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/* -*- 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/.
*/
#pragma once
#include <pdf/IPDFEncryptor.hxx>
namespace vcl::pdf
{
/** Writes the "Carousel" object structure (COS) to the string buffer.
*
* "Carousel" object structure (COS) is used by PDF.
*
* Structure elements like: objects, IDs, dictionaries, key/values, ...
*/
class COSWriter
{
std::unique_ptr<IPDFEncryptor>& mpPDFEncryptor;
OStringBuffer maLine;
void appendLiteralString(const char* pStr, sal_Int32 nLength)
{
while (nLength)
{
switch (*pStr)
{
case '\n':
maLine.append("\\n");
break;
case '\r':
maLine.append("\\r");
break;
case '\t':
maLine.append("\\t");
break;
case '\b':
maLine.append("\\b");
break;
case '\f':
maLine.append("\\f");
break;
case '(':
case ')':
case '\\':
maLine.append("\\");
maLine.append(static_cast<char>(*pStr));
break;
default:
maLine.append(static_cast<char>(*pStr));
break;
}
pStr++;
nLength--;
}
}
template <typename T> void appendHex(T nValue)
{
static constexpr const auto constHexDigits = std::to_array<char>(
{ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' });
maLine.append(constHexDigits[(nValue >> 4) & 15]);
maLine.append(constHexDigits[nValue & 15]);
}
void appendHexArray(sal_uInt8* pArray, size_t nSize)
{
for (size_t i = 0; i < nSize; i++)
appendHex(pArray[i]);
}
public:
COSWriter(std::unique_ptr<IPDFEncryptor>& pPDFEncryptor)
: mpPDFEncryptor(pPDFEncryptor)
, maLine(1024)
{
}
void startObject(sal_Int32 nObjectID)
{
maLine.append(nObjectID);
maLine.append(" 0 obj\n");
}
void endObject() { maLine.append("endobj\n\n"); }
OStringBuffer& getLine() { return maLine; }
void startDict() { maLine.append("<<"); }
void endDict() { maLine.append(">>\n"); }
void write(std::string_view key, std::string_view value)
{
maLine.append(key);
maLine.append(value);
}
void write(std::string_view key, sal_Int32 value)
{
maLine.append(key);
maLine.append(" ");
maLine.append(value);
}
void writeString(std::string_view key, char* pString, sal_Int32 nSize)
{
maLine.append(key);
maLine.append(" (");
appendLiteralString(pString, nSize);
maLine.append(")");
}
void writeUnicodeEncrypt(std::string_view key, OUString const& rString, sal_Int32 nObject,
bool bEncrypt, std::vector<sal_uInt8>& rKey)
{
maLine.append(key);
maLine.append("<");
if (bEncrypt)
{
const sal_Unicode* pString = rString.getStr();
size_t nLength = rString.getLength();
//prepare a unicode string, encrypt it
mpPDFEncryptor->setupEncryption(rKey, nObject);
sal_Int32 nChars = 2 + (nLength * 2);
std::vector<sal_uInt8> aEncryptionBuffer(nChars);
sal_uInt8* pCopy = aEncryptionBuffer.data();
*pCopy++ = 0xFE;
*pCopy++ = 0xFF;
// we need to prepare a byte stream from the unicode string buffer
for (size_t i = 0; i < nLength; i++)
{
sal_Unicode aUnicodeChar = pString[i];
*pCopy++ = sal_uInt8(aUnicodeChar >> 8);
*pCopy++ = sal_uInt8(aUnicodeChar & 255);
}
std::vector<sal_uInt8> aNewBuffer(nChars);
mpPDFEncryptor->encrypt(aEncryptionBuffer.data(), nChars, aNewBuffer, nChars);
//now append, hexadecimal (appendHex), the encrypted result
appendHexArray(aNewBuffer.data(), aNewBuffer.size());
}
else
{
//PDFWriter::AppendUnicodeTextString(rInString, maLine);
maLine.append("FEFF");
const sal_Unicode* pString = rString.getStr();
size_t nLength = rString.getLength();
for (size_t i = 0; i < nLength; i++)
{
sal_Unicode aChar = pString[i];
appendHex(sal_Int8(aChar >> 8));
appendHex(sal_Int8(aChar & 255));
}
}
maLine.append(">");
}
void writeLiteralEncrypt(std::string_view key, std::string_view value, sal_Int32 nObject,
bool bEncrypt, std::vector<sal_uInt8>& rKey)
{
maLine.append(key);
maLine.append("(");
size_t nChars = value.size();
if (bEncrypt)
{
std::vector<sal_uInt8> aEncryptionBuffer(nChars);
mpPDFEncryptor->setupEncryption(rKey, nObject);
mpPDFEncryptor->encrypt(value.data(), nChars, aEncryptionBuffer, nChars);
appendLiteralString(reinterpret_cast<char*>(aEncryptionBuffer.data()),
aEncryptionBuffer.size());
}
else
{
appendLiteralString(value.data(), nChars);
}
maLine.append(")");
}
void writeHexArray(std::string_view key, sal_uInt8* pData, size_t nSize)
{
maLine.append(key);
maLine.append(" <");
appendHexArray(pData, nSize);
maLine.append(">");
}
};
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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