1/*
 2    Copyright 2018 0KIMS association.
 3
 4    This file is part of circom (Zero Knowledge Circuit Compiler).
 5
 6    circom is a free software: you can redistribute it and/or modify it
 7    under the terms of the GNU General Public License as published by
 8    the Free Software Foundation, either version 3 of the License, or
 9    (at your option) any later version.
10
11    circom is distributed in the hope that it will be useful, but WITHOUT
12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14    License for more details.
15
16    You should have received a copy of the GNU General Public License
17    along with circom. If not, see <https://www.gnu.org/licenses/>.
18*/
19
20/*
21    Assume sel is binary.
22
23    If sel == 0 then outL = L and outR=R
24    If sel == 1 then outL = R and outR=L
25
26 */
27
28template Switcher() {
29    signal input sel;
30    signal input L;
31    signal input R;
32    signal output outL;
33    signal output outR;
34
35    signal aux;
36
37    aux <== (R-L)*sel;    // We create aux in order to have only one multiplication
38    outL <==  aux + L;
39    outR <== -aux + R;
40}