diff --git a/cpdfjson.ml b/cpdfjson.ml index 141d4e1..922f66d 100644 --- a/cpdfjson.ml +++ b/cpdfjson.ml @@ -6,12 +6,12 @@ object, one for each object in the file and two special ones: Object -1: CPDF's own data with the PDF version number, CPDF JSON format number, and flags used when writing (which may be required when reading): - o /CPDFJSONformatversion (integer, currently 2) + o /CPDFJSONformatversion (CPDFJSON integer (see below), currently 2) o /CPDFJSONcontentparsed (boolean, true if content streams have been parsed) o /CPDFJSONstreamdataincluded (boolean, true if stream data included. Cannot round-trip if false). - o /CPDFJSONmajorpdfversion (integer) - o /CPDFJSONminorpdfversion (integer) + o /CPDFJSONmajorpdfversion (CPDFJSON integer) + o /CPDFJSONminorpdfversion (CPDFJSON integer) Object 0: The PDF's trailer dictionary @@ -24,6 +24,11 @@ Objects 1..n: The PDF's objects. 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. + There are two subformats: parsing content streams or not. Hello World in CPDF JSON without parsing content streams: @@ -448,10 +453,33 @@ let precombine_page_content pdf = in Pdfpage.change_pages true pdf pages' +(* PDF strings (except /ID in the trailer dictionary) are either PDFDocEncoding +or UTF16BE. Many times the UTF16BE can all be represented in PDFDocEncoding. +In this case, there are just lots of \000 bytes getting in the way making the +JSON hard to edit. So we preprocess such simple UTF16BE strings into +PDFDocEncoding. *) +let preprocess_string s = + if Pdftext.is_unicode s + then Pdftext.pdfdocstring_of_utf8 (Pdftext.utf8_of_pdfdocstring s) + else s + +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)}) -> + Pdf.Stream {contents = (Pdf.recurse_dict (ppstring_single_object pdf) dict, data)} + | Pdf.Array a -> Pdf.recurse_array (ppstring_single_object pdf) a + | Pdf.String s -> Pdf.String (preprocess_string s) + | x -> x + +let preprocess_strings pdf = + Pdf.objselfmap (ppstring_single_object pdf) pdf; + pdf.Pdf.trailerdict <- ppstring_single_object pdf pdf.Pdf.trailerdict + let json_of_pdf ~parse_content ~no_stream_data ~decompress_streams pdf = + 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;