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

   1 /* Copyright (C) 2008, 2014 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 #undef NDEBUG
  27
  28 #include <libguile.h>
  29 #include <assert.h>
  30
  31
  32 \f
  33 /* Size of our port's internal buffer.  */
  34 #define PORT_BUFFER_SIZE 1024
  35
  36 /* Return a new port of type PORT_TYPE.  */
  37 static inline SCM
  38 make_port (scm_t_bits port_type)
  39 {
  40   SCM port;
  41   char *c_buffer;
  42   scm_t_port *c_port;
  43
  44   c_buffer = scm_gc_calloc (PORT_BUFFER_SIZE, "custom-port-buffer");
  45
  46   port = scm_new_port_table_entry (port_type);
  47
  48   /* Associate C_BUFFER with PORT, for test purposes.  */
  49   SCM_SETSTREAM (port, (scm_t_bits) c_buffer);
  50
  51   /* Use C_BUFFER as PORT's internal buffer.  */
  52   c_port = SCM_PTAB_ENTRY (port);
  53   c_port->read_pos = c_port->read_buf = (unsigned char *) c_buffer;
  54   c_port->read_end = (unsigned char *) c_buffer + PORT_BUFFER_SIZE;
  55   c_port->read_buf_size = PORT_BUFFER_SIZE;
  56
  57   /* Mark PORT as open and readable.  */
  58   SCM_SET_CELL_TYPE (port, port_type | SCM_OPN | SCM_RDNG);
  59
  60   return port;
  61 }
  62
  63 /* Read one byte from PORT.  */
  64 static int
  65 fill_input (SCM port)
  66 {
  67   int result;
  68   scm_t_port *c_port = SCM_PTAB_ENTRY (port);
  69
  70   /* Make sure that C_PORT's internal buffer wasn't changed behind our back.
  71      See http://lists.gnu.org/archive/html/guile-devel/2008-11/msg00042.html
  72      for an example where this assumption matters.  */
  73   assert (c_port->read_buf == (unsigned char *) SCM_STREAM (port));
  74   assert (c_port->read_buf_size == PORT_BUFFER_SIZE);
  75
  76   if (c_port->read_pos >= c_port->read_end)
  77     result = EOF;
  78   else
  79     result = (int) *c_port->read_pos++;
  80
  81   return result;
  82 }
  83
  84 /* Return true (non-zero) if BUF contains only zeros.  */
  85 static inline int
  86 zeroed_buffer_p (const char *buf, size_t len)
  87 {
  88   size_t i;
  89
  90   for (i = 0; i < len; i++)
  91     if (buf[i] != 0)
  92       return 0;
  93
  94   return 1;
  95 }
  96
  97 /* Run the test.  */
  98 static void *
  99 do_start (void *arg)
 100 {
 101   SCM port;
 102   scm_t_bits port_type;
 103   char buffer[PORT_BUFFER_SIZE + (PORT_BUFFER_SIZE / 2)];
 104   size_t read, last_read;
 105
 106   port_type = scm_make_port_type ("custom-input-port", fill_input, NULL);
 107   port = make_port (port_type);
 108
 109   read = 0;
 110   do
 111     {
 112       last_read = scm_c_read (port, &buffer[read], 123);
 113       assert (last_read <= 123);
 114       assert (zeroed_buffer_p (&buffer[read], last_read));
 115
 116       read += last_read;
 117     }
 118   while (last_read > 0 && read < sizeof (buffer));
 119
 120   /* We shouldn't be able to read more than what's in PORT's buffer.  */
 121   assert (read == PORT_BUFFER_SIZE);
 122
 123   return NULL;
 124 }
 125
 126 \f
 127 int
 128 main (int argc, char *argv[])
 129 {
 130   scm_with_guile (do_start, NULL);
 131
 132   return 0;
 133 }