From: ts <decoux@...>
Date: 2000-08-24T02:42:40+09:00
Subject: [ruby-talk:4570] Re: Q's on Marshal

>>>>> "R" == Robert Feldt <feldt@ce.chalmers.se> writes:

R> I have an object in an extension that have some Fixnum's and some Bignum's
R> and some internal state (in char[1000]).

 What you can do is create an array with contains :
  * string (the internal state)
  * fixnums, bignums

 Now you can :
  * return this array and let the user call Marshal#dump
  * or call Marshal#dump on this object and return the result.

R> Anyone got a simple example using _dump and _load in an extension?

 Well, this example is *completely* stupid, normally tt_restore must return
 a good object (I've written it very quickly, verify it)

pigeon% cat toto.c
#include <ruby.h>
 
static VALUE tt_mMarshal;
 
static VALUE
tt_save(obj, limit)
    VALUE obj, limit;
{
    VALUE ary;
    ary = rb_ary_new();
    rb_ary_push(ary, rb_str_new("aaabbbb", 7));
    rb_ary_push(ary, INT2NUM(12));
    rb_ary_push(ary, rb_float_new(24));
    return rb_funcall(tt_mMarshal, rb_intern("dump"), 1, ary);
}
 
static VALUE
tt_restore(obj, a)
    VALUE obj, a;
{
    VALUE ary;
    ary = rb_funcall(tt_mMarshal, rb_intern("load"), 1, a);
    rb_warn("result : %s %d %f", 
            RSTRING(RARRAY(ary)->ptr[0])->ptr,
            NUM2INT(RARRAY(ary)->ptr[1]),
            NUM2DBL(RARRAY(ary)->ptr[2]));
    return Qtrue;
}
void
Init_toto()
{
    VALUE toto, tt;
    tt_mMarshal = rb_const_get(rb_cObject, rb_intern("Marshal"));
    tt =  rb_define_class("Tt", rb_cObject);
    rb_define_method(tt, "_dump", tt_save, 1);
    rb_define_singleton_method(tt, "_load", tt_restore, 1);
}
pigeon%

 
pigeon% cat b.rb
#!/usr/bin/ruby
require 'toto'
a = Tt.new
b = Marshal.dump(a)
p b
Marshal.load(b)
pigeon%
 
pigeon% b.rb
"\004\003u:\001\002Tt\001\027\004\003[\001\003\"\001\aaaabbbbi\001\ff\001..."
./b.rb:6: warning: result : aaabbbb 12 24.000000
pigeon% 


Guy Decoux