Fix for Issue #8 and Issue #6

Resolves incomplete padding on multi-ecc blocks resulting in atoms in
final bitmap
Should cope with all circumstances.
Also exposes encode/2

src/qrcode.erl

@@ -17,7 +17,7 @@
 -include("qrcode.hrl").
 -include("qrcode_params.hrl").
 
--export([encode/1, decode/1]).
+-export([encode/1, encode/2, decode/1]).
 
 %%
 decode(_Bin) ->
@@ -76,22 +76,42 @@ encode_content(byte, Version, Bin) ->
 
 %%
 generate_ecc_blocks(#qr_params{block_defs = ECCBlockDefs}, Bin) ->
-	generate_ecc(Bin, ECCBlockDefs, []).
+	Bin0 = pad_data(Bin, ECCBlockDefs),
-%
+	generate_ecc(Bin0, ECCBlockDefs, []).
+
+
+pad_data(Bin, ECCBlockDefs) ->
+	DataSize = byte_size(Bin),
+	TotalSize = get_ecc_size(ECCBlockDefs),
+	PaddingSize = TotalSize - DataSize,
+	Padding = binary:copy(<<?DATA_PAD_0, ?DATA_PAD_1>>, PaddingSize bsr 1),
+	case PaddingSize band 1 of
+	0 ->
+		<<Bin/binary, Padding/binary>>;
+	1 ->
+		<<Bin/binary, Padding/binary, ?DATA_PAD_0>>
+	end.
+
+
+get_ecc_size(ECCBlockDefs) ->
+	get_ecc_size(ECCBlockDefs, 0).
+get_ecc_size([{C, _, D}|T], Acc) ->
+	get_ecc_size(T, C * D + Acc);
+get_ecc_size([], Acc) ->
+	Acc.
+
+
 generate_ecc(Bin, [{C, L, D}|T], Acc) ->
 	{Result, Bin0} = generate_ecc0(Bin, C, L, D, []),
 	generate_ecc(Bin0, T, [Result|Acc]);
 generate_ecc(<<>>, [], Acc) ->
 	lists:flatten(lists:reverse(Acc)).
-%	
+
+
 generate_ecc0(Bin, Count, TotalLength, BlockLength, Acc) when byte_size(Bin) >= BlockLength, Count > 0 ->
 	<<Block:BlockLength/binary, Bin0/binary>> = Bin,
 	EC = qrcode_reedsolomon:encode(Block, TotalLength - BlockLength),
 	generate_ecc0(Bin0, Count - 1, TotalLength, BlockLength, [{Block, EC}|Acc]);
-generate_ecc0(Bin, Count, TotalLength, BlockLength, Acc) when Count > 0 ->
-	Block = pad_block(Bin, BlockLength),
-	EC = qrcode_reedsolomon:encode(Block, TotalLength - BlockLength),
-	{lists:reverse([{Block, EC}|Acc]), <<>>}; 
 generate_ecc0(Bin, 0, _, _, Acc) ->
 	{lists:reverse(Acc), Bin}.
 
@@ -121,17 +141,7 @@ encode_bytes(Version, Bin) when is_binary(Bin) ->
 	Size = size(Bin),
 	CharacterCountBitSize = cci(?BYTE_MODE, Version),
 	<<?BYTE_MODE:4, Size:CharacterCountBitSize, Bin/binary, 0:4>>.
-%
+
-pad_block(Bin, BlockLength) ->
-	PadCount = BlockLength - byte_size(Bin),
-	Pad = binary:copy(<<?DATA_PAD_0, ?DATA_PAD_1>>, PadCount bsr 1),
-	case PadCount band 1 of
-	0 ->
-		Padding = Pad;
-	1 ->
-		Padding = <<Pad/binary, ?DATA_PAD_0>>
-	end,
-	<<Bin/binary, Padding/binary>>.
 
 %% Table 25. Error correction level indicators
 ecc('L') -> 1;
@@ -191,4 +201,3 @@ format_info_bits(#qr_params{ec_level = ECLevel, mask = MaskType}) ->
 	InfoWithEC = (Info bsl 10) bor BCH,
 	Value = InfoWithEC bxor ?FORMAT_INFO_MASK,
 	<<Value:15>>.
-