add date

gleam.toml

@@ -9,6 +9,7 @@ gleam = ">= 1.6.2"
 [dependencies]
 gleam_stdlib = ">= 0.34.0 and < 2.0.0"
 ieee_float = ">= 1.0.3 and < 2.0.0"
+birl = ">= 1.7.1 and < 2.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -2,13 +2,16 @@
 # You typically do not need to edit this file
 
 packages = [
+  { name = "birl", version = "1.7.1", build_tools = ["gleam"], requirements = ["gleam_stdlib", "ranger"], otp_app = "birl", source = "hex", outer_checksum = "5C66647D62BCB11FE327E7A6024907C4A17954EF22865FE0940B54A852446D01" },
   { name = "gleam_erlang", version = "0.32.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "B18643083A0117AC5CFD0C1AEEBE5469071895ECFA426DCC26517A07F6AD9948" },
   { name = "gleam_stdlib", version = "0.45.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "206FCE1A76974AECFC55AEBCD0217D59EDE4E408C016E2CFCCC8FF51278F186E" },
   { name = "gleeunit", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "F7A7228925D3EE7D0813C922E062BFD6D7E9310F0BEE585D3A42F3307E3CFD13" },
   { name = "ieee_float", version = "1.0.3", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "ieee_float", source = "hex", outer_checksum = "0E9B6233343BD8EDBF813B50D5480139A3E318D257EA206D5C500984A829C515" },
+  { name = "ranger", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "ranger", source = "hex", outer_checksum = "B8F3AFF23A3A5B5D9526B8D18E7C43A7DFD3902B151B97EC65397FE29192B695" },
 ]
 
 [requirements]
+birl = { version = ">= 1.7.1 and < 2.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
 ieee_float = { version = ">= 1.0.3 and < 2.0.0" }

src/kmer.gleam

@@ -1,8 +1,10 @@
+import birl.{type Time}
 import gleam/bit_array
 import gleam/list.{reverse}
 import gleam/result.{try}
 import ieee_float.{
-  type IEEEFloat, from_bytes_16_be, from_bytes_32_be, from_bytes_64_be,
+  type IEEEFloat, finite, from_bytes_16_be, from_bytes_32_be, from_bytes_64_be,
+  multiply, power, round,
 }
 
 pub type DecodedValue {
@@ -13,6 +15,7 @@ pub type DecodedValue {
   String(value: String)
   Array(List(DecodedValue))
   Map(List(#(DecodedValue, DecodedValue)))
+  DateTime(Time)
   Null
   Undefined
 }
@@ -24,9 +27,6 @@ pub type DecodeResult =
   DecoderResult(DecodedValue)
 
 pub opaque type DecodeError {
-  // More data was expected but file/stream ended prematurely
-  UnexpectedEnd
-
   // Malformed sequence found
   Malformed
 }
@@ -51,6 +51,7 @@ pub fn decode(bits: BitArray) -> DecodeResult {
     <<5:3, rest:bits>> ->
       decode_map(rest)
       |> map_decoded(Map)
+    <<6:3, rest:bits>> -> decode_tag(rest)
     <<7:3, x:5, rest:bits>> if x < 25 -> decode_simple(<<x:5, rest:bits>>)
     <<7:3, x:5, rest:bits>> if x >= 25 ->
       decode_float(<<x:5, rest:bits>>)
@@ -68,7 +69,7 @@ fn decode_int(bits: BitArray) -> DecoderResult(Int) {
     <<27:5, val:int-unsigned-size(64), rest:bits>> -> Ok(#(val, rest))
     <<x:5, rest:bits>> if x < 24 -> Ok(#(x, rest))
     <<x:5, _:bits>> if x >= 24 -> Error(Malformed)
-    _ -> Error(UnexpectedEnd)
+    _ -> Error(Malformed)
   }
 }
 
@@ -106,6 +107,57 @@ fn decode_map(
   Ok(#(pairs, remainder))
 }
 
+fn decode_tag(bits: BitArray) -> DecodeResult {
+  use #(tag, rest) <- try(decode_int(bits))
+
+  case tag {
+    0 -> decode_datestring(rest) |> map_decoded(DateTime)
+    1 -> decode_unixtime(rest) |> map_decoded(DateTime)
+    // CBOR magic number (no-op for us)
+    55_799 -> decode(rest)
+    _ -> Error(Malformed)
+  }
+}
+
+fn decode_datestring(bits: BitArray) -> DecoderResult(Time) {
+  use string_content <- try(case bits {
+    <<3:3, remainder:bits>> -> Ok(remainder)
+    _ -> Error(Malformed)
+  })
+
+  use #(datestring, rest) <- try(decode_string(string_content))
+
+  case birl.parse(datestring) {
+    Ok(datetime) -> Ok(#(datetime, rest))
+    _ -> Error(Malformed)
+  }
+}
+
+fn decode_unixtime(bits: BitArray) -> DecoderResult(Time) {
+  case bits {
+    <<0:3, rest:bits>> ->
+      decode_int(rest)
+      |> map_decoded(birl.from_unix)
+    // This is probably undefined behavior, as I doubt birl supports negative unixtimes
+    <<1:3, rest:bits>> ->
+      decode_int(rest)
+      |> map_decoded(birl.from_unix)
+    // Float unixtimes is also very iffy and the spec says we should be able to ignore it
+    // However, lets give it a shot and turn it into a millisecond value
+    <<7:3, rest:bits>> ->
+      decode_float(rest)
+      |> try(fn(x) {
+        let #(time, remainder) = x
+        let milli_time = multiply(time, power(finite(10.0), finite(3.0)))
+        case round(milli_time) {
+          Ok(milli_int) -> Ok(#(birl.from_unix_milli(milli_int), remainder))
+          _ -> Error(Malformed)
+        }
+      })
+    _ -> Error(Malformed)
+  }
+}
+
 fn decode_float(bits: BitArray) -> DecoderResult(IEEEFloat) {
   case bits {
     <<25:5, float16:bytes-size(2), rest:bits>> ->
@@ -157,8 +209,8 @@ fn decode_next_n(
 
 fn map_decoded(
   result: DecoderResult(t),
-  map_fn: fn(t) -> DecodedValue,
-) -> DecodeResult {
+  map_fn: fn(t) -> out,
+) -> DecoderResult(out) {
   use #(value, rest) <- try(result)
   Ok(#(map_fn(value), rest))
 }

test/kmer_test.gleam

@@ -1,10 +1,11 @@
+import birl
 import gleam/list
 import gleeunit
 import gleeunit/should
 import ieee_float.{finite, nan, positive_infinity}
 import kmer.{
-  type DecodeResult, type DecodedValue, Array, Boolean, Bytes, Float, Integer,
-  Map, Null, String, Undefined,
+  type DecodeResult, type DecodedValue, Array, Boolean, Bytes, DateTime, Float,
+  Integer, Map, Null, String, Undefined,
 }
 
 pub fn main() {
@@ -155,6 +156,28 @@ pub fn decode_map_test() {
   |> table_fn(table_test_decode)
 }
 
+pub fn decode_time_test() {
+  let assert Ok(textdate_example) = birl.parse("2024-11-30T21:56:27Z")
+
+  [
+    // ISO8601 date
+    #(
+      <<6:3, 0:5, 3:3, 20:5, "2024-11-30T21:56:27Z">>,
+      DateTime(textdate_example),
+    ),
+    // Unixtime
+    #(
+      <<6:3, 1:5, 1:3, 26:5, 1_733_005_876:32>>,
+      DateTime(birl.from_unix(1_733_005_876)),
+    ),
+    #(
+      <<6:3, 1:5, 7:3, 27:5, 0x41D9D2E48D200000:64>>,
+      DateTime(birl.from_unix_milli(1_733_005_876_500)),
+    ),
+  ]
+  |> table_fn(table_test_decode)
+}
+
 fn table_fn(tests: List(#(a, b)), test_fn: fn(a, b) -> Nil) {
   list.map(tests, fn(t) {
     let #(test_case, expected) = t