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// Copyright 2017 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fpdfapi/edit/cpdf_objectstream.h"
#include "core/fpdfapi/edit/cpdf_creator.h"
#include "core/fpdfapi/edit/cpdf_encryptor.h"
#include "core/fpdfapi/edit/cpdf_flateencoder.h"
#include "core/fpdfapi/parser/fpdf_parser_utility.h"
namespace {
const int kObjectStreamMaxLength = 256 * 1024;
} // namespace
CPDF_ObjectStream::CPDF_ObjectStream() : m_dwObjNum(0), m_index(0) {}
CPDF_ObjectStream::~CPDF_ObjectStream() {}
bool CPDF_ObjectStream::IsNotFull() const {
return m_Buffer.GetLength() < kObjectStreamMaxLength;
}
void CPDF_ObjectStream::Start() {
m_Items.clear();
m_Buffer.Clear();
m_dwObjNum = 0;
m_index = 0;
}
void CPDF_ObjectStream::CompressIndirectObject(uint32_t dwObjNum,
const CPDF_Object* pObj) {
m_Items.push_back({dwObjNum, m_Buffer.GetLength()});
m_Buffer << pObj;
}
void CPDF_ObjectStream::CompressIndirectObject(uint32_t dwObjNum,
const uint8_t* pBuffer,
uint32_t dwSize) {
m_Items.push_back({dwObjNum, m_Buffer.GetLength()});
m_Buffer.AppendBlock(pBuffer, dwSize);
}
FX_FILESIZE CPDF_ObjectStream::End(CPDF_Creator* pCreator) {
ASSERT(pCreator);
if (m_Items.empty())
return 0;
CFX_FileBufferArchive* pFile = pCreator->GetFile();
FX_FILESIZE ObjOffset = pCreator->GetOffset();
if (!m_dwObjNum)
m_dwObjNum = pCreator->GetNextObjectNumber();
CFX_ByteTextBuf tempBuffer;
for (const auto& pair : m_Items)
tempBuffer << pair.objnum << " " << pair.offset << " ";
int32_t len = pFile->AppendDWord(m_dwObjNum);
if (len < 0)
return -1;
pCreator->IncrementOffset(len);
len = pFile->AppendString(" 0 obj\r\n<</Type /ObjStm /N ");
if (len < 0)
return -1;
pCreator->IncrementOffset(len);
len = pFile->AppendDWord(pdfium::CollectionSize<uint32_t>(m_Items));
if (len < 0)
return -1;
pCreator->IncrementOffset(len);
if (pFile->AppendString("/First ") < 0)
return -1;
len = pFile->AppendDWord(static_cast<uint32_t>(tempBuffer.GetLength()));
if (len < 0 || pFile->AppendString("/Length ") < 0)
return -1;
pCreator->IncrementOffset(len + 15);
tempBuffer << m_Buffer;
CPDF_FlateEncoder encoder(tempBuffer.GetBuffer(), tempBuffer.GetLength(),
true, false);
CPDF_Encryptor encryptor(pCreator->GetCryptoHandler(), m_dwObjNum,
encoder.GetData(), encoder.GetSize());
len = pFile->AppendDWord(encryptor.GetSize());
if (len < 0)
return -1;
pCreator->IncrementOffset(len);
if (pFile->AppendString("/Filter /FlateDecode") < 0)
return -1;
pCreator->IncrementOffset(20);
len = pFile->AppendString(">>stream\r\n");
if (len < 0 ||
pFile->AppendBlock(encryptor.GetData(), encryptor.GetSize()) < 0) {
return -1;
}
pCreator->IncrementOffset(len + encryptor.GetSize());
len = pFile->AppendString("\r\nendstream\r\nendobj\r\n");
if (len < 0)
return -1;
pCreator->IncrementOffset(len);
return ObjOffset;
}
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