/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
#include <vcl/filter/pdfdocument.hxx>
#include <pdf/pdfcompat.hxx>
 
#include <map>
#include <memory>
#include <vector>
 
#include <com/sun/star/uno/Sequence.hxx>
#include <com/sun/star/security/XCertificate.hpp>
 
#include <comphelper/scopeguard.hxx>
#include <comphelper/string.hxx>
#include <o3tl/string_view.hxx>
#include <rtl/character.hxx>
#include <rtl/strbuf.hxx>
#include <rtl/string.hxx>
#include <sal/log.hxx>
#include <sal/types.h>
#include <svl/cryptosign.hxx>
#include <tools/zcodec.hxx>
#include <vcl/pdfwriter.hxx>
#include <o3tl/safeint.hxx>
 
#include <pdf/objectcopier.hxx>
 
using namespace com::sun::star;
 
namespace vcl::filter
{
XRefEntry::XRefEntry() = default;
 
PDFDocument::PDFDocument() = default;
 
PDFDocument::~PDFDocument() = default;
 
bool PDFDocument::RemoveSignature(size_t nPosition)
{
    std::vector<PDFObjectElement*> aSignatures = GetSignatureWidgets();
    if (nPosition >= aSignatures.size())
    {
        SAL_WARN("vcl.filter", "PDFDocument::RemoveSignature: invalid nPosition");
        return false;
    }
 
    if (aSignatures.size() != m_aEOFs.size() - 1)
    {
        SAL_WARN("vcl.filter", "PDFDocument::RemoveSignature: no 1:1 mapping between signatures "
                               "and incremental updates");
        return false;
    }
 
    // The EOF offset is the end of the original file, without the signature at
    // nPosition.
    m_aEditBuffer.Seek(m_aEOFs[nPosition]);
    // Drop all bytes after the current position.
    m_aEditBuffer.SetStreamSize(m_aEditBuffer.Tell() + 1);
 
    return m_aEditBuffer.good();
}
 
sal_Int32 PDFDocument::createObject()
{
    sal_Int32 nObject = m_aXRef.size();
    m_aXRef[nObject] = XRefEntry();
    return nObject;
}
 
bool PDFDocument::updateObject(sal_Int32 nObject)
{
    if (o3tl::make_unsigned(nObject) >= m_aXRef.size())
    {
        SAL_WARN("vcl.filter", "PDFDocument::updateObject: invalid nObject");
        return false;
    }
 
    XRefEntry aEntry;
    aEntry.SetOffset(m_aEditBuffer.Tell());
    aEntry.SetDirty(true);
    m_aXRef[nObject] = aEntry;
    return true;
}
 
bool PDFDocument::writeBufferBytes(const void* pBuffer, sal_uInt64 nBytes)
{
    std::size_t nWritten = m_aEditBuffer.WriteBytes(pBuffer, nBytes);
    return nWritten == nBytes;
}
 
void PDFDocument::SetSignatureLine(std::vector<sal_Int8>&& rSignatureLine)
{
    m_aSignatureLine = std::move(rSignatureLine);
}
 
void PDFDocument::SetSignaturePage(size_t nPage) { m_nSignaturePage = nPage; }
 
sal_uInt32 PDFDocument::GetNextSignature()
{
    sal_uInt32 nRet = 0;
    for (const auto& pSignature : GetSignatureWidgets())
    {
        auto pT = dynamic_cast<PDFLiteralStringElement*>(pSignature->Lookup("T"_ostr));
        if (!pT)
            continue;
 
        const OString& rValue = pT->GetValue();
        std::string_view rest;
        if (!rValue.startsWith("Signature", &rest))
            continue;
 
        nRet = std::max(nRet, o3tl::toUInt32(rest));
    }
 
    return nRet + 1;
}
 
sal_Int32 PDFDocument::WriteSignatureObject(svl::crypto::SigningContext& rSigningContext,
                                            const OUString& rDescription, bool bAdES,
                                            sal_uInt64& rLastByteRangeOffset,
                                            sal_Int64& rContentOffset)
{
    // Write signature object.
    sal_Int32 nSignatureId = m_aXRef.size();
    XRefEntry aSignatureEntry;
    aSignatureEntry.SetOffset(m_aEditBuffer.Tell());
    aSignatureEntry.SetDirty(true);
    m_aXRef[nSignatureId] = aSignatureEntry;
    OStringBuffer aSigBuffer(OString::number(nSignatureId)
                             + " 0 obj\n"
                               "<</Contents <");
    rContentOffset = aSignatureEntry.GetOffset() + aSigBuffer.getLength();
    // Reserve space for the PKCS#7 object.
    OStringBuffer aContentFiller(MAX_SIGNATURE_CONTENT_LENGTH);
    comphelper::string::padToLength(aContentFiller, MAX_SIGNATURE_CONTENT_LENGTH, '0');
    aSigBuffer.append(aContentFiller + ">\n/Type/Sig/SubFilter");
    if (bAdES)
        aSigBuffer.append("/ETSI.CAdES.detached");
    else
        aSigBuffer.append("/adbe.pkcs7.detached");
 
    // Time of signing.
    aSigBuffer.append(" /M (" + vcl::PDFWriter::GetDateTime(&rSigningContext)
                      + ")"
 
                        // Byte range: we can write offset1-length1 and offset2 right now, will
                        // write length2 later.
                        " /ByteRange [ 0 "
                      // -1 and +1 is the leading "<" and the trailing ">" around the hex string.
                      + OString::number(rContentOffset - 1) + " "
                      + OString::number(rContentOffset + MAX_SIGNATURE_CONTENT_LENGTH + 1) + " ");
    rLastByteRangeOffset = aSignatureEntry.GetOffset() + aSigBuffer.getLength();
    // We don't know how many bytes we need for the last ByteRange value, this
    // should be enough.
    OStringBuffer aByteRangeFiller;
    comphelper::string::padToLength(aByteRangeFiller, 100, ' ');
    aSigBuffer.append(aByteRangeFiller
                      // Finish the Sig obj.
                      + " /Filter/Adobe.PPKMS");
 
    if (!rDescription.isEmpty())
    {
        aSigBuffer.append("/Reason<");
        vcl::PDFWriter::AppendUnicodeTextString(rDescription, aSigBuffer);
        aSigBuffer.append(">");
    }
 
    aSigBuffer.append(" >>\nendobj\n\n");
    m_aEditBuffer.WriteOString(aSigBuffer);
 
    return nSignatureId;
}
 
sal_Int32 PDFDocument::WriteAppearanceObject(tools::Rectangle& rSignatureRectangle)
{
    PDFDocument aPDFDocument;
    filter::PDFObjectElement* pPage = nullptr;
    std::vector<filter::PDFObjectElement*> aContentStreams;
 
    if (!m_aSignatureLine.empty())
    {
        // Parse the PDF data of signature line: we can set the signature rectangle to non-empty
        // based on it.
        SvMemoryStream aPDFStream;
        aPDFStream.WriteBytes(m_aSignatureLine.data(), m_aSignatureLine.size());
        aPDFStream.Seek(0);
        if (!aPDFDocument.Read(aPDFStream))
        {
            SAL_WARN("vcl.filter",
                     "PDFDocument::WriteAppearanceObject: failed to read the PDF document");
            return -1;
        }
 
        std::vector<filter::PDFObjectElement*> aPages = aPDFDocument.GetPages();
        if (aPages.empty())
        {
            SAL_WARN("vcl.filter", "PDFDocument::WriteAppearanceObject: no pages");
            return -1;
        }
 
        pPage = aPages[0];
        if (!pPage)
        {
            SAL_WARN("vcl.filter", "PDFDocument::WriteAppearanceObject: no page");
            return -1;
        }
 
        // Calculate the bounding box.
        PDFElement* pMediaBox = pPage->Lookup("MediaBox"_ostr);
        auto pMediaBoxArray = dynamic_cast<PDFArrayElement*>(pMediaBox);
        if (!pMediaBoxArray || pMediaBoxArray->GetElements().size() < 4)
        {
            SAL_WARN("vcl.filter",
                     "PDFDocument::WriteAppearanceObject: MediaBox is not an array of 4");
            return -1;
        }
        const std::vector<PDFElement*>& rMediaBoxElements = pMediaBoxArray->GetElements();
        auto pWidth = dynamic_cast<PDFNumberElement*>(rMediaBoxElements[2]);
        if (!pWidth)
        {
            SAL_WARN("vcl.filter", "PDFDocument::WriteAppearanceObject: MediaBox has no width");
            return -1;
        }
        rSignatureRectangle.setWidth(pWidth->GetValue());
        auto pHeight = dynamic_cast<PDFNumberElement*>(rMediaBoxElements[3]);
        if (!pHeight)
        {
            SAL_WARN("vcl.filter", "PDFDocument::WriteAppearanceObject: MediaBox has no height");
            return -1;
        }
        rSignatureRectangle.setHeight(pHeight->GetValue());
 
        if (PDFObjectElement* pContentStream = pPage->LookupObject("Contents"_ostr))
        {
            aContentStreams.push_back(pContentStream);
        }
 
        if (aContentStreams.empty())
        {
            SAL_WARN("vcl.filter", "PDFDocument::WriteAppearanceObject: no content stream");
            return -1;
        }
    }
    m_aSignatureLine.clear();
 
    // Write appearance object: allocate an ID.
    sal_Int32 nAppearanceId = m_aXRef.size();
    m_aXRef[nAppearanceId] = XRefEntry();
 
    // Write the object content.
    SvMemoryStream aEditBuffer;
    aEditBuffer.WriteNumberAsString(nAppearanceId);
    aEditBuffer.WriteOString(" 0 obj\n");
    aEditBuffer.WriteOString("<</Type/XObject\n/Subtype/Form\n");
 
    PDFObjectCopier aCopier(*this);
    if (!aContentStreams.empty())
    {
        assert(pPage && "aContentStreams is only filled if there was a pPage");
        OStringBuffer aBuffer;
        aCopier.copyPageResources(pPage, aBuffer);
        aEditBuffer.WriteOString(aBuffer);
    }
 
    aEditBuffer.WriteOString("/BBox[0 0 ");
    aEditBuffer.WriteNumberAsString(rSignatureRectangle.getOpenWidth());
    aEditBuffer.WriteOString(" ");
    aEditBuffer.WriteNumberAsString(rSignatureRectangle.getOpenHeight());
    aEditBuffer.WriteOString("]\n/Length ");
 
    // Add the object to the doc-level edit buffer and update the offset.
    SvMemoryStream aStream;
    bool bCompressed = false;
    sal_Int32 nLength = 0;
    if (!aContentStreams.empty())
    {
        nLength = PDFObjectCopier::copyPageStreams(aContentStreams, aStream, bCompressed);
    }
    aEditBuffer.WriteNumberAsString(nLength);
    if (bCompressed)
    {
        aEditBuffer.WriteOString(" /Filter/FlateDecode");
    }
 
    aEditBuffer.WriteOString("\n>>\n");
 
    aEditBuffer.WriteOString("stream\n");
 
    // Copy the original page streams to the form XObject stream.
    aStream.Seek(0);
    aEditBuffer.WriteStream(aStream);
 
    aEditBuffer.WriteOString("\nendstream\nendobj\n\n");
 
    aEditBuffer.Seek(0);
    XRefEntry aAppearanceEntry;
    aAppearanceEntry.SetOffset(m_aEditBuffer.Tell());
    aAppearanceEntry.SetDirty(true);
    m_aXRef[nAppearanceId] = aAppearanceEntry;
    m_aEditBuffer.WriteStream(aEditBuffer);
 
    return nAppearanceId;
}
 
sal_Int32 PDFDocument::WriteAnnotObject(PDFObjectElement const& rFirstPage, sal_Int32 nSignatureId,
                                        sal_Int32 nAppearanceId,
                                        const tools::Rectangle& rSignatureRectangle)
{
    // Decide what identifier to use for the new signature.
    sal_uInt32 nNextSignature = GetNextSignature();
 
    // Write the Annot object, references nSignatureId and nAppearanceId.
    sal_Int32 nAnnotId = m_aXRef.size();
    XRefEntry aAnnotEntry;
    aAnnotEntry.SetOffset(m_aEditBuffer.Tell());
    aAnnotEntry.SetDirty(true);
    m_aXRef[nAnnotId] = aAnnotEntry;
    m_aEditBuffer.WriteNumberAsString(nAnnotId);
    m_aEditBuffer.WriteOString(" 0 obj\n");
    m_aEditBuffer.WriteOString("<</Type/Annot/Subtype/Widget/F 132\n");
    m_aEditBuffer.WriteOString("/Rect[0 0 ");
    m_aEditBuffer.WriteNumberAsString(rSignatureRectangle.getOpenWidth());
    m_aEditBuffer.WriteOString(" ");
    m_aEditBuffer.WriteNumberAsString(rSignatureRectangle.getOpenHeight());
    m_aEditBuffer.WriteOString("]\n");
    m_aEditBuffer.WriteOString("/FT/Sig\n");
    m_aEditBuffer.WriteOString("/P ");
    m_aEditBuffer.WriteNumberAsString(rFirstPage.GetObjectValue());
    m_aEditBuffer.WriteOString(" 0 R\n");
    m_aEditBuffer.WriteOString("/T(Signature");
    m_aEditBuffer.WriteNumberAsString(nNextSignature);
    m_aEditBuffer.WriteOString(")\n");
    m_aEditBuffer.WriteOString("/V ");
    m_aEditBuffer.WriteNumberAsString(nSignatureId);
    m_aEditBuffer.WriteOString(" 0 R\n");
    m_aEditBuffer.WriteOString("/DV ");
    m_aEditBuffer.WriteNumberAsString(nSignatureId);
    m_aEditBuffer.WriteOString(" 0 R\n");
    m_aEditBuffer.WriteOString("/AP<<\n/N ");
    m_aEditBuffer.WriteNumberAsString(nAppearanceId);
    m_aEditBuffer.WriteOString(" 0 R\n>>\n");
    m_aEditBuffer.WriteOString(">>\nendobj\n\n");
 
    return nAnnotId;
}
 
bool PDFDocument::WritePageObject(PDFObjectElement& rFirstPage, sal_Int32 nAnnotId)
{
    PDFElement* pAnnots = rFirstPage.Lookup("Annots"_ostr);
    auto pAnnotsReference = dynamic_cast<PDFReferenceElement*>(pAnnots);
    if (pAnnotsReference)
    {
        // Write the updated Annots key of the Page object.
        PDFObjectElement* pAnnotsObject = pAnnotsReference->LookupObject();
        if (!pAnnotsObject)
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: invalid Annots reference");
            return false;
        }
 
        sal_uInt32 nAnnotsId = pAnnotsObject->GetObjectValue();
        m_aXRef[nAnnotsId].SetType(XRefEntryType::NOT_COMPRESSED);
        m_aXRef[nAnnotsId].SetOffset(m_aEditBuffer.Tell());
        m_aXRef[nAnnotsId].SetDirty(true);
        m_aEditBuffer.WriteNumberAsString(nAnnotsId);
        m_aEditBuffer.WriteOString(" 0 obj\n[");
 
        // Write existing references.
        PDFArrayElement* pArray = pAnnotsObject->GetArray();
        if (!pArray)
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: Page Annots is a reference to a non-array");
            return false;
        }
 
        for (size_t i = 0; i < pArray->GetElements().size(); ++i)
        {
            auto pReference = dynamic_cast<PDFReferenceElement*>(pArray->GetElements()[i]);
            if (!pReference)
                continue;
 
            if (i)
                m_aEditBuffer.WriteOString(" ");
            m_aEditBuffer.WriteNumberAsString(pReference->GetObjectValue());
            m_aEditBuffer.WriteOString(" 0 R");
        }
        // Write our reference.
        m_aEditBuffer.WriteOString(" ");
        m_aEditBuffer.WriteNumberAsString(nAnnotId);
        m_aEditBuffer.WriteOString(" 0 R");
 
        m_aEditBuffer.WriteOString("]\nendobj\n\n");
    }
    else
    {
        // Write the updated first page object, references nAnnotId.
        sal_uInt32 nFirstPageId = rFirstPage.GetObjectValue();
        if (nFirstPageId >= m_aXRef.size())
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: invalid first page obj id");
            return false;
        }
        m_aXRef[nFirstPageId].SetOffset(m_aEditBuffer.Tell());
        m_aXRef[nFirstPageId].SetDirty(true);
        m_aEditBuffer.WriteNumberAsString(nFirstPageId);
        m_aEditBuffer.WriteOString(" 0 obj\n");
        m_aEditBuffer.WriteOString("<<");
        auto pAnnotsArray = dynamic_cast<PDFArrayElement*>(pAnnots);
        if (!pAnnotsArray)
        {
            // No Annots key, just write the key with a single reference.
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + rFirstPage.GetDictionaryOffset(),
                                     rFirstPage.GetDictionaryLength());
            m_aEditBuffer.WriteOString("/Annots[");
            m_aEditBuffer.WriteNumberAsString(nAnnotId);
            m_aEditBuffer.WriteOString(" 0 R]");
        }
        else
        {
            // Annots key is already there, insert our reference at the end.
            PDFDictionaryElement* pDictionary = rFirstPage.GetDictionary();
 
            // Offset right before the end of the Annots array.
            sal_uInt64 nAnnotsEndOffset = pDictionary->GetKeyOffset("Annots"_ostr)
                                          + pDictionary->GetKeyValueLength("Annots"_ostr) - 1;
            // Length of beginning of the dictionary -> Annots end.
            sal_uInt64 nAnnotsBeforeEndLength = nAnnotsEndOffset - rFirstPage.GetDictionaryOffset();
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + rFirstPage.GetDictionaryOffset(),
                                     nAnnotsBeforeEndLength);
            m_aEditBuffer.WriteOString(" ");
            m_aEditBuffer.WriteNumberAsString(nAnnotId);
            m_aEditBuffer.WriteOString(" 0 R");
            // Length of Annots end -> end of the dictionary.
            sal_uInt64 nAnnotsAfterEndLength = rFirstPage.GetDictionaryOffset()
                                               + rFirstPage.GetDictionaryLength()
                                               - nAnnotsEndOffset;
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + nAnnotsEndOffset,
                                     nAnnotsAfterEndLength);
        }
        m_aEditBuffer.WriteOString(">>");
        m_aEditBuffer.WriteOString("\nendobj\n\n");
    }
 
    return true;
}
 
bool PDFDocument::WriteCatalogObject(sal_Int32 nAnnotId, PDFReferenceElement*& pRoot)
{
    if (m_pXRefStream)
        pRoot = dynamic_cast<PDFReferenceElement*>(m_pXRefStream->Lookup("Root"_ostr));
    else
    {
        if (!m_pTrailer)
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: found no trailer");
            return false;
        }
        pRoot = dynamic_cast<PDFReferenceElement*>(m_pTrailer->Lookup("Root"_ostr));
    }
    if (!pRoot)
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: trailer has no root reference");
        return false;
    }
    PDFObjectElement* pCatalog = pRoot->LookupObject();
    if (!pCatalog)
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: invalid catalog reference");
        return false;
    }
    sal_uInt32 nCatalogId = pCatalog->GetObjectValue();
    if (nCatalogId >= m_aXRef.size())
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: invalid catalog obj id");
        return false;
    }
    PDFElement* pAcroForm = pCatalog->Lookup("AcroForm"_ostr);
    auto pAcroFormReference = dynamic_cast<PDFReferenceElement*>(pAcroForm);
    if (pAcroFormReference)
    {
        // Write the updated AcroForm key of the Catalog object.
        PDFObjectElement* pAcroFormObject = pAcroFormReference->LookupObject();
        if (!pAcroFormObject)
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: invalid AcroForm reference");
            return false;
        }
 
        sal_uInt32 nAcroFormId = pAcroFormObject->GetObjectValue();
        m_aXRef[nAcroFormId].SetType(XRefEntryType::NOT_COMPRESSED);
        m_aXRef[nAcroFormId].SetOffset(m_aEditBuffer.Tell());
        m_aXRef[nAcroFormId].SetDirty(true);
        m_aEditBuffer.WriteNumberAsString(nAcroFormId);
        m_aEditBuffer.WriteOString(" 0 obj\n");
 
        // If this is nullptr, then the AcroForm object is not in an object stream.
        SvMemoryStream* pStreamBuffer = pAcroFormObject->GetStreamBuffer();
 
        if (!pAcroFormObject->Lookup("Fields"_ostr))
        {
            SAL_WARN("vcl.filter",
                     "PDFDocument::Sign: AcroForm object without required Fields key");
            return false;
        }
 
        PDFDictionaryElement* pAcroFormDictionary = pAcroFormObject->GetDictionary();
        if (!pAcroFormDictionary)
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: AcroForm object has no dictionary");
            return false;
        }
 
        // Offset right before the end of the Fields array.
        sal_uInt64 nFieldsEndOffset = pAcroFormDictionary->GetKeyOffset("Fields"_ostr)
                                      + pAcroFormDictionary->GetKeyValueLength("Fields"_ostr)
                                      - strlen("]");
 
        // Length of beginning of the object dictionary -> Fields end.
        sal_uInt64 nFieldsBeforeEndLength = nFieldsEndOffset;
        if (pStreamBuffer)
            m_aEditBuffer.WriteBytes(pStreamBuffer->GetData(), nFieldsBeforeEndLength);
        else
        {
            nFieldsBeforeEndLength -= pAcroFormObject->GetDictionaryOffset();
            m_aEditBuffer.WriteOString("<<");
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + pAcroFormObject->GetDictionaryOffset(),
                                     nFieldsBeforeEndLength);
        }
 
        // Append our reference at the end of the Fields array.
        m_aEditBuffer.WriteOString(" ");
        m_aEditBuffer.WriteNumberAsString(nAnnotId);
        m_aEditBuffer.WriteOString(" 0 R");
 
        // Length of Fields end -> end of the object dictionary.
        if (pStreamBuffer)
        {
            sal_uInt64 nFieldsAfterEndLength = pStreamBuffer->GetSize() - nFieldsEndOffset;
            m_aEditBuffer.WriteBytes(static_cast<const char*>(pStreamBuffer->GetData())
                                         + nFieldsEndOffset,
                                     nFieldsAfterEndLength);
        }
        else
        {
            sal_uInt64 nFieldsAfterEndLength = pAcroFormObject->GetDictionaryOffset()
                                               + pAcroFormObject->GetDictionaryLength()
                                               - nFieldsEndOffset;
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + nFieldsEndOffset,
                                     nFieldsAfterEndLength);
            m_aEditBuffer.WriteOString(">>");
        }
 
        m_aEditBuffer.WriteOString("\nendobj\n\n");
    }
    else
    {
        // Write the updated Catalog object, references nAnnotId.
        auto pAcroFormDictionary = dynamic_cast<PDFDictionaryElement*>(pAcroForm);
        m_aXRef[nCatalogId].SetOffset(m_aEditBuffer.Tell());
        m_aXRef[nCatalogId].SetDirty(true);
        m_aEditBuffer.WriteNumberAsString(nCatalogId);
        m_aEditBuffer.WriteOString(" 0 obj\n");
        m_aEditBuffer.WriteOString("<<");
        if (!pAcroFormDictionary)
        {
            // No AcroForm key, assume no signatures.
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + pCatalog->GetDictionaryOffset(),
                                     pCatalog->GetDictionaryLength());
            m_aEditBuffer.WriteOString("/AcroForm<</Fields[\n");
            m_aEditBuffer.WriteNumberAsString(nAnnotId);
            m_aEditBuffer.WriteOString(" 0 R\n]/SigFlags 3>>\n");
        }
        else
        {
            // AcroForm key is already there, insert our reference at the Fields end.
            auto it = pAcroFormDictionary->GetItems().find("Fields"_ostr);
            if (it == pAcroFormDictionary->GetItems().end())
            {
                SAL_WARN("vcl.filter", "PDFDocument::Sign: AcroForm without required Fields key");
                return false;
            }
 
            auto pFields = dynamic_cast<PDFArrayElement*>(it->second);
            if (!pFields)
            {
                SAL_WARN("vcl.filter", "PDFDocument::Sign: AcroForm Fields is not an array");
                return false;
            }
 
            // Offset right before the end of the Fields array.
            sal_uInt64 nFieldsEndOffset = pAcroFormDictionary->GetKeyOffset("Fields"_ostr)
                                          + pAcroFormDictionary->GetKeyValueLength("Fields"_ostr)
                                          - 1;
            // Length of beginning of the Catalog dictionary -> Fields end.
            sal_uInt64 nFieldsBeforeEndLength = nFieldsEndOffset - pCatalog->GetDictionaryOffset();
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + pCatalog->GetDictionaryOffset(),
                                     nFieldsBeforeEndLength);
            m_aEditBuffer.WriteOString(" ");
            m_aEditBuffer.WriteNumberAsString(nAnnotId);
            m_aEditBuffer.WriteOString(" 0 R");
            // Length of Fields end -> end of the Catalog dictionary.
            sal_uInt64 nFieldsAfterEndLength = pCatalog->GetDictionaryOffset()
                                               + pCatalog->GetDictionaryLength() - nFieldsEndOffset;
            m_aEditBuffer.WriteBytes(static_cast<const char*>(m_aEditBuffer.GetData())
                                         + nFieldsEndOffset,
                                     nFieldsAfterEndLength);
        }
        m_aEditBuffer.WriteOString(">>\nendobj\n\n");
    }
 
    return true;
}
 
void PDFDocument::WriteXRef(sal_uInt64 nXRefOffset, PDFReferenceElement const* pRoot)
{
    if (m_pXRefStream)
    {
        // Write the xref stream.
        // This is a bit meta: the xref stream stores its own offset.
        sal_Int32 nXRefStreamId = m_aXRef.size();
        XRefEntry aXRefStreamEntry;
        aXRefStreamEntry.SetOffset(nXRefOffset);
        aXRefStreamEntry.SetDirty(true);
        m_aXRef[nXRefStreamId] = aXRefStreamEntry;
 
        // Write stream data.
        SvMemoryStream aXRefStream;
        const size_t nOffsetLen = 3;
        // 3 additional bytes: predictor, the first and the third field.
        const size_t nLineLength = nOffsetLen + 3;
        // This is the line as it appears before tweaking according to the predictor.
        std::vector<unsigned char> aOrigLine(nLineLength);
        // This is the previous line.
        std::vector<unsigned char> aPrevLine(nLineLength);
        // This is the line as written to the stream.
        std::vector<unsigned char> aFilteredLine(nLineLength);
        for (const auto& rXRef : m_aXRef)
        {
            const XRefEntry& rEntry = rXRef.second;
 
            if (!rEntry.GetDirty())
                continue;
 
            // Predictor.
            size_t nPos = 0;
            // PNG prediction: up (on all rows).
            aOrigLine[nPos++] = 2;
 
            // First field.
            unsigned char nType = 0;
            switch (rEntry.GetType())
            {
                case XRefEntryType::FREE:
                    nType = 0;
                    break;
                case XRefEntryType::NOT_COMPRESSED:
                    nType = 1;
                    break;
                case XRefEntryType::COMPRESSED:
                    nType = 2;
                    break;
            }
            aOrigLine[nPos++] = nType;
 
            // Second field.
            for (size_t i = 0; i < nOffsetLen; ++i)
            {
                size_t nByte = nOffsetLen - i - 1;
                // Fields requiring more than one byte are stored with the
                // high-order byte first.
                unsigned char nCh = (rEntry.GetOffset() & (0xff << (nByte * 8))) >> (nByte * 8);
                aOrigLine[nPos++] = nCh;
            }
 
            // Third field.
            aOrigLine[nPos++] = 0;
 
            // Now apply the predictor.
            aFilteredLine[0] = aOrigLine[0];
            for (size_t i = 1; i < nLineLength; ++i)
            {
                // Count the delta vs the previous line.
                aFilteredLine[i] = aOrigLine[i] - aPrevLine[i];
                // Remember the new reference.
                aPrevLine[i] = aOrigLine[i];
            }
 
            aXRefStream.WriteBytes(aFilteredLine.data(), aFilteredLine.size());
        }
 
        m_aEditBuffer.WriteNumberAsString(nXRefStreamId);
        m_aEditBuffer.WriteOString(
            " 0 obj\n<</DecodeParms<</Columns 5/Predictor 12>>/Filter/FlateDecode");
 
        // ID.
        auto pID = dynamic_cast<PDFArrayElement*>(m_pXRefStream->Lookup("ID"_ostr));
        if (pID)
        {
            const std::vector<PDFElement*>& rElements = pID->GetElements();
            m_aEditBuffer.WriteOString("/ID [ <");
            for (size_t i = 0; i < rElements.size(); ++i)
            {
                auto pIDString = dynamic_cast<PDFHexStringElement*>(rElements[i]);
                if (!pIDString)
                    continue;
 
                m_aEditBuffer.WriteOString(pIDString->GetValue());
                if ((i + 1) < rElements.size())
                    m_aEditBuffer.WriteOString("> <");
            }
            m_aEditBuffer.WriteOString("> ] ");
        }
 
        // Index.
        m_aEditBuffer.WriteOString("/Index [ ");
        for (const auto& rXRef : m_aXRef)
        {
            if (!rXRef.second.GetDirty())
                continue;
 
            m_aEditBuffer.WriteNumberAsString(rXRef.first);
            m_aEditBuffer.WriteOString(" 1 ");
        }
        m_aEditBuffer.WriteOString("] ");
 
        // Info.
        auto pInfo = dynamic_cast<PDFReferenceElement*>(m_pXRefStream->Lookup("Info"_ostr));
        if (pInfo)
        {
            m_aEditBuffer.WriteOString("/Info ");
            m_aEditBuffer.WriteNumberAsString(pInfo->GetObjectValue());
            m_aEditBuffer.WriteOString(" ");
            m_aEditBuffer.WriteNumberAsString(pInfo->GetGenerationValue());
            m_aEditBuffer.WriteOString(" R ");
        }
 
        // Length.
        m_aEditBuffer.WriteOString("/Length ");
        {
            ZCodec aZCodec;
            aZCodec.BeginCompression();
            aXRefStream.Seek(0);
            SvMemoryStream aStream;
            aZCodec.Compress(aXRefStream, aStream);
            aZCodec.EndCompression();
            aXRefStream.Seek(0);
            aXRefStream.SetStreamSize(0);
            aStream.Seek(0);
            aXRefStream.WriteStream(aStream);
        }
        m_aEditBuffer.WriteNumberAsString(aXRefStream.GetSize());
 
        if (!m_aStartXRefs.empty())
        {
            // Write location of the previous cross-reference section.
            m_aEditBuffer.WriteOString("/Prev ");
            m_aEditBuffer.WriteNumberAsString(m_aStartXRefs.back());
        }
 
        // Root.
        m_aEditBuffer.WriteOString("/Root ");
        m_aEditBuffer.WriteNumberAsString(pRoot->GetObjectValue());
        m_aEditBuffer.WriteOString(" ");
        m_aEditBuffer.WriteNumberAsString(pRoot->GetGenerationValue());
        m_aEditBuffer.WriteOString(" R ");
 
        // Size.
        m_aEditBuffer.WriteOString("/Size ");
        m_aEditBuffer.WriteNumberAsString(m_aXRef.size());
 
        m_aEditBuffer.WriteOString("/Type/XRef/W[1 3 1]>>\nstream\n");
        aXRefStream.Seek(0);
        m_aEditBuffer.WriteStream(aXRefStream);
        m_aEditBuffer.WriteOString("\nendstream\nendobj\n\n");
    }
    else
    {
        // Write the xref table.
        m_aEditBuffer.WriteOString("xref\n");
        for (const auto& rXRef : m_aXRef)
        {
            size_t nObject = rXRef.first;
            size_t nOffset = rXRef.second.GetOffset();
            if (!rXRef.second.GetDirty())
                continue;
 
            m_aEditBuffer.WriteNumberAsString(nObject);
            m_aEditBuffer.WriteOString(" 1\n");
            OStringBuffer aBuffer = OString::number(static_cast<sal_Int32>(nOffset));
            while (aBuffer.getLength() < 10)
                aBuffer.insert(0, "0");
            if (nObject == 0)
                aBuffer.append(" 65535 f \n");
            else
                aBuffer.append(" 00000 n \n");
            m_aEditBuffer.WriteOString(aBuffer);
        }
 
        // Write the trailer.
        m_aEditBuffer.WriteOString("trailer\n<</Size ");
        m_aEditBuffer.WriteNumberAsString(m_aXRef.size());
        m_aEditBuffer.WriteOString("/Root ");
        m_aEditBuffer.WriteNumberAsString(pRoot->GetObjectValue());
        m_aEditBuffer.WriteOString(" ");
        m_aEditBuffer.WriteNumberAsString(pRoot->GetGenerationValue());
        m_aEditBuffer.WriteOString(" R\n");
        auto pInfo = dynamic_cast<PDFReferenceElement*>(m_pTrailer->Lookup("Info"_ostr));
        if (pInfo)
        {
            m_aEditBuffer.WriteOString("/Info ");
            m_aEditBuffer.WriteNumberAsString(pInfo->GetObjectValue());
            m_aEditBuffer.WriteOString(" ");
            m_aEditBuffer.WriteNumberAsString(pInfo->GetGenerationValue());
            m_aEditBuffer.WriteOString(" R\n");
        }
        auto pID = dynamic_cast<PDFArrayElement*>(m_pTrailer->Lookup("ID"_ostr));
        if (pID)
        {
            const std::vector<PDFElement*>& rElements = pID->GetElements();
            m_aEditBuffer.WriteOString("/ID [ <");
            for (size_t i = 0; i < rElements.size(); ++i)
            {
                auto pIDString = dynamic_cast<PDFHexStringElement*>(rElements[i]);
                if (!pIDString)
                    continue;
 
                m_aEditBuffer.WriteOString(pIDString->GetValue());
                if ((i + 1) < rElements.size())
                    m_aEditBuffer.WriteOString(">\n<");
            }
            m_aEditBuffer.WriteOString("> ]\n");
        }
 
        if (!m_aStartXRefs.empty())
        {
            // Write location of the previous cross-reference section.
            m_aEditBuffer.WriteOString("/Prev ");
            m_aEditBuffer.WriteNumberAsString(m_aStartXRefs.back());
        }
 
        m_aEditBuffer.WriteOString(">>\n");
    }
}
 
bool PDFDocument::Sign(svl::crypto::SigningContext& rSigningContext, const OUString& rDescription,
                       bool bAdES)
{
    m_aEditBuffer.Seek(STREAM_SEEK_TO_END);
    m_aEditBuffer.WriteOString("\n");
 
    sal_uInt64 nSignatureLastByteRangeOffset = 0;
    sal_Int64 nSignatureContentOffset = 0;
    sal_Int32 nSignatureId
        = WriteSignatureObject(rSigningContext, rDescription, bAdES, nSignatureLastByteRangeOffset,
                               nSignatureContentOffset);
    assert(nSignatureContentOffset > 0
           && "WriteSignatureObject guarantees a length for nSignatureContentOffset");
    tools::Rectangle aSignatureRectangle;
    sal_Int32 nAppearanceId = WriteAppearanceObject(aSignatureRectangle);
 
    std::vector<PDFObjectElement*> aPages = GetPages();
    if (aPages.empty())
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: found no pages");
        return false;
    }
 
    size_t nPage = 0;
    if (m_nSignaturePage < aPages.size())
    {
        nPage = m_nSignaturePage;
    }
    if (!aPages[nPage])
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: failed to find page #" << nPage);
        return false;
    }
 
    PDFObjectElement& rPage = *aPages[nPage];
    sal_Int32 nAnnotId = WriteAnnotObject(rPage, nSignatureId, nAppearanceId, aSignatureRectangle);
 
    if (!WritePageObject(rPage, nAnnotId))
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: failed to write the updated Page object");
        return false;
    }
 
    PDFReferenceElement* pRoot = nullptr;
    if (!WriteCatalogObject(nAnnotId, pRoot))
    {
        SAL_WARN("vcl.filter", "PDFDocument::Sign: failed to write the updated Catalog object");
        return false;
    }
 
    sal_uInt64 nXRefOffset = m_aEditBuffer.Tell();
    WriteXRef(nXRefOffset, pRoot);
 
    // Write startxref.
    m_aEditBuffer.WriteOString("startxref\n");
    m_aEditBuffer.WriteNumberAsString(nXRefOffset);
    m_aEditBuffer.WriteOString("\n%%EOF\n");
 
    // Finalize the signature, now that we know the total file size.
    // Calculate the length of the last byte range.
    sal_uInt64 nFileEnd = m_aEditBuffer.Tell();
    sal_Int64 nLastByteRangeLength
        = nFileEnd - (nSignatureContentOffset + MAX_SIGNATURE_CONTENT_LENGTH + 1);
    // Write the length to the buffer.
    m_aEditBuffer.Seek(nSignatureLastByteRangeOffset);
    OString aByteRangeBuffer = OString::number(nLastByteRangeLength) + " ]";
    m_aEditBuffer.WriteOString(aByteRangeBuffer);
 
    // Create the PKCS#7 object.
    if (rSigningContext.m_xCertificate)
    {
        css::uno::Sequence<sal_Int8> aDerEncoded = rSigningContext.m_xCertificate->getEncoded();
        if (!aDerEncoded.hasElements())
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: empty certificate");
            return false;
        }
    }
 
    m_aEditBuffer.Seek(0);
    sal_uInt64 nBufferSize1 = nSignatureContentOffset - 1;
    std::unique_ptr<char[]> aBuffer1(new char[nBufferSize1]);
    m_aEditBuffer.ReadBytes(aBuffer1.get(), nBufferSize1);
 
    m_aEditBuffer.Seek(nSignatureContentOffset + MAX_SIGNATURE_CONTENT_LENGTH + 1);
    sal_uInt64 nBufferSize2 = nLastByteRangeLength;
    std::unique_ptr<char[]> aBuffer2(new char[nBufferSize2]);
    m_aEditBuffer.ReadBytes(aBuffer2.get(), nBufferSize2);
 
    OStringBuffer aCMSHexBuffer;
    svl::crypto::Signing aSigning(rSigningContext);
    aSigning.AddDataRange(aBuffer1.get(), nBufferSize1);
    aSigning.AddDataRange(aBuffer2.get(), nBufferSize2);
    if (!aSigning.Sign(aCMSHexBuffer))
    {
        if (rSigningContext.m_xCertificate.is())
        {
            SAL_WARN("vcl.filter", "PDFDocument::Sign: PDFWriter::Sign() failed");
        }
        return false;
    }
 
    assert(aCMSHexBuffer.getLength() <= MAX_SIGNATURE_CONTENT_LENGTH);
 
    m_aEditBuffer.Seek(nSignatureContentOffset);
    m_aEditBuffer.WriteOString(aCMSHexBuffer);
 
    return true;
}
 
bool PDFDocument::Write(SvStream& rStream)
{
    m_aEditBuffer.Seek(0);
    rStream.WriteStream(m_aEditBuffer);
    return rStream.good();
}
 
bool PDFDocument::Tokenize(SvStream& rStream, TokenizeMode eMode,
                           std::vector<std::unique_ptr<PDFElement>>& rElements,
                           PDFObjectElement* pObjectElement)
{
    // Last seen object token.
    PDFObjectElement* pObject = pObjectElement;
    PDFNameElement* pObjectKey = nullptr;
    PDFObjectElement* pObjectStream = nullptr;
    bool bInXRef = false;
    // The next number will be an xref offset.
    bool bInStartXRef = false;
    // Dictionary depth, so we know when we're outside any dictionaries.
    int nDepth = 0;
    // Last seen array token that's outside any dictionaries.
    PDFArrayElement* pArray = nullptr;
    // If we're inside an obj/endobj pair.
    bool bInObject = false;
 
    while (true)
    {
        char ch;
        rStream.ReadChar(ch);
        if (rStream.eof())
            break;
 
        switch (ch)
        {
            case '%':
            {
                auto pComment = new PDFCommentElement(*this);
                rElements.push_back(std::unique_ptr<PDFElement>(pComment));
                rStream.SeekRel(-1);
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::Tokenize: PDFCommentElement::Read() failed");
                    return false;
                }
                if (eMode == TokenizeMode::EOF_TOKEN && !m_aEOFs.empty()
                    && m_aEOFs.back() == rStream.Tell())
                {
                    // Found EOF and partial parsing requested, we're done.
                    return true;
                }
                break;
            }
            case '<':
            {
                // Dictionary or hex string.
                rStream.ReadChar(ch);
                rStream.SeekRel(-2);
                if (ch == '<')
                {
                    rElements.push_back(std::unique_ptr<PDFElement>(new PDFDictionaryElement()));
                    ++nDepth;
                }
                else
                    rElements.push_back(std::unique_ptr<PDFElement>(new PDFHexStringElement));
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::Tokenize: PDFDictionaryElement::Read() failed");
                    return false;
                }
                break;
            }
            case '>':
            {
                rElements.push_back(std::unique_ptr<PDFElement>(new PDFEndDictionaryElement()));
                --nDepth;
                rStream.SeekRel(-1);
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::Tokenize: PDFEndDictionaryElement::Read() failed");
                    return false;
                }
                break;
            }
            case '[':
            {
                auto pArr = new PDFArrayElement(pObject);
                rElements.push_back(std::unique_ptr<PDFElement>(pArr));
                if (nDepth == 0)
                {
                    // The array is attached directly, inform the object.
                    pArray = pArr;
                    if (pObject)
                    {
                        pObject->SetArray(pArray);
                        pObject->SetArrayOffset(rStream.Tell());
                    }
                }
                ++nDepth;
                rStream.SeekRel(-1);
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter", "PDFDocument::Tokenize: PDFArrayElement::Read() failed");
                    return false;
                }
                break;
            }
            case ']':
            {
                rElements.push_back(std::unique_ptr<PDFElement>(new PDFEndArrayElement()));
                --nDepth;
                rStream.SeekRel(-1);
                if (nDepth == 0)
                {
                    if (pObject)
                    {
                        pObject->SetArrayLength(rStream.Tell() - pObject->GetArrayOffset());
                    }
                }
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::Tokenize: PDFEndArrayElement::Read() failed");
                    return false;
                }
                break;
            }
            case '/':
            {
                auto pNameElement = new PDFNameElement();
                rElements.push_back(std::unique_ptr<PDFElement>(pNameElement));
                rStream.SeekRel(-1);
                if (!pNameElement->Read(rStream))
                {
                    SAL_WARN("vcl.filter", "PDFDocument::Tokenize: PDFNameElement::Read() failed");
                    return false;
                }
 
                if (pObject && pObjectKey && pObjectKey->GetValue() == "Type"
                    && pNameElement->GetValue() == "ObjStm")
                    pObjectStream = pObject;
                else
                    pObjectKey = pNameElement;
 
                if (bInObject && !nDepth && pObject)
                {
                    // Name element inside an object, but outside a
                    // dictionary / array: remember it.
                    pObject->SetNameElement(pNameElement);
                }
 
                break;
            }
            case '(':
            {
                rElements.push_back(std::unique_ptr<PDFElement>(new PDFLiteralStringElement));
                rStream.SeekRel(-1);
                if (!rElements.back()->Read(rStream))
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::Tokenize: PDFLiteralStringElement::Read() failed");
                    return false;
                }
                break;
            }
            default:
            {
                if (rtl::isAsciiDigit(static_cast<unsigned char>(ch)) || ch == '-' || ch == '+'
                    || ch == '.')
                {
                    // Numbering object: an integer or a real.
                    auto pNumberElement = new PDFNumberElement();
                    rElements.push_back(std::unique_ptr<PDFElement>(pNumberElement));
                    rStream.SeekRel(-1);
                    if (!pNumberElement->Read(rStream))
                    {
                        SAL_WARN("vcl.filter",
                                 "PDFDocument::Tokenize: PDFNumberElement::Read() failed");
                        return false;
                    }
                    if (bInStartXRef)
                    {
                        bInStartXRef = false;
                        m_aStartXRefs.push_back(pNumberElement->GetValue());
 
                        auto it = m_aOffsetObjects.find(pNumberElement->GetValue());
                        if (it != m_aOffsetObjects.end())
                            m_pXRefStream = it->second;
                    }
                    else if (bInObject && !nDepth && pObject)
                        // Number element inside an object, but outside a
                        // dictionary / array: remember it.
                        pObject->SetNumberElement(pNumberElement);
                }
                else if (rtl::isAsciiAlpha(static_cast<unsigned char>(ch)))
                {
                    // Possible keyword, like "obj".
                    rStream.SeekRel(-1);
                    OString aKeyword = ReadKeyword(rStream);
 
                    bool bObj = aKeyword == "obj";
                    if (bObj || aKeyword == "R")
                    {
                        size_t nElements = rElements.size();
                        if (nElements < 2)
                        {
                            SAL_WARN("vcl.filter", "PDFDocument::Tokenize: expected at least two "
                                                   "tokens before 'obj' or 'R' keyword");
                            return false;
                        }
 
                        auto pObjectNumber
                            = dynamic_cast<PDFNumberElement*>(rElements[nElements - 2].get());
                        auto pGenerationNumber
                            = dynamic_cast<PDFNumberElement*>(rElements[nElements - 1].get());
                        if (!pObjectNumber || !pGenerationNumber)
                        {
                            SAL_WARN("vcl.filter", "PDFDocument::Tokenize: missing object or "
                                                   "generation number before 'obj' or 'R' keyword");
                            return false;
                        }
 
                        if (bObj)
                        {
                            pObject = new PDFObjectElement(*this, pObjectNumber->GetValue(),
                                                           pGenerationNumber->GetValue());
                            rElements.push_back(std::unique_ptr<PDFElement>(pObject));
                            m_aOffsetObjects[pObjectNumber->GetLocation()] = pObject;
                            m_aIDObjects[pObjectNumber->GetValue()] = pObject;
                            bInObject = true;
                        }
                        else
                        {
                            auto pReference = new PDFReferenceElement(*this, *pObjectNumber,
                                                                      *pGenerationNumber);
                            rElements.push_back(std::unique_ptr<PDFElement>(pReference));
                            if (bInObject && nDepth > 0 && pObject)
                                // Inform the object about a new in-dictionary reference.
                                pObject->AddDictionaryReference(pReference);
                        }
                        if (!rElements.back()->Read(rStream))
                        {
                            SAL_WARN("vcl.filter",
                                     "PDFDocument::Tokenize: PDFElement::Read() failed");
                            return false;
                        }
                    }
                    else if (aKeyword == "stream")
                    {
                        // Look up the length of the stream from the parent object's dictionary.
                        size_t nLength = 0;
                        for (size_t nElement = 0; nElement < rElements.size(); ++nElement)
                        {
                            // Iterate in reverse order.
                            size_t nIndex = rElements.size() - nElement - 1;
                            PDFElement* pElement = rElements[nIndex].get();
                            auto pObj = dynamic_cast<PDFObjectElement*>(pElement);
                            if (!pObj)
                                continue;
 
                            PDFElement* pLookup = pObj->Lookup("Length"_ostr);
                            auto pReference = dynamic_cast<PDFReferenceElement*>(pLookup);
                            if (pReference)
                            {
                                // Length is provided as a reference.
                                nLength = pReference->LookupNumber(rStream);
                                break;
                            }
 
                            auto pNumber = dynamic_cast<PDFNumberElement*>(pLookup);
                            if (pNumber)
                            {
                                // Length is provided directly.
                                nLength = pNumber->GetValue();
                                break;
                            }
 
                            SAL_WARN(
                                "vcl.filter",
                                "PDFDocument::Tokenize: found no Length key for stream keyword");
                            return false;
                        }
 
                        PDFDocument::SkipLineBreaks(rStream);
                        auto pStreamElement = new PDFStreamElement(nLength);
                        if (pObject)
                            pObject->SetStream(pStreamElement);
                        rElements.push_back(std::unique_ptr<PDFElement>(pStreamElement));
                        if (!rElements.back()->Read(rStream))
                        {
                            SAL_WARN("vcl.filter",
                                     "PDFDocument::Tokenize: PDFStreamElement::Read() failed");
                            return false;
                        }
                    }
                    else if (aKeyword == "endstream")
                    {
                        rElements.push_back(std::unique_ptr<PDFElement>(new PDFEndStreamElement));
                        if (!rElements.back()->Read(rStream))
                        {
                            SAL_WARN("vcl.filter",
                                     "PDFDocument::Tokenize: PDFEndStreamElement::Read() failed");
                            return false;
                        }
                    }
                    else if (aKeyword == "endobj")
                    {
                        rElements.push_back(std::unique_ptr<PDFElement>(new PDFEndObjectElement));
                        if (!rElements.back()->Read(rStream))
                        {
                            SAL_WARN("vcl.filter",
                                     "PDFDocument::Tokenize: PDFEndObjectElement::Read() failed");
                            return false;
                        }
                        if (eMode == TokenizeMode::END_OF_OBJECT)
                        {
                            // Found endobj and only object parsing was requested, we're done.
                            return true;
                        }
 
                        if (pObjectStream)
                        {
                            // We're at the end of an object stream, parse the stored objects.
                            pObjectStream->ParseStoredObjects();
                            pObjectStream = nullptr;
                            pObjectKey = nullptr;
                        }
                        bInObject = false;
                    }
                    else if (aKeyword == "true" || aKeyword == "false")
                        rElements.push_back(std::unique_ptr<PDFElement>(
                            new PDFBooleanElement(aKeyword.toBoolean())));
                    else if (aKeyword == "null")
                        rElements.push_back(std::unique_ptr<PDFElement>(new PDFNullElement));
                    else if (aKeyword == "xref")
                        // Allow 'f' and 'n' keywords.
                        bInXRef = true;
                    else if (bInXRef && (aKeyword == "f" || aKeyword == "n"))
                    {
                    }
                    else if (aKeyword == "trailer")
                    {
                        auto pTrailer = new PDFTrailerElement(*this);
 
                        // Make it possible to find this trailer later by offset.
                        pTrailer->Read(rStream);
                        m_aOffsetTrailers[pTrailer->GetLocation()] = pTrailer;
 
                        // When reading till the first EOF token only, remember
                        // just the first trailer token.
                        if (eMode != TokenizeMode::EOF_TOKEN || !m_pTrailer)
                            m_pTrailer = pTrailer;
                        rElements.push_back(std::unique_ptr<PDFElement>(pTrailer));
                    }
                    else if (aKeyword == "startxref")
                    {
                        bInStartXRef = true;
                    }
                    else
                    {
                        SAL_WARN("vcl.filter", "PDFDocument::Tokenize: unexpected '"
                                                   << aKeyword << "' keyword at byte position "
                                                   << rStream.Tell());
                        return false;
                    }
                }
                else
                {
                    auto uChar = static_cast<unsigned char>(ch);
                    // Be more lenient and allow unexpected null char
                    if (!rtl::isAsciiWhiteSpace(uChar) && uChar != 0)
                    {
                        SAL_WARN("vcl.filter",
                                 "PDFDocument::Tokenize: unexpected character with code "
                                     << sal_Int32(ch) << " at byte position " << rStream.Tell());
                        return false;
                    }
                    SAL_WARN_IF(uChar == 0, "vcl.filter",
                                "PDFDocument::Tokenize: unexpected null character at "
                                    << rStream.Tell() << " - ignoring");
                }
                break;
            }
        }
    }
 
    return true;
}
 
void PDFDocument::SetIDObject(size_t nID, PDFObjectElement* pObject)
{
    m_aIDObjects[nID] = pObject;
}
 
bool PDFDocument::ReadWithPossibleFixup(SvStream& rStream)
{
    if (Read(rStream))
        return true;
 
    // Read failed, try a roundtrip through pdfium and then retry.
    rStream.Seek(0);
    SvMemoryStream aStandardizedStream;
    vcl::pdf::convertToHighestSupported(rStream, aStandardizedStream);
    return Read(aStandardizedStream);
}
 
bool PDFDocument::Read(SvStream& rStream)
{
    // Check file magic.
    std::vector<sal_Int8> aHeader(5);
    rStream.Seek(0);
    rStream.ReadBytes(aHeader.data(), aHeader.size());
    if (aHeader[0] != '%' || aHeader[1] != 'P' || aHeader[2] != 'D' || aHeader[3] != 'F'
        || aHeader[4] != '-')
    {
        SAL_WARN("vcl.filter", "PDFDocument::Read: header mismatch");
        return false;
    }
 
    // Allow later editing of the contents in-memory.
    rStream.Seek(0);
    m_aEditBuffer.WriteStream(rStream);
 
    // clear out key items that may have been filled with info from any previous read attempt
    m_aOffsetTrailers.clear();
    m_aTrailerOffsets.clear();
    m_pTrailer = nullptr;
    m_pXRefStream = nullptr;
 
    // Look up the offset of the xref table.
    size_t nStartXRef = FindStartXRef(rStream);
    SAL_INFO("vcl.filter", "PDFDocument::Read: nStartXRef is " << nStartXRef);
    if (nStartXRef == 0)
    {
        SAL_WARN("vcl.filter", "PDFDocument::Read: found no xref start offset");
        return false;
    }
    while (true)
    {
        rStream.Seek(nStartXRef);
        OString aKeyword = ReadKeyword(rStream);
        if (aKeyword.isEmpty())
            ReadXRefStream(rStream);
 
        else
        {
            if (aKeyword != "xref")
            {
                SAL_WARN("vcl.filter", "PDFDocument::Read: xref is not the first keyword");
                return false;
            }
            ReadXRef(rStream);
            if (!Tokenize(rStream, TokenizeMode::EOF_TOKEN, m_aElements, nullptr))
            {
                SAL_WARN("vcl.filter", "PDFDocument::Read: failed to tokenizer trailer after xref");
                return false;
            }
        }
 
        PDFNumberElement* pPrev = nullptr;
        if (m_pTrailer)
        {
            pPrev = dynamic_cast<PDFNumberElement*>(m_pTrailer->Lookup("Prev"_ostr));
 
            // Remember the offset of this trailer in the correct order. It's
            // possible that newer trailers don't have a larger offset.
            m_aTrailerOffsets.push_back(m_pTrailer->GetLocation());
        }
        else if (m_pXRefStream)
            pPrev = dynamic_cast<PDFNumberElement*>(m_pXRefStream->Lookup("Prev"_ostr));
        if (pPrev)
            nStartXRef = pPrev->GetValue();
 
        // Reset state, except the edit buffer.
        m_aOffsetTrailers.clear(); // contents are lifecycle managed by m_aElements
        m_aElements.clear();
        m_aOffsetObjects.clear();
        m_aIDObjects.clear();
        m_aStartXRefs.clear();
        m_aEOFs.clear();
        m_pTrailer = nullptr;
        m_pXRefStream = nullptr;
        if (!pPrev)
            break;
    }
 
    // Then we can tokenize the stream.
    rStream.Seek(0);
    return Tokenize(rStream, TokenizeMode::END_OF_STREAM, m_aElements, nullptr);
}
 
OString PDFDocument::ReadKeyword(SvStream& rStream)
{
    OStringBuffer aBuf;
    char ch;
    rStream.ReadChar(ch);
    if (rStream.eof())
        return {};
    while (rtl::isAsciiAlpha(static_cast<unsigned char>(ch)))
    {
        aBuf.append(ch);
        rStream.ReadChar(ch);
        if (rStream.eof())
            return aBuf.toString();
    }
    rStream.SeekRel(-1);
    return aBuf.toString();
}
 
size_t PDFDocument::FindStartXRef(SvStream& rStream)
{
    // Find the "startxref" token, somewhere near the end of the document.
    std::vector<char> aBuf(1024);
    rStream.Seek(STREAM_SEEK_TO_END);
    if (rStream.Tell() > aBuf.size())
        rStream.SeekRel(static_cast<sal_Int64>(-1) * aBuf.size());
    else
        // The document is really short, then just read it from the start.
        rStream.Seek(0);
    size_t nBeforePeek = rStream.Tell();
    size_t nSize = rStream.ReadBytes(aBuf.data(), aBuf.size());
    rStream.Seek(nBeforePeek);
    if (nSize != aBuf.size())
        aBuf.resize(nSize);
    OString aPrefix("startxref"_ostr);
    // Find the last startxref at the end of the document.
    auto itLastValid = aBuf.end();
    auto it = aBuf.begin();
    while (true)
    {
        it = std::search(it, aBuf.end(), aPrefix.getStr(), aPrefix.getStr() + aPrefix.getLength());
        if (it == aBuf.end())
            break;
 
        itLastValid = it;
        ++it;
    }
    if (itLastValid == aBuf.end())
    {
        SAL_WARN("vcl.filter", "PDFDocument::FindStartXRef: found no startxref");
        return 0;
    }
 
    rStream.SeekRel(itLastValid - aBuf.begin() + aPrefix.getLength());
    if (rStream.eof())
    {
        SAL_WARN("vcl.filter",
                 "PDFDocument::FindStartXRef: unexpected end of stream after startxref");
        return 0;
    }
 
    PDFDocument::SkipWhitespace(rStream);
    PDFNumberElement aNumber;
    if (!aNumber.Read(rStream))
        return 0;
    return aNumber.GetValue();
}
 
void PDFDocument::ReadXRefStream(SvStream& rStream)
{
    // Look up the stream length in the object dictionary.
    if (!Tokenize(rStream, TokenizeMode::END_OF_OBJECT, m_aElements, nullptr))
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: failed to read object");
        return;
    }
 
    if (m_aElements.empty())
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: no tokens found");
        return;
    }
 
    PDFObjectElement* pObject = nullptr;
    for (const auto& pElement : m_aElements)
    {
        if (auto pObj = dynamic_cast<PDFObjectElement*>(pElement.get()))
        {
            pObject = pObj;
            break;
        }
    }
    if (!pObject)
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: no object token found");
        return;
    }
 
    // So that the Prev key can be looked up later.
    m_pXRefStream = pObject;
 
    PDFElement* pLookup = pObject->Lookup("Length"_ostr);
    auto pNumber = dynamic_cast<PDFNumberElement*>(pLookup);
    if (!pNumber)
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: stream length is not provided");
        return;
    }
    sal_uInt64 nLength = pNumber->GetValue();
 
    // Look up the stream offset.
    PDFStreamElement* pStream = nullptr;
    for (const auto& pElement : m_aElements)
    {
        if (auto pS = dynamic_cast<PDFStreamElement*>(pElement.get()))
        {
            pStream = pS;
            break;
        }
    }
    if (!pStream)
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: no stream token found");
        return;
    }
 
    // Read and decompress it.
    rStream.Seek(pStream->GetOffset());
    std::vector<char> aBuf(nLength);
    rStream.ReadBytes(aBuf.data(), aBuf.size());
 
    auto pFilter = dynamic_cast<PDFNameElement*>(pObject->Lookup("Filter"_ostr));
    if (!pFilter)
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: no Filter found");
        return;
    }
 
    if (pFilter->GetValue() != "FlateDecode")
    {
        SAL_WARN("vcl.filter",
                 "PDFDocument::ReadXRefStream: unexpected filter: " << pFilter->GetValue());
        return;
    }
 
    int nColumns = 1;
    int nPredictor = 1;
    if (auto pDecodeParams
        = dynamic_cast<PDFDictionaryElement*>(pObject->Lookup("DecodeParms"_ostr)))
    {
        const std::map<OString, PDFElement*>& rItems = pDecodeParams->GetItems();
        auto it = rItems.find("Columns"_ostr);
        if (it != rItems.end())
            if (auto pColumns = dynamic_cast<PDFNumberElement*>(it->second))
                nColumns = pColumns->GetValue();
        it = rItems.find("Predictor"_ostr);
        if (it != rItems.end())
            if (auto pPredictor = dynamic_cast<PDFNumberElement*>(it->second))
                nPredictor = pPredictor->GetValue();
    }
 
    SvMemoryStream aSource(aBuf.data(), aBuf.size(), StreamMode::READ);
    SvMemoryStream aStream;
    ZCodec aZCodec;
    aZCodec.BeginCompression();
    aZCodec.Decompress(aSource, aStream);
    if (!aZCodec.EndCompression())
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: decompression failed");
        return;
    }
 
    // Look up the first and the last entry we need to read.
    auto pIndex = dynamic_cast<PDFArrayElement*>(pObject->Lookup("Index"_ostr));
    std::vector<size_t> aFirstObjects;
    std::vector<size_t> aNumberOfObjects;
    if (!pIndex)
    {
        auto pSize = dynamic_cast<PDFNumberElement*>(pObject->Lookup("Size"_ostr));
        if (pSize)
        {
            aFirstObjects.push_back(0);
            aNumberOfObjects.push_back(pSize->GetValue());
        }
        else
        {
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: Index and Size not found");
            return;
        }
    }
    else
    {
        const std::vector<PDFElement*>& rIndexElements = pIndex->GetElements();
        size_t nFirstObject = 0;
        for (size_t i = 0; i < rIndexElements.size(); ++i)
        {
            if (i % 2 == 0)
            {
                auto pFirstObject = dynamic_cast<PDFNumberElement*>(rIndexElements[i]);
                if (!pFirstObject)
                {
                    SAL_WARN("vcl.filter",
                             "PDFDocument::ReadXRefStream: Index has no first object");
                    return;
                }
                nFirstObject = pFirstObject->GetValue();
                continue;
            }
 
            auto pNumberOfObjects = dynamic_cast<PDFNumberElement*>(rIndexElements[i]);
            if (!pNumberOfObjects)
            {
                SAL_WARN("vcl.filter",
                         "PDFDocument::ReadXRefStream: Index has no number of objects");
                return;
            }
            aFirstObjects.push_back(nFirstObject);
            aNumberOfObjects.push_back(pNumberOfObjects->GetValue());
        }
    }
 
    // Look up the format of a single entry.
    const int nWSize = 3;
    auto pW = dynamic_cast<PDFArrayElement*>(pObject->Lookup("W"_ostr));
    if (!pW || pW->GetElements().size() < nWSize)
    {
        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: W not found or has < 3 elements");
        return;
    }
    int aW[nWSize];
    // First character is the (kind of) repeated predictor.
    int nLineLength = 1;
    for (size_t i = 0; i < nWSize; ++i)
    {
        auto pI = dynamic_cast<PDFNumberElement*>(pW->GetElements()[i]);
        if (!pI)
        {
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: W contains non-number");
            return;
        }
        aW[i] = pI->GetValue();
        nLineLength += aW[i];
    }
 
    if (nPredictor > 1 && nLineLength - 1 != nColumns)
    {
        SAL_WARN("vcl.filter",
                 "PDFDocument::ReadXRefStream: /DecodeParms/Columns is inconsistent with /W");
        return;
    }
 
    aStream.Seek(0);
    for (size_t nSubSection = 0; nSubSection < aFirstObjects.size(); ++nSubSection)
    {
        size_t nFirstObject = aFirstObjects[nSubSection];
        size_t nNumberOfObjects = aNumberOfObjects[nSubSection];
 
        // This is the line as read from the stream.
        std::vector<unsigned char> aOrigLine(nLineLength);
        // This is the line as it appears after tweaking according to nPredictor.
        std::vector<unsigned char> aFilteredLine(nLineLength);
        for (size_t nEntry = 0; nEntry < nNumberOfObjects; ++nEntry)
        {
            size_t nIndex = nFirstObject + nEntry;
 
            aStream.ReadBytes(aOrigLine.data(), aOrigLine.size());
            if (nPredictor > 1 && aOrigLine[0] + 10 != nPredictor)
            {
                SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: in-stream predictor is "
                                       "inconsistent with /DecodeParms/Predictor for object #"
                                           << nIndex);
                return;
            }
 
            for (int i = 0; i < nLineLength; ++i)
            {
                switch (nPredictor)
                {
                    case 1:
                        // No prediction.
                        break;
                    case 12:
                        // PNG prediction: up (on all rows).
                        aFilteredLine[i] = aFilteredLine[i] + aOrigLine[i];
                        break;
                    default:
                        SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: unexpected predictor: "
                                                   << nPredictor);
                        return;
                }
            }
 
            // First character is already handled above.
            int nPos = 1;
            size_t nType = 0;
            // Start of the current field in the stream data.
            int nOffset = nPos;
            for (; nPos < nOffset + aW[0]; ++nPos)
            {
                unsigned char nCh = aFilteredLine[nPos];
                nType = (nType << 8) + nCh;
            }
 
            // Start of the object in the file stream.
            size_t nStreamOffset = 0;
            nOffset = nPos;
            for (; nPos < nOffset + aW[1]; ++nPos)
            {
                unsigned char nCh = aFilteredLine[nPos];
                nStreamOffset = (nStreamOffset << 8) + nCh;
            }
 
            // Generation number of the object.
            size_t nGenerationNumber = 0;
            nOffset = nPos;
            for (; nPos < nOffset + aW[2]; ++nPos)
            {
                unsigned char nCh = aFilteredLine[nPos];
                nGenerationNumber = (nGenerationNumber << 8) + nCh;
            }
 
            // Ignore invalid nType.
            if (nType <= 2)
            {
                if (m_aXRef.find(nIndex) == m_aXRef.end())
                {
                    XRefEntry aEntry;
                    switch (nType)
                    {
                        case 0:
                            aEntry.SetType(XRefEntryType::FREE);
                            break;
                        case 1:
                            aEntry.SetType(XRefEntryType::NOT_COMPRESSED);
                            break;
                        case 2:
                            aEntry.SetType(XRefEntryType::COMPRESSED);
                            break;
                    }
                    aEntry.SetOffset(nStreamOffset);
                    m_aXRef[nIndex] = aEntry;
                }
            }
        }
    }
}
 
void PDFDocument::ReadXRef(SvStream& rStream)
{
    PDFDocument::SkipWhitespace(rStream);
 
    while (true)
    {
        PDFNumberElement aFirstObject;
        if (!aFirstObject.Read(rStream))
        {
            // Next token is not a number, it'll be the trailer.
            return;
        }
 
        if (aFirstObject.GetValue() < 0)
        {
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: expected first object number >= 0");
            return;
        }
 
        PDFDocument::SkipWhitespace(rStream);
        PDFNumberElement aNumberOfEntries;
        if (!aNumberOfEntries.Read(rStream))
        {
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: failed to read number of entries");
            return;
        }
 
        if (aNumberOfEntries.GetValue() < 0)
        {
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: expected zero or more entries");
            return;
        }
 
        size_t nSize = aNumberOfEntries.GetValue();
        for (size_t nEntry = 0; nEntry < nSize; ++nEntry)
        {
            size_t nIndex = aFirstObject.GetValue() + nEntry;
            PDFDocument::SkipWhitespace(rStream);
            PDFNumberElement aOffset;
            if (!aOffset.Read(rStream))
            {
                SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: failed to read offset");
                return;
            }
 
            PDFDocument::SkipWhitespace(rStream);
            PDFNumberElement aGenerationNumber;
            if (!aGenerationNumber.Read(rStream))
            {
                SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: failed to read generation number");
                return;
            }
 
            PDFDocument::SkipWhitespace(rStream);
            OString aKeyword = ReadKeyword(rStream);
            if (aKeyword != "f" && aKeyword != "n")
            {
                SAL_WARN("vcl.filter", "PDFDocument::ReadXRef: unexpected keyword");
                return;
            }
            // xrefs are read in reverse order, so never update an existing
            // offset with an older one.
            if (m_aXRef.find(nIndex) == m_aXRef.end())
            {
                XRefEntry aEntry;
                aEntry.SetOffset(aOffset.GetValue());
                // Initially only the first entry is dirty.
                if (nIndex == 0)
                    aEntry.SetDirty(true);
                m_aXRef[nIndex] = aEntry;
            }
            PDFDocument::SkipWhitespace(rStream);
        }
    }
}
 
void PDFDocument::SkipWhitespace(SvStream& rStream)
{
    char ch = 0;
 
    while (true)
    {
        rStream.ReadChar(ch);
        if (rStream.eof())
            break;
 
        if (!rtl::isAsciiWhiteSpace(static_cast<unsigned char>(ch)))
        {
            rStream.SeekRel(-1);
            return;
        }
    }
}
 
void PDFDocument::SkipLineBreaks(SvStream& rStream)
{
    char ch = 0;
 
    while (true)
    {
        rStream.ReadChar(ch);
        if (rStream.eof())
            break;
 
        if (ch != '\n' && ch != '\r')
        {
            rStream.SeekRel(-1);
            return;
        }
    }
}
 
size_t PDFDocument::GetObjectOffset(size_t nIndex) const
{
    auto it = m_aXRef.find(nIndex);
    if (it == m_aXRef.end() || it->second.GetType() == XRefEntryType::COMPRESSED)
    {
        SAL_WARN("vcl.filter", "PDFDocument::GetObjectOffset: wanted to look up index #"
                                   << nIndex << ", but failed");
        return 0;
    }
 
    return it->second.GetOffset();
}
 
const std::vector<std::unique_ptr<PDFElement>>& PDFDocument::GetElements() const
{
    return m_aElements;
}
 
/// Visits the page tree recursively, looking for page objects.
static void visitPages(PDFObjectElement* pPages, std::vector<PDFObjectElement*>& rRet)
{
    auto pKidsRef = pPages->Lookup("Kids"_ostr);
    auto pKids = dynamic_cast<PDFArrayElement*>(pKidsRef);
    if (!pKids)
    {
        auto pRefKids = dynamic_cast<PDFReferenceElement*>(pKidsRef);
        if (!pRefKids)
        {
            SAL_WARN("vcl.filter", "visitPages: pages has no kids");
            return;
        }
        auto pObjWithKids = pRefKids->LookupObject();
        if (!pObjWithKids)
        {
            SAL_WARN("vcl.filter", "visitPages: pages has no kids");
            return;
        }
 
        pKids = pObjWithKids->GetArray();
    }
 
    if (!pKids)
    {
        SAL_WARN("vcl.filter", "visitPages: pages has no kids");
        return;
    }
 
    pPages->setVisiting(true);
 
    for (const auto& pKid : pKids->GetElements())
    {
        auto pReference = dynamic_cast<PDFReferenceElement*>(pKid);
        if (!pReference)
            continue;
 
        PDFObjectElement* pKidObject = pReference->LookupObject();
        if (!pKidObject)
            continue;
 
        // detect if visiting reenters itself
        if (pKidObject->alreadyVisiting())
        {
            SAL_WARN("vcl.filter", "visitPages: loop in hierarchy");
            continue;
        }
 
        auto pName = dynamic_cast<PDFNameElement*>(pKidObject->Lookup("Type"_ostr));
        if (pName && pName->GetValue() == "Pages")
            // Pages inside pages: recurse.
            visitPages(pKidObject, rRet);
        else
            // Found an actual page.
            rRet.push_back(pKidObject);
    }
 
    pPages->setVisiting(false);
}
 
PDFObjectElement* PDFDocument::GetCatalog()
{
    PDFReferenceElement* pRoot = nullptr;
 
    PDFTrailerElement* pTrailer = nullptr;
    if (!m_aTrailerOffsets.empty())
    {
        // Get access to the latest trailer, and work with the keys of that
        // one.
        auto it = m_aOffsetTrailers.find(m_aTrailerOffsets[0]);
        if (it != m_aOffsetTrailers.end())
            pTrailer = it->second;
    }
 
    if (pTrailer)
        pRoot = dynamic_cast<PDFReferenceElement*>(pTrailer->Lookup("Root"_ostr));
    else if (m_pXRefStream)
        pRoot = dynamic_cast<PDFReferenceElement*>(m_pXRefStream->Lookup("Root"_ostr));
 
    if (!pRoot)
    {
        SAL_WARN("vcl.filter", "PDFDocument::GetCatalog: trailer has no Root key");
        return nullptr;
    }
 
    return pRoot->LookupObject();
}
 
std::vector<PDFObjectElement*> PDFDocument::GetPages()
{
    std::vector<PDFObjectElement*> aRet;
 
    PDFObjectElement* pCatalog = GetCatalog();
    if (!pCatalog)
    {
        SAL_WARN("vcl.filter", "PDFDocument::GetPages: trailer has no catalog");
        return aRet;
    }
 
    PDFObjectElement* pPages = pCatalog->LookupObject("Pages"_ostr);
    if (!pPages)
    {
        SAL_WARN("vcl.filter", "PDFDocument::GetPages: catalog (obj " << pCatalog->GetObjectValue()
                                                                      << ") has no pages");
        return aRet;
    }
 
    visitPages(pPages, aRet);
 
    return aRet;
}
 
void PDFDocument::PushBackEOF(size_t nOffset) { m_aEOFs.push_back(nOffset); }
 
std::vector<PDFObjectElement*> PDFDocument::GetSignatureWidgets()
{
    std::vector<PDFObjectElement*> aRet;
 
    std::vector<PDFObjectElement*> aPages = GetPages();
 
    for (const auto& pPage : aPages)
    {
        if (!pPage)
            continue;
 
        PDFElement* pAnnotsElement = pPage->Lookup("Annots"_ostr);
        auto pAnnots = dynamic_cast<PDFArrayElement*>(pAnnotsElement);
        if (!pAnnots)
        {
            // Annots is not an array, see if it's a reference to an object
            // with a direct array.
            auto pAnnotsRef = dynamic_cast<PDFReferenceElement*>(pAnnotsElement);
            if (pAnnotsRef)
            {
                if (PDFObjectElement* pAnnotsObject = pAnnotsRef->LookupObject())
                {
                    pAnnots = pAnnotsObject->GetArray();
                }
            }
        }
 
        if (!pAnnots)
            continue;
 
        for (const auto& pAnnot : pAnnots->GetElements())
        {
            auto pReference = dynamic_cast<PDFReferenceElement*>(pAnnot);
            if (!pReference)
                continue;
 
            PDFObjectElement* pAnnotObject = pReference->LookupObject();
            if (!pAnnotObject)
                continue;
 
            auto pFT = dynamic_cast<PDFNameElement*>(pAnnotObject->Lookup("FT"_ostr));
            if (!pFT || pFT->GetValue() != "Sig")
                continue;
 
            aRet.push_back(pAnnotObject);
        }
    }
 
    return aRet;
}
 
std::vector<unsigned char> PDFDocument::DecodeHexString(PDFHexStringElement const* pElement)
{
    return svl::crypto::DecodeHexString(pElement->GetValue());
}
 
OUString PDFDocument::DecodeHexStringUTF16BE(PDFHexStringElement const& rElement)
{
    std::vector<unsigned char> const encoded(DecodeHexString(&rElement));
    // Text strings can be PDF-DocEncoding or UTF-16BE with mandatory BOM;
    // only the latter supported is here
    if (encoded.size() < 2 || encoded[0] != 0xFE || encoded[1] != 0xFF || (encoded.size() & 1) != 0)
    {
        return {};
    }
    OUStringBuffer buf(encoded.size() - 2);
    for (size_t i = 2; i < encoded.size(); i += 2)
    {
        buf.append(sal_Unicode((static_cast<sal_uInt16>(encoded[i]) << 8) | encoded[i + 1]));
    }
    return buf.makeStringAndClear();
}
 
PDFCommentElement::PDFCommentElement(PDFDocument& rDoc)
    : m_rDoc(rDoc)
{
}
 
bool PDFCommentElement::Read(SvStream& rStream)
{
    // Read from (including) the % char till (excluding) the end of the line/stream.
    OStringBuffer aBuf;
    char ch;
    rStream.ReadChar(ch);
    while (true)
    {
        if (ch == '\n' || ch == '\r' || rStream.eof())
        {
            m_aComment = aBuf.makeStringAndClear();
 
            if (m_aComment.startsWith("%%EOF"))
            {
                sal_uInt64 nPos = rStream.Tell();
                if (ch == '\r')
                {
                    rStream.ReadChar(ch);
                    rStream.SeekRel(-1);
                    // If the comment ends with a \r\n, count the \n as well to match Adobe Acrobat
                    // behavior.
                    if (ch == '\n')
                    {
                        nPos += 1;
                    }
                }
                m_rDoc.PushBackEOF(nPos);
            }
 
            SAL_INFO("vcl.filter", "PDFCommentElement::Read: m_aComment is '" << m_aComment << "'");
            return true;
        }
        aBuf.append(ch);
        rStream.ReadChar(ch);
    }
 
    return false;
}
 
PDFNumberElement::PDFNumberElement() = default;
 
bool PDFNumberElement::Read(SvStream& rStream)
{
    OStringBuffer aBuf;
    m_nOffset = rStream.Tell();
    char ch;
    rStream.ReadChar(ch);
    if (rStream.eof())
    {
        return false;
    }
    if (!rtl::isAsciiDigit(static_cast<unsigned char>(ch)) && ch != '-' && ch != '+' && ch != '.')
    {
        rStream.SeekRel(-1);
        return false;
    }
    while (!rStream.eof())
    {
        if (!rtl::isAsciiDigit(static_cast<unsigned char>(ch)) && ch != '-' && ch != '+'
            && ch != '.')
        {
            rStream.SeekRel(-1);
            m_nLength = rStream.Tell() - m_nOffset;
            m_fValue = o3tl::toDouble(aBuf);
            aBuf.setLength(0);
            SAL_INFO("vcl.filter", "PDFNumberElement::Read: m_fValue is '" << m_fValue << "'");
            return true;
        }
        aBuf.append(ch);
        rStream.ReadChar(ch);
    }
 
    return false;
}
 
sal_uInt64 PDFNumberElement::GetLocation() const { return m_nOffset; }
 
sal_uInt64 PDFNumberElement::GetLength() const { return m_nLength; }
 
bool PDFBooleanElement::Read(SvStream& /*rStream*/) { return true; }
 
bool PDFNullElement::Read(SvStream& /*rStream*/) { return true; }
 
bool PDFHexStringElement::Read(SvStream& rStream)
{
    char ch;
    rStream.ReadChar(ch);
    if (ch != '<')
    {
        SAL_INFO("vcl.filter", "PDFHexStringElement::Read: expected '<' as first character");
        return false;
    }
    rStream.ReadChar(ch);
 
    OStringBuffer aBuf;
    while (!rStream.eof())
    {
        if (ch == '>')
        {
            m_aValue = aBuf.makeStringAndClear();
            SAL_INFO("vcl.filter",
                     "PDFHexStringElement::Read: m_aValue length is " << m_aValue.getLength());
            return true;
        }
        aBuf.append(ch);
        rStream.ReadChar(ch);
    }
 
    return false;
}
 
const OString& PDFHexStringElement::GetValue() const { return m_aValue; }
 
bool PDFLiteralStringElement::Read(SvStream& rStream)
{
    char nPrevCh = 0;
    char ch = 0;
    rStream.ReadChar(ch);
    if (ch != '(')
    {
        SAL_INFO("vcl.filter", "PDFHexStringElement::Read: expected '(' as first character");
        return false;
    }
    nPrevCh = ch;
    rStream.ReadChar(ch);
 
    // Start with 1 nesting level as we read a '(' above already.
    int nDepth = 1;
    OStringBuffer aBuf;
    while (!rStream.eof())
    {
        if (ch == '(' && nPrevCh != '\\')
            ++nDepth;
 
        if (ch == ')' && nPrevCh != '\\')
            --nDepth;
 
        if (nDepth == 0)
        {
            // ')' of the outermost '(' is reached.
            m_aValue = aBuf.makeStringAndClear();
            SAL_INFO("vcl.filter",
                     "PDFLiteralStringElement::Read: m_aValue is '" << m_aValue << "'");
            return true;
        }
        aBuf.append(ch);
        nPrevCh = ch;
        rStream.ReadChar(ch);
    }
 
    return false;
}
 
const OString& PDFLiteralStringElement::GetValue() const { return m_aValue; }
 
PDFTrailerElement::PDFTrailerElement(PDFDocument& rDoc)
    : m_rDoc(rDoc)
    , m_pDictionaryElement(nullptr)
{
}
 
bool PDFTrailerElement::Read(SvStream& rStream)
{
    m_nOffset = rStream.Tell();
    return true;
}
 
PDFElement* PDFTrailerElement::Lookup(const OString& rDictionaryKey)
{
    if (!m_pDictionaryElement)
    {
        PDFObjectParser aParser(m_rDoc.GetElements());
        aParser.parse(this);
    }
    if (!m_pDictionaryElement)
        return nullptr;
    return m_pDictionaryElement->LookupElement(rDictionaryKey);
}
 
sal_uInt64 PDFTrailerElement::GetLocation() const { return m_nOffset; }
 
double PDFNumberElement::GetValue() const { return m_fValue; }
 
PDFObjectElement::PDFObjectElement(PDFDocument& rDoc, double fObjectValue, double fGenerationValue)
    : m_rDoc(rDoc)
    , m_fObjectValue(fObjectValue)
    , m_fGenerationValue(fGenerationValue)
    , m_pNumberElement(nullptr)
    , m_pNameElement(nullptr)
    , m_nDictionaryOffset(0)
    , m_nDictionaryLength(0)
    , m_pDictionaryElement(nullptr)
    , m_nArrayOffset(0)
    , m_nArrayLength(0)
    , m_pArrayElement(nullptr)
    , m_pStreamElement(nullptr)
    , m_bParsed(false)
{
}
 
bool PDFObjectElement::Read(SvStream& /*rStream*/)
{
    SAL_INFO("vcl.filter",
             "PDFObjectElement::Read: " << m_fObjectValue << " " << m_fGenerationValue << " obj");
    return true;
}
 
PDFDictionaryElement::PDFDictionaryElement() = default;
 
PDFElement* PDFDictionaryElement::Lookup(const std::map<OString, PDFElement*>& rDictionary,
                                         const OString& rKey)
{
    auto it = rDictionary.find(rKey);
    if (it == rDictionary.end())
        return nullptr;
 
    return it->second;
}
 
PDFObjectElement* PDFDictionaryElement::LookupObject(const OString& rDictionaryKey)
{
    auto pKey = dynamic_cast<PDFReferenceElement*>(
        PDFDictionaryElement::Lookup(m_aItems, rDictionaryKey));
    if (!pKey)
    {
        SAL_WARN("vcl.filter",
                 "PDFDictionaryElement::LookupObject: no such key with reference value: "
                     << rDictionaryKey);
        return nullptr;
    }
 
    return pKey->LookupObject();
}
 
PDFElement* PDFDictionaryElement::LookupElement(const OString& rDictionaryKey)
{
    return PDFDictionaryElement::Lookup(m_aItems, rDictionaryKey);
}
 
void PDFObjectElement::parseIfNecessary()
{
    if (m_bParsed)
        return;
 
    if (!m_aElements.empty())
    {
        // This is a stored object in an object stream.
        PDFObjectParser aParser(m_aElements);
        aParser.parse(this);
    }
    else
    {
        // Normal object: elements are stored as members of the document itself.
        PDFObjectParser aParser(m_rDoc.GetElements());
        aParser.parse(this);
    }
    m_bParsed = true;
}
 
PDFElement* PDFObjectElement::Lookup(const OString& rDictionaryKey)
{
    parseIfNecessary();
    if (!m_pDictionaryElement)
        return nullptr;
    return PDFDictionaryElement::Lookup(GetDictionaryItems(), rDictionaryKey);
}
 
PDFObjectElement* PDFObjectElement::LookupObject(const OString& rDictionaryKey)
{
    auto pKey = dynamic_cast<PDFReferenceElement*>(Lookup(rDictionaryKey));
    if (!pKey)
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::LookupObject: no such key with reference value: "
                                   << rDictionaryKey);
        return nullptr;
    }
 
    return pKey->LookupObject();
}
 
double PDFObjectElement::GetObjectValue() const { return m_fObjectValue; }
 
void PDFObjectElement::SetDictionaryOffset(sal_uInt64 nDictionaryOffset)
{
    m_nDictionaryOffset = nDictionaryOffset;
}
 
sal_uInt64 PDFObjectElement::GetDictionaryOffset()
{
    parseIfNecessary();
    return m_nDictionaryOffset;
}
 
void PDFObjectElement::SetArrayOffset(sal_uInt64 nArrayOffset) { m_nArrayOffset = nArrayOffset; }
 
sal_uInt64 PDFObjectElement::GetArrayOffset() const { return m_nArrayOffset; }
 
void PDFDictionaryElement::SetKeyOffset(const OString& rKey, sal_uInt64 nOffset)
{
    m_aDictionaryKeyOffset[rKey] = nOffset;
}
 
void PDFDictionaryElement::SetKeyValueLength(const OString& rKey, sal_uInt64 nLength)
{
    m_aDictionaryKeyValueLength[rKey] = nLength;
}
 
sal_uInt64 PDFDictionaryElement::GetKeyOffset(const OString& rKey) const
{
    auto it = m_aDictionaryKeyOffset.find(rKey);
    if (it == m_aDictionaryKeyOffset.end())
        return 0;
 
    return it->second;
}
 
sal_uInt64 PDFDictionaryElement::GetKeyValueLength(const OString& rKey) const
{
    auto it = m_aDictionaryKeyValueLength.find(rKey);
    if (it == m_aDictionaryKeyValueLength.end())
        return 0;
 
    return it->second;
}
 
const std::map<OString, PDFElement*>& PDFDictionaryElement::GetItems() const { return m_aItems; }
 
void PDFObjectElement::SetDictionaryLength(sal_uInt64 nDictionaryLength)
{
    m_nDictionaryLength = nDictionaryLength;
}
 
sal_uInt64 PDFObjectElement::GetDictionaryLength()
{
    parseIfNecessary();
    return m_nDictionaryLength;
}
 
void PDFObjectElement::SetArrayLength(sal_uInt64 nArrayLength) { m_nArrayLength = nArrayLength; }
 
sal_uInt64 PDFObjectElement::GetArrayLength() const { return m_nArrayLength; }
 
PDFDictionaryElement* PDFObjectElement::GetDictionary()
{
    parseIfNecessary();
    return m_pDictionaryElement;
}
 
void PDFObjectElement::SetDictionary(PDFDictionaryElement* pDictionaryElement)
{
    m_pDictionaryElement = pDictionaryElement;
}
 
void PDFObjectElement::SetNumberElement(PDFNumberElement* pNumberElement)
{
    m_pNumberElement = pNumberElement;
}
 
PDFNumberElement* PDFObjectElement::GetNumberElement() const { return m_pNumberElement; }
 
void PDFObjectElement::SetNameElement(PDFNameElement* pNameElement)
{
    m_pNameElement = pNameElement;
}
 
PDFNameElement* PDFObjectElement::GetNameElement() const { return m_pNameElement; }
 
const std::vector<PDFReferenceElement*>& PDFObjectElement::GetDictionaryReferences() const
{
    return m_aDictionaryReferences;
}
 
void PDFObjectElement::AddDictionaryReference(PDFReferenceElement* pReference)
{
    m_aDictionaryReferences.push_back(pReference);
}
 
const std::map<OString, PDFElement*>& PDFObjectElement::GetDictionaryItems()
{
    parseIfNecessary();
    return m_pDictionaryElement->GetItems();
}
 
void PDFObjectElement::SetArray(PDFArrayElement* pArrayElement) { m_pArrayElement = pArrayElement; }
 
void PDFObjectElement::SetStream(PDFStreamElement* pStreamElement)
{
    m_pStreamElement = pStreamElement;
}
 
PDFStreamElement* PDFObjectElement::GetStream() const { return m_pStreamElement; }
 
PDFArrayElement* PDFObjectElement::GetArray()
{
    parseIfNecessary();
    return m_pArrayElement;
}
 
void PDFObjectElement::ParseStoredObjects()
{
    if (!m_pStreamElement)
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::ParseStoredObjects: no stream");
        return;
    }
 
    auto pType = dynamic_cast<PDFNameElement*>(Lookup("Type"_ostr));
    if (!pType || pType->GetValue() != "ObjStm")
    {
        if (!pType)
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: missing unexpected type");
        else
            SAL_WARN("vcl.filter",
                     "PDFDocument::ReadXRefStream: unexpected type: " << pType->GetValue());
        return;
    }
 
    auto pFilter = dynamic_cast<PDFNameElement*>(Lookup("Filter"_ostr));
    if (!pFilter || pFilter->GetValue() != "FlateDecode")
    {
        if (!pFilter)
            SAL_WARN("vcl.filter", "PDFDocument::ReadXRefStream: missing filter");
        else
            SAL_WARN("vcl.filter",
                     "PDFDocument::ReadXRefStream: unexpected filter: " << pFilter->GetValue());
        return;
    }
 
    auto pFirst = dynamic_cast<PDFNumberElement*>(Lookup("First"_ostr));
    if (!pFirst)
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::ParseStoredObjects: no First");
        return;
    }
 
    auto pN = dynamic_cast<PDFNumberElement*>(Lookup("N"_ostr));
    if (!pN)
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::ParseStoredObjects: no N");
        return;
    }
    size_t nN = pN->GetValue();
 
    auto pLength = dynamic_cast<PDFNumberElement*>(Lookup("Length"_ostr));
    if (!pLength)
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::ParseStoredObjects: no length");
        return;
    }
    size_t nLength = pLength->GetValue();
 
    // Read and decompress it.
    SvMemoryStream& rEditBuffer = m_rDoc.GetEditBuffer();
    rEditBuffer.Seek(m_pStreamElement->GetOffset());
    std::vector<char> aBuf(nLength);
    rEditBuffer.ReadBytes(aBuf.data(), aBuf.size());
    SvMemoryStream aSource(aBuf.data(), aBuf.size(), StreamMode::READ);
    SvMemoryStream aStream;
    ZCodec aZCodec;
    aZCodec.BeginCompression();
    aZCodec.Decompress(aSource, aStream);
    if (!aZCodec.EndCompression())
    {
        SAL_WARN("vcl.filter", "PDFObjectElement::ParseStoredObjects: decompression failed");
        return;
    }
 
    nLength = aStream.TellEnd();
    aStream.Seek(0);
    std::vector<size_t> aObjNums;
    std::vector<size_t> aOffsets;
    std::vector<size_t> aLengths;
    // First iterate over and find out the lengths.
    for (size_t nObject = 0; nObject < nN; ++nObject)
    {
        PDFNumberElement aObjNum;
        if (!aObjNum.Read(aStream))
        {
            SAL_WARN("vcl.filter",
                     "PDFObjectElement::ParseStoredObjects: failed to read object number");
            return;
        }
        aObjNums.push_back(aObjNum.GetValue());
 
        PDFDocument::SkipWhitespace(aStream);
 
        PDFNumberElement aByteOffset;
        if (!aByteOffset.Read(aStream))
        {
            SAL_WARN("vcl.filter",
                     "PDFObjectElement::ParseStoredObjects: failed to read byte offset");
            return;
        }
        aOffsets.push_back(pFirst->GetValue() + aByteOffset.GetValue());
 
        if (aOffsets.size() > 1)
            aLengths.push_back(aOffsets.back() - aOffsets[aOffsets.size() - 2]);
        if (nObject + 1 == nN)
            aLengths.push_back(nLength - aOffsets.back());
 
        PDFDocument::SkipWhitespace(aStream);
    }
 
    // Now create streams with the proper length and tokenize the data.
    for (size_t nObject = 0; nObject < nN; ++nObject)
    {
        size_t nObjNum = aObjNums[nObject];
        size_t nOffset = aOffsets[nObject];
        size_t nLen = aLengths[nObject];
 
        aStream.Seek(nOffset);
        m_aStoredElements.push_back(std::make_unique<PDFObjectElement>(m_rDoc, nObjNum, 0));
        PDFObjectElement* pStored = m_aStoredElements.back().get();
 
        aBuf.clear();
        aBuf.resize(nLen);
        aStream.ReadBytes(aBuf.data(), aBuf.size());
        SvMemoryStream aStoredStream(aBuf.data(), aBuf.size(), StreamMode::READ);
 
        m_rDoc.Tokenize(aStoredStream, TokenizeMode::STORED_OBJECT, pStored->GetStoredElements(),
                        pStored);
        // This is how references know the object is stored inside this object stream.
        m_rDoc.SetIDObject(nObjNum, pStored);
 
        // Store the stream of the object in the object stream for later use.
        std::unique_ptr<SvMemoryStream> pStreamBuffer(new SvMemoryStream());
        aStoredStream.Seek(0);
        pStreamBuffer->WriteStream(aStoredStream);
        pStored->SetStreamBuffer(pStreamBuffer);
    }
}
 
std::vector<std::unique_ptr<PDFElement>>& PDFObjectElement::GetStoredElements()
{
    return m_aElements;
}
 
SvMemoryStream* PDFObjectElement::GetStreamBuffer() const { return m_pStreamBuffer.get(); }
 
void PDFObjectElement::SetStreamBuffer(std::unique_ptr<SvMemoryStream>& pStreamBuffer)
{
    m_pStreamBuffer = std::move(pStreamBuffer);
}
 
PDFDocument& PDFObjectElement::GetDocument() { return m_rDoc; }
 
PDFReferenceElement::PDFReferenceElement(PDFDocument& rDoc, PDFNumberElement& rObject,
                                         PDFNumberElement const& rGeneration)
    : m_rDoc(rDoc)
    , m_fObjectValue(rObject.GetValue())
    , m_fGenerationValue(rGeneration.GetValue())
    , m_rObject(rObject)
{
}
 
PDFNumberElement& PDFReferenceElement::GetObjectElement() const { return m_rObject; }
 
bool PDFReferenceElement::Read(SvStream& rStream)
{
    SAL_INFO("vcl.filter",
             "PDFReferenceElement::Read: " << m_fObjectValue << " " << m_fGenerationValue << " R");
    m_nOffset = rStream.Tell();
    return true;
}
 
sal_uInt64 PDFReferenceElement::GetOffset() const { return m_nOffset; }
 
double PDFReferenceElement::LookupNumber(SvStream& rStream) const
{
    size_t nOffset = m_rDoc.GetObjectOffset(m_fObjectValue);
    if (nOffset == 0)
    {
        SAL_WARN("vcl.filter", "PDFReferenceElement::LookupNumber: found no offset for object #"
                                   << m_fObjectValue);
        return 0;
    }
 
    sal_uInt64 nOrigPos = rStream.Tell();
    comphelper::ScopeGuard g([&]() { rStream.Seek(nOrigPos); });
 
    rStream.Seek(nOffset);
    {
        PDFDocument::SkipWhitespace(rStream);
        PDFNumberElement aNumber;
        bool bRet = aNumber.Read(rStream);
        if (!bRet || aNumber.GetValue() != m_fObjectValue)
        {
            SAL_WARN("vcl.filter",
                     "PDFReferenceElement::LookupNumber: offset points to not matching object");
            return 0;
        }
    }
 
    {
        PDFDocument::SkipWhitespace(rStream);
        PDFNumberElement aNumber;
        bool bRet = aNumber.Read(rStream);
        if (!bRet || aNumber.GetValue() != m_fGenerationValue)
        {
            SAL_WARN("vcl.filter",
                     "PDFReferenceElement::LookupNumber: offset points to not matching generation");
            return 0;
        }
    }
 
    {
        PDFDocument::SkipWhitespace(rStream);
        OString aKeyword = PDFDocument::ReadKeyword(rStream);
        if (aKeyword != "obj")
        {
            SAL_WARN("vcl.filter",
                     "PDFReferenceElement::LookupNumber: offset doesn't point to an obj keyword");
            return 0;
        }
    }
 
    PDFDocument::SkipWhitespace(rStream);
    PDFNumberElement aNumber;
    if (!aNumber.Read(rStream))
    {
        SAL_WARN("vcl.filter",
                 "PDFReferenceElement::LookupNumber: failed to read referenced number");
        return 0;
    }
 
    return aNumber.GetValue();
}
 
PDFObjectElement* PDFReferenceElement::LookupObject()
{
    return m_rDoc.LookupObject(m_fObjectValue);
}
 
PDFObjectElement* PDFDocument::LookupObject(size_t nObjectNumber)
{
    auto itIDObjects = m_aIDObjects.find(nObjectNumber);
 
    if (itIDObjects != m_aIDObjects.end())
        return itIDObjects->second;
 
    SAL_WARN("vcl.filter", "PDFDocument::LookupObject: can't find obj " << nObjectNumber);
    return nullptr;
}
 
SvMemoryStream& PDFDocument::GetEditBuffer() { return m_aEditBuffer; }
 
int PDFReferenceElement::GetObjectValue() const { return m_fObjectValue; }
 
int PDFReferenceElement::GetGenerationValue() const { return m_fGenerationValue; }
 
bool PDFDictionaryElement::Read(SvStream& rStream)
{
    char ch;
    rStream.ReadChar(ch);
    if (ch != '<')
    {
        SAL_WARN("vcl.filter", "PDFDictionaryElement::Read: unexpected character: " << ch);
        return false;
    }
 
    if (rStream.eof())
    {
        SAL_WARN("vcl.filter", "PDFDictionaryElement::Read: unexpected end of file");
        return false;
    }
 
    rStream.ReadChar(ch);
    if (ch != '<')
    {
        SAL_WARN("vcl.filter", "PDFDictionaryElement::Read: unexpected character: " << ch);
        return false;
    }
 
    m_nLocation = rStream.Tell();
 
    SAL_INFO("vcl.filter", "PDFDictionaryElement::Read: '<<'");
 
    return true;
}
 
PDFEndDictionaryElement::PDFEndDictionaryElement() = default;
 
sal_uInt64 PDFEndDictionaryElement::GetLocation() const { return m_nLocation; }
 
bool PDFEndDictionaryElement::Read(SvStream& rStream)
{
    m_nLocation = rStream.Tell();
    char ch;
    rStream.ReadChar(ch);
    if (ch != '>')
    {
        SAL_WARN("vcl.filter", "PDFEndDictionaryElement::Read: unexpected character: " << ch);
        return false;
    }
 
    if (rStream.eof())
    {
        SAL_WARN("vcl.filter", "PDFEndDictionaryElement::Read: unexpected end of file");
        return false;
    }
 
    rStream.ReadChar(ch);
    if (ch != '>')
    {
        SAL_WARN("vcl.filter", "PDFEndDictionaryElement::Read: unexpected character: " << ch);
        return false;
    }
 
    SAL_INFO("vcl.filter", "PDFEndDictionaryElement::Read: '>>'");
 
    return true;
}
 
PDFNameElement::PDFNameElement() = default;
 
bool PDFNameElement::Read(SvStream& rStream)
{
    char ch;
    rStream.ReadChar(ch);
    if (ch != '/')
    {
        SAL_WARN("vcl.filter", "PDFNameElement::Read: unexpected character: " << ch);
        return false;
    }
    m_nLocation = rStream.Tell();
 
    if (rStream.eof())
    {
        SAL_WARN("vcl.filter", "PDFNameElement::Read: unexpected end of file");
        return false;
    }
 
    // Read till the first white-space.
    OStringBuffer aBuf;
    rStream.ReadChar(ch);
    while (!rStream.eof())
    {
        if (rtl::isAsciiWhiteSpace(static_cast<unsigned char>(ch)) || ch == '/' || ch == '['
            || ch == ']' || ch == '<' || ch == '>' || ch == '(')
        {
            rStream.SeekRel(-1);
            m_aValue = aBuf.makeStringAndClear();
            SAL_INFO("vcl.filter", "PDFNameElement::Read: m_aValue is '" << m_aValue << "'");
            return true;
        }
        aBuf.append(ch);
        rStream.ReadChar(ch);
    }
 
    return false;
}
 
const OString& PDFNameElement::GetValue() const { return m_aValue; }
 
sal_uInt64 PDFNameElement::GetLocation() const { return m_nLocation; }
 
PDFStreamElement::PDFStreamElement(size_t nLength)
    : m_nLength(nLength)
    , m_nOffset(0)
{
}
 
bool PDFStreamElement::Read(SvStream& rStream)
{
    SAL_INFO("vcl.filter", "PDFStreamElement::Read: length is " << m_nLength);
    m_nOffset = rStream.Tell();
    std::vector<unsigned char> aBytes(m_nLength);
    rStream.ReadBytes(aBytes.data(), aBytes.size());
    m_aMemory.WriteBytes(aBytes.data(), aBytes.size());
 
    return rStream.good();
}
 
SvMemoryStream& PDFStreamElement::GetMemory() { return m_aMemory; }
 
sal_uInt64 PDFStreamElement::GetOffset() const { return m_nOffset; }
 
bool PDFEndStreamElement::Read(SvStream& /*rStream*/) { return true; }
 
bool PDFEndObjectElement::Read(SvStream& /*rStream*/) { return true; }
 
PDFArrayElement::PDFArrayElement(PDFObjectElement* pObject)
    : m_pObject(pObject)
{
}
 
bool PDFArrayElement::Read(SvStream& rStream)
{
    char ch;
    rStream.ReadChar(ch);
    if (ch != '[')
    {
        SAL_WARN("vcl.filter", "PDFArrayElement::Read: unexpected character: " << ch);
        return false;
    }
 
    SAL_INFO("vcl.filter", "PDFArrayElement::Read: '['");
 
    return true;
}
 
void PDFArrayElement::PushBack(PDFElement* pElement)
{
    if (m_pObject)
        SAL_INFO("vcl.filter",
                 "PDFArrayElement::PushBack: object is " << m_pObject->GetObjectValue());
    m_aElements.push_back(pElement);
}
 
const std::vector<PDFElement*>& PDFArrayElement::GetElements() const { return m_aElements; }
 
PDFEndArrayElement::PDFEndArrayElement() = default;
 
bool PDFEndArrayElement::Read(SvStream& rStream)
{
    m_nOffset = rStream.Tell();
    char ch;
    rStream.ReadChar(ch);
    if (ch != ']')
    {
        SAL_WARN("vcl.filter", "PDFEndArrayElement::Read: unexpected character: " << ch);
        return false;
    }
 
    SAL_INFO("vcl.filter", "PDFEndArrayElement::Read: ']'");
 
    return true;
}
 
sal_uInt64 PDFEndArrayElement::GetOffset() const { return m_nOffset; }
 
// PDFObjectParser
 
size_t PDFObjectParser::parse(PDFElement* pParsingElement, size_t nStartIndex, int nCurrentDepth)
{
    // The index of last parsed element
    size_t nReturnIndex = 0;
 
    pParsingElement->setParsing(true);
 
    comphelper::ScopeGuard aGuard([pParsingElement]() { pParsingElement->setParsing(false); });
 
    // Current object, if root is an object, else nullptr
    auto pParsingObject = dynamic_cast<PDFObjectElement*>(pParsingElement);
    auto pParsingTrailer = dynamic_cast<PDFTrailerElement*>(pParsingElement);
 
    // Current dictionary, if root is an dictionary, else nullptr
    auto pParsingDictionary = dynamic_cast<PDFDictionaryElement*>(pParsingElement);
 
    // Current parsing array, if root is an array, else nullptr
    auto pParsingArray = dynamic_cast<PDFArrayElement*>(pParsingElement);
 
    // Find out where the dictionary for this object starts.
    size_t nIndex = nStartIndex;
    for (size_t i = nStartIndex; i < mrElements.size(); ++i)
    {
        if (mrElements[i].get() == pParsingElement)
        {
            nIndex = i;
            break;
        }
    }
 
    OString aName;
    sal_uInt64 nNameOffset = 0;
    std::vector<PDFNumberElement*> aNumbers;
 
    sal_uInt64 nDictionaryOffset = 0;
 
    // Current depth; 1 is current
    int nDepth = 0;
 
    for (size_t i = nIndex; i < mrElements.size(); ++i)
    {
        auto* pCurrentElement = mrElements[i].get();
 
        // Dictionary tokens can be nested, track enter/leave.
        if (auto pCurrentDictionary = dynamic_cast<PDFDictionaryElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingDictionary)
                {
                    PDFNumberElement* pNumber = aNumbers.back();
                    sal_uInt64 nLength
                        = pNumber->GetLocation() + pNumber->GetLength() - nNameOffset;
 
                    pParsingDictionary->insert(aName, pNumber);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nLength);
                }
                else if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                else
                {
                    SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
                }
                aName.clear();
                aNumbers.clear();
            }
 
            nDepth++;
 
            if (nDepth == 1) // pParsingDictionary is the current one
            {
                // First dictionary start, track start offset.
                nDictionaryOffset = pCurrentDictionary->GetLocation();
 
                if (pParsingObject)
                {
                    // Then the toplevel dictionary of the object.
                    pParsingObject->SetDictionary(pCurrentDictionary);
                    pParsingObject->SetDictionaryOffset(nDictionaryOffset);
                    pParsingDictionary = pCurrentDictionary;
                }
                else if (pParsingTrailer)
                {
                    pParsingTrailer->SetDictionary(pCurrentDictionary);
                    pParsingDictionary = pCurrentDictionary;
                }
            }
            else if (!pCurrentDictionary->alreadyParsing())
            {
                if (pParsingArray)
                {
                    pParsingArray->PushBack(pCurrentDictionary);
                }
                else if (pParsingDictionary)
                {
                    // Dictionary toplevel value.
                    pParsingDictionary->insert(aName, pCurrentDictionary);
                }
                else
                {
                    SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
                }
                // Nested dictionary.
                const size_t nNextElementIndex = parse(pCurrentDictionary, i, nCurrentDepth + 1);
                i = std::max(i, nNextElementIndex - 1);
            }
        }
        else if (auto pCurrentEndDictionary
                 = dynamic_cast<PDFEndDictionaryElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingDictionary)
                {
                    PDFNumberElement* pNumber = aNumbers.back();
                    sal_uInt64 nLength
                        = pNumber->GetLocation() + pNumber->GetLength() - nNameOffset;
 
                    pParsingDictionary->insert(aName, pNumber);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nLength);
                }
                else if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                else
                {
                    SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
                }
                aName.clear();
                aNumbers.clear();
            }
 
            if (pParsingDictionary)
            {
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                sal_uInt64 nLength = pCurrentEndDictionary->GetLocation() - nNameOffset + 2;
                pParsingDictionary->SetKeyValueLength(aName, nLength);
                aName.clear();
            }
 
            if (nDepth == 1) // did the parsing ended
            {
                // Last dictionary end, track length and stop parsing.
                if (pParsingObject)
                {
                    sal_uInt64 nDictionaryLength
                        = pCurrentEndDictionary->GetLocation() - nDictionaryOffset;
                    pParsingObject->SetDictionaryLength(nDictionaryLength);
                }
                nReturnIndex = i;
                break;
            }
 
            nDepth--;
        }
        else if (auto pCurrentArray = dynamic_cast<PDFArrayElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingDictionary)
                {
                    PDFNumberElement* pNumber = aNumbers.back();
 
                    sal_uInt64 nLength
                        = pNumber->GetLocation() + pNumber->GetLength() - nNameOffset;
                    pParsingDictionary->insert(aName, pNumber);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nLength);
                }
                else if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                else
                {
                    SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
                }
                aName.clear();
                aNumbers.clear();
            }
 
            nDepth++;
            if (nDepth == 1) // pParsingDictionary is the current one
            {
                if (pParsingObject)
                {
                    pParsingObject->SetArray(pCurrentArray);
                    pParsingArray = pCurrentArray;
                }
            }
            else if (!pCurrentArray->alreadyParsing())
            {
                if (pParsingArray)
                {
                    // Array is toplevel
                    pParsingArray->PushBack(pCurrentArray);
                }
                else if (pParsingDictionary)
                {
                    // Dictionary toplevel value.
                    pParsingDictionary->insert(aName, pCurrentArray);
                }
 
                const size_t nNextElementIndex = parse(pCurrentArray, i, nCurrentDepth + 1);
 
                // ensure we go forwards and not endlessly loop
                i = std::max(i, nNextElementIndex - 1);
            }
        }
        else if (auto pCurrentEndArray = dynamic_cast<PDFEndArrayElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingDictionary)
                {
                    PDFNumberElement* pNumber = aNumbers.back();
 
                    sal_uInt64 nLength
                        = pNumber->GetLocation() + pNumber->GetLength() - nNameOffset;
                    pParsingDictionary->insert(aName, pNumber);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nLength);
                }
                else if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                else
                {
                    SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
                }
                aName.clear();
                aNumbers.clear();
            }
 
            if (nDepth == 1) // did the pParsing ended
            {
                // Last array end, track length and stop parsing.
                nReturnIndex = i;
                break;
            }
 
            if (pParsingDictionary)
            {
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                // Include the ending ']' in the length of the key - (array)value pair length.
                sal_uInt64 nLength = pCurrentEndArray->GetOffset() - nNameOffset + 1;
                pParsingDictionary->SetKeyValueLength(aName, nLength);
                aName.clear();
            }
            nDepth--;
        }
        else if (auto pCurrentName = dynamic_cast<PDFNameElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingDictionary)
                {
                    PDFNumberElement* pNumber = aNumbers.back();
 
                    sal_uInt64 nLength
                        = pNumber->GetLocation() + pNumber->GetLength() - nNameOffset;
                    pParsingDictionary->insert(aName, pNumber);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nLength);
                }
                else if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                aName.clear();
                aNumbers.clear();
            }
 
            // Now handle name
            if (pParsingArray)
            {
                // if we are in an array, just push the name to array
                pParsingArray->PushBack(pCurrentName);
            }
            else if (pParsingDictionary)
            {
                // if we are in a dictionary, we need to store the name as a possible key
                if (aName.isEmpty())
                {
                    aName = pCurrentName->GetValue();
                    nNameOffset = pCurrentName->GetLocation();
                }
                else
                {
                    sal_uInt64 nKeyLength
                        = pCurrentName->GetLocation() + pCurrentName->GetLength() - nNameOffset;
                    pParsingDictionary->insert(aName, pCurrentName);
                    pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                    pParsingDictionary->SetKeyValueLength(aName, nKeyLength);
                    aName.clear();
                }
            }
        }
        else if (auto pReference = dynamic_cast<PDFReferenceElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (aNumbers.size() > 2)
            {
                aNumbers.resize(aNumbers.size() - 2);
                if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                aNumbers.clear();
            }
 
            if (pParsingArray)
            {
                pParsingArray->PushBack(pReference);
            }
            else if (pParsingDictionary)
            {
                sal_uInt64 nLength = pReference->GetOffset() - nNameOffset;
                pParsingDictionary->insert(aName, pReference);
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                pParsingDictionary->SetKeyValueLength(aName, nLength);
                aName.clear();
            }
            else
            {
                SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
            }
            aNumbers.clear();
        }
        else if (auto pLiteralString = dynamic_cast<PDFLiteralStringElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                aNumbers.clear();
            }
 
            if (pParsingArray)
            {
                pParsingArray->PushBack(pLiteralString);
            }
            else if (pParsingDictionary)
            {
                pParsingDictionary->insert(aName, pLiteralString);
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                aName.clear();
            }
            else
            {
                SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
            }
        }
        else if (auto pBoolean = dynamic_cast<PDFBooleanElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                aNumbers.clear();
            }
 
            if (pParsingArray)
            {
                pParsingArray->PushBack(pBoolean);
            }
            else if (pParsingDictionary)
            {
                pParsingDictionary->insert(aName, pBoolean);
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                aName.clear();
            }
            else
            {
                SAL_INFO("vcl.filter", "neither Dictionary nor Array available");
            }
        }
        else if (auto pHexString = dynamic_cast<PDFHexStringElement*>(pCurrentElement))
        {
            // Handle previously stored number
            if (!aNumbers.empty())
            {
                if (pParsingArray)
                {
                    for (auto& pNumber : aNumbers)
                        pParsingArray->PushBack(pNumber);
                }
                aNumbers.clear();
            }
 
            if (pParsingArray)
            {
                pParsingArray->PushBack(pHexString);
            }
            else if (pParsingDictionary)
            {
                pParsingDictionary->insert(aName, pHexString);
                pParsingDictionary->SetKeyOffset(aName, nNameOffset);
                aName.clear();
            }
        }
        else if (auto pNumberElement = dynamic_cast<PDFNumberElement*>(pCurrentElement))
        {
            // Just remember this, so that in case it's not a reference parameter,
            // we can handle it later.
            aNumbers.push_back(pNumberElement);
        }
        else if (dynamic_cast<PDFEndObjectElement*>(pCurrentElement))
        {
            // parsing of the object is finished
            break;
        }
        else if (dynamic_cast<PDFObjectElement*>(pCurrentElement)
                 || dynamic_cast<PDFTrailerElement*>(pCurrentElement))
        {
            continue;
        }
        else
        {
            SAL_INFO("vcl.filter", "Unhandled element while parsing.");
        }
    }
 
    return nReturnIndex;
}
 
} // namespace vcl
 
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

V530 The return value of function 'padToLength' is required to be utilized.

V530 The return value of function 'padToLength' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V530 The return value of function 'append' is required to be utilized.

V1085 Negative value is implicitly converted to unsigned integer type in arithmetic expression. This may lead to unexpected results.