Wrote JSON outputter

Changes

@@ -2,6 +2,8 @@ Version 2.4 (to come)
 
 o Vendored in tiny_json from Yoshihiro Imai via Jan Furuse
 o New -labels-progress option to improve page labels interface
+o New options -output-json and -output-json-parse-content streams to export PDF
+files in JSON format
 
 Version 2.3 (patchlevel 1, December 2019)
 

cpdfwriteJSON.ml

@@ -1,11 +1,61 @@
 module J = Tjjson
+module P = Pdf
 
-let test = J.Array [J.Number "100"; J.String "foo"]
+let rec json_of_object fcs = function
+  | P.Null -> J.String "null"
+  | P.Boolean b -> J.Bool b
+  | P.Integer i -> J.Number (string_of_int i)
+  | P.Real r -> J.Number (string_of_float r)
+  | P.String s -> J.String s
+  | P.Name n -> J.String n
+  | P.Array objs -> J.Array (List.map (json_of_object fcs) objs)
+  | P.Dictionary elts ->
+      (* Detect contents stream object numbers for second pass *)
+      List.iter (function ("/Contents", P.Indirect i) -> fcs i | _ -> ()) elts;
+      J.Object (List.map (fun (k, v) -> (k, json_of_object fcs v)) elts)
+  | P.Stream {contents = (Pdf.Dictionary dict, stream)} as thestream ->
+      Pdf.getstream thestream;
+      let str = match stream with Got b -> Pdfio.string_of_bytes b | ToGet _ -> "failure: toget" in
+        json_of_object fcs (P.Array [P.Dictionary dict; P.String str])
+  | P.Stream _ -> J.String "error: stream with not-a-dictioary"
+  | P.Indirect i -> J.Number (string_of_int i)
+
+let parse_content_stream str = J.String ("PARSED: str")
+
+let json_of_pdf parse_content pdf =
+  let trailerdict = (0, json_of_object (fun x -> ()) pdf.Pdf.trailerdict) in
+  let content_streams = ref [] in
+  let pairs =
+    let ps = ref [] in
+      Pdf.objiter
+        (fun i pdfobj ->
+          ps := (i, json_of_object (fun n -> content_streams := n::!content_streams) pdfobj)::!ps)
+        pdf;
+      trailerdict::!ps
+  in
+    let pairs_parsed =
+      if not parse_content then pairs else
+        List.map
+          (fun (objnum, obj) ->
+             if Pdfutil.mem objnum !content_streams then
+               begin match obj with
+               | J.Array [dict; J.String streamdata] ->
+                   (objnum, J.Array [dict; parse_content_stream streamdata])
+               | _ -> failwith "json_of_pdf: stream parsing inconsistency"
+               end
+             else
+               (objnum, obj))
+          pairs
+    in
+      J.Array
+        (List.map
+          (fun (objnum, jsonobj) -> J.Array [J.String (string_of_int objnum); jsonobj])
+          pairs_parsed)
 
 let write fh parse_content pdf =
   let b = Buffer.create 256 in
   let formatter = Format.formatter_of_buffer b in
-    Tjjson.format formatter test;
+    Tjjson.format formatter (json_of_pdf parse_content pdf);
     Format.pp_print_flush formatter ();
     output_string fh (Buffer.contents b)