merge revision(s) r45187,r45205,r45212,r45213: [Backport #9570]

	* numeric.c (ruby_num_interval_step_size): check signs and get rid
	  of implementation dependent behavior of negative division.
	  [ruby-core:61106] [Bug #9570]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@45250 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 13 insertions, 5 deletions

diff --git a/numeric.c b/numeric.c
index d37edd719f..2c15e2fbe9 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1816,21 +1816,29 @@ VALUE
 num_interval_step_size(VALUE from, VALUE to, VALUE step, int excl)
 {
     if (FIXNUM_P(from) && FIXNUM_P(to) && FIXNUM_P(step)) {
-	long delta, diff, result;
+	long delta, diff;
 
 	diff = FIX2LONG(step);
+	if (!diff) rb_num_zerodiv();
 	delta = FIX2LONG(to) - FIX2LONG(from);
+	if (diff < 0) {
+	    diff = -diff;
+	    delta = -delta;
+	}
 	if (excl) {
-	    delta += (diff > 0 ? -1 : +1);
+	    delta--;
+	}
+	if (delta < 0) {
+	    return INT2FIX(0);
 	}
-	result = delta / diff;
-	return LONG2FIX(result >= 0 ? result + 1 : 0);
+	return ULONG2NUM(delta / diff + 1UL);
     }
     else if (RB_TYPE_P(from, T_FLOAT) || RB_TYPE_P(to, T_FLOAT) || RB_TYPE_P(step, T_FLOAT)) {
 	double n = ruby_float_step_size(NUM2DBL(from), NUM2DBL(to), NUM2DBL(step), excl);
 
 	if (isinf(n)) return DBL2NUM(n);
-	return LONG2FIX(n);
+	if (POSFIXABLE(n)) return LONG2FIX(n);
+	return rb_dbl2big(n);
     }
     else {
 	VALUE result;