You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_SpUtil.m
    path of file: ./repos/spm12
    
    the code of the file until where you have to start completion: function varargout = spm_SpUtil(varargin)
% Space matrix utilities
% FORMAT varargout = spm_SpUtil(action,varargin)
%
%___________________________________
    
function c = sf_X0_2_c(X0,sX)  
%
%- Algorithm to avoids the pinv(X0) and insure consistency
%- Get a contrast that span the space of X0 and is estimable
%- Get the orthogonal complement and project onto the estimable space
%- Strip zeros columns and use the rotation making X1o orthog. to X0
% !!! tolerance dealing ?

if ~isempty(X0)

   sc0 = spm_sp('set',spm_sp('x-',sX,X0));
   if  sc0.rk
      c = spm_sp('oPp:',sX,spm_sp('r',sc0));
   else 
      c = spm_sp('oPp',sX);
   end