CSDS Key-Value Notation parser
Add ocaml-kvn and ocaml-ocm: KVN parser and OCM message support
ocaml-kvn: CCSDS Key-Value Notation parser.
ocaml-ocm: CCSDS 505.0-B-2 Orbit Comprehensive Message parser.
Tested against TraCSS LANDSAT 5 OCM file.
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.ocamlformat
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.ocamlformat
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version = 0.28.1
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dune-project
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dune-project
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(lang dune 3.21)
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(name kvn)
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(source (tangled gazagnaire.org/ocaml-kvn))
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(generate_opam_files true)
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(license ISC)
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(authors "Thomas Gazagnaire <thomas@gazagnaire.org>")
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(maintainers "Thomas Gazagnaire <thomas@gazagnaire.org>")
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(package
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(name kvn)
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(synopsis "CCSDS Key-Value Notation parser")
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(description
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"Typed parser for CCSDS Key-Value Notation (KVN), the text format \
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used by OEM, OCM, TDM, ADM, CDM, and other CCSDS navigation data \
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messages.")
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(depends
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(ocaml (>= 4.14))
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ptime
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fmt))
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kvn.opam
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kvn.opam
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# This file is generated by dune, edit dune-project instead
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opam-version: "2.0"
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synopsis: "CCSDS Key-Value Notation parser"
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description:
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"Typed parser for CCSDS Key-Value Notation (KVN), the text format used by OEM, OCM, TDM, ADM, CDM, and other CCSDS navigation data messages."
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maintainer: ["Thomas Gazagnaire <thomas@gazagnaire.org>"]
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authors: ["Thomas Gazagnaire <thomas@gazagnaire.org>"]
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license: "ISC"
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homepage: "https://tangled.org/gazagnaire.org/ocaml-kvn"
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bug-reports: "https://tangled.org/gazagnaire.org/ocaml-kvn/issues"
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depends: [
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"dune" {>= "3.21"}
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"ocaml" {>= "4.14"}
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"ptime"
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"fmt"
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"odoc" {with-doc}
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]
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build: [
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["dune" "subst"] {dev}
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[
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"dune"
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"build"
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"-p"
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name
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"-j"
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jobs
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"@install"
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"@runtest" {with-test}
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"@doc" {with-doc}
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]
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]
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dev-repo: "git+https://tangled.org/gazagnaire.org/ocaml-kvn"
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x-maintenance-intent: ["(latest)"]
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lib/kvn.ml
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lib/kvn.ml
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(** CCSDS Key-Value Notation (KVN) parser.
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{b Reference}: CCSDS 502.0-B-3 Annex A *)
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(* {1 Line classification} *)
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type line =
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| Keyword of string * string
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| Data of string
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| Comment of string
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| Blank
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let classify s =
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let s = String.trim s in
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if String.length s = 0 || s.[0] = '#' then Blank
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else if String.length s >= 7 && String.sub s 0 7 = "COMMENT" then
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Comment (String.trim (String.sub s 7 (String.length s - 7)))
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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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let key = String.trim (String.sub s 0 i) in
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let value =
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String.trim (String.sub s (i + 1) (String.length s - i - 1))
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in
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Keyword (key, value)
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| None ->
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(* Check for block delimiters (no = sign): META_START, TRAJ_STOP, etc. *)
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if
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String.length s > 4
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&&
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let suffix = String.sub s (String.length s - 5) 5 in
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suffix = "START" || suffix = "_STOP"
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then Keyword (s, "")
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else Data s
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(* {1 Epoch parsing} *)
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let parse_epoch s =
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let s = String.trim s in
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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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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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(* {1 Line-by-line parser} *)
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type state = { lines : (int * string) array; mutable pos : int }
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let of_lines lines = { lines; pos = 0 }
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let of_string s =
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let lines = String.split_on_char '\n' s in
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let numbered = List.mapi (fun i l -> (i + 1, l)) lines |> Array.of_list in
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of_lines numbered
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let of_channel ic =
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let lines = ref [] in
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let n = ref 0 in
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(try
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while true do
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incr n;
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lines := (!n, input_line ic) :: !lines
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done
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with End_of_file -> ());
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of_lines (Array.of_list (List.rev !lines))
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let peek st =
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if st.pos >= Array.length st.lines then None else Some st.lines.(st.pos)
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let advance st = if st.pos < Array.length st.lines then st.pos <- st.pos + 1
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let eof st = st.pos >= Array.length st.lines
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let next st =
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match peek st with
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| None -> None
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| Some l ->
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advance st;
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Some l
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let skip_blanks st =
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let cont = ref true in
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while !cont do
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match peek st with
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| Some (_, s) -> (
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match classify s with
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| Blank | Comment _ -> advance st
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| _ -> cont := false)
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| None -> cont := false
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done
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(* {1 Block iteration} *)
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let iter_block ~start ~stop st ~on_keyword ~on_data =
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skip_blanks st;
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(* Skip the start delimiter if present *)
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(match peek st with
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| Some (_, s) when String.trim s = start -> advance st
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| _ -> ());
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let cont = ref true in
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while !cont do
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match peek st with
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| Some (n, s) -> (
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let trimmed = String.trim s in
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if trimmed = stop then begin
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advance st;
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cont := false
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end
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else
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match classify s with
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| Keyword (k, v) ->
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on_keyword k v;
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advance st
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| Data d ->
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on_data n d;
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advance st
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| Comment _ | Blank -> advance st)
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| None -> cont := false
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done
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let expect_keyword st key =
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skip_blanks st;
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match peek st with
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| Some (_, s) -> (
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match classify s with
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| Keyword (k, v) when k = key ->
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advance st;
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Some v
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| _ -> None)
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| None -> None
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(* {1 Value parsing} *)
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let parse_float s =
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match float_of_string_opt (String.trim s) with
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| Some f -> Some f
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| None -> None
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let parse_int s =
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match int_of_string_opt (String.trim s) with Some i -> Some i | None -> None
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let split_data s =
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String.split_on_char ' ' s
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|> List.filter (fun s -> String.length (String.trim s) > 0)
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|> List.map String.trim
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let parse_floats s =
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split_data s
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|> List.map (fun s ->
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match float_of_string_opt s with Some f -> f | None -> 0.0)
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|> Array.of_list
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(* {1 Pretty-printing} *)
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let pp_line ppf = function
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| Keyword (k, v) -> Fmt.pf ppf "%s = %s" k v
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| Data d -> Fmt.pf ppf "DATA: %s" d
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| Comment c -> Fmt.pf ppf "COMMENT %s" c
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| Blank -> Fmt.pf ppf "(blank)"
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lib/kvn.mli
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lib/kvn.mli
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(** CCSDS Key-Value Notation (KVN) parser.
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KVN is the text format used by CCSDS navigation data messages: OEM, OCM,
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TDM, ADM, CDM, and others. This library provides low-level parsing
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primitives and block iteration.
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{b Reference}: CCSDS 502.0-B-3 Annex A (KVN format definition) *)
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(** {1 Line classification} *)
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type line =
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| Keyword of string * string (** [KEY = VALUE] *)
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| Data of string (** Epoch + numeric data (no [=] sign) *)
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| Comment of string (** [COMMENT ...] *)
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| Blank (** Empty line or whitespace *)
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val classify : string -> line
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(** [classify s] classifies a KVN line. *)
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(** {1 Epoch parsing} *)
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val parse_epoch : string -> Ptime.t option
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(** [parse_epoch s] parses a CCSDS epoch string to [Ptime.t]. Accepts
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["YYYY-MM-DDThh:mm:ss.sss"] and space-separated variants. *)
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(** {1 Line-by-line parser} *)
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type state
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(** Mutable parser state over numbered lines. *)
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val of_string : string -> state
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(** [of_string s] creates a parser from a KVN string. *)
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val of_channel : in_channel -> state
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(** [of_channel ic] creates a parser from a channel. *)
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val peek : state -> (int * string) option
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(** [peek st] returns the current line (number, text) without advancing. *)
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val advance : state -> unit
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(** [advance st] moves to the next line. *)
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val next : state -> (int * string) option
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(** [next st] returns the current line and advances. *)
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val skip_blanks : state -> unit
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(** [skip_blanks st] skips blank and comment lines. *)
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val eof : state -> bool
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(** [eof st] is [true] if all lines have been consumed. *)
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(** {1 Block iteration} *)
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val iter_block :
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start:string ->
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stop:string ->
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state ->
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on_keyword:(string -> string -> unit) ->
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on_data:(int -> string -> unit) ->
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unit
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(** [iter_block ~start ~stop st ~on_keyword ~on_data] iterates over a KVN block
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delimited by [start] and [stop] keywords (e.g., ["META_START"] /
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["META_STOP"]). Calls [on_keyword key value] for keyword lines and
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[on_data line_num text] for data lines. Advances [st] past the stop
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delimiter. *)
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val expect_keyword : state -> string -> string option
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(** [expect_keyword st key] checks if the next non-blank line is [key = value]
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and returns [Some value], or [None] if it's something else. Advances past
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the keyword if found. *)
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(** {1 Value parsing} *)
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val parse_float : string -> float option
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(** [parse_float s] parses a float, returning [None] on failure. *)
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val parse_int : string -> int option
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(** [parse_int s] parses an integer, returning [None] on failure. *)
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val split_data : string -> string list
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(** [split_data s] splits a data line on whitespace, filtering empty tokens. *)
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val parse_floats : string -> float array
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(** [parse_floats s] splits a data line and parses all tokens as floats.
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Non-parseable tokens become [0.0]. *)
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(** {1 Pretty-printing} *)
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val pp_line : line Fmt.t