diff options
| -rw-r--r-- | integer.rb | 41 | ||||
| -rw-r--r-- | numeric.c | 45 |
2 files changed, 41 insertions, 45 deletions
diff --git a/integer.rb b/integer.rb index f2f1e79a5e..b9cde8f390 100644 --- a/integer.rb +++ b/integer.rb @@ -4,6 +4,47 @@ class Integer Primitive.cexpr! 'rb_int_abs(self)' end + # call-seq: + # int.bit_length -> integer + # + # Returns the number of bits of the value of +int+. + # + # "Number of bits" means the bit position of the highest bit + # which is different from the sign bit + # (where the least significant bit has bit position 1). + # If there is no such bit (zero or minus one), zero is returned. + # + # I.e. this method returns <i>ceil(log2(int < 0 ? -int : int+1))</i>. + # + # (-2**1000-1).bit_length #=> 1001 + # (-2**1000).bit_length #=> 1000 + # (-2**1000+1).bit_length #=> 1000 + # (-2**12-1).bit_length #=> 13 + # (-2**12).bit_length #=> 12 + # (-2**12+1).bit_length #=> 12 + # -0x101.bit_length #=> 9 + # -0x100.bit_length #=> 8 + # -0xff.bit_length #=> 8 + # -2.bit_length #=> 1 + # -1.bit_length #=> 0 + # 0.bit_length #=> 0 + # 1.bit_length #=> 1 + # 0xff.bit_length #=> 8 + # 0x100.bit_length #=> 9 + # (2**12-1).bit_length #=> 12 + # (2**12).bit_length #=> 13 + # (2**12+1).bit_length #=> 13 + # (2**1000-1).bit_length #=> 1000 + # (2**1000).bit_length #=> 1001 + # (2**1000+1).bit_length #=> 1001 + # + # This method can be used to detect overflow in Array#pack as follows: + # + # if n.bit_length < 32 + # [n].pack("l") # no overflow + # else + # raise "overflow" + # end def bit_length Primitive.attr! 'inline' Primitive.cexpr! 'rb_int_bit_length(self)' @@ -4890,51 +4890,6 @@ int_size(VALUE num) return Qnil; } -/* - * Document-method: Integer#bit_length - * call-seq: - * int.bit_length -> integer - * - * Returns the number of bits of the value of +int+. - * - * "Number of bits" means the bit position of the highest bit - * which is different from the sign bit - * (where the least significant bit has bit position 1). - * If there is no such bit (zero or minus one), zero is returned. - * - * I.e. this method returns <i>ceil(log2(int < 0 ? -int : int+1))</i>. - * - * (-2**1000-1).bit_length #=> 1001 - * (-2**1000).bit_length #=> 1000 - * (-2**1000+1).bit_length #=> 1000 - * (-2**12-1).bit_length #=> 13 - * (-2**12).bit_length #=> 12 - * (-2**12+1).bit_length #=> 12 - * -0x101.bit_length #=> 9 - * -0x100.bit_length #=> 8 - * -0xff.bit_length #=> 8 - * -2.bit_length #=> 1 - * -1.bit_length #=> 0 - * 0.bit_length #=> 0 - * 1.bit_length #=> 1 - * 0xff.bit_length #=> 8 - * 0x100.bit_length #=> 9 - * (2**12-1).bit_length #=> 12 - * (2**12).bit_length #=> 13 - * (2**12+1).bit_length #=> 13 - * (2**1000-1).bit_length #=> 1000 - * (2**1000).bit_length #=> 1001 - * (2**1000+1).bit_length #=> 1001 - * - * This method can be used to detect overflow in Array#pack as follows: - * - * if n.bit_length < 32 - * [n].pack("l") # no overflow - * else - * raise "overflow" - * end - */ - static VALUE rb_fix_bit_length(VALUE fix) { |