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Fixing up JSON text output

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John Whitington
2021-12-30 15:25:24 +00:00
parent 618da13a80
commit dd2f8fd161
8 changed files with 44 additions and 22 deletions
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34
cpdfjson.ml
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@ -23,11 +23,12 @@ Objects 1..n: The PDF's objects.
o Names are written as {"N": "/Pages"}
o Indirect references are integers
o Streams are {"S": [dict, data]}
o Strings are converted from PDFDocEncoding to UTF8 before being encoded in
JSON. When they are read back the process is JSON encoded --> UTF8 -->
PDFDocEncoding. This process is to allow easier editing of strings. This
does not happen to strings within text operators in parsed content streams.
o Strings are converted from UTF16BE/PDFDocEncoding to UTF8 before being
encoded in JSON. When they are read back the process is JSON encoded --> UTF8
--> UTF16BE/PDFDocEncoding. This process is fully reversible: it is to allow
easier editing of strings. This does not happen to strings within text
operators in parsed content streams, nor to /ID values in the
trailerdictionary, since neither is UTF16BE/PdfDocEncoding to begin with.
There are two subformats: parsing content streams or not. Hello World in CPDF
JSON without parsing content streams:
@ -81,7 +82,7 @@ When parsing content streams:
CPDF currently never preserves object streams, and only outputs unencrypted files.
When reloading a JSON file, CPDF knows how to correct /Length entries in
When reloading a JSON file, CPDF knows how to correct or add /Length entries in
streams, so you need not worry about them. *)
open Pdfutil
@ -277,12 +278,12 @@ let mkfloat f = `Assoc [("F", `Float f)]
let mkint i = `Assoc [("I", `Int i)]
let mkname n = `Assoc [("N", `String n)]
let rec json_of_object pdf fcs no_stream_data pcs = function
let rec json_of_object ?(clean_strings=false) pdf fcs no_stream_data pcs = function
| P.Null -> `Null
| P.Boolean b -> `Bool b
| P.Integer i -> mkint i
| P.Real r -> mkfloat r
| P.String s -> `String s
| P.String s -> `String (if clean_strings then Pdftext.simplify_utf16be s else s)
| P.Name n -> mkname n
| P.Array objs -> `List (map (json_of_object pdf fcs no_stream_data pcs) objs)
| P.Dictionary elts ->
@ -453,9 +454,8 @@ let precombine_page_content pdf =
in
Pdfpage.change_pages true pdf pages'
(* FIXME make this optional? And maybe move into actual JSON reader, instead of
preprocessing PDF, so it helps us when writing, say, the output of
-print-dict-entry? *)
(* Convert any strings in UTF16BE which could actually be in PDFDocEncoding
(due to having no high bytes) to make editing JSON easier. *)
let rec ppstring_single_object pdf = function
| Pdf.Dictionary d -> Pdf.recurse_dict (ppstring_single_object pdf) d
| (Pdf.Stream {contents = (Pdf.Dictionary dict, data)}) ->
@ -464,16 +464,16 @@ let rec ppstring_single_object pdf = function
| Pdf.String s -> Pdf.String (Pdftext.simplify_utf16be s)
| x -> x
(* Do all objects, but skip the trailer dictionary since may mess up /ID if it
happens to begin with UTF16BE BOM *)
let preprocess_strings pdf =
Pdf.objselfmap (ppstring_single_object pdf) pdf
(* Skip the trailer dictionary since may mess up /ID if it happens to begin with UTF16BE BOM *)
(*pdf.Pdf.trailerdict <- ppstring_single_object pdf pdf.Pdf.trailerdict*)
let json_of_pdf
~parse_content ~no_stream_data ~decompress_streams
~parse_content ~no_stream_data ~decompress_streams ~clean_strings
pdf
=
preprocess_strings pdf;
if clean_strings then preprocess_strings pdf;
let pdf = if parse_content then precombine_page_content pdf else pdf in
if decompress_streams then
Pdf.objiter (fun _ obj -> Pdfcodec.decode_pdfstream_until_unknown pdf obj) pdf;
@ -532,8 +532,8 @@ let json_of_pdf
(fun (objnum, jsonobj) -> `List [`Int objnum; jsonobj])
pairs_parsed)
let to_output o ~parse_content ~no_stream_data ~decompress_streams pdf =
let json = json_of_pdf ~parse_content ~no_stream_data ~decompress_streams pdf in
let to_output o ~parse_content ~no_stream_data ~decompress_streams ?(clean_strings=false) pdf =
let json = json_of_pdf ~parse_content ~no_stream_data ~decompress_streams ~clean_strings pdf in
match o.Pdfio.out_caml_channel with
| Some ch -> J.pretty_to_channel ch json
| None -> o.Pdfio.output_string (J.pretty_to_string json)