vcl/source/filter/ipdf/pdfcompat.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <pdf/pdfcompat.hxx>
  11
  12 #include <o3tl/string_view.hxx>
  13 #include <tools/solar.h>
  14 #include <vcl/filter/PDFiumLibrary.hxx>
  15 #include <sal/log.hxx>
  16
  17 namespace vcl::pdf
  18 {
  19 /// Decide if PDF data is old enough to be compatible.
  20 bool isCompatible(SvStream& rInStream, sal_uInt64 nPos, sal_uInt64 nSize)
  21 {
  22     if (nSize < 8)
  23         return false;
  24
  25     // %PDF-x.y
  26     sal_uInt8 aFirstBytes[8];
  27     rInStream.Seek(nPos);
  28     sal_uLong nRead = rInStream.ReadBytes(aFirstBytes, 8);
  29     if (nRead < 8)
  30         return false;
  31
  32     if (aFirstBytes[0] != '%' || aFirstBytes[1] != 'P' || aFirstBytes[2] != 'D'
  33         || aFirstBytes[3] != 'F' || aFirstBytes[4] != '-')
  34         return false;
  35
  36     sal_Int32 nMajor = o3tl::toInt32(std::string_view(reinterpret_cast<char*>(&aFirstBytes[5]), 1));
  37     sal_Int32 nMinor = o3tl::toInt32(std::string_view(reinterpret_cast<char*>(&aFirstBytes[7]), 1));
  38     return !(nMajor > 1 || (nMajor == 1 && nMinor > 6));
  39 }
  40
  41 /// Converts to highest supported format version (1.6).
  42 /// Usually used to deal with missing referenced objects in source
  43 /// pdf stream.
  44 bool convertToHighestSupported(SvStream& rInStream, SvStream& rOutStream)
  45 {
  46     sal_uInt64 nPos = STREAM_SEEK_TO_BEGIN;
  47     sal_uInt64 nSize = STREAM_SEEK_TO_END;
  48     rInStream.Seek(nPos);
  49     // Convert to PDF-1.6.
  50     auto pPdfium = vcl::pdf::PDFiumLibrary::get();
  51     if (!pPdfium)
  52         return false;
  53
  54     // Read input into a buffer.
  55     SvMemoryStream aInBuffer;
  56     aInBuffer.WriteStream(rInStream, nSize);
  57
  58     SvMemoryStream aSaved;
  59     {
  60         // Load the buffer using pdfium.
  61         std::unique_ptr<vcl::pdf::PDFiumDocument> pPdfDocument
  62             = pPdfium->openDocument(aInBuffer.GetData(), aInBuffer.GetSize(), OString());
  63         if (!pPdfDocument)
  64             return false;
  65
  66         // 16 means PDF-1.6.
  67         if (!pPdfDocument->saveWithVersion(aSaved, 16))
  68             return false;
  69     }
  70
  71     aSaved.Seek(STREAM_SEEK_TO_BEGIN);
  72     rOutStream.WriteStream(aSaved);
  73
  74     return rOutStream.good();
  75 }
  76
  77 /// Takes care of transparently downgrading the version of the PDF stream in
  78 /// case it's too new for our PDF export.
  79 bool getCompatibleStream(SvStream& rInStream, SvStream& rOutStream)
  80 {
  81     sal_uInt64 nPos = STREAM_SEEK_TO_BEGIN;
  82     sal_uInt64 nSize = STREAM_SEEK_TO_END;
  83     bool bCompatible = isCompatible(rInStream, nPos, nSize);
  84     rInStream.Seek(nPos);
  85     if (bCompatible)
  86         // Not converting.
  87         rOutStream.WriteStream(rInStream, nSize);
  88     else
  89         convertToHighestSupported(rInStream, rOutStream);
  90
  91     return rOutStream.good();
  92 }
  93
  94 BinaryDataContainer createBinaryDataContainer(SvStream& rStream)
  95 {
  96     // Save the original PDF stream for later use.
  97     SvMemoryStream aMemoryStream;
  98     if (!getCompatibleStream(rStream, aMemoryStream))
  99         return {};
 100
 101     const sal_uInt64 nStreamLength = aMemoryStream.TellEnd();
 102
 103     aMemoryStream.Seek(STREAM_SEEK_TO_BEGIN);
 104     BinaryDataContainer aPdfData(aMemoryStream, nStreamLength);
 105     if (aMemoryStream.GetError())
 106         return {};
 107
 108     return aPdfData;
 109 }
 110
 111 } // end vcl::filter::ipdf namespace
 112
 113 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */