CCSDS 502.0-B-3 Orbit Ephemeris Message parser and interpolator
Replace custom date/time code with ptime across 4 packages
- ocaml-sgp4: epoch_unix uses Ptime.of_date instead of manual leap year math
- ocaml-oem: parse_epoch uses Ptime.of_rfc3339 ~strict:false, replacing
60 lines of manual ISO 8601 splitting
- space: parse_since uses Ptime.of_rfc3339 ~strict:false instead of Scanf
- monopam: day_of_week uses Ptime.weekday, add_days uses Ptime.add_span
Reviewed all 12 flagged spots in mono — the remaining 8 either already
use ptime properly (tomlt, cookeio, requests) or are not date parsing
(coordinate Julian arithmetic, filename extraction).
+5
-55
+5
-55
lib/oem.ml
+5
-55
lib/oem.ml
···
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(** Parse CCSDS epoch: "YYYY-MM-DDThh:mm:ss.sss" or "YYYY-MM-DD hh:mm:ss.sss". *)
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let parse_epoch s =
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let s = String.trim s in
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-
(* Normalize separator *)
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let s =
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if String.contains s 'T' then s
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else
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match String.index_opt s ' ' with
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| Some i ->
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String.sub s 0 i ^ "T" ^ String.sub s (i + 1) (String.length s - i - 1)
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| None -> s
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+
let rfc =
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if String.contains s 'Z' || String.contains s '+' then s else s ^ "Z"
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in
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(* Split at T *)
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match String.split_on_char 'T' s with
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| [ date; time ] ->
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let parse_date d =
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match String.split_on_char '-' d with
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| [ y; m; d ] ->
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(try Some (int_of_string y, int_of_string m, int_of_string d)
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with Failure _ | Invalid_argument _ -> None)
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| _ -> None
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in
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let parse_time t =
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(* Handle fractional seconds *)
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let parts = String.split_on_char ':' t in
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match parts with
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| [ h; m; s ] ->
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let sec_parts = String.split_on_char '.' s in
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let sec_int =
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match sec_parts with
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| si :: _ -> (try int_of_string si with Failure _ -> 0)
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| [] -> 0
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in
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let frac =
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match sec_parts with
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| _ :: f :: _ ->
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let f = if String.length f > 9 then String.sub f 0 9 else f in
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let denom = Float.of_int (int_of_float (10. ** Float.of_int (String.length f))) in
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(try Float.of_int (int_of_string f) /. denom with Failure _ -> 0.)
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| _ -> 0.
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in
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(try
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Some
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(int_of_string h, int_of_string m, sec_int, frac)
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with Failure _ | Invalid_argument _ -> None)
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| _ -> None
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in
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(match (parse_date date, parse_time time) with
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| Some (y, mo, d), Some (h, mi, s, frac) ->
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let frac_ps = Int64.of_float (frac *. 1e12) in
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(match Ptime.of_date_time ((y, mo, d), ((h, mi, s), 0)) with
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| Some t ->
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(match Ptime.Span.of_d_ps (0, frac_ps) with
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| Some span ->
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Some (Ptime.add_span t span |> Option.value ~default:t)
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| None -> Some t)
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| None -> None)
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| _ -> None)
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| _ -> None
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match Ptime.of_rfc3339 ~strict:false rfc with
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| Ok (t, _, _) -> Some t
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| Error _ -> None
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(* ------------------------------------------------------------------ *)
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(* KVN Parser *)