static VALUE
range_step(int argc, VALUE *argv, VALUE range)
{
VALUE b, e, step, tmp;
RETURN_ENUMERATOR(range, argc, argv);
b = RANGE_BEG(range);
e = RANGE_END(range);
if (argc == 0) {
step = INT2FIX(1);
}
else {
rb_scan_args(argc, argv, "01", &step);
if (!rb_obj_is_kind_of(step, rb_cNumeric)) {
step = rb_to_int(step);
}
if (rb_funcall(step, '<', 1, INT2FIX(0))) {
rb_raise(rb_eArgError, "step can't be negative");
}
else if (!rb_funcall(step, '>', 1, INT2FIX(0))) {
rb_raise(rb_eArgError, "step can't be 0");
}
}
if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(step)) { /* fixnums are special */
long end = FIX2LONG(e);
long i, unit = FIX2LONG(step);
if (!EXCL(range))
end += 1;
i = FIX2LONG(b);
while (i < end) {
rb_yield(LONG2NUM(i));
if (i + unit < i) break;
i += unit;
}
}
else if (SYMBOL_P(b) && SYMBOL_P(e)) { /* symbols are special */
VALUE args[2], iter[2];
args[0] = rb_sym_to_s(e);
args[1] = EXCL(range) ? Qtrue : Qfalse;
iter[0] = INT2FIX(1);
iter[1] = step;
rb_block_call(rb_sym_to_s(b), rb_intern("upto"), 2, args, sym_step_i, (VALUE)iter);
}
else if (ruby_float_step(b, e, step, EXCL(range))) {
/* done */
}
else if (rb_obj_is_kind_of(b, rb_cNumeric) ||
!NIL_P(rb_check_to_integer(b, "to_int")) ||
!NIL_P(rb_check_to_integer(e, "to_int"))) {
ID op = EXCL(range) ? '<' : rb_intern("<=");
VALUE v = b;
int i = 0;
while (RTEST(rb_funcall(v, op, 1, e))) {
rb_yield(v);
i++;
v = rb_funcall(b, '+', 1, rb_funcall(INT2NUM(i), '*', 1, step));
}
}
else {
tmp = rb_check_string_type(b);
if (!NIL_P(tmp)) {
VALUE args[2], iter[2];
b = tmp;
args[0] = e;
args[1] = EXCL(range) ? Qtrue : Qfalse;
iter[0] = INT2FIX(1);
iter[1] = step;
rb_block_call(b, rb_intern("upto"), 2, args, step_i, (VALUE)iter);
}
else {
VALUE args[2];
if (!discrete_object_p(b)) {
rb_raise(rb_eTypeError, "can't iterate from %s",
rb_obj_classname(b));
}
args[0] = INT2FIX(1);
args[1] = step;
range_each_func(range, step_i, args);
}
}
return range;
}