test-suite/standalone/test-scm-c-read.c

   1 /* Copyright (C) 2008 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * 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.
  12  *
  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
  16  * 02110-1301 USA
  17  */
  18
  19 /* Exercise `scm_c_read ()' and the port type API.  Verify assumptions that
  20    can be made by port type implementations.  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #include <libguile.h>
  27 #include <assert.h>
  28
  29
  30 \f
  31 /* Size of our port's internal buffer.  */
  32 #define PORT_BUFFER_SIZE 1024
  33
  34 /* Return a new port of type PORT_TYPE.  */
  35 static inline SCM
  36 make_port (scm_t_bits port_type)
  37 {
  38   SCM port;
  39   char *c_buffer;
  40   scm_t_port *c_port;
  41
  42   c_buffer = scm_gc_calloc (PORT_BUFFER_SIZE, "custom-port-buffer");
  43
  44   port = scm_new_port_table_entry (port_type);
  45
  46   /* Associate C_BUFFER with PORT, for test purposes.  */
  47   SCM_SETSTREAM (port, (scm_t_bits) c_buffer);
  48
  49   /* Use C_BUFFER as PORT's internal buffer.  */
  50   c_port = SCM_PTAB_ENTRY (port);
  51   c_port->read_pos = c_port->read_buf = (unsigned char *) c_buffer;
  52   c_port->read_end = (unsigned char *) c_buffer + PORT_BUFFER_SIZE;
  53   c_port->read_buf_size = PORT_BUFFER_SIZE;
  54
  55   /* Mark PORT as open and readable.  */
  56   SCM_SET_CELL_TYPE (port, port_type | SCM_OPN | SCM_RDNG);
  57
  58   return port;
  59 }
  60
  61 /* Read one byte from PORT.  */
  62 static int
  63 fill_input (SCM port)
  64 {
  65   int result;
  66   scm_t_port *c_port = SCM_PTAB_ENTRY (port);
  67
  68   /* Make sure that C_PORT's internal buffer wasn't changed behind our back.
  69      See http://lists.gnu.org/archive/html/guile-devel/2008-11/msg00042.html
  70      for an example where this assumption matters.  */
  71   assert (c_port->read_buf == (unsigned char *) SCM_STREAM (port));
  72   assert (c_port->read_buf_size == PORT_BUFFER_SIZE);
  73
  74   if (c_port->read_pos >= c_port->read_end)
  75     result = EOF;
  76   else
  77     result = (int) *c_port->read_pos++;
  78
  79   return result;
  80 }
  81
  82 /* Return true (non-zero) if BUF contains only zeros.  */
  83 static inline int
  84 zeroed_buffer_p (const char *buf, size_t len)
  85 {
  86   size_t i;
  87
  88   for (i = 0; i < len; i++)
  89     if (buf[i] != 0)
  90       return 0;
  91
  92   return 1;
  93 }
  94
  95 /* Run the test.  */
  96 static void *
  97 do_start (void *arg)
  98 {
  99   SCM port;
 100   scm_t_bits port_type;
 101   char buffer[PORT_BUFFER_SIZE + (PORT_BUFFER_SIZE / 2)];
 102   size_t read, last_read;
 103
 104   port_type = scm_make_port_type ("custom-input-port", fill_input, NULL);
 105   port = make_port (port_type);
 106
 107   read = 0;
 108   do
 109     {
 110       last_read = scm_c_read (port, &buffer[read], 123);
 111       assert (last_read <= 123);
 112       assert (zeroed_buffer_p (&buffer[read], last_read));
 113
 114       read += last_read;
 115     }
 116   while (last_read > 0 && read < sizeof (buffer));
 117
 118   /* We shouldn't be able to read more than what's in PORT's buffer.  */
 119   assert (read == PORT_BUFFER_SIZE);
 120
 121   return NULL;
 122 }
 123
 124 \f
 125 int
 126 main (int argc, char *argv[])
 127 {
 128   scm_with_guile (do_start, NULL);
 129
 130   return 0;
 131 }