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: trimeshEdgeFaces.m
    path of file: ./repos/matGeom/matGeom/meshes3d
    
    the code of the file until where you have to start completion: function edgeFaces = trimeshEdgeFaces(faces, varargin)
%TRIMESHEDGEFACES Compute index of faces adjacent to each edge of a triangular mesh.
%
%   EF = trimeshEdgeFaces(FACES)
%   EF = trimeshEdgeFaces(VERTICES, FACES)
%   EF = trimeshEdgeFaces(VERTICES, EDGES, FACES)

    
function edgeFaces = trimeshEdgeFaces(faces, varargin)
%TRIMESHEDGEFACES Compute index of faces adjacent to each edge of a triangular mesh.
%
%   EF = trimeshEdgeFaces(FACES)
%   EF = trimeshEdgeFaces(VERTICES, FACES)
%   EF = trimeshEdgeFaces(VERTICES, EDGES, FACES)
%   Compute index array of faces adjacent to each edge of a mesh.
%   FACES is a NF-by-3 array containing vertex indices of each face. The
%   result EF is a NE-by-2 array containing the indices of the two faces
%   incident to each edge. If an edge belongs to only one face, the other
%   face index is ZERO.
%
%   The list of edges (as array of source and target vertex indices) can be
%   obtained from the function 'meshEdges'.
%
%   Note: faces are listed in increasing order for each edge, and no
%   information is kept about relative orientation of edge and face.
%
%   Example
%     % compute incidence list of each edge of an octahedron. For example,
%     % first edge is incident to faces 1 and 5. Second edge is incident to
%     % faces 4 and 8, and so on.
%     [v, f] = createOctahedron;
%     ef = trimeshEdgeFaces(v, f)
%     ef =
%          1     5
%          4     8
%          4     1
%          5     8
%          2     6
%          1     2
%          6     5
%          3     7
%          2     3
%          7     6
%          3     4
%          7     8
%
%   See also 
%   meshes3d, meshEdgeFaces, trimeshMeanBreadth, meshEdges

% ------
% Author: David Legland
% E-mail: david.legland@inrae.fr
% Created: 2015-08-19, using Matlab 8.5.0.197613 (R2015a)
% Copyright 2015-2023 INRA - Cepia Software Platform

if nargin == 2
    faces = varargin{1};
elseif nargin == 3
    faces = varargin{2};
end