diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | bignum.c | 7 | ||||
| -rw-r--r-- | test/ruby/test_bignum.rb | 3 |
3 files changed, 12 insertions, 3 deletions
@@ -1,3 +1,8 @@ +Sun Mar 18 17:17:48 2012 Nobuyoshi Nakada <nobu@ruby-lang.org> + + * bignum.c (rb_big_pow): estimate result bit size more precisely. + [ruby-core:30735][Feature #3429] + Sun Mar 18 17:17:36 2012 Nobuyoshi Nakada <nobu@ruby-lang.org> * gc.c (free_method_entry_i): method entry may be in @@ -3095,10 +3095,11 @@ rb_big_pow(VALUE x, VALUE y) else { VALUE z = 0; SIGNED_VALUE mask; - const long BIGLEN_LIMIT = 1024*1024 / SIZEOF_BDIGITS; + const long xlen = RBIGNUM_LEN(x) - 1; + const long xbits = ffs(RBIGNUM_DIGITS(x)[xlen]) + SIZEOF_BDIGITS*BITSPERDIG*xlen; + const long BIGLEN_LIMIT = BITSPERDIG*1024*1024; - if ((RBIGNUM_LEN(x) > BIGLEN_LIMIT) || - (RBIGNUM_LEN(x) > BIGLEN_LIMIT / yy)) { + if ((xbits > BIGLEN_LIMIT) || (xbits * yy > BIGLEN_LIMIT)) { rb_warn("in a**b, b may be too big"); d = (double)yy; break; diff --git a/test/ruby/test_bignum.rb b/test/ruby/test_bignum.rb index 8281aed7b2..d9e689ce48 100644 --- a/test/ruby/test_bignum.rb +++ b/test/ruby/test_bignum.rb @@ -326,6 +326,9 @@ class TestBignum < Test::Unit::TestCase ### rational changes the behavior of Bignum#** #assert_raise(TypeError) { T32**"foo" } assert_raise(TypeError, ArgumentError) { T32**"foo" } + + feature3429 = '[ruby-core:30735]' + assert_instance_of(Bignum, (2 ** 7830457), feature3429) end def test_and |