[wip] factoring vdk out into several packages

2023-05-25 15:05:48 -06:00
parent 35ef2e0b1d
commit ee30eaaf7f
231 changed files with 13800 additions and 0 deletions
@@ -0,0 +1,166 @@
+-module(bits).
+
+-compile([export_all, nowarn_export_all]).
+
+
+rand_bits(N) when N =< 8 ->
+    <<Foo:N, _/bits>> = rand:bytes(1),
+    <<Foo:N>>;
+rand_bits(N) when N > 8 ->
+    Num_Bytes         = N div 8,
+    Num_Trailing_Bits = N rem 8,
+    <<( rand_bits(Num_Trailing_Bits) )/bits,
+      ( rand:bytes(Num_Bytes)        )/binary>>.
+
+
+
+fmt(Bits) ->
+    io:format("~ts~n", [format_bits(Bits)]).
+
+
+
+format_bits(Bits) ->
+    ["<<", format_bits2(Bits), ">>"].
+
+
+format_bits2(Bits)                                          when 8 =< bit_size(Bits) ->
+    NBits  = bit_size(Bits),
+    NBytes = NBits div 8,
+    NRem   = NBits rem 8,
+    <<Bytes:NBytes/bytes, NewBits:NRem/bits>> = Bits,
+    case NRem of
+        0 ->
+            format_bytes(Bytes);
+        _ ->
+            [format_bytes(Bytes), ", ", format_bits2(NewBits)]
+    end;
+format_bits2(Bits = <<Start:4/bits, Rem/bits>>)             when 5 =< bit_size(Bits) ->
+    [format_bits2(Start), "_", format_bits2(Rem)];
+format_bits2(Bits = <<B:1, Rest/bits>>)                     when 1 =< bit_size(Bits) ->
+    case B of
+        0 ->
+            ["0", format_bits2(Rest)];
+        1 ->
+            ["1", format_bits2(Rest)]
+    end;
+format_bits2(<<>>) ->
+    [].
+
+
+%% hack: split into two groups of 4 bits
+format_bytes(<<A:4/bits, B:4/bits>>) ->
+    [format_bits2(A), "_", format_bits2(B)];
+%% byte_size(Rest) >= 1 by previous case
+format_bytes(<<N:1/bytes, Rest/bytes>>) ->
+    [format_bytes(N), ", ", format_bytes(Rest)];
+format_bytes(<<>>) ->
+    [].
+
+
+
+
+%% ten random cases for each pair of bit lengths, 0 =< N =< 32
+rand_cases() ->
+    rand_cases(0, 0, []).
+
+%% ten random cases for 
+rand_cases(32, 32, Acc) ->
+    [ten_cases(32, 32) | Acc];
+rand_cases(N, 32, Acc) ->
+    NewAcc = [ten_cases(N, 32) | Acc],
+    rand_cases(N + 1, 0, NewAcc);
+rand_cases(N, M, Acc) ->
+    rand_cases(N, M + 1, [ten_cases(N, M) | Acc]).
+
+
+ten_cases(N, M) ->
+    [cs(N, M) || _ <- lists:seq(1, 10)].
+
+cs(N, M) ->
+    A = rand_bits(N),
+    B = rand_bits(M),
+    C = <<A/bits, B/bits>>,
+    {A, B, C}.
+
+
+fmt_rand_cases_(Cases) ->
+    io:format("~ts~n", [fmt_rand_cases(Cases)]).
+
+
+fmt_rand_cases(Cases) ->
+    ["[", fmt_rand_cases2(Cases, ""), "]"].
+
+%% one more case
+%% no trailing comma
+fmt_rand_cases2([TenCases], Acc) ->
+    [Acc, fmt_ten_cases(TenCases)];
+%% at least two more cases
+%% add trailing comma
+fmt_rand_cases([TenCases | Rest]) ->
+    lists:map(fun fmt_ten_cases/1, Cases).
+
+
+fmt_ten_cases
+
+
+fmt_case_(Case) ->
+    io:format("~ts~n", [fmt_case(Case)]).
+
+fmt_case({A, B, AB}) ->
+    ["{a  : ", fmtjs(A),  ",\n",
+     " b  : ", fmtjs(B),  ",\n",
+     " ab : ", fmtjs(AB), "}"].
+
+
+%% format bitstring as JS bits
+fmtjs_(Bits) ->
+    io:format("~ts~n", [fmtjs(Bits)]).
+
+fmtjs(Bits) ->
+    BS = bit_size(Bits),
+    BF = format_bytes_js(Bits),
+    io_lib:format("{bit_size : ~tp,~n"
+                  " bytes    : ~ts}",
+                  [BS, BF]).
+
+
+format_bytes_js(Bits) ->
+    ["new Uint8Array([", format_bytes_js2(Bits), "])"].
+
+
+%% formats the contents of the array
+%% empty array
+format_bytes_js2(<<>>) ->
+    "";
+%% exactly one entry
+format_bytes_js2(Bits) when bit_size(Bits) =< 8 ->
+    BS       = bit_size(Bits),
+    <<N:BS>> = Bits,
+    %% ah... right, ok we have to bitshift left by the missing zeros
+    NumMissingZeros = 8 - BS,
+    N_              = N bsl NumMissingZeros,
+    io_lib:format("~tp", [N_]);
+%% more than one entry, need to call format_bytes_js3 with a nontrivial initial
+%% accumulator
+format_bytes_js2(<<N:8, Rest/bits>>) ->
+    InitAcc = io_lib:format("~tp", [N]),
+    format_bytes_js3(Rest, InitAcc).
+
+
+
+%% empty array case; should only happen on initial call
+format_bytes_js3(<<>>, Acc) ->
+    Acc;
+%% terminal case: one bit remaining
+format_bytes_js3(Bits, Acc) when bit_size(Bits) =< 8 ->
+    BS       = bit_size(Bits),
+    <<N:BS>> = Bits,
+    %% ah... right, ok we have to bitshift left by the missing zeros
+    NumMissingZeros = 8 - BS,
+    N_              = N bsl NumMissingZeros,
+    FinalAcc = [Acc, ", ", io_lib:format("~tp", [N_])],
+    FinalAcc;
+%% general case
+format_bytes_js3(<<N:8, Rest/bits>>, Acc) ->
+    NewAcc = [Acc, ", ", io_lib:format("~tp", [N])],
+    format_bytes_js3(Rest, NewAcc).