HDB3 signal to bitstream.

Hello I want to write a function, the input is +, - and 0; the output is bitstream 0, 1.

if input(i)=0 =>bit(i)=0

if (+)(0)(0)(+) or (-)(0)(0)(-)=> bit(i:i+3)=0

if (0)(0)(0)(previously input~=0) => bit(i+3)=0

and elseif others bit~=0 =>bit=1;

Example: input= '+ 0 0 - + 0 0 + 0 - 0 0 0 - + -'

output: 1 0 0 1 0 0 0 0 1 0 0 0 0 1 1

Thank you