sf_fill_input");
 118   {
 119     scm_port *pt = SCM_PTAB_ENTRY (port);
 120
 121     *pt->read_buf = SCM_CHAR (ans);
 122     pt->read_pos = pt->read_buf;
 123     pt->read_end = pt->read_buf + 1;
 124     return *pt->read_buf;
 125   }
 126 }
 127
 128
 129 static int
 130 sf_close (SCM port)
 131 {
 132   SCM p = SCM_PACK (SCM_STREAM (port));
 133   SCM f = SCM_VELTS (p)[4];
 134   if (SCM_FALSEP (f))
 135     return 0;
 136   f = scm_apply (f, SCM_EOL, SCM_EOL);
 137   errno = 0;
 138   return SCM_FALSEP (f) ? EOF : 0;
 139 }
 140
 141
 142
 143 SCM_DEFINE (scm_make_soft_port, "make-soft-port", 2, 0, 0,
 144            (SCM pv, SCM modes),
 145             "Returns a port capable of receiving or delivering characters as\n"
 146             "specified by the @var{modes} string (@pxref{File Ports,\n"
 147             "open-file}).  @var{vector} must be a vector of length 6.  Its components\n"
 148             "are as follows:\n\n"
 149             "@enumerate 0\n"
 150             "@item\n"
 151             "procedure accepting one character for output\n"
 152             "@item\n"
 153             "procedure accepting a string for output\n"
 154             "@item\n"
 155             "thunk for flushing output\n"
 156             "@item\n"
 157             "thunk for getting one character\n"
 158             "@item\n"
 159             "thunk for closing port (not by garbage collection)\n"
 160             "@end enumerate\n\n"
 161             "For an output-only port only elements 0, 1, 2, and 4 need be\n"
 162             "procedures.  For an input-only port only elements 3 and 4 need be\n"
 163             "procedures.  Thunks 2 and 4 can instead be @code{#f} if there is no useful\n"
 164             "operation for them to perform.\n\n"
 165             "If thunk 3 returns @code{#f} or an @code{eof-object} (@pxref{Input,\n"
 166             "eof-object?, ,r4rs, The Revised^4 Report on Scheme}) it indicates that\n"
 167             "the port has reached end-of-file.  For example:\n\n"
 168             "@example\n"
 169             "(define stdout (current-output-port))\n"
 170             "(define p (make-soft-port\n"
 171             "           (vector\n"
 172             "            (lambda (c) (write c stdout))\n"
 173             "            (lambda (s) (display s stdout))\n"
 174             "            (lambda () (display \".\" stdout))\n"
 175             "            (lambda () (char-upcase (read-char)))\n"
 176             "            (lambda () (display \"@@\" stdout)))\n"
 177             "           \"rw\"))\n\n"
 178             "(write p p) @result{} #<input-output-soft#\space45d10#\>\n"
 179             "@end example")
 180 #define FUNC_NAME s_scm_make_soft_port
 181 {
 182   scm_port *pt;
 183   SCM z;
 184   SCM_VALIDATE_VECTOR_LEN (1,pv,5);
 185   SCM_VALIDATE_ROSTRING (2,modes);
 186   SCM_COERCE_SUBSTR (modes);
 187   SCM_NEWCELL (z);
 188   SCM_DEFER_INTS;
 189   pt = scm_add_to_port_table (z);
 190   scm_port_non_buffer (pt);
 191   SCM_SET_CELL_TYPE (z, scm_tc16_sfport | scm_mode_bits (SCM_ROCHARS (modes)));
 192   SCM_SETPTAB_ENTRY (z, pt);
 193   SCM_SETSTREAM (z, SCM_UNPACK (pv));
 194   SCM_ALLOW_INTS;
 195   return z;
 196 }
 197 #undef FUNC_NAME
 198
 199
 200 void scm_make_sfptob (void); /* Called from ports.c */
 201
 202 void
 203 scm_make_sfptob ()
 204 {
 205   long tc = scm_make_port_type ("soft", sf_fill_input, sf_write);
 206   scm_set_port_mark (tc, scm_markstream);
 207   scm_set_port_flush (tc, sf_flush);
 208   scm_set_port_close (tc, sf_close);
 209 }
 210
 211 void
 212 scm_init_vports ()
 213 {
 214 #include "vports.x"
 215 }
 216
 217 /*
 218   Local Variables:
 219   c-file-style: "gnu"
 220   End:
 221 */