static VALUE cParser_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE source, opts;
    GET_PARSER_INIT;

    if (json->Vsource) {
        rb_raise(rb_eTypeError, "already initialized instance");
    }
#ifdef HAVE_RB_SCAN_ARGS_OPTIONAL_HASH
    rb_scan_args(argc, argv, "1:", &source, &opts);
#else
    rb_scan_args(argc, argv, "11", &source, &opts);
#endif
    if (!NIL_P(opts)) {
#ifndef HAVE_RB_SCAN_ARGS_OPTIONAL_HASH
        opts = rb_convert_type(opts, T_HASH, "Hash", "to_hash");
        if (NIL_P(opts)) {
            rb_raise(rb_eArgError, "opts needs to be like a hash");
        } else {
#endif
            VALUE tmp = ID2SYM(i_max_nesting);
            if (option_given_p(opts, tmp)) {
                VALUE max_nesting = rb_hash_aref(opts, tmp);
                if (RTEST(max_nesting)) {
                    Check_Type(max_nesting, T_FIXNUM);
                    json->max_nesting = FIX2INT(max_nesting);
                } else {
                    json->max_nesting = 0;
                }
            } else {
                json->max_nesting = 100;
            }
            tmp = ID2SYM(i_allow_nan);
            if (option_given_p(opts, tmp)) {
                json->allow_nan = RTEST(rb_hash_aref(opts, tmp)) ? 1 : 0;
            } else {
                json->allow_nan = 0;
            }
            tmp = ID2SYM(i_symbolize_names);
            if (option_given_p(opts, tmp)) {
                json->symbolize_names = RTEST(rb_hash_aref(opts, tmp)) ? 1 : 0;
            } else {
                json->symbolize_names = 0;
            }
            tmp = ID2SYM(i_create_additions);
            if (option_given_p(opts, tmp)) {
                json->create_additions = RTEST(rb_hash_aref(opts, tmp));
            } else {
                json->create_additions = 0;
            }
            if (json->symbolize_names && json->create_additions) {
              rb_raise(rb_eArgError,
                "options :symbolize_names and :create_additions cannot be "
                " used in conjunction");
            }
            tmp = ID2SYM(i_create_id);
            if (option_given_p(opts, tmp)) {
                json->create_id = rb_hash_aref(opts, tmp);
            } else {
                json->create_id = rb_funcall(mJSON, i_create_id, 0);
            }
            tmp = ID2SYM(i_object_class);
            if (option_given_p(opts, tmp)) {
                json->object_class = rb_hash_aref(opts, tmp);
            } else {
                json->object_class = Qnil;
            }
            tmp = ID2SYM(i_array_class);
            if (option_given_p(opts, tmp)) {
                json->array_class = rb_hash_aref(opts, tmp);
            } else {
                json->array_class = Qnil;
            }
            tmp = ID2SYM(i_decimal_class);
            if (option_given_p(opts, tmp)) {
                json->decimal_class = rb_hash_aref(opts, tmp);
            } else {
                json->decimal_class = Qnil;
            }
            tmp = ID2SYM(i_match_string);
            if (option_given_p(opts, tmp)) {
                VALUE match_string = rb_hash_aref(opts, tmp);
                json->match_string = RTEST(match_string) ? match_string : Qnil;
            } else {
                json->match_string = Qnil;
            }
#ifndef HAVE_RB_SCAN_ARGS_OPTIONAL_HASH
        }
#endif
    } else {
        json->max_nesting = 100;
        json->allow_nan = 0;
        json->create_additions = 1;
        json->create_id = rb_funcall(mJSON, i_create_id, 0);
        json->object_class = Qnil;
        json->array_class = Qnil;
        json->decimal_class = Qnil;
    }
    source = convert_encoding(StringValue(source));
    StringValue(source);
    json->len = RSTRING_LEN(source);
    json->source = RSTRING_PTR(source);;
    json->Vsource = source;
    return self;
}