random_number(n=0)
public
SecureRandom.random_number generates a random number.
If an positive integer is given as n, SecureRandom.random_number returns an
integer: 0 <= SecureRandom.random_number(n) < n.
If 0 is given or an argument is not given, SecureRandom.random_number
returns an float: 0.0 <= SecureRandom.random_number() < 1.0.
# File activesupport/lib/active_support/secure_random.rb, line 164
def self.random_number(n=0)
if 0 < n
hex = n.to_s(16)
hex = '0' + hex if (hex.length & 1) == 1
bin = [hex].pack("H*")
mask = bin[0]
mask |= mask >> 1
mask |= mask >> 2
mask |= mask >> 4
begin
rnd = SecureRandom.random_bytes(bin.length)
rnd[0] = rnd[0] & mask
end until rnd < bin
rnd.unpack("H*")[0].hex
else
# assumption: Float::MANT_DIG <= 64
i64 = SecureRandom.random_bytes(8).unpack("Q")[0]
Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG)
end
end