%%% -*- erlang-indent-level: 2 -*-
%%%-------------------------------------------------------------------
%%% File    : bs_bincomp.erl
%%% Author  : Per Gustafsson <pergu@it.uu.se>
%%% Purpose : Test bit comprehensions
%%% Created : 13 Sep 2006
%%%-------------------------------------------------------------------
-module(bs_bincomp).

-export([test/0]).

test() ->
  ok = byte_aligned(),
  ok = bit_aligned(),
  ok = extended_byte_aligned(),
  ok = extended_bit_aligned(),
  ok = mixed(),
  ok.

byte_aligned() ->
  <<"abcdefg">> = << <<(X+32)>> || <<X>> <= <<"ABCDEFG">> >>,
  <<1:32/little,2:32/little,3:32/little,4:32/little>> =
    << <<X:32/little>> || <<X:32>> <= <<1:32,2:32,3:32,4:32>> >>,
  <<1:32/little,2:32/little,3:32/little,4:32/little>> =
    << <<X:32/little>> || <<X:16>> <= <<1:16,2:16,3:16,4:16>> >>,
  ok.

bit_aligned() ->
  <<$a:7,$b:7,$c:7,$d:7,$e:7,$f:7,$g:7>> =
    << <<(X+32):7>> || <<X>> <= <<"ABCDEFG">> >>,
  <<"ABCDEFG">> =
    << <<(X-32)>> || <<X:7>> <= <<$a:7,$b:7,$c:7,$d:7,$e:7,$f:7,$g:7>> >>,
  <<1:31/little,2:31/little,3:31/little,4:31/little>> =
    << <<X:31/little>> || <<X:31>> <= <<1:31,2:31,3:31,4:31>> >>,
  <<1:31/little,2:31/little,3:31/little,4:31/little>> =
    << <<X:31/little>> || <<X:15>> <= <<1:15,2:15,3:15,4:15>> >>,
  ok.

extended_byte_aligned() ->
  <<"abcdefg">> = << <<(X+32)>> || X <- "ABCDEFG" >>,
  "abcdefg" = [(X+32) || <<X>> <= <<"ABCDEFG">>],
  <<1:32/little,2:32/little,3:32/little,4:32/little>> =
    << <<X:32/little>> || X <- [1,2,3,4] >>,
  [256,512,768,1024] =
    [X || <<X:16/little>> <= <<1:16,2:16,3:16,4:16>>],
  ok.

extended_bit_aligned() ->
  <<$a:7,$b:7,$c:7,$d:7,$e:7,$f:7,$g:7>> =
    << <<(X+32):7>> || X <- "ABCDEFG" >>,
  "ABCDEFG" = [(X-32) || <<X:7>> <= <<$a:7,$b:7,$c:7,$d:7,$e:7,$f:7,$g:7>>],
  <<1:31/little,2:31/little,3:31/little,4:31/little>> =
    << <<X:31/little>> || X <- [1,2,3,4] >>,
  [256,512,768,1024] =
    [X || <<X:15/little>> <= <<1:15,2:15,3:15,4:15>>],
  ok.

mixed() ->
  <<2,3,3,4,4,5,5,6>> =
    << <<(X+Y)>> || <<X>> <= <<1,2,3,4>>, <<Y>> <= <<1,2>> >>,
  <<2,3,3,4,4,5,5,6>> =
    << <<(X+Y)>> || <<X>> <= <<1,2,3,4>>, Y <- [1,2] >>,
  <<2,3,3,4,4,5,5,6>> =
    << <<(X+Y)>> || X <- [1,2,3,4], Y <- [1,2] >>,
  [2,3,3,4,4,5,5,6] =
    [(X+Y) || <<X>> <= <<1,2,3,4>>, <<Y>> <= <<1,2>>],
  [2,3,3,4,4,5,5,6] =
    [(X+Y) || <<X>> <= <<1,2,3,4>>, Y <- [1,2]],
  <<2:3,3:3,3:3,4:3,4:3,5:3,5:3,6:3>> =
    << <<(X+Y):3>> || <<X:3>> <= <<1:3,2:3,3:3,4:3>>, <<Y:3>> <= <<1:3,2:3>> >>,
  <<2:3,3:3,3:3,4:3,4:3,5:3,5:3,6:3>> =
    << <<(X+Y):3>> || <<X:3>> <= <<1:3,2:3,3:3,4:3>>, Y <- [1,2] >>,
  <<2:3,3:3,3:3,4:3,4:3,5:3,5:3,6:3>> =
    << <<(X+Y):3>> || X <- [1,2,3,4], Y <- [1,2] >>,
  [2,3,3,4,4,5,5,6] =
    [(X+Y) || <<X:3>> <= <<1:3,2:3,3:3,4:3>>, <<Y:3>> <= <<1:3,2:3>>],
  [2,3,3,4,4,5,5,6] =
    [(X+Y) || <<X:3>> <= <<1:3,2:3,3:3,4:3>>, Y <- [1,2]],
  ok.