date_core.c: defensive code

* ext/date/date_core.c (f_cmp): check comparison failure.

* ext/date/date_core.c (d_lite_step): deal with the comparison
  result more defensively.  [ruby-core:85796] [Bug #14549]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62572 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/date/date_core.c

@@ -51,18 +51,18 @@ static double positive_inf, negative_inf;
 #define f_add3(x,y,z) f_add(f_add(x, y), z)
 #define f_sub3(x,y,z) f_sub(f_sub(x, y), z)
 
-inline static VALUE
+inline static int
 f_cmp(VALUE x, VALUE y)
 {
     if (FIXNUM_P(x) && FIXNUM_P(y)) {
 	long c = FIX2LONG(x) - FIX2LONG(y);
 	if (c > 0)
-	    c = 1;
+	    return 1;
 	else if (c < 0)
-	    c = -1;
-	return INT2FIX(c);
+	    return -1;
+	return 0;
     }
-    return rb_funcall(x, id_cmp, 1, y);
+    return rb_cmpint(rb_funcallv(x, id_cmp, 1, &y), x, y);
 }
 
 inline static VALUE
@@ -6154,6 +6154,7 @@ static VALUE
 d_lite_step(int argc, VALUE *argv, VALUE self)
 {
     VALUE limit, step, date;
+    int c;
 
     rb_scan_args(argc, argv, "11", &limit, &step);
 
@@ -6168,25 +6169,22 @@ d_lite_step(int argc, VALUE *argv, VALUE self)
     RETURN_ENUMERATOR(self, argc, argv);
 
     date = self;
-    switch (FIX2INT(f_cmp(step, INT2FIX(0)))) {
-      case -1:
+    c = f_cmp(step, INT2FIX(0));
+    if (c < 0) {
 	while (FIX2INT(d_lite_cmp(date, limit)) >= 0) {
 	    rb_yield(date);
 	    date = d_lite_plus(date, step);
 	}
-	break;
-      case 0:
+    }
+    else if (c == 0) {
 	while (1)
 	    rb_yield(date);
-	break;
-      case 1:
+    }
+    else /* if (c > 0) */ {
 	while (FIX2INT(d_lite_cmp(date, limit)) <= 0) {
 	    rb_yield(date);
 	    date = d_lite_plus(date, step);
 	}
-	break;
-      default:
-	abort();
     }
     return self;
 }
@@ -6241,9 +6239,9 @@ cmp_gen(VALUE self, VALUE other)
     get_d1(self);
 
     if (k_numeric_p(other))
-	return f_cmp(m_ajd(dat), other);
+	return INT2FIX(f_cmp(m_ajd(dat), other));
     else if (k_date_p(other))
-	return f_cmp(m_ajd(dat), f_ajd(other));
+	return INT2FIX(f_cmp(m_ajd(dat), f_ajd(other)));
     return rb_num_coerce_cmp(self, other, rb_intern("<=>"));
 }
 

test/date/test_date_arith.rb

@@ -262,4 +262,17 @@ class TestDateArith < Test::Unit::TestCase
     assert_equal(8, e.to_a.size)
   end
 
+  def test_step__compare
+    o = Object.new
+    def o.<=>(*);end
+    assert_raise(ArgumentError) {
+      Date.new(2000, 1, 1).step(3, o).to_a
+    }
+
+    o = Object.new
+    def o.<=>(*);2;end
+    a = []
+    Date.new(2000, 1, 1).step(3, o) {|d| a << d}
+    assert_empty(a)
+  end
 end