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124 lines
3.3 KiB
Text
124 lines
3.3 KiB
Text
interface Bytes.Encode exposes [ Encoder, sequence, u8, u16, bytes, empty, encode ] imports []
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Endianness : [ BE, LE ]
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Encoder : [ Signed8 I8, Unsigned8 U8, Signed16 Endianness I16, Unsigned16 Endianness U16, Sequence Nat (List Encoder), Bytes (List U8) ]
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u8 : U8 -> Encoder
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u8 = \value -> Unsigned8 value
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empty : Encoder
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empty =
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foo : List Encoder
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foo = []
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Sequence 0 foo
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u16 : Endianness, U16 -> Encoder
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u16 = \endianness, value -> Unsigned16 endianness value
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bytes : List U8 -> Encoder
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bytes = \bs -> Bytes bs
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sequence : List Encoder -> Encoder
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sequence = \encoders ->
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Sequence (getWidths encoders 0) encoders
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getWidth : Encoder -> Nat
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getWidth = \encoder ->
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when encoder is
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Signed8 _ -> 1
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Unsigned8 _ -> 1
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Signed16 _ _ -> 2
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Unsigned16 _ _ -> 2
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# Signed32 _ -> 4
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# Unsigned32 _ -> 4
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# Signed64 _ -> 8
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# Unsigned64 _ -> 8
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# Signed128 _ -> 16
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# Unsigned128 _ -> 16
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Sequence w _ -> w
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Bytes bs -> List.len bs
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getWidths : List Encoder, Nat -> Nat
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getWidths = \encoders, initial -> List.walk encoders (\encoder, accum -> accum + getWidth encoder) initial
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encode : Encoder -> List U8
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encode = \encoder ->
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output = List.repeat (getWidth encoder) 0
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encodeHelp encoder 0 output
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|> .output
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encodeHelp = \encoder, offset, output ->
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when encoder is
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Unsigned8 value ->
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{
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output: List.set output offset value,
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offset: offset + 1
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}
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Signed8 value ->
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cast : U8
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cast = Num.intCast value
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{
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output: List.set output offset cast,
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offset: offset + 1
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}
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Unsigned16 endianness value ->
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a : U8
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a = Num.intCast (Num.shiftRightBy 8 value)
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b : U8
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b = Num.intCast value
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newOutput =
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when endianness is
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BE ->
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output
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|> List.set (offset + 0) a
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|> List.set (offset + 1) b
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LE ->
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output
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|> List.set (offset + 0) b
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|> List.set (offset + 1) a
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{
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output: newOutput,
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offset: offset + 2
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}
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Signed16 endianness value ->
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a : U8
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a = Num.intCast (Num.shiftRightBy 8 value)
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b : U8
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b = Num.intCast value
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newOutput =
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when endianness is
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BE ->
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output
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|> List.set (offset + 0) a
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|> List.set (offset + 1) b
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LE ->
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output
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|> List.set (offset + 0) b
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|> List.set (offset + 1) a
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{
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output: newOutput,
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offset: offset + 1
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}
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Bytes bs ->
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List.walk bs (\byte, accum -> { offset: accum.offset + 1, output : List.set accum.output offset byte }) { output, offset }
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Sequence _ encoders ->
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List.walk encoders (\single, accum -> encodeHelp single accum.offset accum.output) { output, offset }
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