/* -*- 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/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#include <sal/types.h>

#include <rtl/character.hxx>

#include <rtl/math.hxx>

#include <osl/time.h>

#include <comphelper/hash.hxx>

#include <pdf/COSWriter.hxx>

#include "pdfwriter_utils.hxx"

#include <memory>

#include <stdlib.h>

namespace vcl::pdf

{

void appendObjectID(sal_Int32 nObjectID, OStringBuffer & aLine)

{

    aLine.append(nObjectID);

    aLine.append(" 0 obj\n");

}

void appendObjectReference(sal_Int32 nObjectID, OStringBuffer & aLine)

{

    aLine.append(nObjectID);

    aLine.append(" 0 R ");

}

/*

 * Convert a string before using it.

 *

 * This string conversion function is needed because the destination name

 * in a PDF file seen through an Internet browser should be

 * specially crafted, in order to be used directly by the browser.

 * In this way the fragment part of a hyperlink to a PDF file (e.g. something

 * as 'test1/test2/a-file.pdf\#thefragment) will be (hopefully) interpreted by the

 * PDF reader (currently only Adobe Reader plug-in seems to be working that way) called

 * from inside the Internet browser as: 'open the file test1/test2/a-file.pdf

 * and go to named destination thefragment using default zoom'.

 * The conversion is needed because in case of a fragment in the form: Slide%201

 * (meaning Slide 1) as it is converted obeying the Inet rules, it will become Slide25201

 * using this conversion, in both the generated named destinations, fragment and GoToR

 * destination.

 *

 * The names for destinations are name objects and so they don't need to be encrypted

 * even though they expose the content of PDF file (e.g. guessing the PDF content from the

 * destination name).

 *

 * Further limitation: it is advisable to use standard ASCII characters for

 * OOo bookmarks.

*/

void appendDestinationName( std::u16string_view rString, OStringBuffer& rBuffer )

{

    for( auto aChar: rString)

    {

        if( rtl::isAsciiAlphanumeric(aChar) || aChar == '-' )

        {

            rBuffer.append(static_cast<char>(aChar));

        }

        else

        {

            const sal_Int8 nValueHigh = sal_Int8(aChar >> 8);

            if (nValueHigh > 0)

                COSWriter::appendHex(nValueHigh, rBuffer);

            COSWriter::appendHex(static_cast<sal_Int8>(aChar & 255 ), rBuffer);

        }

    }

}

void appendFixedInt( sal_Int32 nValue, OStringBuffer& rBuffer )

{

    if( nValue < 0 )

    {

        rBuffer.append( '-' );

        nValue = -nValue;

    }

    sal_Int32 nFactor = 1, nDiv = nLog10Divisor;

    while( nDiv-- )

        nFactor *= 10;

    sal_Int32 nInt = nValue / nFactor;

    rBuffer.append( nInt );

    if (nFactor > 1 && nValue % nFactor)

    {

        rBuffer.append( '.' );

        do

        {

            nFactor /= 10;

            rBuffer.append((nValue / nFactor) % 10);

        }

        while (nFactor > 1 && nValue % nFactor); // omit trailing zeros

    }

}

// appends a double. PDF does not accept exponential format, only fixed point

void appendDouble(double fValue, OStringBuffer& rBuffer, sal_Int32 nPrecision)

{

    rtl::math::doubleToStringBuffer(rBuffer, fValue, rtl_math_StringFormat_F, nPrecision, '.', true);

}

void appendColor( const Color& rColor, OStringBuffer& rBuffer, bool bConvertToGrey )

{

    if( rColor == COL_TRANSPARENT )

        return;

    if( bConvertToGrey )

    {

        sal_uInt8 cByte = rColor.GetLuminance();

        appendDouble( cByte / 255.0, rBuffer );

    }

    else

    {

        appendDouble( rColor.GetRed() / 255.0, rBuffer );

        rBuffer.append( ' ' );

        appendDouble( rColor.GetGreen() / 255.0, rBuffer );

        rBuffer.append( ' ' );

        appendDouble( rColor.GetBlue() / 255.0, rBuffer );

    }

}

void appendPdfTimeDate(OStringBuffer & rBuffer,

    sal_Int16 year, sal_uInt16 month, sal_uInt16 day, sal_uInt16 hours, sal_uInt16 minutes, sal_uInt16 seconds, sal_Int32 tzDelta)

{

    rBuffer.append("D:");

    rBuffer.append(char('0' + ((year / 1000) % 10)));

    rBuffer.append(char('0' + ((year / 100) % 10)));

    rBuffer.append(char('0' + ((year / 10) % 10)));

    rBuffer.append(char('0' + (year % 10)));

    rBuffer.append(char('0' + ((month / 10) % 10)));

    rBuffer.append(char('0' + (month % 10)));

    rBuffer.append(char('0' + ((day / 10) % 10)));

    rBuffer.append(char('0' + (day % 10)));

    rBuffer.append(char('0' + ((hours / 10) % 10)));

    rBuffer.append(char('0' + (hours % 10)));

    rBuffer.append(char('0' + ((minutes / 10) % 10)));

    rBuffer.append(char('0' + (minutes % 10)));

    rBuffer.append(char('0' + ((seconds / 10) % 10)));

    rBuffer.append(char('0' + (seconds % 10)));

    if (tzDelta == 0)

    {

        rBuffer.append("Z");

        return;

    }

    if (tzDelta > 0 )

        rBuffer.append("+");

    else

    {

        rBuffer.append("-");

        tzDelta = -tzDelta;

    }

    rBuffer.append(char('0' + ((tzDelta / 36000) % 10)));

    rBuffer.append(char('0' + ((tzDelta / 3600) % 10)));

    rBuffer.append("'");

    rBuffer.append(char('0' + ((tzDelta / 600) % 6)));

    rBuffer.append(char('0' + ((tzDelta / 60) % 10)));

}

const char* getPDFVersionStr(PDFWriter::PDFVersion ePDFVersion)

{

    switch (ePDFVersion)

    {

        case PDFWriter::PDFVersion::PDF_A_1:

        case PDFWriter::PDFVersion::PDF_1_4:

            return "1.4";

        case PDFWriter::PDFVersion::PDF_1_5:

            return "1.5";

        case PDFWriter::PDFVersion::PDF_1_6:

            return "1.6";

        default:

        case PDFWriter::PDFVersion::PDF_A_2:

        case PDFWriter::PDFVersion::PDF_A_3:

        case PDFWriter::PDFVersion::PDF_1_7:

            return "1.7";

        // PDF 2.0

        case PDFWriter::PDFVersion::PDF_A_4:

        case PDFWriter::PDFVersion::PDF_2_0:

            return "2.0";

    }

}

void computeDocumentIdentifier(std::vector<sal_uInt8>& o_rIdentifier,

                               const PDFWriter::PDFDocInfo& i_rDocInfo,

                               const OString& i_rCString1,

                               const css::util::DateTime& rCreationMetaDate, OString& o_rCString2)

{

    o_rIdentifier.clear();

    //build the document id

    OString aInfoValuesOut;

    OStringBuffer aID(1024);

    if (!i_rDocInfo.Title.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Title, aID);

    if (!i_rDocInfo.Author.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Author, aID);

    if (!i_rDocInfo.Subject.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Subject, aID);

    if (!i_rDocInfo.Keywords.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Keywords, aID);

    if (!i_rDocInfo.Creator.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Creator, aID);

    if (!i_rDocInfo.Producer.isEmpty())

        COSWriter::appendUnicodeTextString(i_rDocInfo.Producer, aID);

    TimeValue aTVal, aGMT;

    oslDateTime aDT;

    aDT.NanoSeconds = rCreationMetaDate.NanoSeconds;

    aDT.Seconds = rCreationMetaDate.Seconds;

    aDT.Minutes = rCreationMetaDate.Minutes;

    aDT.Hours = rCreationMetaDate.Hours;

    aDT.Day = rCreationMetaDate.Day;

    aDT.Month = rCreationMetaDate.Month;

    aDT.Year = rCreationMetaDate.Year;

    osl_getSystemTime(&aGMT);

    osl_getLocalTimeFromSystemTime(&aGMT, &aTVal);

    OStringBuffer aCreationMetaDateString(64);

    // i59651: we fill the Metadata date string as well, if PDF/A is requested

    // according to ISO 19005-1:2005 6.7.3 the date is corrected for

    // local time zone offset UTC only, whereas Acrobat 8 seems

    // to use the localtime notation only

    // according to a recommendation in XMP Specification (Jan 2004, page 75)

    // the Acrobat way seems the right approach

    aCreationMetaDateString.append(

        OStringChar(char('0' + ((aDT.Year / 1000) % 10)))

        + OStringChar(char('0' + ((aDT.Year / 100) % 10)))

        + OStringChar(char('0' + ((aDT.Year / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Year) % 10)))

        + OStringChar('-')

        + OStringChar(char('0' + ((aDT.Month / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Month) % 10)))

        + OStringChar('-')

        + OStringChar(char('0' + ((aDT.Day / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Day) % 10)))

        + OStringChar('T')

        + OStringChar(char('0' + ((aDT.Hours / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Hours) % 10)))

        + OStringChar(':')

        + OStringChar(char('0' + ((aDT.Minutes / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Minutes) % 10)))

        + OStringChar(':')

        + OStringChar(char('0' + ((aDT.Seconds / 10) % 10)))

        + OStringChar(char('0' + ((aDT.Seconds) % 10))));

    sal_uInt32 nDelta = 0;

    if (aGMT.Seconds > aTVal.Seconds)

    {

        nDelta = aGMT.Seconds - aTVal.Seconds;

        aCreationMetaDateString.append("-");

    }

    else if (aGMT.Seconds < aTVal.Seconds)

    {

        nDelta = aTVal.Seconds - aGMT.Seconds;

        aCreationMetaDateString.append("+");

    }

    else

    {

        aCreationMetaDateString.append("Z");

    }

    if (nDelta)

    {

        aCreationMetaDateString.append(char('0' + ((nDelta / 36000) % 10)));

        aCreationMetaDateString.append(char('0' + ((nDelta / 3600) % 10)));

        aCreationMetaDateString.append(":");

        aCreationMetaDateString.append(char('0' + ((nDelta / 600) % 6)));

        aCreationMetaDateString.append(char('0' + ((nDelta / 60) % 10)));

    }

    aID.append(i_rCString1.getStr(), i_rCString1.getLength());

    aInfoValuesOut = aID.makeStringAndClear();

    o_rCString2 = aCreationMetaDateString.makeStringAndClear();

    ::comphelper::Hash aDigest(::comphelper::HashType::MD5);

    aDigest.update(&aGMT, sizeof(aGMT));

    aDigest.update(aInfoValuesOut.getStr(), aInfoValuesOut.getLength());

    //the binary form of the doc id is needed for encryption stuff

    o_rIdentifier = aDigest.finalize();

}

} // end namespace vcl::pdf

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