Ruby Newbie: Simple C Wrappers?

Hello,

My apologies if this has already been discussed in detail on the list
but I’ve been working with the Pragmatics an O’Rielly’s for some time
now and I think it’s time to call for a ‘help.’

I would like to interface what seems to be a straightforward main
program (as I understand it that’s all I need to interface, not the rest
of the .c files, please correct me if this is in error) and have
achieved a compile with an empty Init function like so:

void
Init_jzipr()
{

}

irb works:

$ irb
irb(main):001:0> require ‘jzipr’
=> true

I am finding the next step–creating the class–difficult. Here’s
jzip.c–it’s doesn’t look like much but doing it for the first time…

------------------Begin jzip.c------------------------

/* $Id: jzip.c,v 1.3 2000/10/04 23:07:57 jholder Exp $


  • see doc/License.txt for License Information

  • File name: $Id: jzip.c,v 1.3 2000/10/04 23:07:57 jholder Exp $
  • Description:
  • Modification history:
  • $Log: jzip.c,v $
  • Revision 1.3 2000/10/04 23:07:57 jholder
  • fixed redirect problem with isolatin1 range chars
  • Revision 1.2 2000/05/25 22:28:56 jholder
  • changes routine names to reflect zmachine opcode names per spec 1.0
  • Revision 1.1.1.1 2000/05/10 14:21:34 jholder
  • imported

*/

/*

  • jzip.c
  • Z code interpreter main routine.
  • Revisions list:
  • Mark Howell 10-Mar-1993 V2.0 [email protected]
  •                     V2.0.1(some of a-f)
    
  • John Holder 22-Nov-1995 V2.0.1g [email protected]
  • John Holder 06-Feb-1998 V2.0.2 [email protected] Zstrict & Quetzal
  • If you have problems with this interpreter and/or fix bugs in it,
  • please notify John Holder ([email protected]) and he will add your
  • fix to the official JZIP distribution.
    */

#include “ztypes.h”

extern int GLOBALVER;

static void configure( zbyte_t, zbyte_t );

/*

  • main
  • Initialise environment, start interpreter, clean up.
    */

int main( int argc, char *argv[] )
{
process_arguments( argc, argv );

configure( V1, V8 );

initialize_screen(  );

load_cache(  );

z_restart(  );

( void ) interpret(  );

unload_cache(  );

close_story(  );

close_script(  );

reset_screen(  );

exit( EXIT_SUCCESS );

return ( 0 );

} /* main */

/*

  • configure
  • Initialise global and type specific variables.

*/

static void configure( zbyte_t min_version, zbyte_t max_version )
{
zbyte_t header[PAGE_SIZE], second;

read_page( 0, header );
datap = header;

h_type = get_byte( H_TYPE );

   GLOBALVER = h_type;

if ( h_type < min_version || h_type > max_version ||
     ( get_byte( H_CONFIG ) & CONFIG_BYTE_SWAPPED ) )
   fatal( "Wrong game or version" );
/*
 * if (h_type == V6 || h_type == V7)
 * fatal ("Unsupported zcode version.");
 */

if ( h_type < V4 )
{
   story_scaler = 2;
   story_shift = 1;
   property_mask = P3_MAX_PROPERTIES - 1;
   property_size_mask = 0xe0;
}
else if ( h_type < V8 )
{
   story_scaler = 4;
   story_shift = 2;
   property_mask = P4_MAX_PROPERTIES - 1;
   property_size_mask = 0x3f;
}
else
{
   story_scaler = 8;
   story_shift = 3;
   property_mask = P4_MAX_PROPERTIES - 1;
   property_size_mask = 0x3f;
}

h_config = get_byte( H_CONFIG );
h_version = get_word( H_VERSION );
h_data_size = get_word( H_DATA_SIZE );
h_start_pc = get_word( H_START_PC );
h_words_offset = get_word( H_WORDS_OFFSET );
h_objects_offset = get_word( H_OBJECTS_OFFSET );
h_globals_offset = get_word( H_GLOBALS_OFFSET );
h_restart_size = get_word( H_RESTART_SIZE );
h_flags = get_word( H_FLAGS );
h_synonyms_offset = get_word( H_SYNONYMS_OFFSET );
h_file_size = get_word( H_FILE_SIZE );
if ( h_file_size == 0 )
   h_file_size = get_story_size(  );
h_checksum = get_word( H_CHECKSUM );
h_alternate_alphabet_offset = get_word( H_ALTERNATE_ALPHABET_OFFSET 

);

if ( h_type >= V5 )
{
   h_unicode_table = get_word( H_UNICODE_TABLE );
}
datap = NULL;

} /* configure */

------------------End jzip.c------------------------

Any help is greatly appreciated.

-Cooper

Cooper Stevenson wrote:

{
jzip.c–it’s doesn’t look like much but doing it for the first time…
What are you trying to achieve?
Do you want to start the main function from ruby?
(I don’t see the benefit here, just shell out to the program)

If so, write a small wrapper like

VALUE rb_main(VALUE self, VALUE args)
{
// you could/should use args here to build up a C array with parameters
main(0, 0);
return self;
}

and call rb_define_method in your Init_jzipr to make that method
available
in ruby.

void
Init_jzipr()
{
rb_define_method(rb_cObject, “main”, rb_main, -2)
}

cheers

Simon

If so, write a small wrapper like

VALUE rb_main(VALUE self, VALUE args)
[snip]

Thanks, Simon. I’m working on this now!

I’m trying to run this C application and capture the user’s input and
output to a Ruby string array. This way, I can use the values via Ruby
on Rails to display content based on what’s going on with the C
application.

Thanks again!

-Cooper

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