Colored Coins Precision Encoding Scheme

colored-coins-encoding.rb

require 'terminal-table'

MAX_SATOSHIS = 21*(10**6)*(10**8)

def max_num(mantis_bits,available_bits)
  mantis(mantis_bits)*(10**exponent(mantis_bits,available_bits))
end

def mantis(mantis_bits)
  2**mantis_bits
end

def exponent(mantis_bits,available_bits)
  2**(available_bits-mantis_bits)
end

def threshold_mantis?(mantis_bits,available_bits)
  max_num(mantis_bits,available_bits) > MAX_SATOSHIS &&  
  max_num(mantis_bits+1,available_bits) < MAX_SATOSHIS
end

table = Terminal::Table.new do |t|
  t.title = "Encoding for maximum #{MAX_SATOSHIS} Satoshis"
  t << ['Bytes','Bits','Available','Mantisa','Digits', 'Exponent']
  t.add_separator
  mantis_bits = 0
  (2..10).each do |total_bytes|
    total_bits = 8*total_bytes
    available_bits = total_bits -3		
    until threshold_mantis?(mantis_bits,available_bits) do
      break if mantis_bits == available_bits -1
      mantis_bits +=1 
    end
    significant = (2**mantis_bits).to_s.size-1
    t<<[total_bytes,total_bits, available_bits, mantis_bits,significant, available_bits - mantis_bits]
  end
end

puts table

=begin
+-------+------+-----------+---------+--------+----------+
|     Encoding for maximum 2100000000000000 Satoshis     |
+-------+------+-----------+---------+--------+----------+
| Bytes | Bits | Available | Mantisa | Digits | Exponent |
+-------+------+-----------+---------+--------+----------+
| 2     | 16   | 13        | 9       | 2      | 4        |
| 3     | 24   | 21        | 17      | 5      | 4        |
| 4     | 32   | 29        | 26      | 7      | 3        |
| 5     | 40   | 37        | 34      | 10     | 3        |
| 6     | 48   | 45        | 43      | 12     | 2        |
| 7     | 56   | 53        | 52      | 15     | 1        |
| 8     | 64   | 61        | 60      | 18     | 1        |
| 9     | 72   | 69        | 68      | 20     | 1        |
| 10    | 80   | 77        | 76      | 22     | 1        |
+-------+------+-----------+---------+--------+----------+
=end