uheprng.rb

def generate(megs)
    prng = uheprng
    mb = 1024**2
    count = megs * mb
    block = Array.new
    stream = File.new("uheprng.bin", "w")
    Kernel.printf("Running uheprng.rb to generate %d megabytes of pseudo-random data...\n", megs)
    count.times do |i|
        block.push(prng.call(0x100))
        (i+1)%16384 == 0 or next
        stream.write(block.pack("C*"))
        block.clear
        Kernel.printf("%s%.2f mb, (%.1f%%)", 8.chr*22, ((i+1).fdiv(mb)), ((i+1).fdiv(count)*100))
    end
    stream.close
    Kernel.printf("\n\n--- Done!! ---\n")
end
def uheprng
    size = 48
    c = 1
    pos = size
    state = mash(size, 0xefc8249d)

    rawprng = proc do
        (pos+=1) >= size and pos = 0
        t = 1768863 * state[pos] + c * 2.3283064365386963e-10 # 2^-32
        state[pos] = t - (c = t.to_i)
    end

    proc do |range|
        (range * (rawprng.call + (rawprng.call * 0x200000).to_i * 1.1102230246251565e-16)).floor # 2^-53
    end
end
def mash(count, n)
    count.times.map do
        Kernel.rand.to_s.bytes do |b|
            n += b
            h = 0.02519603282416938 * n
            n = h.to_i
            h -= n
            h *= n
            n = h.to_i
            h -= n
            n += h * 0x100000000 # 2^32
        end
        n.to_i * 2.3283064365386963e-10 # 2^-32
    end
end

generate(ARGV.shift.to_i)