1 /* Copyright (C) 2008 Free Software Foundation, Inc.
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
8 * This library 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 GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 /* Exercise `scm_c_read ()' and the port type API. Verify assumptions that
19 can be made by port type implementations. */
30 /* Size of our port's internal buffer. */
31 #define PORT_BUFFER_SIZE 1024
33 /* Return a new port of type PORT_TYPE. */
35 make_port (scm_t_bits port_type
)
41 c_buffer
= scm_gc_calloc (PORT_BUFFER_SIZE
, "custom-port-buffer");
43 port
= scm_new_port_table_entry (port_type
);
45 /* Attach it the underlying u8vector, which we'll use as PORT's buffer. */
46 SCM_SETSTREAM (port
, (scm_t_bits
) c_buffer
);
48 /* Have the port directly access the buffer (bytevector). */
49 c_port
= SCM_PTAB_ENTRY (port
);
50 c_port
->read_pos
= c_port
->read_buf
= (unsigned char *) c_buffer
;
51 c_port
->read_end
= (unsigned char *) c_buffer
+ PORT_BUFFER_SIZE
;
52 c_port
->read_buf_size
= PORT_BUFFER_SIZE
;
54 /* Mark PORT as open and readable. */
55 SCM_SET_CELL_TYPE (port
, port_type
| SCM_OPN
| SCM_RDNG
);
60 /* Read one byte from PORT. */
65 scm_t_port
*c_port
= SCM_PTAB_ENTRY (port
);
67 /* Make sure that C_PORT's internal buffer wasn't changed behind our back.
68 See http://lists.gnu.org/archive/html/guile-devel/2008-11/msg00042.html
69 for an example where this assumption matters. */
70 assert (c_port
->read_buf
== (unsigned char *) SCM_STREAM (port
));
71 assert (c_port
->read_buf_size
== PORT_BUFFER_SIZE
);
73 if (c_port
->read_pos
>= c_port
->read_end
)
76 result
= (int) *c_port
->read_pos
++;
81 /* Return true (non-zero) if BUF contains only zeros. */
83 zeroed_buffer_p (const char *buf
, size_t len
)
87 for (i
= 0; i
< len
; i
++)
100 char buffer
[PORT_BUFFER_SIZE
+ (PORT_BUFFER_SIZE
/ 2)];
101 size_t read
, last_read
;
103 port_type
= scm_make_port_type ("custom-input-port", fill_input
, NULL
);
104 port
= make_port (port_type
);
109 last_read
= scm_c_read (port
, &buffer
[read
], 123);
110 assert (last_read
<= 123);
111 assert (zeroed_buffer_p (&buffer
[read
], last_read
));
115 while (last_read
> 0 && read
< sizeof (buffer
));
117 /* We shouldn't be able to read more than what's in PORT's buffer. */
118 assert (read
== PORT_BUFFER_SIZE
);
125 main (int argc
, char *argv
[])
127 scm_with_guile (do_start
, NULL
);