* bignum.c (big_shift3): Big shift width is not a problem for right

  shift.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42004 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 14 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 5f90d7c7f4..41c27ea7e2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Jul 16 19:05:12 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (big_shift3): Big shift width is not a problem for right
+	  shift.
+
 Tue Jul 16 18:50:08 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_count): [DOC] fix typo.  Array#count uses ==, not
@@ -7,7 +12,7 @@ Tue Jul 16 18:35:48 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (bary_mul_karatsuba): Avoid duplicate calculation when
 	  squaring.
-	  ((bary_mul_toom3_branch): Ditto.
+	  (bary_mul_toom3_branch): Ditto.
 
 Tue Jul 16 17:43:22 2013  Koichi Sasada  <ko1@atdot.net>
 
diff --git a/bignum.c b/bignum.c
index 3a03f1bbfc..15ec5810ed 100644
--- a/bignum.c
+++ b/bignum.c
@@ -3263,14 +3263,12 @@ big_shift3(VALUE x, int lshift_p, size_t shift_numdigits, int shift_numbits)
     VALUE z;
     long xn;
 
-    if (LONG_MAX < shift_numdigits) {
-        rb_raise(rb_eArgError, "too big number");
-    }
-
-    s1 = shift_numdigits;
-    s2 = shift_numbits;
-
     if (lshift_p) {
+        if (LONG_MAX < shift_numdigits) {
+            rb_raise(rb_eArgError, "too big number");
+        }
+        s1 = shift_numdigits;
+        s2 = shift_numbits;
         xn = RBIGNUM_LEN(x);
         z = bignew(xn+s1+1, RBIGNUM_SIGN(x));
         zds = BDIGITS(z);
@@ -3281,13 +3279,15 @@ big_shift3(VALUE x, int lshift_p, size_t shift_numdigits, int shift_numbits)
     else {
         long zn;
         BDIGIT hibitsx;
-        if (s1 >= RBIGNUM_LEN(x)) {
+        if (LONG_MAX < shift_numdigits || (size_t)RBIGNUM_LEN(x) <= shift_numdigits) {
             if (RBIGNUM_POSITIVE_P(x) ||
                 bary_zero_p(BDIGITS(x), RBIGNUM_LEN(x)))
                 return INT2FIX(0);
             else
                 return INT2FIX(-1);
         }
+        s1 = shift_numdigits;
+        s2 = shift_numbits;
         hibitsx = abs2twocomp(&x, &xn);
         xds = BDIGITS(x);
         if (xn <= s1) {