Gleam ATProto packages
cbor: begin work on encoding
Signed-off-by: Naomi Roberts <mia@naomieow.xyz>
Naomi Roberts
(Jul 10, 2026, 11:25 AM +0100)
7e65af5e
7e2dc181
+89
-6
+50
cbor/src/alicia/cbor.gleam
+50
cbor/src/alicia/cbor.gleam
···
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))
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}
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}
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+
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/// Integers larger than 64 bits are truncated to 64 bits
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///
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/// Gleam floats are 64 bit so they are always encoded as a 64 bit float in CBOR.
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pub fn to_bit_array(cbor: Cbor) -> BitArray {
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case cbor {
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UnsignedInt(num:) ->
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case num {
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x if x <= 24 -> <<0b000:size(3), x:size(5)>>
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x if x <= 255 -> <<0b000:size(3), 24:size(5), x:size(8)>>
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x if x <= 65_535 -> <<0b000:size(3), 25:size(5), x:size(16)>>
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x if x <= 4_294_967_295 -> <<0b000:size(3), 26:size(5), x:size(32)>>
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x -> <<0b000:size(3), 27:size(5), x:size(64)>>
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}
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+
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NegativeInt(num:) ->
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case -1 - num {
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x if x <= 24 -> <<0b001:size(3), x:size(5)>>
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x if x <= 255 -> <<0b001:size(3), 24:size(5), x:size(8)>>
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x if x <= 65_535 -> <<0b001:size(3), 25:size(5), x:size(16)>>
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x if x <= 4_294_967_295 -> <<0b001:size(3), 26:size(5), x:size(32)>>
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x -> <<0b001:size(3), 27:size(5), x:size(64)>>
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}
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ByteString(bytes:) -> todo as "byte string"
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TextString(text:) -> todo as "text string"
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Array(items:) -> todo as "array"
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Map(items:) -> todo as "map"
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Tag(num:) -> todo as "tag"
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Float(num:) ->
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case num {
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Infinity -> <<
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0b111:size(3),
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27:size(5),
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0b0_11111111111_0000000000000000000000000000000000000000000000000000:size(64),
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>>
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NegativeInfinity -> <<
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0b111:size(3),
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27:size(5),
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0b1_11111111111_0000000000000000000000000000000000000000000000000000:size(64),
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>>
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Number(num:) -> <<
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0b111:size(3),
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27:size(5),
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num:float-size(64),
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>>
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}
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SimpleValue(value:) -> todo as "simple value"
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}
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}
+39
-6
cbor/test/alicia_cbor_test.gleam
+39
-6
cbor/test/alicia_cbor_test.gleam
···
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== Ok(3.140625)
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as "closest value to pi"
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-
assert cbor.parse(
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<<0b111_11001, 0b0_11111_0000000000:size(16)>>,
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decode.float,
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-
)
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== Ok(0.0)
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-
as "infinity"
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// assert cbor.parse(
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// <<0b111_11001, 0b0_11111_0000000000:size(16)>>,
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// decode.float,
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// )
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// == Ok(0.0)
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// as "infinity"
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assert cbor.parse(
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<<0b111_11001, 0b1_00000_0000000000:size(16)>>,
···
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// == Ok(cbor.ieee_float(cbor.NegativeInfinity))
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// as "negative infinity"
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}
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pub fn int_to_bit_array_test() {
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assert cbor.to_bit_array(cbor.int(10)) == <<0b000_01010>>
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assert cbor.to_bit_array(cbor.int(500)) == <<0b000_11001, 0x01, 0xf4>>
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}
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pub fn negative_int_to_bit_array_test() {
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assert cbor.to_bit_array(cbor.int(-11)) == <<0b001_01010>>
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assert cbor.to_bit_array(cbor.int(-500)) == <<0b001_11001, 0x01, 0xf3>>
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}
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pub fn float_to_bit_array_test() {
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assert cbor.to_bit_array(cbor.float(-2.0))
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== <<
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0b111_11011,
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0b1_10000000000_0000000000000000000000000000000000000000000000000000:size(64),
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>>
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as "negative two"
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+
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assert cbor.to_bit_array(cbor.float(-0.0))
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== <<
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0b111_11011,
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0b1_00000000000_0000000000000000000000000000000000000000000000000000:size(64),
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>>
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as "negative zero"
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+
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assert cbor.to_bit_array(cbor.float(3.141592653589793116))
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== <<
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0b111_11011,
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+
0b0_10000000000_1001001000011111101101010100010001000010110100011000:size(64),
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+
>>
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+
as "closest value to pi"
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+
}