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require File.expand_path('../../../spec_helper', __FILE__)
describe "Fixnum#bit_length" do
it "returns the position of the leftmost bit of a positive number" do
0.bit_length.should == 0
1.bit_length.should == 1
2.bit_length.should == 2
3.bit_length.should == 2
4.bit_length.should == 3
n = fixnum_max.bit_length
fixnum_max[n].should == 0
fixnum_max[n-1].should == 1
0.bit_length.should == 0
1.bit_length.should == 1
0xff.bit_length.should == 8
0x100.bit_length.should == 9
(2**12-1).bit_length.should == 12
(2**12).bit_length.should == 13
(2**12+1).bit_length.should == 13
end
it "returns the position of the leftmost 0 bit of a negative number" do
-1.bit_length.should == 0
-2.bit_length.should == 1
-3.bit_length.should == 2
-4.bit_length.should == 2
-5.bit_length.should == 3
n = fixnum_min.bit_length
fixnum_min[n].should == 1
fixnum_min[n-1].should == 0
(-2**12-1).bit_length.should == 13
(-2**12).bit_length.should == 12
(-2**12+1).bit_length.should == 12
-0x101.bit_length.should == 9
-0x100.bit_length.should == 8
-0xff.bit_length.should == 8
-2.bit_length.should == 1
-1.bit_length.should == 0
end
end
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