--- /dev/null
+/* Copyright (C) 2008 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
+ */
+
+/* Exercise `scm_c_read ()' and the port type API. Verify assumptions that
+ can be made by port type implementations. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <libguile.h>
+#include <assert.h>
+
+
+\f
+/* Size of our port's internal buffer. */
+#define PORT_BUFFER_SIZE 1024
+
+/* Return a new port of type PORT_TYPE. */
+static inline SCM
+make_port (scm_t_bits port_type)
+{
+ SCM port;
+ char *c_buffer;
+ scm_t_port *c_port;
+
+ c_buffer = scm_gc_calloc (PORT_BUFFER_SIZE, "custom-port-buffer");
+
+ port = scm_new_port_table_entry (port_type);
+
+ /* Associate C_BUFFER with PORT, for test purposes. */
+ SCM_SETSTREAM (port, (scm_t_bits) c_buffer);
+
+ /* Use C_BUFFER as PORT's internal buffer. */
+ c_port = SCM_PTAB_ENTRY (port);
+ c_port->read_pos = c_port->read_buf = (unsigned char *) c_buffer;
+ c_port->read_end = (unsigned char *) c_buffer + PORT_BUFFER_SIZE;
+ c_port->read_buf_size = PORT_BUFFER_SIZE;
+
+ /* Mark PORT as open and readable. */
+ SCM_SET_CELL_TYPE (port, port_type | SCM_OPN | SCM_RDNG);
+
+ return port;
+}
+
+/* Read one byte from PORT. */
+static int
+fill_input (SCM port)
+{
+ int result;
+ scm_t_port *c_port = SCM_PTAB_ENTRY (port);
+
+ /* Make sure that C_PORT's internal buffer wasn't changed behind our back.
+ See http://lists.gnu.org/archive/html/guile-devel/2008-11/msg00042.html
+ for an example where this assumption matters. */
+ assert (c_port->read_buf == (unsigned char *) SCM_STREAM (port));
+ assert (c_port->read_buf_size == PORT_BUFFER_SIZE);
+
+ if (c_port->read_pos >= c_port->read_end)
+ result = EOF;
+ else
+ result = (int) *c_port->read_pos++;
+
+ return result;
+}
+
+/* Return true (non-zero) if BUF contains only zeros. */
+static inline int
+zeroed_buffer_p (const char *buf, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++)
+ if (buf[i] != 0)
+ return 0;
+
+ return 1;
+}
+
+/* Run the test. */
+static void *
+do_start (void *arg)
+{
+ SCM port;
+ scm_t_bits port_type;
+ char buffer[PORT_BUFFER_SIZE + (PORT_BUFFER_SIZE / 2)];
+ size_t read, last_read;
+
+ port_type = scm_make_port_type ("custom-input-port", fill_input, NULL);
+ port = make_port (port_type);
+
+ read = 0;
+ do
+ {
+ last_read = scm_c_read (port, &buffer[read], 123);
+ assert (last_read <= 123);
+ assert (zeroed_buffer_p (&buffer[read], last_read));
+
+ read += last_read;
+ }
+ while (last_read > 0 && read < sizeof (buffer));
+
+ /* We shouldn't be able to read more than what's in PORT's buffer. */
+ assert (read == PORT_BUFFER_SIZE);
+
+ return NULL;
+}
+
+\f
+int
+main (int argc, char *argv[])
+{
+ scm_with_guile (do_start, NULL);
+
+ return 0;
+}