summaryrefslogtreecommitdiff
path: root/libguile/vports.c
blob: 6aec948a46f00cc64c1208da9f7caf5ff626351c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/* Copyright (C) 1995,1996,1998,1999,2000,2001, 2002, 2003, 2006 Free Software Foundation, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */



#if HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdio.h>
#include <errno.h>

#include "libguile/_scm.h"
#include "libguile/eval.h"
#include "libguile/chars.h"
#include "libguile/fports.h"
#include "libguile/root.h"
#include "libguile/strings.h"
#include "libguile/vectors.h"

#include "libguile/validate.h"
#include "libguile/vports.h"

#ifdef HAVE_STRING_H
#include <string.h>
#endif



/* {Ports - soft ports}
 * 
 */


static scm_t_bits scm_tc16_sfport;


static void
sf_flush (SCM port)
{
  scm_t_port *pt = SCM_PTAB_ENTRY (port);
  SCM stream = SCM_PACK (pt->stream);

  if (pt->write_pos > pt->write_buf)
    {
      /* write the byte. */
      scm_call_1 (SCM_SIMPLE_VECTOR_REF (stream, 0),
		  SCM_MAKE_CHAR (*pt->write_buf));
      pt->write_pos = pt->write_buf;
  
      /* flush the output.  */
      {
	SCM f = SCM_SIMPLE_VECTOR_REF (stream, 2);

	if (scm_is_true (f))
	  scm_call_0 (f);
      }
    }
}

static void
sf_write (SCM port, const void *data, size_t size)
{
  SCM p = SCM_PACK (SCM_STREAM (port));

  scm_call_1 (SCM_SIMPLE_VECTOR_REF (p, 1),
	      scm_from_locale_stringn ((char *) data, size));
}

/* calling the flush proc (element 2) is in case old code needs it,
   but perhaps softports could the use port buffer in the same way as
   fports.  */

/* places a single char in the input buffer.  */
static int 
sf_fill_input (SCM port)
{
  SCM p = SCM_PACK (SCM_STREAM (port));
  SCM ans;

  ans = scm_call_0 (SCM_SIMPLE_VECTOR_REF (p, 3)); /* get char.  */
  if (scm_is_false (ans) || SCM_EOF_OBJECT_P (ans))
    return EOF;
  SCM_ASSERT (SCM_CHARP (ans), ans, SCM_ARG1, "sf_fill_input");
  {
    scm_t_port *pt = SCM_PTAB_ENTRY (port);    

    *pt->read_buf = SCM_CHAR (ans);
    pt->read_pos = pt->read_buf;
    pt->read_end = pt->read_buf + 1;
    return *pt->read_buf;
  }
}


static int 
sf_close (SCM port)
{
  SCM p = SCM_PACK (SCM_STREAM (port));
  SCM f = SCM_SIMPLE_VECTOR_REF (p, 4);
  if (scm_is_false (f))
    return 0;
  f = scm_call_0 (f);
  errno = 0;
  return scm_is_false (f) ? EOF : 0;
}


static int 
sf_input_waiting (SCM port)
{
  SCM p = SCM_PACK (SCM_STREAM (port));
  if (SCM_SIMPLE_VECTOR_LENGTH (p) >= 6)
    {
      SCM f = SCM_SIMPLE_VECTOR_REF (p, 5);
      if (scm_is_true (f))
	return scm_to_int (scm_call_0 (f));
    }
  /* Default is such that char-ready? for soft ports returns #t, as it
     did before this extension was implemented. */
  return 1;
}



SCM_DEFINE (scm_make_soft_port, "make-soft-port", 2, 0, 0,
           (SCM pv, SCM modes),
	    "Return a port capable of receiving or delivering characters as\n"
	    "specified by the @var{modes} string (@pxref{File Ports,\n"
	    "open-file}).  @var{pv} must be a vector of length 5 or 6.  Its\n"
	    "components are as follows:\n"
	    "\n"
	    "@enumerate 0\n"
	    "@item\n"
	    "procedure accepting one character for output\n"
	    "@item\n"
	    "procedure accepting a string for output\n"
	    "@item\n"
	    "thunk for flushing output\n"
	    "@item\n"
	    "thunk for getting one character\n"
	    "@item\n"
	    "thunk for closing port (not by garbage collection)\n"
	    "@item\n"
	    "(if present and not @code{#f}) thunk for computing the number of\n"
	    "characters that can be read from the port without blocking.\n"
	    "@end enumerate\n"
	    "\n"
	    "For an output-only port only elements 0, 1, 2, and 4 need be\n"
	    "procedures.  For an input-only port only elements 3 and 4 need\n"
	    "be procedures.  Thunks 2 and 4 can instead be @code{#f} if\n"
	    "there is no useful operation for them to perform.\n"
	    "\n"
	    "If thunk 3 returns @code{#f} or an @code{eof-object}\n"
	    "(@pxref{Input, eof-object?, ,r5rs, The Revised^5 Report on\n"
	    "Scheme}) it indicates that the port has reached end-of-file.\n"
	    "For example:\n"
	    "\n"
	    "@lisp\n"
	    "(define stdout (current-output-port))\n"
	    "(define p (make-soft-port\n"
	    "           (vector\n"
	    "            (lambda (c) (write c stdout))\n"
	    "            (lambda (s) (display s stdout))\n"
	    "            (lambda () (display \".\" stdout))\n"
	    "            (lambda () (char-upcase (read-char)))\n"
	    "            (lambda () (display \"@@\" stdout)))\n"
	    "           \"rw\"))\n"
	    "\n"
	    "(write p p) @result{} #<input-output: soft 8081e20>\n"
	    "@end lisp")
#define FUNC_NAME s_scm_make_soft_port
{
  int vlen;
  scm_t_port *pt;
  SCM z;

  SCM_VALIDATE_VECTOR (1, pv);
  vlen = SCM_SIMPLE_VECTOR_LENGTH (pv);
  SCM_ASSERT ((vlen == 5) || (vlen == 6), pv, 1, FUNC_NAME);
  SCM_VALIDATE_STRING (2, modes);
  
  scm_i_scm_pthread_mutex_lock (&scm_i_port_table_mutex);
  z = scm_new_port_table_entry (scm_tc16_sfport);
  pt = SCM_PTAB_ENTRY (z);
  scm_port_non_buffer (pt);
  SCM_SET_CELL_TYPE (z, scm_tc16_sfport | scm_i_mode_bits (modes));

  SCM_SETSTREAM (z, SCM_UNPACK (pv));
  scm_i_pthread_mutex_unlock (&scm_i_port_table_mutex);
  return z;
}
#undef FUNC_NAME


static scm_t_bits
scm_make_sfptob ()
{
  scm_t_bits tc = scm_make_port_type ("soft", sf_fill_input, sf_write);

  scm_set_port_mark (tc, scm_markstream);
  scm_set_port_flush (tc, sf_flush);
  scm_set_port_close (tc, sf_close);
  scm_set_port_input_waiting (tc, sf_input_waiting);

  return tc;
}

void
scm_init_vports ()
{
  scm_tc16_sfport = scm_make_sfptob ();

#include "libguile/vports.x"
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/